I have an 88' Iroc 350 TPI, car only has 30,000 miles on it. The car will crank forever and then when it fires it coughs and sputters until you clear it out, also after it starts you can smell the raw unburned fuel out the exhaust?? It does it the worst when it's cold, but it does it all of the time even after five minutes?? I have already set the TPS to .62, new TPIS adj. fuel pressur regulator 44 psi w/vac hose off, new sensor under plenum, new 24lb accel injectors, just set the timing. Questions are the scanner i ran through it said history of high voltage from the mass air flow sensor. Also i have K&N air filters, and i read in a chevy magazine that the oil out of the filters can reuin a mass air flow sensor. I also question the cold start valve, but it starts like this all of the time. ANYBODY PLEASE HELP!!!!!!!!!! thanks justin

 

Have you checked your plugs, inside distributor cap and rotor?

 

Yes those parts are all new only 4,000 miles on them. It has Napa cap and rotor, MSD 8mm wires, Napa control module, and AcDelco rapid fire spark plugs.

 

Have you checked your temp sensor? Also try running it with the MAF unplugged and see if it gets any better.

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91 Z28
Come see The Vicious...

[This message has been edited by ViciousZ (edited November 24, 2001).]

 

you said the codes says high voltage at maf..
try lowering your TPS,, .54Vdc is stock..
if that doesnt work try replacing your MAF burnoff and power relays..(10bucks each)
good luck

 

I was told by mitchel on demand that it is suppose to be .62 with the key on, not started. This a computer program at my work for trouble shooting. Also were is the MAF burnout, and how many power relays are there, and also were are they located. Thanks JUSTIN

 

I read the post about the temp. sensor but i don't think thta its the problem on my car. I have already replaced both sensors in the head, the gauge one, and the fans one. Ya but read my first post my car does this hot and cold???? and all i smell is raw fuel out the exhaust after it fires. If i don't put my foot on the gas it will take 2 minutes to start???????

 

Sounds to me like you need a coolant temp sensor. It sounds like your ECM thinks it's something like -57° all the time, and is massively dumping fuel in it because it thinks it's a cold start.

The coolant temp sensor is not in the heads. It's in ths water outlet. It has 2 wires, one yellow, one black.

The problem could also be either a leaking cold start injector, or its temp sensor (yet another discrete one).

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"So many Mustangs, so little time..."
ICON Motorsports

[This message has been edited by RB83L69 (edited November 27, 2001).]

 

Thanks i'll first change the temp. sensor in the intake next to the water neck w/ the yellow and black wires. If it doesn't work did you say the cold start valve, which is located in the drivers side runners correct??? Thanks for the help!!!!

 

I agree with the cts as well.This $11 sensor sent my ecm into open loop,dumped all kinds of fuel,made my car smoke and not start,and smelled of a very strong gas. This is a critical sensor and one I bought 2 of since it controls so much! Start there,you may be amazed at how much it can fix...


Niko

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*1989 IROC Z(White)
>305 TPI/700R4
>Flowmaster 3" Catback
>K&N Filters
>50k miles

 

Well i changed the cts in the intake manifold next to the water outlet the one with the two wires, one yellow,and one black and it didn't change a thing????? What does the sensor next to cts do, it has the injector type connecter on it? Should i try and change the cold start valve or should i try and change the MAF burnoff relay, and the other power relays???, or is it the MAF sensor it self????? ANYBODY!!!!!!!!!!!!!!!

 

Well i changed the cts in the intake manifold next to the water outlet the one with the two wires, one yellow,and one black and it didn't change a thing????? What does the sensor next to cts do, it has the injector type connecter on it? Should i try and change the cold start valve or should i try and change the MAF burnoff relay, and the other power relays???, or is it the MAF sensor it self????? ANYBODY!!!!!!!!!!!!!!!

 

ANYBODY??

 

The sensor next to the CTS is for the cold start valve, you cold unplug it to see if that's the cause. This won't rule out the vakve though, only the sensor.

Did you unplug the electrical connector under the MAF as asked above? Did it make any differnce?

 

i disconnected the MAF sensor and it was ten times worse, it sound like a big block at idle. the thing barely stayed running.

 

it would help us if you give us the ses codes you are getting???

 

Thats the thing i'm not getting any codes at all. I have replaced just about every sensor and did eveything you guys said and it is still doing it hot and cold, and my fuel mileage is like 14mpg around town. I have ran out of ideas and patients this thing is really anoying????

 

Leaky injectors, maybe...?

 

Well, with the CTS already replaced, and the MAF sensor showing signs of life, I would say something is wrong with the cold start injector circuit or one or more of your injectors is leaking, or a little less likely - maybe the fuel pressure regulator diaphragm has ruptured. I say the FPR is less likely because usually when it fails, the car always run like complete crap and barely starts unless you go to clear flood mode (WOT while cranking) as it is getting WAY too much fuel.

If you want to check the FPR just for $hits and giggles, just pull the vacuum line off of it and turn the ignition on and look for fuel to come out of the vacuum port of the regulator.

The CS Injector is somewhat known to be prone to leaking and might be the problem. But if the car has a lot of miles on it, it very easily could be leaking injectors. You will need a remote fuel pressure gauge to put on the fuel rail shroeder valve to watch fuel pressure to diagnose this - or the CS Injector really. What you want to do to diagnose the injectors or CS inj. is to put the gauge on the fuel rail, get a couple of hose clamp off pliers (vise grips will work but be careful) and use them to pinch off the rubber fuel hoses near the brake master cylinder while the gauge is reading *** pressure. You then play the waiting game and see how long it takes for the pressure to blead down out of the fuel rail. If you get the rubber hoses pinched off very well, and everything is working properly, you really shouldn't see any drop in pressure unless you let it sit for a day or two like that. But if you see the pressure take a $hit after a few minutes (or quicker), you know you have a problem with the injectors or the CS injector.

Well, I hope that helps some......
Good Luck!!!

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1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club

 

I just replaced the injectors 500 miles ago, with accel 24lb, the car has only 36,000 miles on it. The fuel pressure regulator was just put in 100 miles ago, and the diafram was "mint". I just adjusted the fuel pressure to 47psi with the vacum line off. I am just going to replace the cold start vave, but GM has dicontinued it, and no part stores have it???????? HELP

 

I called the local GM dealer today, and the guy at the sales dep. told me that the cold start valve has to be special ordered, and that the part number was 17112073 at a price of 110.55 . Hope that helps, good luck, and keep us informed.

 

Even though you stated you bought new injectors, it sure sounds like 1 or more is leaking and flooding the engine while it's off which will make it a PITA to start and spit raw fumes out the exhaust.