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This was my last post to refresh symptoms. Bought new MAF and still doing same thing. As it dies, the check engine light comes on. When I checked, it gives Code 33. MAF is two days old, wires/plug in excellent shape. Can I put a volt/ohm meter to harness to find anything out?

The only thing I did prior from running like brand new, to barley starting is de-screening my MAF. So I bought new one. That was money down drain. Still only runs good for few seconds then dies. This thing better not of munched up this new MAF. I'll kill it! What the hell is going on?

 

Ok...

Maybe you injectors are not firing, maybe it is just running of the cold start injector. I have read before that it will put enough fuel out for a car to idle OK. Fuses for the injectors?

Maybe you ignition module is giving up, it gives a pulse reference to to ECM to let it know to fire the injectors. It does several things and on or more of them can die at different times.

I didn't read the other post all the way through, so please forgive if you tired these.

 

83350Z,

Would the injectors not firing or ignition module give a code 33 (Faulty MAF, Open in MAF circuit, Faulty ECM)? When I got that code, I pulled negative battery cable, reconnected, then started again. Ran beautiful for 20 seconds, I even revved it up to 2000rpm, then instant death. Although, I seemed to be able to keep it running "somewhat" by pumping the hell out of the gas pedal as it died. Got same code again. MAF is brand new! Inspected wires and harness. I'm lost.

 

I am sorry, must haev misunderstood. I thought it when the light came on.

I know that the relays associated with the MAF can be confusing.

I got this pic off the board, I do not remember from who. I know they appear similar but have internal differences.

What kind of condition is you distributor in? Anything to note when you pulled the cap off? Yellowish dust? alot of rust in the rectifier?

look at my post https://www.thirdgen.org/forums/tpi/...rich-post.html

read through it. Do some of the things I have done if you haven't already.

When I first got my car a month ago it would die alot and it was a bad dizzy, same thing with my Dad's TBI truck and my friends 87 TPI T/A

 

did you try replacing the MAF burnoff relay????

 

Not yet, but if not too expensive, I will pick one up Friday. Getting fuel pressure tester and fuel filter then also. Worth a try and cant hurt.

83350Z,

Condition of dizzy looks good. Has brand new Mallory cap, rotor, coil, wires, with Accel plugs. All were replaced just prior to me taking possession of car. Is there a way to test the components in the dizzy?

 

I think there is some tests, but you will have to look in a manual for the specifics. I have never had to do the tests as something was always visually evident there was a problem when I had to replace them.

See what happens with the relay, maybe even do the visual test to see if the wires in the MAF glow red after you turn the car off. If they do, the burnoff relay is working.

 

Code 33 on a TPI car is set when MAF sensor indicated an air flow of 45 gm/sec or more for 1 second when TPS was less than 1/4 throttle and engine speed was under 2000 RPM. Which means that signal voltage or frequency is high during engine idle. I found this OLD GM bulletin

G007
SUBJECT: MASS AIRFLOW RELAYS AND MAF TROUBLESHOOTING FOR 86-88 VIN F AND 8

SYMPTOM: CODE 33,34,OR 36 ( ANY OR ALL, HARD OR SOFT )ROUGH RUNNING, HARD STARTING, ENGINE SURGE, AND STALLING

FOLLOW THESE STEPS TO TROUBLESHOOT A CODE 33,34,OR 36 ( INCLUDING POSSIBLE FALSE CODES)ON ANY OF THE SUBJECT ENGINES WITH MAF SENSORS

1. MAKE SURE THE LATEST MAF RELAYS ARE BEING USED. THE CORRECT PART NUMBERS ARE AS FOLLOWS:

86 CORVETTE - PR:10067925 BR:10094701
86-87 CAMARO,FIREBIRD - PR:10067925 BR:10094701
87-89 VETTE - PR:14089936 BR:14089936

CHECK VOLTAGE DROP ACROSS THE MAF POWER RELAY CONTACTS. IT SHOULD BE .2V OR LESS

ALSO CHECK FOR LACK OF CURRENT FLOW (EXCESSIVE VOLTAGE DROP) ACROSS CONTACTS OF MAF POWER RELAY AND BURNOFF RELAY WITH 12V TEST LIGHT. CHECK CIRCUIT 993 FOR PROPER OPERATION OF THE POWER RELAY AND CIRCUIT 994 OF THE BURNOFF RELAY. IF TEST LIGHT IS DIMMER THAN NORMAL WHEN CONNECTED TO RELAYS AS EXPLAINED BELOW, THE RELAY MAY BE FAULTY.

TO DUPLICATE INTERMITTENT FAILURE, YOU MAY NEED TO CYCLE THE RELAYS SEVERAL TIMES AS FOLLOWS:

CYCLE THE POWER RELAY BY STARTING THE ENGINE TO CLOSE THE RELAY AND THEN STOPPING THE ENGINE TO OPEN IT. THE TEST LIGHT SHOULD LIGHT WHEN THE RELAY CLOSES AND NOT LIGHT WHEN THE RELAY IS OPEN.

CYCLE BURNOFF RELAY BY RUNNING THE ENGINE TO NORMAL OP TEMP. IN CLOSED LOOP AND THEN SHUTTING IT OFF. THE TEST LIGHT SHOULD LIGHT FOR A FEW SECONDS AFTER THE ENGINE STOPS AS POWER IS APPLIED TO THE BURNOFF RELAY TO MAF SENSOR.

IF CORRECT RELAYS ARE INSTALLED ON THE CAR AND OPERATING PROPERLY, CHECK THE OTHER ITEMS LISTED ON THE FAST TRACK TROUBLESHOOTER CARTRIDGE.

Code 33 can be set by an open circuit in the ground path (pin A) on the MAF burn off relay, a short on the MAF signal line (pin C on the burn off relay, bad MAF burn off relay itself, bad power relay, etc. Also, there is a possibility of a failure that is blowing out the quad drivers of the ECM which is the worst of all possibilities.

I hope this helps

Happy Thanksgiving
//RF

 

Yeah it helps. Helps confuse the heck out of me...lol Just kidding, but really confusing and thanks for the trouble you went through finding that info. I think I can follow these directions to check. I have a test light, but no worky today on car. Belly too full!!! Getting fuel pressure and vacuum testers tomorrow and will try to concur this weekend. Will post findings. Thanks again to everybody and Happy Thanksgiving!

 

Connect a voltmeter to the MAF output terminal (back-probe the connector) and monitor the voltage while the engine is idling. You can find a complete description of the procedure if you search the archives. I've posted it dozens of times.

 

Car won't idle. Only for few seconds (and idles great by the way), then dead. Found some of your previous posts Vader on checking MAF. Printed out and taking with me to troubleshoot. Also, RF's previous' reply above a few. Bought a fuel injection pressure tester and vacuum tester, grabbing my voltmeter and heading out to try to figure out prob... Stopping at parts store to buy MAF relay (like 6 bucks) and new fuel filter. Cant hurt. Will post any/all findings later on.

Please God! Throw a little luck my way for once...lol

 

Grab two while your at it and have some peace of mind, I'm thinking it's one of the two relays for the maf. (you have checked for spark and fuel pressure and state of tune is good right?)

 

Grab two? Where is the other one? I did buy a new MAF relay and changed it out. No go on that. Car started great, ran BEAUTIFUL for 30 or so seconds, and just when I thought it was cured, WHAM!! dead. Dies like I turn key off. I checked pressure at fuel rail and gauge shot to roughly 37 psi the moment I turned key on. Held that pressure for over 5 minuets. Needle would wiggle a bit when cranking, and when it did fire up the gauge held steady at 35 psi. Vacuum was harder to test. Car would barley start for that test but could see the needle jump to 45 - 50 on dial.

What other relays are there for that MAF? I changed the one that was next to the brake booster. On driver side, there are three. Farthest one to driver side is (I think) fan relay?. Middle one is (I think) MAF relay, and closest to brake booster is, I don't know. I just figured out that the "Burn Off Relay" is part of the MAF itself? Anyway, nothing seemed to help.

I did check the resistance of the 5 wire plug at MAF. Pin A and B was 0 ohms resistance at negative battery terminal. Turned key to on position then checked pin E (red wire) for 12v power supply. I had 0 volts (zero). Is this right? Then I checked red wire, pin E at MAF relay, zero volts there also. Does car have to be running to get 12 volts to them wires?

Thanks for any info guys...

 

Hello? Anybody? Vader? RF? I don't know what to try next. I'm starting to think this problem might be beyond my expertise. I am in the hole for a new MAF, MAF relay, fuel filter, testing equipment, and who knows what will be next. And no better off. But, I have yet begun to fight...

Please, someone has to know something...

 

Do you have a service manual? If not, I can scan the pages out of the service manual and send tomorrow. There is a circuit description & good electrical diagram for a code 33 as well as a good decision tree to follow for troubleshooting. If you follow this diagram you will find your problem.
Corky

 

There are two for the MAF the power relay and the burnoff relay. The fuel pump relay, iirc is the third of that grouping. Vader has a good pic floating around that shows them, I'd search for that.

 

Maybe you have two problems.

Sounds to me like something is telling the car to stop giving spark or fuel.
I can't imagine a MAF problem would shut the car off like you describe. I have unplugged all my MAF stuff and my car keeps running, not good, but it runs.

And there are two relays for the MAF, MAF power and MAF burnoff. Both are next to the brake booster, the other one there should be for your fuel pump.

Have you tried running the fuel pump through the aldl diagnostic port? It bypasses relays, ECM and everything and just makes the pump run.

At this point I would try that to see if the car is turning off because something fuel related is telling it too.

 

I like the sounds of that! I do have a Haynes manual. Is this what you are talking about? If so, what pages or what do I look for? I have searched book until I was blue in the face. I don't always understand the lingo used here sometimes. Like when Red Devil asked if the, "state of tune was good". I drove the car the night before ALL this happened. Ran like brand new. Next morning, crap!

Maybe you could send what you have just to be on the safe side. I'm not the shiniest apple on tree, but I am far from the dullest. Sometimes you just have to take the bull by the horns and show him(me) what to do. I would GREATLY appreciate your efforts. Thanx buddy...

 

Don't remember where I got this but here is the port info

 

And I think this is the pic from Vader about the relays.

 

So, I should turn fuel pump on via ALDL and then start/run car? See if it keeps doing the same thing? Or just see if pump runs? Do you know what pins/ports I should jump to turn pump on? Thanx for any info.

Red Devil, the hunt for that picture is on. Wife has been getting on my case about me and garage and computer. I guess we haven't been getting "our" time. DAMN IT WOMAN!!! Can't she see I am in the middle of troubleshooting? I feel I am almost there!...lol

 

DAMN! 83350Z, U DA MAN!!!

 

Ü I'm tryin'


.....and I mean to run the pump and start the car to see if it will keep running with the pump in test mode.

 

Uh oh, Well, I notice one BIG mistake I made. The relay I changed, according to that picture, was the fuel pump relay. Maybe thats why nothing changed. I will go out and put old relay back on fuel pump relay and new one on MAF relay. Will try that and maybe buy new burn off relay. Or should I?

 

Going out to try right now. No lovin for me tonight...lol

 

Get your wife involved and you put your hand on the fuel pump relay and have her turn the ignition to on, don't start the car just on. You should feel the fuel pump relay click. That will verify which one is the fuel pump relay for you. I had to do that because one of my past cars was all jacked up. The only other thing is to look at a wiring diagram and verify the color wires goign into each relay. Some of the relays appear interchangeable but there are slight internal differences.

 

Well, I just returned from garage. I changed that relay. Started car and did the same thing. Then I used the ALDL to start the fuel pump like you mentioned. Car started, ran great for 15 seconds then died. Now the weird part.

I noticed when I turn key on, I always see the SES light come on for few seconds then go out. Now that light wont come on at all. Also, every time I turn key to on position, I hear the fuel pump run for 2 or 3 seconds then off. Now, nothing. Even using the ALDL, I can't get pump to run. I tried to do a quick check of the ALDL diagnostics and can't even get that to work. No flashing check engine light. I disconnect the battery and try again, still nothing.

What the heck? Is what you had me do an old trick or something for the rookie...lol? If I were confused before, I'm totally lost now...

 

Sounds like you popped the fuel pump/ECM fuse next to the battery. No biggie.
No trick. the way I always run it from the aldl is to run a lead from the aldl to an ignition hot in the fuse box.

When you ran the pump from the aldl, when the car died, was the pump still running?

 

Alright, first thing I did (probably wrong) was I jumped the ALDL pin A to pin G to get pump to run. I didn't notice pump running any different than usual (until I noticed it not running at all). I will try your way if I didn't fry the ECM by jumping wires that way. Also, where is that fuse by battery located? I sure hope thats why fuel pump and SES light wont function now. Thanx a million for yer info...

 

It is a fuse that has a cap over it, it actually looks like a small relay. The cap is usually attached to the car and you unclip the fuse holder from it. I believe it is a thick orange and red wire running to it. Don't worry about the ECM. it will not have hurt it. I have done the same thing.
Sorry, I forgot to mention the fuse box thing.
If you do it like I said the pump should run continuously once you turn the key to the on position. The car probably died thsi time form the fuse.

On that fuse. In maro's the battery is on the pass side and the fuse cap is attached right at the fender. I think in T/A'a it is on the the left with the battery. My Formula was TBI and it was on the pass side. My T/A was TPI and it was on the left side.

 

Pin A is an ecm GROUND. You need to bring 12v to the G terminal yourself. Look at Vader's pics (that other one is also Vader's 83350Z, he has a tendancy to have lots of good stuff. ) and read the pin out descriptions. Be careful there b/c you can do some damage if you screw the pooch there.

 

Thanks 83350Z. Yes, on my GTA, battery is on drivers side. I'm pretty sure I have seen the wire you speak of. Didn't know it was a fuse. I am, however, done for the night. I will change fuse tomorrow after work and try running that lead wire to fuse box. Hope to see you on again then. Thanks...

I also noticed you have a post going about wondering what FP tester to get. I just bought one by MityVac at our local JC Whitney (discount auto outlet store) and it performed great. A cheapy at 30 something bucks. Screwed right on. Comes with adapters for Ford, and everything else. L8r...

 

Cool, thanks. I will try and be on again tomorrow night.
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Hey RD, were in TN are you? I am in the Murfreesboro.

 

Oups I did it again - sounds like you are in a middle of a serious troubleshooting session... and I missing all the action

General comments:
Fuel pressure - 37 PSI is way on low end of spec - stock TPI cars like to see 39 to 45 PSI of fuel pressure.
Vacuum - 45 to 50 I assume that you vacuum gauge reads in kPA - it is kinda on low side, but your car would not idle properly. So we'll look at this later.
Depending on Fuel Pump type it may require 4 to 6 Amps of current to run. So to run pump in test mode you need to bring 10 AMP fused line either from battery or sig lighter. Like RD said - be very careful when running FP in test mode.

When ECM goes through boot sequence it will power FP for 2 seconds then shut off - this is normal sequence. Also SES will light up and turn off once boot sequence has been completed. Find that main Fuse and replace it.

Promise - I'll check tomorrow.

//RF

 

Hey if you are near Murfreesboro, Maybe I can help. I know a guy that is a whiz at this stuff in the Boro. He loves problems that no one else can fix, and he is pretty reasonable. OOps youre not close to Boro sorry

 

Here's the troubleshooting charts for code 33. I agree with others, you've got multiple problems with the engine shutting down.

Corky

 

Thanx Corky for those pictures. I will study them like the bible.

Although, I have discovered some more info that raised a couple more questions. Last night I blew the FP/ECM fuse at battery. I found that connector (looked like a small relay (thanx 83350Z)) that had a red and white wire to it, unplugged and there was a flat type (20 amp) fuse that was blown. Replaced.

However, the first thing I checked before discovering that was a cylinder shaped connector that was burnt and crumbled in my hands when I tried to disconnect.

There are two wires that come from the main positive battery connector where it mounts to battery (at terminal), One big black wire (goes to starter), and one smaller black wire (about a third of the size). This smaller black wire goes into a cylinder shaped black box were it turns into three wires. One the same size, one small and black, and one small and orange. The same sized one goes to back of alternator. The black one goes to a cylinder shaped connector with a red wire on other end. The orange wire goes to a cylinder shaped connector and stays orange. Both orange and red wires go into the wiring harness, into some big wire loom. The orange wire connector was burnt looking at connector and when I tried to disconnect, it crumbled.

What is this wire and what was it. Was it an inline fuse? The only thing I can see is a small round piece of metal (maybe 1/16th inch diameter and 3/4 inch long). My first thought is it's a round, glass type buss fuse. Both ends of connector are destroyed/melted. If it were an in line fuse, I can go to store, buy a universal flat type inline fuse and cut old one out and splice new in (giving I know what sized fuse to install. And I don't). Or even if thats what it is...

Now, I do not know if this was like this prior to all my problems or if it happened last night. I inspected wire further up and seems to be in alright shape. No burnt/melted except for 1/4" inch passed connector. Just don't know what it is, or is for. I will go and buy an inline fuse but wait till I get some needed info before I cut/splice/replace.

Sorry to hammer you guys with such a big post here, just trying to get all info out here to help. Oh, and haven't tried to run the power wire to pin G for FP test. Figure I would wait for info and fix this problem first. Thanx for any info...

 

Were is everybody??? Bump?!?

 

Did the car have an aftermarket alarm or anything? I cannot think of what that could be as a factory item.
Or maybe some aftermarket stereo equipment like and amp and subs?
Where was the "cylinder" located?

 

This is tough without seeing a picture. The service manual shows the large positive cable going to the starter, one smaller cable goes to the bat terminal on the alternator & the other smaller cable goes to the orange ecm power harness connector. It almost sounds like someone put a cylindrical in-line fuse on a wire there to possibly power up an amp for subs. I can only guess without seeing what you see.

Corky

 

Its located right in the battery compartment area. The positive battery cable has two wires to start. One fat/big one to starter. One smaller one that goes to small (3/4" round tube shaped box). Out of there comes three wires Two out one end of tube and one out on same side as bigger wire goes into box. Bigger one to back of alt., one small black to factory looking plug/connector, and one orange to same type plug/connector. This orange wire is the one originally I thought you were speaking of (FP,ECM).

No alarm I can spot anywhere. What you think I should do? By-pass wire? Hook up inline fuse? I will try to get a picture of and post. Will have to figure out how to make my camera take smaller sized pictures. This site funny about size of pictures you can upload.

 

I think I would try bypassing it first. If it fell apart in your hands something has been going on awhile there. Maybe it was a part of an alarm and had some kind of power kill feature. How long you had the car?
It sounds like some kind of relay spliced into your factory wiring, and a wire added for whatever it went to.
As far as pics, do you have something to downsize a photo on your computer, if not you can download "Irfanview" for free, it has a resize/resample feature.
It is possible this could be the whole problem, or not... Ü

 

I just reread your long post. The orange wire that crumbled in your hands is the +12v power feed for the ECM. This may very well be your problem. If this connector loses continuity, the engine will die. Cut out the burnt section and jump this with a FUSED jumper wire to start with (precaution when burnt wires are around). If the fuse doesn't blow, start engine and see if it stays running. This connection may have been loose & generated a lot of heat causing the connection and insulation to deteriorate to the point of loosing continuity. If all works well, replace the bad section and connector with new stuff & you may be good to go - or at least on to the code 33 problem!
Give it a shot,
Corky

 

Ok, I will give this a try. Couple pics I just took.

 

...edited as pics came in after this

 

Small black went to plug with red wire. Orange to orange. You were right, FP/ECM was orange and red, these are orange and red, and blue purple? from windshield washer pump. All are taped and go to harness. What youz think???

 

How many amp fuse do you think I should use? I have anywhere from 5 to 30 amp flat type...

 

I think that went to some kind of aftermarket equipment that may be only half there and is causing a short which when hot enough the car shuts off as corky mentioned. I think the more you can get the wiring back to stock the closer to solving your problem you will be. Do you have any kind of manual with the wiring diagram? That blue wire grouping does not look factory at all to me. Almost like someone mixed their own verison of a wiring harness with the factory type
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I think 20, good generic value

 

Ooooh!! I think I am getting close. Here's the situation. I put a 20 amp back in the FP/ECM capped fuse. Turn on key and noticed fuel pump not running. I recheck fuse and see its already blown. Biggest I have left is 10 amp. So I put a 10 amp in and hit key. Fuel pump comes alive and SES light is back on. Then I hooked up an inline fuse to this orange wire set up. Start car. Runs great for 5 seconds then dead. Check fuses and that 10 amp one to FP/ECM is fine. Orange wire set up fuse is blown. I put in another 10 amp to orange wire connection. Start car again. Runs great for another 5 seconds, then dead. Blew fuse again.

Seems to me if I can get this wire to keep from blowing fuses, I would be in business. Very temped to straight wire without fuse to see if it stays running. But I know I could cook alot more and have even bigger troubles. What you guys think my next step should be??? Bigger fuse? 20 amp, 30 amp?
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The only blue wire I see in pictures goes to my windshield washer pump. But I agree with you. Stock or not, I think it might be my problem. Read my last one.

 

You need to find the source of the short. After that is found repair your wiring with the fuse link still in place like Corky said and see what happens.
At this point I bet this is the answer to the whole problem.


I "THINK" the ECM has a failsafe in it to keep from overloading due to a short and that could be why it was turning off after 30 seconds before.