When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
My Trans Am came out of long term storage recently. I put marvel oil in the cylinders and let it sit for a few weeks before trying to start. Had to empty fuel tank and replace pump. Now I have fuel pressure and fuel from rail bleeder. It still won't start, just cranks. I tried a little starting fluid and it has spark.
So fuel at the rail, fuel pump works and there is spark. Could the ecu have died of old age just sitting? Service engine soon light stays lit with key on. Not sure if it's supposed to stay on.
Any ideas? Car ran when parked, but that was twenty years ago. I'm guessing ecu, but hoping I'm missing something simple.
Fuel pressure is ? Injector pulse and spark tested ?
in 20 years the injectors are probably varnished shut.
I think you may be right about the injectors, fuel pressure is around 40, has spark since it tried turning over with starting fluid. Injectors are mostly likely. Unless the ecu died from sitting, but I don't think the check engine light would go on with the key if it was dead. I'll try to pull codes today to see if that works. If the ecu responds with codes, I'll assume it's good and order injectors. The fuel pump was trash from sitting, it would make sense the injectors would be too.
The people I’ve had datalog blms are pegged at 160 but some people say they are fine. I’ve adjusted battery voltage offsets in the tuning to correct. Not sure if higher fuel pressure would be enough to compensate.
The nice thing about sb d3 is the press on extensions. I just recently saw a post on a c4 page where an engine fire happened with the fic because one didn’t seat right.
I’d definitely go with sb good customer service and product
One more thing. I found a set of new matched Delphi injectors for sale. Are they worth double the price of the bosch? Only worry with the bosch is doing all of the labor installing and then having it run rough.
Maybe someone else will chime in with first hand experience. I have seen the d3 run lean . When I had a set they ran rich and I tuned for them. So I really dont know first hand. A good friend installed the delphis no tuning and is thrilled with the quality. But if you have grey body multecs don’t waste a dime towards serving them.
I have put two sets of Bosch D3 injectors in and no issues with either . As I was replacing original multecs, it was a huge improvement. My 92 went from 18 miles per gallon to 24 on the highway... And the idle got much smoother... Car drives and starts so nice.
I am thinking about adding them to my 88 now ...
I have heard about lean running but I can't say I have had any issues on my 92 or 89...they are so much better at atomizing the fuel, car runs better... Even if it's slightly lean, I doubt it would hurt the car, just give up a little power....
And you cannot beat the price....South Bay has been good to us thirdgen people....
I have put two sets of Bosch D3 injectors in and no issues with either . As I was replacing original multecs, it was a huge improvement. My 92 went from 18 miles per gallon to 24 on the highway... And the idle got much smoother... Car drives and starts so nice.
I am thinking about adding them to my 88 now ...
I have heard about lean running but I can't say I have had any issues on my 92 or 89...they are so much better at atomizing the fuel, car runs better... Even if it's slightly lean, I doubt it would hurt the car, just give up a little power....
And you cannot beat the price....South Bay has been good to us thirdgen people....
This makes me feel better. I parked the car over twenty years ago running. One headlight wouldn't go up, lol. Now it won't start and the headlight still won't go up 😏
Hey everyone, I installed the new bosch injectors from South Bay. I also installed a BBK adjustable fuel pressure regulator at the same time. The car starts now, so I'm sure it was the old injectors were stuck. The diaphragm in the stock FPR looked perfect, so I refused it.
Now I'm trying to figure out fuel pressure. The car doesn't run right at all, fuel pressure is a solid 44-45 psi running at idle or wot. It never never goes lower, even if I remove vacuum from FPR. I have vacuum at the manifold, though I don't know how much, just checked port with finger.
I'm guessing this is making it run rich. The afpr adjuster is backed out to where it's just touching the diaphragm. Will tightening the screw raise pressure further or reduce it?
Fuel pressure is ? Injector pulse and spark tested ?
in 20 years the injectors are probably varnished shut.
Long time luker here, first time poster. I have a 89 Trans Am GTA. This most likely is the problem. I had the same problem years ago with mine, searched the forums and purchased a set of injectors from South Bay injectors.
Also the owners manual advises you to use at least 92 octane gas. My T/A runs like crap if I use anything below 92 octane gas. Avoid gas with ethanol at all cost.
Thank you to everyone who posts here, I've learned a lot over the years reading these posts!
So an update, I installed the new spark plugs, checked wires, cap, rotor. All of the ignition is good. Installed new factory fuel pump, adjusted pressure regulator to 40psi, new bosch 3 injectors installed. Fuel pressure is solid while running and holds after key is off.
So good fuel, good ignition. But it still idles very rough until warm and it has no off idle throttle response. It has what feels like a dead spot until nearly full throttle on the pedal and under 3000rpm it just wants to stall.
I'm running out of ideas, could this be tps or maf?
So am update, I installed the new spark plugs, checked wires, cap, rotor. All of the ignition is good. Installed new factory fuel pump, adjusted pressure regulator to 40psi, new bosch 3 injectors installed. Fuel pressure is solid while running and holds after key is off.
So good fuel, good ignition. But it still idles very rough until warm and it has no off idle throttle response. It has what feels like a dead spot until nearly full throttle on the pedal and under 3000rpm it just wants to stall.
I'm running out of ideas, could this be tps or maf?
Looks like you are going down the rabbit hole of throwing parts at it!
From your past posts: Could the ecu have died of old age just sitting?
Possible. But they might not just die, they might just get a stroke or heart attack. So they function but do funky things.
Service engine soon light stays lit with key on. Not sure if it's supposed to stay on.
Normal
Any ideas?
Could be a lot of things
I'm guessing ecu
Just a guess
in 20 years the injectors are probably varnished shut.
A guess again
but I don't think the check engine light would go on with the key if it was dead
It could because ECM might be half dead
I'll try to pull codes today to see if that works
That would be a start
If the ecu responds with codes, I'll assume it's good
Wrong
I'm running out of ideas Well, here are some: 1) A complete scan (scan tool) to see what all sensors are doing (specially MAF, O2, IAC, MAT and CT). Make sure ECM is not in limp home mode.
2) Voltage drop test at pretty much any exposed connections
3) Thorough MAF circuitry test.
4) Inspect any blockage of air intake/exhaust (critter's nest and sh**)
5) Test PCV system for leak and obstruction
6) Test EVAP system for leak and obstruction
7) Test AIRS system for malfunction
8) Test for any vacuum leak around intake (post MAF)
9) Idle vacuum test
10) Change Fuel filter and make sure gas tank is purged and clean.
11) Inspect all wiring including under dash for rodents damage and oxidation
12) Get to know how your TPI works https://www.summitracing.com/parts/sad-sa53p
13) Until AI takes over, you'll have to get creative, read, research, test and retest until you understand. Or you can keep throwing parts at it, I'll work eventually
So am update, I installed the new spark plugs, checked wires, cap, rotor. All of the ignition is good. Installed new factory fuel pump, adjusted pressure regulator to 40psi, new bosch 3 injectors installed. Fuel pressure is solid while running and holds after key is off.
So good fuel, good ignition. But it still idles very rough until warm and it has no off idle throttle response. It has what feels like a dead spot until nearly full throttle on the pedal and under 3000rpm it just wants to stall.
I'm running out of ideas, could this be tps or maf?
Do you have fresh gas in the tank? Have you tried driving it? I have no idea, but be patient and the more knowledgeable people will point you in the right direction. Don't give up, you have a great car and once it's running properly you'll have a blast. Remember, use high octane fuel with no ethanol.
After 20 years sitting, that will blow the cobweb off it and everything that is made of rubber will fail so you will know what needs repair (ask me how I know). Make sure you change your engine oil first. Could have been washed with fuel during those early attempt to start.
After 20 years sitting, that will blow the cobweb off it and everything that is made of rubber will fail so you will know what needs repair (ask me how I know). Make sure you change your engine oil first. Could have been washed with fuel during those early attempt to start.
I don't think it's a great idea, but I did that with my 89 T/A after it sat close to 10 years haha. Also, THANK YOU for the book you recommend from summit racing about TPI engines. I just ordered it. I wish I had that book several years ago....
Looks like you are going down the rabbit hole of throwing parts at it!
From your past posts: Could the ecu have died of old age just sitting?
Possible. But they might not just die, they might just get a stroke or heart attack. So they function but do funky things.
Service engine soon light stays lit with key on. Not sure if it's supposed to stay on.
Normal
Any ideas?
Could be a lot of things
I'm guessing ecu
Just a guess
in 20 years the injectors are probably varnished shut.
A guess again
but I don't think the check engine light would go on with the key if it was dead
It could because ECM might be half dead
I'll try to pull codes today to see if that works
That would be a start
If the ecu responds with codes, I'll assume it's good
Wrong
I'm running out of ideas Well, here are some: 1) A complete scan (scan tool) to see what all sensors are doing (specially MAF, O2, IAC, MAT and CT). Make sure ECM is not in limp home mode.
2) Voltage drop test at pretty much any exposed connections
3) Thorough MAF circuitry test.
4) Inspect any blockage of air intake/exhaust (critter's nest and sh**)
5) Test PCV system for leak and obstruction
6) Test EVAP system for leak and obstruction
7) Test AIRS system for malfunction
8) Test for any vacuum leak around intake (post MAF)
9) Idle vacuum test
10) Change Fuel filter and make sure gas tank is purged and clean.
11) Inspect all wiring including under dash for rodents damage and oxidation
12) Get to know how your TPI works https://www.summitracing.com/parts/sad-sa53p
13) Until AI takes over, you'll have to get creative, read, research, test and retest until you understand. Or you can keep throwing parts at it, I'll work eventually
That's a lot of great ideas, thank you. I did clean out the tank when I changed the pump. Besides the old fuel, it looked pristine inside. Thankfully there were no mice since it was stored in a sealed semi trailer. Most of the hoses were replaced with silicone hose, they look and feel like new still.
The parts I threw at it definitely needed to be replaced, pump wouldn't run, injectors were stuck.
I'm working on the diagnostic stuff now. I'm thinking TPS or MAF, but maybe it is the ECU.
After 20 years sitting, that will blow the cobweb off it and everything that is made of rubber will fail so you will know what needs repair (ask me how I know). Make sure you change your engine oil first. Could have been washed with fuel during those early attempt to start.
Thankfully, most of the hoses were replaced with silicone and they look and feel like new still. The suspension is all urethane and looks like it held up as well.
Early attempts to start were fuel starved due to bad pump and then bad injectors, but I'll replace all of the fluids before driving it. I ran seafoam through it before I replaced the plugs.
Do you have fresh gas in the tank? Have you tried driving it? I have no idea, but be patient and the more knowledgeable people will point you in the right direction. Don't give up, you have a great car and once it's running properly you'll have a blast. Remember, use high octane fuel with no ethanol.
I cleaned out the tank when I changed the pump. Fresh high octane in it. I'm sure at this point it will be something minor, like a bad sensor or ECU.
I don't think it's a great idea, but I did that with my 89 T/A after it sat close to 10 years haha. Also, THANK YOU for the book you recommend from summit racing about TPI engines. I just ordered it. I wish I had that book several years ago....
No worries
You can probably order from Amazon as well. I just picked the first link at top of search!
Thankfully, most of the hoses were replaced with silicone and they look and feel like new still. The suspension is all urethane and looks like it held up as well.
Early attempts to start were fuel starved due to bad pump and then bad injectors, but I'll replace all of the fluids before driving it. I ran seafoam through it before I replaced the plugs.
Thankfully, most of the hoses were replaced with silicone and they look and feel like new still. The suspension is all urethane and looks like it held up as well.
Great!
I'm also thinking valve stem seals, rear main seal, brake hoses, brake cylinder's, belt, engine mounts, power steering pump, water pump, axle seals, pinion seal, slip yoke seal, etc...
While testing the MAF, I realized that it ran much better while disconnected, but the MAF sensor tested good and wiring was good. Then I realized it ran good with MAF plugged in, but air filter removed. Looks like the oil on the filter has become a solid and the engine could breath. I cleaned the filter and will check again once it's dry, but I think it's all good.
While testing the MAF, I realized that it ran much better while disconnected, but the MAF sensor tested good and wiring was good. Then I realized it ran good with MAF plugged in, but air filter removed. Looks like the oil on the filter has become a solid and the engine could breath. I cleaned the filter and will check again once it's dry, but I think it's all good.
Great. Glad you resolved it.
It had fuel, compression and gas... but no air hahaha!! Cover your basics
Keep digging, you'll probably find more I'd love to see the state of that water pump after sitting for 20 years. I would flush that coolant thoroughly, get a new thermostat and water pump... and acc belt
It had fuel, compression and gas... but no air hahaha!! Cover your basics
Keep digging, you'll probably find more I'd love to see the state of that water pump after sitting for 20 years. I would flush that coolant thoroughly, get a new thermostat and water pump... and acc belt
Crazy thing is it didn't look that dirty, so never even thought about it.
Yeah, needs tires too. They were new in 2001 when I parked it.
05-26-2024, 09:26 PM
I'd love to see the state of that water pump after sitting for 20 years. I would flush that coolant thoroughly, get a new thermostat and water pump... and acc belt 