Hi everyone,

I am new to this site, and today I bought an 88 IROC Z as my DD/project car. As we were coming home, it drove fine, had loads of power. The trip home was about 45min, majority highway. It was fine until about the last 15min. First,i was going up a hill and i went to give it gas, i noticed it had very little power at all, and started acting like it was starving for gas. I let off the gas for a sec, and got back on lightly, it was fine. i kept going, just a couple min later and i get to the exit ramp i needed, put my signal on and when i went to get back on the gas the car was dead. Im coasting along so i threw it in neutral, spin it over, nothing. I stop, put it in park, push the gas pedal in a few times and spin it over, it starts up. I give it a few short bursts of gas, hoping to possibly clean out the injectors or anything that may be possibly clogged or clogging, and keep going. The tank is full, i filled it right before i left for home. we keep going and its ok, then it starts losing power again. I throw it in neutral to take the load off the engine, it takes a second but it "catchs up" and starts running ok again. put it back in gear, stalls after a couple of seconds. it ended up stalling another two times after, all within apprx 10min it stalled 4times. I did make it home, and when it was running it was either running fine, or weak like it starved for gas.

NOW.. Since you know what happened, let me tell you about the cars recent history..

The car was parked for apprx a yr 1/2. The owner had to sell it due to health problems, sold it to the man i bought it from. He drove it for a little while, parked it for almost a year, both times put away wet. The guy i got it from JUST replaced the fuel pump, and cleaned out the fuel tank, so he says. I noticed the pump squeeled when you turn the car on or shut it off. I thought only pumps that were going bad did this, he said it was an "aftermarket pump", and that it did that. Its got a full tank of fresh gas (again, so he says). Also the gas gauge doesnt work, neither does the tach. He said its probably the cluster, i think that may be so for the tach, but im not sure about the gas gauge. He said he made sure the wiring at the pump was right, and that it was. When i test drove it it ran fine, loads of power. Never stumbled, sputtered, let alone stalled. Thats whats got me confused about this. I also noticed that when the car was off the needle was a little under the 4th mark on the temp gauge, at apprx 230-235. When i put it in accessories, the fan came on and the gauge went down to abt 210ish. Which is still hot. I did not notice this until i reached my house. Would overheating cause this problem? Would it cause it to stall?

I plan to first get some spray cleaner to spray into the throttle body, and some seafoam to put in the tank too. Im praying it is something small. I'll do a tune up on it, new plugs, plug wires, maybe new carp and rotor. But does anyone have anything else to recommend trying? Any imput on the situation?

Thank you,

Adam

 

Plugs, wires, cap, and rotor may be a good idea, but in my opinion the kinds of problems you're having aren't related to that.

I'd suspect a few things:

1. My favorite - the ignition control module going out.
2. Fuel pump just being flaky
3. Oxygen sensor
4. Coolant Temperature sending unit - or the CTS.

Try unplugging the oxygen sensor. It'll throw a code and run weird as the computer resorts to a different routine to determine how to fuel the engine. Dont romp on it like this or anything - if it were supposed to run well this way it wouldn't need an oxygen sensor at all. But if these intermittent stalling issues resolve themselves this way then you may have found your culprit.

The CTS is separate from what's going to your gauge. It is a different sensor that goes to your ECM and tells it how hot or cold the engine is. If it fails, it usually fails electrically and the ECM interprets this as the engine being -273F or something like that. It dumps TONS of fuel into the engine because it thinks it's so cold, this can cause it to run like garbage for obvious reasons. Will lead to stalling unless you hold the throttle open enough for the engine to at least have enough rotational inertia to keep turning and at least momentarily enough air coming in to somewhat balance the fuel that's getting dumped in.

Ignition control modules usually will just have the car suddenly dying when warm. It just suddenly wont start because you're getting no spark. Come back later and it may or may not start just fine... and then it gets warm and will fail again. Can be very intermittent, can fail completely and suddenly, either permanently or temporarily, or it can faily slowly and only cause issues, for example, at high RPMs, etc. These usually go bad in a hurry, though.

The CTS, O2 sensor, and Ignition module are, all together, a total of about $70

Whether it's something simple or not in your opinion, I dont know, but you have a car that doesn't appear to have a serious engine issue, so to me that means it's simple. The oil is brown and the coolant is green - so it's simple. Dont fret over it too much, you'll just have to mess with it a bit to figure out what the issue is.

 

Hi, thanks for the response InfernalVortex,

I will check these things tommarow or thursday when I get the chance. I had a little time to look at it and i added fluids where needed (The radiator was only about 3/4 full, the overflow was empty, maybe this was why it was overheating a bit). I checked the air filters- I HAVE NEVER SEEN AIR FILTERS THAT BAD. They were literally deteriorating in my hands, full of dust and dirt, it was terrible. When i hit them together to try to clean them the best I could it looked like I was hitting two bricks of chalk together, no joke. I immediatly went and got new filters for it. Im sure this was part of the problems it was having. I also ran maybe a 1/3 can of throttle body and fuel injector cleaner thru it, it seemed to help a bit. I have seafoam for it just havent put it in yet. I took it for a drive today and it seemed fine (before replacing air filters,too). I dont think it got up to 200 degrees. I only drove it for 10-15min, but it never stalled or lost power, anything. Im really hoping that since the car only had about 3/4 the coolant it needed in the radiator that was what caused it to run so hot. I did top it all off and it seemed to stay at about 195. But again, it was only driven for about 15min or so.

I went to get a thermostat for the car because I figured since its been sitting for a while it probably wouldnt hurt to get a new one, but they said the OEM part is 195 degree?? I thought that seemed a bit high, my '81 TA calls for 180, and theres alot of people that run 160's in theirs. I was surprised by this. Is the 195 the best thermostat for this car? Or would a 180 degree t-stat be a better route?

Thanks for the help,

Adam

 

well?

 

Im still being careful and doing some work, but i BELIEVE it was just the TPS out of adjustment. I pulled it up a bit more (more throttle) and it would stay running and didnt sputter, miss or stall at all. I took it off, cleaned it, put it back on and adjusted it to .54V and it seems to be good to go. crisp throttle response, better idle, no stalling. I also seafoamed the heck out of it and it smoked up my whole yard to the point where we could hardly see! It helped ALOT, needless to say lol. New cap, rotor, plug wires (still gotta do plugs) also helped. But, knock on wood, i havent been having the same problems as before.

 

Damn, i already checked that on mine, i'd drive it off a cliff if it would stay running :-/