First off let me say the search engine on this site has almost always helped me in the past, which is why i dont post that often. However I am Stumped.
The Problem: first start of the day car starts up fine finds idle then dies. This happens maybe 3 times in a row, then starts and runs fine rest of the day (and starts fine for the rest of the day too). Now this doesnt happen every day its intermitent some times 2 or 3 days in a row then not for a week, and then does it again. I've owned this car for three years now and over the past years, replaced many parts and tuned it up.

The Car,88 5.7 tpi camaro with 47,000 miles on it. its pretty much unmolested. The new parts are. Cap and rotor, plugs and wires, afpr (46psi), bosch 3 injectors 22#, new fuel filter, new tps(.56v) cold start injector delete(with prom for 89 from tpis) new 52mm tb with new iac housing and iac motor(did a coolant by pass the old housing was ugly) new intake, runner and plenum gaskets. new maf(descreened). New Ud Pulleys and belt, and vacum lines. timing set at 6deg, and exhaust(new cat back). And of course brakes, bearings etc but that stuff doesnt pretain to motor. All of this stuff was replaced over last winter. Car runs and drives great it put down a 14.37@96 this summer at our beautiful drag track in alaska.

The Problem has been occuring for about the past month, and as i said it is an intermitent problem. So if anyone has any ideas of where to look or what to check. let me know. I have my own tools, garage and enough knowledge to be dangerous.

Ps. I am lost as where to go from here. Ive ohm'd and volt tested everything i know of and checked all relays. Help Please.

 

Also I should note that when I un plug Maf and try to start, it wont start at all. Also it throws no codes when I unplug maf. And when i set timing and unplug est wire also no codes. Through all my problems the cel has never come on. Could it possibly be the ECU? Im almost to the point of begging for help.

 

Ok now I begging. If anyone has any ideas please feel free. I'm just **** about my Cars. and this intermintent problem is driving me Nuts. Please Give suggestions of what too check and where to look. Maf has 6-8grams of air at idle all injectors ohm. did a leak down pressure test and they are all good. Suggestions PLEASE. And yes ive searched to no avail.

 

Just curious, are you sure your ses (cel) light is good? Does it come on when you turn the ignition on? (burnt bulb maybe) Also, have you checked your o2 sensor? As for descreening a MAF, I have read a lot of bad things about that. Some say it won't hurt, but the little more air flow you get isn't worth the problems it can create, usually a code 33 and or 34. I had many idle issues when i got my car, cracked maf, vacuum leaks, bad throttle body. Have you also checked and set your IAC. Just some suggestions.

 

Ya the cel comes on with ignition, and goes off like it should(the bulb works). new iac and minimum air has been set. the blms hover right around 130. checked all vacum lines after replacing all gaskets. pretty sure there good. As far as the O2 sensor it is as well new. However our cars have a single wire 02 and dont auctually work untill they reach temp so i dont think that would contribute to a cold start prob. Thanks for suggestions. More are welcome to chime in any time PLEASE.

 

If this was a stock vehicle I would put a spark tester and an injector tester on the engine and see if you lose injector fire or spark or both. If the injectors quit but you still have spark I would be looking at the ECM. If they both stop at the same time and then the engine dies I would look closer at the module, wiring, or the pickup coil in the distributer. I would also check the injectors for their resistance. Usually this is a hot engine issue but I have seen cold driveability issues with multiple injectors at are marginally low resistance. When I work in the dealership we would bump the ECM with our fist and if the car stalled or stuttered we would replace the ECM.

 

Pulled plug number 1, spark is good enev when dying. The coil is good just replaced 6 months ago. also injectors all ohm at about 16 hot or cold and are new bosch 3's. had a friends scanner about a month ago all injectors open and work great. but i guess ill try and bump the ecu later and see if she stalls. but understand it only does this every so often. and once she stays running she runs great. idles at 650 in gear and about 700 in park and is smoothe.

 

No One has Any other ideas. Im begging here im at the point of paying a shop to look at it. I just dont trust anyone to work on my cars. Please all suggestions welcome.

 

Actually put a injector tester into where you plug the injector into the harness. It is a small light that lights up when the ECM fires the injectors. If the light goes out and the spark is still going I would suspect the ECM. I have the manual from GM If you need a flow chart for a no start condition or wireing.

 

Had a similar issue on my 88, 'twas the MAF power relay. Car would start and die, most of the times it would start fine, sometimes it wouldn't.

 

okay great havent looked there yet. is there a way to check resistance or tell if it is bad, or just replace it? Thank you very much for the idea.

 

mine all ohmed at 16.5, tell tale sign was the surging, the O2 voltage didn't swing through the whole range, the spark plug condition and the surging. CO was high, as was O2 and HC. (no cats)

 

Did it surge during initial start up about 3-5 times then smoothe out? mine does that as well every now and then. Also do you know the Part # off hand? and again thanks for the direction, Jason.

 

no, only in closed loop. That's when the O2 sensor picks up the unspent O2 from the misfire. Bosch IIIs are my choise, instead of Multecs or rochesters

 

Sorry, i meant once idle drops, and goes into closed loop she surges about 3-5 times then smoothes out. I'm gonna replace the relay and O2 sensor this weekend. just went out and looked at car and found the 02 sensor itself is loose (the neck of it I mean). Also fuel pressure might be a little high so im going to throw the gauge on it and look for leak down or a weak pump whil turning it down a little. I'll also borrow my buddies snapon brick to see what she is doing after. Also out of the three relays on the firewall next to my master cylinder, 2 are round and 1 is square. Which one is power relay? The square one? Sorry my kids drew all over my shop manual and my wife threw it away. So i got little refrence to go off. Thanks again, Jason

 

the 2 ovals are maf power and burnoff, Check wire colors to see which is which. Square is fuel pump relay. Check the thread about the maf relay differences, the # is in there.

On the O2 sensor, if it has a crimped coller it should be loose. It's a little shield. Outside air comes in back there.

 

Thanks man good info. Now just finding the relay locally here in alaska is the next task at hand. Doubleb I will buy the injector light this weekend when i got more time. Will keep everyone abreast of progress when repair is complete. Thanks again Everyone.