TPI stuck in open loop. Please help.
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Car: 1991 Trans Am GTA
Engine: L98(5.7 L TPI)
Transmission: 700r4(A4)
Axle/Gears: G80 RPO, 3:23s, Auburn Racer's Diff
TPI stuck in open loop. Please help.
Right now my '91 GTA is in the shop for a surging at idle. L98, TPI, 350
Apparently, the engine is also only operating in "open loop" and won't go into "closed loop." The surge only happens after the engine is warmed up. The mechanic just replaced the valve seals. (This problem existed BEFORE he replaced the valve seals.) He also cleaned the IAC valve and the throttle body. With the engine in "open loop," it is not throwing any codes. Any thoughts?
Thanks!
Bill
Apparently, the engine is also only operating in "open loop" and won't go into "closed loop." The surge only happens after the engine is warmed up. The mechanic just replaced the valve seals. (This problem existed BEFORE he replaced the valve seals.) He also cleaned the IAC valve and the throttle body. With the engine in "open loop," it is not throwing any codes. Any thoughts?
Thanks!
Bill
#2
Re: TPI stuck in open loop. Please help.
Average mechanics can't detect vacuum leaks very well:
Max injector pulsewidth (in Open Loop) will foul cats in short order. Keep driving to a MINIMUM until diagnosed...
Vacuum leak detection is hard to do right: I know of only one guy who did it right and found a leak (in IAC gasket):
Originally Posted by Schrade View Post
No one got the proper technique for vacuum leak detection...
FIRST (fully warmed up motor); block the gas pedal, or block the throttle linkage. YOU HAVE TO DO THIS TO GET A STEADY IDLE , around 1,250 rpms, or a little higher. If you don't, you can fish starting fluid, a propane hose, or WD40, or Krylon, or hair spray, or pee, anything, until you need a sweater in Hades, but if the motor is lopin' idle already from a vacuum leak, you ain't gonna' find any leak, unless it's so big that Little Jack Horner can stick his thumb in it and pull out a pineapple NOPE.
AFTER you get a steady idle, THEN, you can spray starting fluid everywhere - that's the best detector, because it's vapor pressure is very high - a LITTLE at a time, all around the motor, until you get the rpm SURGE. Follow the vacuum lines to the EVAP cannister too. You might even have to follow the EVAP lines from the EVAP cannister to the gas tank too, but that vacuum leak will show up as a DTC 32 EGR fault, and won't normally show as loping idle, unless the EVAP cannister has been by-passed (been there, saw that uh-HUH yup).
If you get a surge in a tight spot, and can't tell exactly where it is, light a book of matches, blow out the match heads while they're still burnin', and feed the smoke to the tight spot to see it get drawn in.
Fear not the starting fluid; you cannot put the can down fast enough and light the matches fast enough to catch the starting fluid, because the vapor pressure is so high.
Bookmark this post YUP.
Wrench Wizard OUT!
No one got the proper technique for vacuum leak detection...
FIRST (fully warmed up motor); block the gas pedal, or block the throttle linkage. YOU HAVE TO DO THIS TO GET A STEADY IDLE , around 1,250 rpms, or a little higher. If you don't, you can fish starting fluid, a propane hose, or WD40, or Krylon, or hair spray, or pee, anything, until you need a sweater in Hades, but if the motor is lopin' idle already from a vacuum leak, you ain't gonna' find any leak, unless it's so big that Little Jack Horner can stick his thumb in it and pull out a pineapple NOPE.
AFTER you get a steady idle, THEN, you can spray starting fluid everywhere - that's the best detector, because it's vapor pressure is very high - a LITTLE at a time, all around the motor, until you get the rpm SURGE. Follow the vacuum lines to the EVAP cannister too. You might even have to follow the EVAP lines from the EVAP cannister to the gas tank too, but that vacuum leak will show up as a DTC 32 EGR fault, and won't normally show as loping idle, unless the EVAP cannister has been by-passed (been there, saw that uh-HUH yup).
If you get a surge in a tight spot, and can't tell exactly where it is, light a book of matches, blow out the match heads while they're still burnin', and feed the smoke to the tight spot to see it get drawn in.
Fear not the starting fluid; you cannot put the can down fast enough and light the matches fast enough to catch the starting fluid, because the vapor pressure is so high.
Bookmark this post YUP.
Wrench Wizard OUT!
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Car: 1991 Trans Am GTA
Engine: L98(5.7 L TPI)
Transmission: 700r4(A4)
Axle/Gears: G80 RPO, 3:23s, Auburn Racer's Diff
Re: TPI stuck in open loop. Please help.
Thanks for the write up. Two questions...
1) I'm not getting a code. Does that mean it's not a vaccum leak?
2) Won't spraying starting fluid everywhere foul up my under-hood plastics?
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Re: TPI stuck in open loop. Please help.
Would be better if you started your own thread instead of hijacking someone else's.
Have you done the obvious and pulled the engine codes to see if anything showing ?
https://www.thirdgen.org/forums/tech...s-dumbies.html
Have you done the obvious and pulled the engine codes to see if anything showing ?
https://www.thirdgen.org/forums/tech...s-dumbies.html
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Re: TPI stuck in open loop. Please help.
A code is only for a problem " seen" by the ECM on one of it's inputs.
There are many " mechanical" faults ( like a vac leak ) that would not necessarily cause a code to be generated unless it upset the parameters expected by the ECM
How do you know?
There are many " mechanical" faults ( like a vac leak ) that would not necessarily cause a code to be generated unless it upset the parameters expected by the ECM
How do you know?
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Car: 1991 Trans Am GTA
Engine: L98(5.7 L TPI)
Transmission: 700r4(A4)
Axle/Gears: G80 RPO, 3:23s, Auburn Racer's Diff
Re: TPI stuck in open loop. Please help.
I'm tracking with you on the lack of a code being thrown.
I know the engine is stuck in open loop because my mechanic's ECM scan tool says so.
Does anyone know of a way to test for a vaccum leak that does not involve spraying starter fluid everywhere? I know from past experience that it will discolor some of my underhood plastics.
Why would a vaccum leak prevent an ECM from going into closed loop?
Are there any other possible causes of this problem besides a vaccum leak?
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Re: TPI stuck in open loop. Please help.
Use propane or WD-40.
Trending Topics
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Re: TPI stuck in open loop. Please help.
Would be better if you started your own thread instead of hijacking someone else's.
Have you done the obvious and pulled the engine codes to see if anything showing ?
https://www.thirdgen.org/forums/tech...s-dumbies.html
Have you done the obvious and pulled the engine codes to see if anything showing ?
https://www.thirdgen.org/forums/tech...s-dumbies.html
So **** off
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Car: 1991 Trans Am GTA
Engine: L98(5.7 L TPI)
Transmission: 700r4(A4)
Axle/Gears: G80 RPO, 3:23s, Auburn Racer's Diff
Re: TPI stuck in open loop. Please help.
well, my mechanic thinks that the problem is probably not a vaccum leak. Any other thoughts?
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The Board Terms of Use, to which you agreed when signing up, and the Message Board Rule posted at the top of every forum, say you don't use language like you just did, and that you don't post off-topic from the original thread topic.
So, you can accept the friendly advice which was offered to you with no ill intent, or you can take a little involuntary break from thirdgen.org. Your choice.
#12
Re: TPI stuck in open loop. Please help.
The vapor pressure of starting fluid (that's how quickly it turns to vapor, from liquid), is EXTREMELY higher than gasoline - that's why it's used as 'starting' fluid.
And not likely that a vac leak alone will keep the ECM in Open Loop. Only a DTC Code, I think, will keep it in Open Loop. But lots of time with loping idle FROM a vac leak WILL foul the O2's.
Once the exhaust is fouled from unburned gas / HC's, the O2's and cats included, it will could stay in OL.
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Car: 1991 Trans Am GTA
Engine: L98(5.7 L TPI)
Transmission: 700r4(A4)
Axle/Gears: G80 RPO, 3:23s, Auburn Racer's Diff
Re: TPI stuck in open loop. Please help.
Not likely that starting fluid will stain plastic.
The vapor pressure of starting fluid (that's how quickly it turns to vapor, from liquid), is EXTREMELY higher than gasoline - that's why it's used as 'starting' fluid.
And not likely that a vac leak alone will keep the ECM in Open Loop. Only a DTC Code, I think, will keep it in Open Loop. But lots of time with loping idle FROM a vac leak WILL foul the O2's.
Once the exhaust is fouled from unburned gas / HC's, the O2's and cats included, it will could stay in OL.
The vapor pressure of starting fluid (that's how quickly it turns to vapor, from liquid), is EXTREMELY higher than gasoline - that's why it's used as 'starting' fluid.
And not likely that a vac leak alone will keep the ECM in Open Loop. Only a DTC Code, I think, will keep it in Open Loop. But lots of time with loping idle FROM a vac leak WILL foul the O2's.
Once the exhaust is fouled from unburned gas / HC's, the O2's and cats included, it will could stay in OL.
What do you think is the cause of my idle and open loop woes?
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Car: 1991 Trans Am GTA
Engine: L98(5.7 L TPI)
Transmission: 700r4(A4)
Axle/Gears: G80 RPO, 3:23s, Auburn Racer's Diff
Re: TPI stuck in open loop. Please help.
Called the mechanic. He said the O2 sensor wasn't doing anything. Does this mean I need a new O2 sensor?
#17
Re: TPI stuck in open loop. Please help.
That's a BS answer from the mechanic. You want to know if he still has the printout, showing the readings of the O2 in millivolts.
No millivolts = DTC [bad O2]
Forget his WORDS. Words go away when the sound stops. Your cash often follows the sound, but the echo effect is never as good.
You tell him that you're from Missouri (Show ME), and you need to see that they're not doing anything.
#18
Re: TPI stuck in open loop. Please help.
SLP? Like ... with re-usable, oil-able filter elements???
Do you have MAF in your TPI? Or MAP?
If MAF, and too much oil on the air filters, it will pull onto, and foul, the MAF FILAMENT. FOULED MAF = GREAT ECM UGLINESS!!!
If you're on MAP, oil can still foul stuff, like plugs...
SHERLOCK the wrench OUT
Do you have MAF in your TPI? Or MAP?
If MAF, and too much oil on the air filters, it will pull onto, and foul, the MAF FILAMENT. FOULED MAF = GREAT ECM UGLINESS!!!
If you're on MAP, oil can still foul stuff, like plugs...
SHERLOCK the wrench OUT
#19
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Car: 82 Z28
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Re: TPI stuck in open loop. Please help.
A code means the ECM has seen a fault somewhere in a system; could be a bad connection , ground or power supply.
Not just that the item of that circuit is faulty
There are diagnostic charts in the factory service manuals ( best investment you will make ) to work through to identify the ACTUAL problem
before throwing $$$ at un-needed new parts
See
http://www.chevythunder.com/o2_sensor_diagnostics.htm
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Car: 1991 Trans Am GTA
Engine: L98(5.7 L TPI)
Transmission: 700r4(A4)
Axle/Gears: G80 RPO, 3:23s, Auburn Racer's Diff
Re: TPI stuck in open loop. Please help.
Up front answer? NO!
That's a BS answer from the mechanic. You want to know if he still has the printout, showing the readings of the O2 in millivolts.
No millivolts = DTC [bad O2]
Forget his WORDS. Words go away when the sound stops. Your cash often follows the sound, but the echo effect is never as good.
You tell him that you're from Missouri (Show ME), and you need to see that they're not doing anything.
That's a BS answer from the mechanic. You want to know if he still has the printout, showing the readings of the O2 in millivolts.
No millivolts = DTC [bad O2]
Forget his WORDS. Words go away when the sound stops. Your cash often follows the sound, but the echo effect is never as good.
You tell him that you're from Missouri (Show ME), and you need to see that they're not doing anything.
#21
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Car: 1991 Trans Am GTA
Engine: L98(5.7 L TPI)
Transmission: 700r4(A4)
Axle/Gears: G80 RPO, 3:23s, Auburn Racer's Diff
Re: TPI stuck in open loop. Please help.
As the man said ;if the ECM is not seeing anything from the O2 then it should have a code up
A code means the ECM has seen a fault somewhere in a system; could be a bad connection , ground or power supply.
Not just that the item of that circuit is faulty
There are diagnostic charts in the factory service manuals ( best investment you will make ) to work through to identify the ACTUAL problem
before throwing $$$ at un-needed new parts
See
http://www.chevythunder.com/o2_sensor_diagnostics.htm
A code means the ECM has seen a fault somewhere in a system; could be a bad connection , ground or power supply.
Not just that the item of that circuit is faulty
There are diagnostic charts in the factory service manuals ( best investment you will make ) to work through to identify the ACTUAL problem
before throwing $$$ at un-needed new parts
See
http://www.chevythunder.com/o2_sensor_diagnostics.htm
#22
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Car: 1991 Trans Am GTA
Engine: L98(5.7 L TPI)
Transmission: 700r4(A4)
Axle/Gears: G80 RPO, 3:23s, Auburn Racer's Diff
Re: TPI stuck in open loop. Please help.
SLP? Like ... with re-usable, oil-able filter elements???
Do you have MAF in your TPI? Or MAP?
If MAF, and too much oil on the air filters, it will pull onto, and foul, the MAF FILAMENT. FOULED MAF = GREAT ECM UGLINESS!!!
If you're on MAP, oil can still foul stuff, like plugs...
SHERLOCK the wrench OUT
Do you have MAF in your TPI? Or MAP?
If MAF, and too much oil on the air filters, it will pull onto, and foul, the MAF FILAMENT. FOULED MAF = GREAT ECM UGLINESS!!!
If you're on MAP, oil can still foul stuff, like plugs...
SHERLOCK the wrench OUT
Yes, that's my cold air intake. Yes, I over-lubed the crap out of it a few years ago when I was cleaning it.
I have a '91. Is that MAP or MAF? If I have MAF, can the filament be cleaned, or do I need a replacement? Will a bad MAF throw an ECM code? Can the filament be tested to see if its still good?
On a side note, the mechanic says its running lean in open loop.
#23
Re: TPI stuck in open loop. Please help.
Schrade, you may be on to something!
Yes, that's my cold air intake. Yes, I over-lubed the crap out of it a few years ago when I was cleaning it.
I have a '91. Is that MAP or MAF? If I have MAF, can the filament be cleaned, or do I need a replacement? Will a bad MAF throw an ECM code? Can the filament be tested to see if its still good?
On a side note, the mechanic says its running lean in open loop.
Yes, that's my cold air intake. Yes, I over-lubed the crap out of it a few years ago when I was cleaning it.
I have a '91. Is that MAP or MAF? If I have MAF, can the filament be cleaned, or do I need a replacement? Will a bad MAF throw an ECM code? Can the filament be tested to see if its still good?
On a side note, the mechanic says its running lean in open loop.
I DO NOT KNOW WHICH IT IS
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Re: TPI stuck in open loop. Please help.
maybe you mentioned it and i missed it, but you checked the temp sender and the wires going to it, right?
#28
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Re: TPI stuck in open loop. Please help.
All documented in your FSM ( when you find it )
The O2 checking values are in the link I posted for you above, did you read it ???
Depends.
A correctly functioning O2 will have a wildly swing Mv output , not a fixed value
The O2 checking values are in the link I posted for you above, did you read it ???
A correctly functioning O2 will have a wildly swing Mv output , not a fixed value
#32
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Car: 1991 Trans Am GTA
Engine: L98(5.7 L TPI)
Transmission: 700r4(A4)
Axle/Gears: G80 RPO, 3:23s, Auburn Racer's Diff
Re: TPI stuck in open loop. Please help.
Nope, no sensor in the ducting in front of the TPI. It's MAP
#33
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Car: 1991 Trans Am GTA
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Transmission: 700r4(A4)
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Re: TPI stuck in open loop. Please help.
Gents,
Thanks for all your help so far! I really appreciate it!
Bill
Thanks for all your help so far! I really appreciate it!
Bill
#34
Re: TPI stuck in open loop. Please help.
MAP voltage, and O2 voltages will be different, depending on conditions. Supply voltage to each one is either 5V, or 12V.
The voltage (signal) that goes BACK to the ECM, as a result of the varying manifold pressure, or varying amount of elemental Oxygen in the exhaust, should fall within a range, which is detailed in the FSM.
When it goes out of the range, the computer registers it as DTC 'X' - MAP is 34(?), O2's are in the 60's. C Current DTC 'X' (caught in the act), or H History DTC 'X' (hide and seek)(sucks too!).
The problems don't go away by themselves either, just because the light is out. That's a H DTC. Will probably light up when it warms up Closed Loop.
You really need FSM to maintain a car, or lots of cash for lousy or unscrupulous hacks. Navigating it - it's HUGE, is a pain. But knowledge goes further than cash. Always. And it makes you a better communicator, and problem solver too.
For starters, get a scan printout from a mechanic. Might have to pay a few $$, but they can't lie to you when something is on paper.
The voltage (signal) that goes BACK to the ECM, as a result of the varying manifold pressure, or varying amount of elemental Oxygen in the exhaust, should fall within a range, which is detailed in the FSM.
When it goes out of the range, the computer registers it as DTC 'X' - MAP is 34(?), O2's are in the 60's. C Current DTC 'X' (caught in the act), or H History DTC 'X' (hide and seek)(sucks too!).
The problems don't go away by themselves either, just because the light is out. That's a H DTC. Will probably light up when it warms up Closed Loop.
You really need FSM to maintain a car, or lots of cash for lousy or unscrupulous hacks. Navigating it - it's HUGE, is a pain. But knowledge goes further than cash. Always. And it makes you a better communicator, and problem solver too.
For starters, get a scan printout from a mechanic. Might have to pay a few $$, but they can't lie to you when something is on paper.
#35
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Car: 1991 Trans Am GTA
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Re: TPI stuck in open loop. Please help.
Ugh, I'm in the military and I've moved a bunch of times. I can't find my manual for the life of me!
#37
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Re: TPI stuck in open loop. Please help.
Allright,
This thing is turning into a disaster.
I spent quite a bit of time this morning digging through boxes, tearing up my attic, etc. I cannot find my service manual for the life of me.
I had dual cats from the factory and a flowmaster 3-inch cat-back exhaust. In order to install my Spohn torque arm (with drive shaft safety loop), my mechanic had to cut a section out of my exhaust. He cut behind the cats and he cut after the y-pipe.
After installing the torque arm, I limped my car to the exhaust shop to have the cut-out section re-welded in. I drove slow, and it was LOUD. But I didn't notice any problems.
I picked up my car from the exhaust shop today. He couldn't save the y-pipe. I paid $156 to have a new one fabbed/welded in. He used 2 1/4 or 2 1/2 inch pipe (the same diameter as the piping before the cats) to replace the cut out section. It seems narrower to me than what was cut off the car. Furthermore, he said all the shops in town use crush benders (not mandrel benders). Ugh. So, I had to settle for crush-bent pipe.
After paying for the repair, he told me the car was shaking at idle. Originally he thought the new exhaust piping he installed was hitting the torque arm (or something like that). But, he put it up on the lift and didn't see anything wrong. After talking, we assumed this was just a symptom of the newer, firmer, crossmember/torque arm/poly urethane trans bushing plus my new Koni yellow shocks up front.
Sure enough, after driving off, I noticed two things. One, the exhaust seemed louder. Two, the idle seemed rougher. Again, I assumed this was a symptom of my new performance parts. Once, I tried to floor the gas pedal from a roll to test my new torque arm. My car didn't respond. It raised an eyebrow. But, I let it go.
Up to this point, I hadn't gone faster than say, 45 mph. I drove the car to a gas station and filled her up. When I tryed to depart the gas station, I couldn't get the car to start. I had to hit the gas pedal while turning the key to get her started. Then, we got on the highway. The car was *******. At first, I couldn't get her past 1.5K RPMS. Then, I couldn't get her past 2.5K RPMS. Then, I couldn't get her past 2K RPMS. At some point during this ordeal, the SES light came on (somewhat briefly) and then turned off. (The light was off for the majority of the time.) I got off the highway, and the car kept dying on me at stoplights. Then, I got her in my driveway and turned her off.
I went inside for several minutes, then came out to put her in the garage. I cranked the motor, but it wouldn't start again. I cranked it and gave it gas, but it still wouldn't start. This went on and on to the point where I thought I would burn out my starter, and I still couldn't start the motor. Then, I let her sit for a few minutes, and was able to start her up and get her in the garage.
Does anyone have ANY idea as to what is causing these issues? I'm afraid that driving her to the mechanic will damage my engine internals!
The worst part is, I'm about to go on a little trip. I don't want the car sitting around and not getting used. That's what dried out my valve seals. It just cost me about $550 to have them repaired! I wanted to be able to let my wife start her up and drive her around while I was gone to keep her working.
This thing is turning into a disaster.
I spent quite a bit of time this morning digging through boxes, tearing up my attic, etc. I cannot find my service manual for the life of me.
I had dual cats from the factory and a flowmaster 3-inch cat-back exhaust. In order to install my Spohn torque arm (with drive shaft safety loop), my mechanic had to cut a section out of my exhaust. He cut behind the cats and he cut after the y-pipe.
After installing the torque arm, I limped my car to the exhaust shop to have the cut-out section re-welded in. I drove slow, and it was LOUD. But I didn't notice any problems.
I picked up my car from the exhaust shop today. He couldn't save the y-pipe. I paid $156 to have a new one fabbed/welded in. He used 2 1/4 or 2 1/2 inch pipe (the same diameter as the piping before the cats) to replace the cut out section. It seems narrower to me than what was cut off the car. Furthermore, he said all the shops in town use crush benders (not mandrel benders). Ugh. So, I had to settle for crush-bent pipe.
After paying for the repair, he told me the car was shaking at idle. Originally he thought the new exhaust piping he installed was hitting the torque arm (or something like that). But, he put it up on the lift and didn't see anything wrong. After talking, we assumed this was just a symptom of the newer, firmer, crossmember/torque arm/poly urethane trans bushing plus my new Koni yellow shocks up front.
Sure enough, after driving off, I noticed two things. One, the exhaust seemed louder. Two, the idle seemed rougher. Again, I assumed this was a symptom of my new performance parts. Once, I tried to floor the gas pedal from a roll to test my new torque arm. My car didn't respond. It raised an eyebrow. But, I let it go.
Up to this point, I hadn't gone faster than say, 45 mph. I drove the car to a gas station and filled her up. When I tryed to depart the gas station, I couldn't get the car to start. I had to hit the gas pedal while turning the key to get her started. Then, we got on the highway. The car was *******. At first, I couldn't get her past 1.5K RPMS. Then, I couldn't get her past 2.5K RPMS. Then, I couldn't get her past 2K RPMS. At some point during this ordeal, the SES light came on (somewhat briefly) and then turned off. (The light was off for the majority of the time.) I got off the highway, and the car kept dying on me at stoplights. Then, I got her in my driveway and turned her off.
I went inside for several minutes, then came out to put her in the garage. I cranked the motor, but it wouldn't start again. I cranked it and gave it gas, but it still wouldn't start. This went on and on to the point where I thought I would burn out my starter, and I still couldn't start the motor. Then, I let her sit for a few minutes, and was able to start her up and get her in the garage.
Does anyone have ANY idea as to what is causing these issues? I'm afraid that driving her to the mechanic will damage my engine internals!
The worst part is, I'm about to go on a little trip. I don't want the car sitting around and not getting used. That's what dried out my valve seals. It just cost me about $550 to have them repaired! I wanted to be able to let my wife start her up and drive her around while I was gone to keep her working.
Last edited by wgripp; 08-08-2013 at 07:59 PM.
#38
Re: TPI stuck in open loop. Please help.
Allright,
This thing is turning into a disaster.
I spent quite a bit of time this morning digging through boxes, tearing up my attic, etc. I cannot find my service manual for the life of me.
I had dual cats from the factory and a flowmaster 3-inch cat-back exhaust. In order to install my Spohn torque arm (with drive shaft safety loop), my mechanic had to cut a section out of my exhaust. He cut behind the cats and he cut after the y-pipe.
After installing the torque arm, I limped my car to the exhaust shop to have the cut-out section re-welded in. I drove slow, and it was LOUD. But I didn't notice any problems.
I picked up my car from the exhaust shop today. He couldn't save the y-pipe. I paid $156 to have a new one fabbed/welded in. He used 2 1/4 or 2 1/2 inch pipe (the same diameter as the piping before the cats) to replace the cut out section. It seems narrower to me than what was cut off the car. Furthermore, he said all the shops in town use crush benders (not mandrel benders). Ugh. So, I had to settle for crush-bent pipe.
After paying for the repair, he told me the car was shaking at idle. Originally he thought the new exhaust piping he installed was hitting the torque arm (or something like that). But, he put it up on the lift and didn't see anything wrong. After talking, we assumed this was just a symptom of the newer, firmer, crossmember/torque arm/poly urethane trans bushing plus my new Koni yellow shocks up front.
Sure enough, after driving off, I noticed two things. One, the exhaust seemed louder. Two, the idle seemed rougher. Again, I assumed this was a symptom of my new performance parts. Once, I tried to floor the gas pedal from a roll to test my new torque arm. My car didn't respond. It raised an eyebrow. But, I let it go.
Up to this point, I hadn't gone faster than say, 45 mph. I drove the car to a gas station and filled her up. When I tryed to depart the gas station, I couldn't get the car to start. I had to hit the gas pedal while turning the key to get her started. Then, we got on the highway. The car was *******. At first, I couldn't get her past 1.5K RPMS. Then, I couldn't get her past 2.5K RPMS. Then, I couldn't get her past 2K RPMS. At some point during this ordeal, the SES light came on (somewhat briefly) and then turned off. (The light was off for the majority of the time.) I got off the highway, and the car kept dying on me at stoplights. Then, I got her in my driveway and turned her off.
I went inside for several minutes, then came out to put her in the garage. I cranked the motor, but it wouldn't start again. I cranked it and gave it gas, but it still wouldn't start. This went on and on to the point where I thought I would burn out my starter, and I still couldn't start the motor. Then, I let her sit for a few minutes, and was able to start her up and get her in the garage.
Does anyone have ANY idea as to what is causing these issues? I'm afraid that driving her to the mechanic will damage my engine internals!
The worst part is, I'm about to go on a little trip. I don't want the car sitting around and not getting used. That's what dried out my valve seals. It just cost me about $550 to have them repaired! I wanted to be able to let my wife start her up and drive her around while I was gone to keep her working.
This thing is turning into a disaster.
I spent quite a bit of time this morning digging through boxes, tearing up my attic, etc. I cannot find my service manual for the life of me.
I had dual cats from the factory and a flowmaster 3-inch cat-back exhaust. In order to install my Spohn torque arm (with drive shaft safety loop), my mechanic had to cut a section out of my exhaust. He cut behind the cats and he cut after the y-pipe.
After installing the torque arm, I limped my car to the exhaust shop to have the cut-out section re-welded in. I drove slow, and it was LOUD. But I didn't notice any problems.
I picked up my car from the exhaust shop today. He couldn't save the y-pipe. I paid $156 to have a new one fabbed/welded in. He used 2 1/4 or 2 1/2 inch pipe (the same diameter as the piping before the cats) to replace the cut out section. It seems narrower to me than what was cut off the car. Furthermore, he said all the shops in town use crush benders (not mandrel benders). Ugh. So, I had to settle for crush-bent pipe.
After paying for the repair, he told me the car was shaking at idle. Originally he thought the new exhaust piping he installed was hitting the torque arm (or something like that). But, he put it up on the lift and didn't see anything wrong. After talking, we assumed this was just a symptom of the newer, firmer, crossmember/torque arm/poly urethane trans bushing plus my new Koni yellow shocks up front.
Sure enough, after driving off, I noticed two things. One, the exhaust seemed louder. Two, the idle seemed rougher. Again, I assumed this was a symptom of my new performance parts. Once, I tried to floor the gas pedal from a roll to test my new torque arm. My car didn't respond. It raised an eyebrow. But, I let it go.
Up to this point, I hadn't gone faster than say, 45 mph. I drove the car to a gas station and filled her up. When I tryed to depart the gas station, I couldn't get the car to start. I had to hit the gas pedal while turning the key to get her started. Then, we got on the highway. The car was *******. At first, I couldn't get her past 1.5K RPMS. Then, I couldn't get her past 2.5K RPMS. Then, I couldn't get her past 2K RPMS. At some point during this ordeal, the SES light came on (somewhat briefly) and then turned off. (The light was off for the majority of the time.) I got off the highway, and the car kept dying on me at stoplights. Then, I got her in my driveway and turned her off.
I went inside for several minutes, then came out to put her in the garage. I cranked the motor, but it wouldn't start again. I cranked it and gave it gas, but it still wouldn't start. This went on and on to the point where I thought I would burn out my starter, and I still couldn't start the motor. Then, I let her sit for a few minutes, and was able to start her up and get her in the garage.
Does anyone have ANY idea as to what is causing these issues? I'm afraid that driving her to the mechanic will damage my engine internals!
The worst part is, I'm about to go on a little trip. I don't want the car sitting around and not getting used. That's what dried out my valve seals. It just cost me about $550 to have them repaired! I wanted to be able to let my wife start her up and drive her around while I was gone to keep her working.
SES light going out means the problem is still there. Rest assured.
Temp Coolant Sensor could keep it in Open Loop. But no need to check it yet.
Get it plugged in for codes - somewhere ELSE. Get a printout of the codes.
Diagnostics for codes often defer to another code FIRST. They have a way of compounding. Once you get the codes, either get the Factory Shop Manual, or an online subscription to Mitchell's Online, or AllData (online). You might get a trial subscription for 30 days with one of them...
#39
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Car: 1991 Trans Am GTA
Engine: L98(5.7 L TPI)
Transmission: 700r4(A4)
Axle/Gears: G80 RPO, 3:23s, Auburn Racer's Diff
Re: TPI stuck in open loop. Please help.
The mechanic should not have done ANYthing except to diagnose the Stuck Open Loop problem.
SES light going out means the problem is still there. Rest assured.
Temp Coolant Sensor could keep it in Open Loop. But no need to check it yet.
Get it plugged in for codes - somewhere ELSE. Get a printout of the codes.
Diagnostics for codes often defer to another code FIRST. They have a way of compounding. Once you get the codes, either get the Factory Shop Manual, or an online subscription to Mitchell's Online, or AllData (online). You might get a trial subscription for 30 days with one of them...
SES light going out means the problem is still there. Rest assured.
Temp Coolant Sensor could keep it in Open Loop. But no need to check it yet.
Get it plugged in for codes - somewhere ELSE. Get a printout of the codes.
Diagnostics for codes often defer to another code FIRST. They have a way of compounding. Once you get the codes, either get the Factory Shop Manual, or an online subscription to Mitchell's Online, or AllData (online). You might get a trial subscription for 30 days with one of them...
Is there a scan tool with all features I can buy for a reasonable price?
#40
Re: TPI stuck in open loop. Please help.
He installed the parts at my request. I was trying to get as much work completed as possible before taking my trip. But, I'm really worried they went with too narrow pipe on my exhaust system, robbing me of power.
Is there a scan tool with all features I can buy for a reasonable price?
Is there a scan tool with all features I can buy for a reasonable price?
Open Loop keeps injectors at max pulsewidth, and the exhaust is gonna' Carbon-foul with excess hydrocarbons and unburned fuel.
Scantool? Tech1 for $250, if you're lucky. Scan software with hardwire connector - $70, with free trial period, and lots of time to learn navigation (I'm doing that now with the ZR-1). No picnic either.
Or a super high-tech code puller:
Jump pins A + G on ALDL. Read SES flashes. You still need FSM to start diags. No fun, but you have to do it.
#41
Re: TPI stuck in open loop. Please help.
I don't understand mods before tune / diagnostics.
Open Loop keeps injectors at max pulsewidth, and the exhaust is gonna' Carbon-foul with excess hydrocarbons and unburned fuel.
Scantool? Tech1 for $250, if you're lucky. Scan software with hardwire connector - $70, with free trial period, and lots of time to learn navigation (I'm doing that now with the ZR-1). No picnic either.
Or a super high-tech code puller:
Jump pins A + G on ALDL. Read SES flashes. You still need FSM to start diags. No fun, but you have to do it.
Open Loop keeps injectors at max pulsewidth, and the exhaust is gonna' Carbon-foul with excess hydrocarbons and unburned fuel.
Scantool? Tech1 for $250, if you're lucky. Scan software with hardwire connector - $70, with free trial period, and lots of time to learn navigation (I'm doing that now with the ZR-1). No picnic either.
Or a super high-tech code puller:
Jump pins A + G on ALDL. Read SES flashes. You still need FSM to start diags. No fun, but you have to do it.
OL does not keep the injectors at full duty cycle but does not use o2 correction due to lack of o2 swing and ect below 146F.
Tunerpro is free
#42
Re: TPI stuck in open loop. Please help.
Just tell OP what to do to fix the problem. Forget about TOPhack's mistake.
#43
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Car: 07 & 01 Buick, 66 vw and 91 camaro
Engine: 3.1 v6
Transmission: Auto
Axle/Gears: Don't know
Re: TPI stuck in open loop. Please help.
For the moderator, You know I am 77 years old with some time in the USMC.
I mentioned I was new on the site and nowhere when I pull up my screen is there any
place for me to start a thread.]
So it looks like you are not doing your job.
I have no further interest in this site so kill my pass word and the gibberish I see
can continue.
I mentioned I was new on the site and nowhere when I pull up my screen is there any
place for me to start a thread.]
So it looks like you are not doing your job.
I have no further interest in this site so kill my pass word and the gibberish I see
can continue.
#44
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Thread Starter
iTrader: (1)
Join Date: Apr 2005
Location: Valdosta, GA
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Car: 1991 Trans Am GTA
Engine: L98(5.7 L TPI)
Transmission: 700r4(A4)
Axle/Gears: G80 RPO, 3:23s, Auburn Racer's Diff
Re: TPI stuck in open loop. Please help.
I'll be purchasing either this
http://www.reddevilriver.com/ALDL_Bluetooth.php
or this
http://www.reddevilriver.com/aldl.html
shortly.
I like the idea of the traditional cable because it's a tried and true method. However, the bluetooth cable would let me pull OBD1 codes with my android phone, once the app is finished. But, I'm worried that if I get the bluetooth cable, I'll have issues getting the software to work correctly on my computer. (I forsee driver and connectivity issues.) (Yes, my laptop has bluetooth.)
What software do you guys reccomend?
http://www.reddevilriver.com/ALDL_Bluetooth.php
or this
http://www.reddevilriver.com/aldl.html
shortly.
I like the idea of the traditional cable because it's a tried and true method. However, the bluetooth cable would let me pull OBD1 codes with my android phone, once the app is finished. But, I'm worried that if I get the bluetooth cable, I'll have issues getting the software to work correctly on my computer. (I forsee driver and connectivity issues.) (Yes, my laptop has bluetooth.)
What software do you guys reccomend?
#45
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Join Date: Aug 2013
Location: NH
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Car: 91 canaro rs
Engine: 5.0
Transmission: 5 speed
Re: TPI stuck in open loop. Please help.
For the moderator, You know I am 77 years old with some time in the USMC.
I mentioned I was new on the site and nowhere when I pull up my screen is there any
place for me to start a thread.]
So it looks like you are not doing your job.
I have no further interest in this site so kill my pass word and the gibberish I see
can continue.
I mentioned I was new on the site and nowhere when I pull up my screen is there any
place for me to start a thread.]
So it looks like you are not doing your job.
I have no further interest in this site so kill my pass word and the gibberish I see
can continue.
#46
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Thread Starter
iTrader: (1)
Join Date: Apr 2005
Location: Valdosta, GA
Posts: 1,165
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Received 1 Like
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1 Post
Car: 1991 Trans Am GTA
Engine: L98(5.7 L TPI)
Transmission: 700r4(A4)
Axle/Gears: G80 RPO, 3:23s, Auburn Racer's Diff
Re: TPI stuck in open loop. Please help.
New mechanic diagnosed my problems as bad O2 sensor and bad fuel injector. I will be replacing all the fuel injectors and the sensor soon.
Thanks
Thanks
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