I'm trying to get my 88 GTA 350 to run nice. It has been sitting for 2 years before I bought it. I believe I did all the necessary tune up that I can do in my driveway.....The problem is durring the first startup the car idles at a bare 100 rpm and dies....this happens until it warms up to about 190 degrees or so....so I have to keep sitting in the car and slamming the gas so it idles without dying. It seems to be running a little rich....What the hell is going on with it?

* Someone told me it could be a faulty knock sensor?
* Or is this a faulty thermostat?

* I already changed the plugs, wires, cap, rotor, air filter, oil has been changed once, then again after about 20 miles and sitting around for 2 months

* The motor has 155k on it or so.

Another problem I have is the seatbelts, they seem to be completely extended on both sides and will not retract, I dont know what the hell is going on, perhaps the springs are shot?

Thanks for all the help, any input is appreciated.

 

Throwing any codes?

 

No 'engine lights' come on what so ever at any time. I don't have a code reader to just plug in either, I'd have to take it to a shop, and by then I'd have to wait an hour for the engine to cool down again.

 

I'd start by either cleaning or just replacing the IAC. If you have to open the throttle blades to idle, it sounds like the IAC is sticking.

 

By IAC do you mean intake air components?

 

PS: The car seems to fire right up and run well if I spray a crap load of starting fluid into the intake before firing it up. What is the IAC again?

 

Don't overuse the starting fluid - it's not exactly "Health Food" for your motor.

The IAC is the Idle Air Control motor or valve. It controls how much air gets into your engine at idle. If you are unfamiliar with what that is, I'd suggest picking up a Chilton's manual ASAP, and familarizing yourself with sensors, their locations, and their functions. It will also tell you how to remove/replace, and in some cases test them.

 

Ahh thanks! I do have a Haynes manual that I've been using for eternity on my thirdgens, is the Chiltons superior and worth buying?

PS I will locate that motor and clean/replace it. Thank you for the info!

 

I prefer Helm's myself, but I wasn't aware you had one, and Chilton's is normally a little cheaper...

 

MINE DOES THE SAME THING I DOUBT AN IAC IS HARDLY THE PROBLEM. THAT IS THE QUICK AND HOPE YOUR LUCKY. OHM THE INJECTORS, NEW FUEL FILTER, AND FLUSH THE FUEL LOGS.

 

Youre right, I better replace the fuel filter and perhaps get the injectors serviced or replaced....I know a few people here have had theirs serviced for something like $12/injector by a "mail in" injector specialist.

I was also thinking about removing the throttle body and intake and completely cleaning them out. Would this be a suggestion or will I probably screw something up?

 

dO SOME TESTING BEFORE YOU FEEL LIKE JUST BUY AND TRY, UNLESS YOUR LIKE ME, BUT I WANT ALL NEW SENSORS AND COMPONENTS ON MY ENGINE. OUT WITH THE OLD, IN WITH NEW AND IMPROVED. TRUTHFULLY I DONT CARE WHAT ANYONE SAYS ONCE ONE THING GOES, YOU MAY AS WELL FOLLOW WITH THE OTHERS OR PLAN ON IT BECAUSE IT IS PROBABLY GOING TO COME. HOWEVER IF YOU ONLY WANT TO IMPROVE THE IMMEDIATE SITUATION MAKE SURE YOU ARE REPLACING THE RIGHT PARTS.

 

IF YOU REMOVE THE INTAKE SERVICE YOUR EGR. MAKE SURE IT IS PERFECT BECAUSE THAT IS PROBABLY ANOTHER ONE OF YOUR PROBLEMS, AND YOU JUST CAN'T PIN IT TO THE EGR YET.

 

KEEP POSTED ON YOUR RESULTS BECAUSE THIS AN EXTREMELY COMMON PROBLEM OF TPI AND MORE PEOPLE LEARN TO DEAL WITH IT THAN FIX IT. SO IF YOU FIND ONE TERRIBLE THING IT COULD FIX MANY PEOPLES PROBLEMS. OHH I HAVE ALSO HEARD THAT THESE CAMS LIKE TO GO FLAT. HENCE ROUGH IDLE, BAD MPG, AND REALLY BAD COLD STARTS. ALSO VACUUM LEAKS ARE COMMON.

 

I will keep you all updated on this problem, I found out that the EGR valve is only $44.00 at autozone, might as well replace it.

Question, is the IAC motor the one pictured here right on the throttle body?

 

YES THAT IS THE IAC AND GOOD , LUCK FINDING THE NEW GASKET FOR THE HOUSING

 

I wonder if I can pick up a replacement IAC from a store, going to check with autozone next time.

Also, can I pull off the entire intake and clean it by myself without screwing up the car? There is no gasket between the intake and the heads, right?

 

Try cleaning it first, don't start thorwing money away in case that's not the problem.

If there's any significant improvement, but still not running "Well" then maybe replace it because the resistance is too high.

 

Autozone has an IAC for $57. Next time I have access to the car I am going to remove the entire intake and clean it out and check for broken components, like the IAC.

 

better look harder an iac should only be 27$

 

Yeah, that price is way off the beatin' path.

 

Ok heres an update: replaced the IAC with a new one. Before that I cleaned out the housing where the IAC sits. Unfortunately the car still ran like crap when it was cold. I took it out on an 1 hour ride, so maybe it adjusted itself somehow. Will see how it runs tomorow morning.

 

My '87 TPI had the very same symptoms. That smell is not rich, it's actually lean. Is it popping back out of the intake too if you try and drive it before the car is warmed up a bit? I'm guessing your 9th injector took a dump and is not firing anymore.

Our solution was to upgrade to 1989 code, which does not use the 9th injector. No more issues with cold start, and it idles beautifully!

Does your GTA have VATS? If so, you could just swap an '89 chip in for kicks, unplug the 9th injector, and see if the issue is gone.

 

Ya I have VATS, can you tell me what the chip is called? I might take a look on ebay. I'm going to take a look at the 9th injector to see if it has $hit to bed.

Will I need a whole ECM or just the PROM for my car? And will I have to get a PROM that was out a car with a 350 or can I use a 305 PROM?. I have no idea where to start looking so any input would help. I have found nothing but aftermarket so called "generic performance" chips on Ebay, but no specific ECMs for 89 and up F-bodies. Any help would be appreciated.

 

You reuse your original ECM. '86-'89 F-bodies all used the same ECM, just the code was changed on '89 models to remove the cold start injector. You could buy a stock PROM from the dealership; just ask them for one for an '89 GTA, 350/auto. Then, swap the PROM and unplug the cold-start injector.

 

Awesome, I know chips are expensive and I hope the dealership does not rip me off on it. Maybe I can get lucky and find one on ebay or 'salvaged' from autozone?

 

I called a Pontiac dealer and found out that they do have the proms but they cannot find them by year/model........they need a specific part number. The guys said they ran for $78, but that I would need the number off the PROM to get the correct one.

Can anyone here please provide me with the number of their PROM from an 89 and up Transam with a 350 and 700R4 auto transmission and VATS?

PS: I got this info on the PROMS available for the 89 Transams.....


89 5.7-8 A/Trans (MD8), Fed, 3.27(GW6)
prom part number: 16150500
prom code: 3516APYU, 9356ANYF

I am wondering if this is the correct part # that I need? I am not sure that I have 3.27 gears....I know my gears are stock though. I believe the 88 GTA only came with 3.27s, right? Will it matter if the PROM is designed for a different gear ratio?

 

Any ideas???

I was thinking about cleaining the cold start injector, how do I go about that without sending it out to a injector cleaning service? Kinda strapped for cash.

 

It shouldn't matter if the PROM is for a different gear ratio, as long as it has an auto trans so it has the lockup function for the torque converter. If you still have the SPID decal inside your center console, look and see if you have the same one listed above - GW6. I think you'd be OK with that prom though. Don't worry about cleaning the 9th injector - disabling it in the code is much better IMO.

 

Will I have to remove the 9th injector? Will it still be active if I just leave it in there after the code is changed?

 

You can leave it installed in the fuel rail, just unplug the wires going to it. It won't fire if there's no power, and you won't have to worry about the fuel rail leaking or having a vacuum leak at the manifold because you're not disturbing anything.

 

If it runs like crap when its cold it is the cold start system. Check the ohms on the the 9th injector. There are two types of sensors in the front of your base manifold. One is the cold start swith, it turns on the 9th injector on when the engine is cold and turns it off when the engine reaches operating temperature. If this sensor is bad it will not fire the injector causing hard starts and poor idle quality until operating temperature is reached. While you are there you might as well replace the coolent temp. sensor. This tells the computer what temp. your engine is at. Sounds like its working, but I changed mine as well when I had this problem. After I replaced these sensors my cold starting and idling were solved.

 

Yes I'm going to replace the coolant sensor, but I'd like to upgrade to 89 and later code............I just need the correct part number for the PROM, so I can get it from a dealer.........or maybe someone has a PROM I can buY?

You know what I'm gona get into programming the chip instead, but where can I get the 89 and up code to burn? I"d realy love to get rid of the damn cold start injector.

PS: How can I tell if my car is running too rich or too lean without taking it to a shop?

 

Just got a chip from an 89 Corvette, as soon as I can I will replace the stock 88 chip and disconnect the cold fuel injector. Will post the results on here on how she idles. I also bought a set of LT1 injectors that I will use to replace the original injectors.

 

any results did you get the problem resolved?

 

Just replaced the chip, but I cannot get the damn cold start valve disconnected, can anyone tell me if it is safe for me to just snip the two wires running to it and then tape them up? Or do I need to remove the entire cold start valve? So far it still runs crappy when cold, maybe I need to drive it around a few times for the compute to reset and reprogram itself with the new chip?

 

Disregard, finaly got that cold start injector disconnected! Wow the car idles much better, but still a little rough (the fuel filter needs to be changed....my next project, also have to replace the EGR valve)

I highly recomend anyone that has a TPI with a 88 and earlier computer code to follow my steps.

1) order a 89 or newer chip: http://tpiparts.net/82_92_ecm_and_prom

2) disable the cold start injector (unplug it or remove it completely)

3) clean intake components

4) replace or clean the IAC (idle air control motor)

5) replace the EGR valve

6) replace fuel filter and spark plugs, air filter, cap, rotor, wires and oil.....anything that is considered "usual maintenance" on the motor

7) check for vacuum leaks

May I suggest we make this a sticky considering many Thirdgen owners have this idle problem.

Thanks to all who have helped me out with this pain of a project.