LilJayV10

How important is the intake air temp sensor? I had it on a scanner before and noticed it was at almost 260 degrees. I just now remembered that.

LilJayV10

We worked on the car again this week and got it running this afternoon. Put new plug wires on it and a borla exhaust, which was unrelated to the problems the car was having. But it was up in the air on all fours so it finally got finished.

Replaced the ignition module on the cylinder head under the coil.
Car ran great as usual for about 15 minutes. Then started bucking and missing.
Put it on a snap on scanner while it was running bad.
ECT sensor said it was about 94 celcius, the worse it runs the hotter it gets, or vise versa. it seems to be working correctly.
O2's seemed to switch slow, BLM were about 115-122, both sides didn't switch the same, neither did the pulse width on the injectors.
When it was running really bad it showed both side injector faults. After it sat and cooled down, it ran fine and no injector faults.
I checked the lo res on the opti, the waveform looked fine.
checked the hi res, the scanner said it was supposed to be 4-4.5 at idle and the car was 2-2.5. Don't know if thats part of it or not.
I about didn't make it home again. I had to drive it extremely hard to keep the rpms up so it would run. it got so bad it didn't matter I had it to the floor,5mph the last mile.
Once the car cools off for a while. It's fine again. It has to be something under the hood heating up and breaking down. I just don't know where to go next.

FlyboyZ28

Just to keep the thread updated we were using the Air Tem Sensor on the bottome of the K&N filter and now we are using the one on the intake elbow and it is reading correctly.

I have searched the boards for something about the injector fault that we are getting. That seems to be the problem on this car becasue we only get that error when the car is warmed up and is running bad. We don't get it when it after it has cooled off.

What bad part would cause an injector fault? Can the PCMforLess Tune go bad?

Thanks

Mushijobah

My car is doing a similar thing. It started on the freeway during rain and hasn't been the same. I was running it pretty hard until I hit the rain. It misses badly at low rpm's but never gets as bad as what you are describing. It bucks horribly in 6th at almost all speeds due to the low rpm. Nothing is coming up on the obdII as far as a miss in a certain cylinder. I appreciate you updating us, it gives me more ideas on what i can check.

FlyboyZ28

In your situation it sounds a lot like the optispark. And at this point that is the only other thing that we can think to replace. I want to make the opti a last resort kind of repair, but we are kind of out of ideas.

FlyboyZ28

I recieved this from a guy on the Speed Density Message Board. I was wondering if this sounded right to anyone. The car does have a few month old autozone alternator on it. I wonder if that went bad since it was a reman.

Thanks

FlyboyZ28

ttt please

LilJayV10

I was told that the tach could cause miss problems, and a way to check it was to cut the tach wire and see if it took care of it. I cut the tach wire and the now the car won't start. If you are looking at the coil from the front, there is a plug in on the left and right side. If I unplug the the plug on the left side(towards the passenger side)and leave the right side plug on, there's a pink wire that has power to it. I checked the coil for voltage on the left hand side and it has power everywhere. Now I have a 94 formula parked next to it, I check the same places on the coil and it doesn't have power on the left side of the coil, with the right side plug in. This is all done with the key on.

Is this right? I am still trying to figure out what in the hell is wrong with this car. I don't know where to start looking.

I know this is an old thread, but I am still trying to get it running right.
Jason

F(ast)-body

My car is doing EXACTLY the same thing as you describe....not that it helps but at least your not alone.....I've already done the coil and ICM...didn't fix it...tomorrow I'll play with the O2's....haven't done anything with the heat sensor yet....maybe together we can figure out this aggravation....

seawolf06

Mine's doing the same thing, except it's all the time, even cold. That's why I figured it wasn't the O2s, although I'm replacing one anyways cause it was reading a little off. The entire ignition is aftermarket, including the MSD opti, so I really hope it's not that. Did a datalog and the big thing I noticed anbout mine was the LBLM was 108 while the RBLM was 160! Subscribing to this thread.

Guest47904

Never EVER buy electrical items like an alternator or a fuel pump from places like Advance or AZ. They are the worst and will not last long at all. Lifetime warranty or not.

If your alternator were the problem you could easily measure the voltage across the battery with the engine running to be sure it is at least 14 volts. Check it with no accy's on then turn them all on and measure again. Don't forget that poor connections like the positive, negative clusters and the frame strap can also give you the same symptom.

One little update for you. I'm having the same problem when mine goes into closed loop, it richens up and runs like crap. Almost stalls when coming to a stop. The long and short term fuel trims are maxing out. I suspect a bad MAF which I will test later today. It's easy to check with a simple multimeter that reads frequency.

LT1_383

It's possible when the engine warms up the injectors warm up with it and creates a short in the injectors. Try measuring the resistance of the injectors before the car warms up, and then once the car warms up and starts acting up. We had a c4 vette in our shop a few months ago with this problem. It wasn't nearly as bad as what your describing but it ended up being 2 bad injectors on one bank.

Gripenfelter

Try swapping out the temp sensor in the water pump.

seawolf06

What should the resistance be at the injectors?

LilJayV10

I appreciate the ideas. I really do. The car hauls *** till it warms up, then it's sad. So should cutting the tach wire kill the car completely?