'92 LT-1

Was running fine and then all of a sudden got in it one morning and pulled out of driveway and BAM it started choking and then quit and SES light came on.

Checked code and got "22" TPS low voltage.

Had it hooked up to a Tech I and all seemed to be okay but then it started acting up. At idle, TPS voltage went from .68 volts to 0. When this occured, that was when it would start acting up again. Replaced TPS sensor on Throttle body and same results. Unhooked the Interface module that has something to do with TPS ARS and Anti-lock. Was wondering if it was somehow interfering with the voltages. Nope, same as before.

Could the main computer be going bad? What can cause a sudden and unexpected surges and flatlining of TPS electrical. Lights in the car and dash do not show signs of fluxuation.

This whole situation is hard to understand completely without seeing the car. Just wondering if someone else has had similar issues. If they have, they will know exactly what I am speaking of.

Thanks!

 

Tap on the ECM firmly and see if you get a change at idle...

 

Zero volts? Hmmm.....

With the connector attached, backprobe(key on-engine off-KOEO) and check each wire. One should be a 5 volt reference signal, one should be ground, and one should be sensor output voltage. With the backprobe hooked to the output wire (around .6v KOEO) check the reading on the tech one. The tech one voltage is what the computer is seeing, the backprobe out on the sensor is what is there. The ECM provides the 5 volts, and then "reads" the voltage on the return side. If the 5 volt reference signal is not being provided, then the return voltage naturally drops to zero. I would try to find out if 5 volts is being supplied, if there is a return voltage at the connector, and finally, determine if the computer is "seeing" the correct voltage.

Also, check the connectors. Wiggle test the connector and check for a voltage drop. Ya never know.

As stated above, if you suspect the computer, "tap" test may yield some good information.

Let us know.

dlmeyers 90 coupe zf6 3 speed shocks

 

Drove the car to work today (20 mi.) with no problems. Left work and drove to a friends house started acting up after about 10 miles. Was acting up at his house so I took that opportunity to try the wiggles and tap test to the ECM. At first it seemed that maybe it could be. Well it turned out to be a coincedence. After a few minutes, the car starting running smooth and I tried wrapping on the ECM and wiggleling the wiring harnesses. Nothing. Ran fine for the rest of the evening.

When it acted up at my friends house, the "Service ASR" came on and the the SES light which of course was a "Code 22".

This thing is going to be the death of me!

Did I mention that this is my daily driver?

 

sounds like you are losing the 5V reference voltage, or possibly the sensor ground.

 

Hate to sound like an idiot, but, I will have to get assistance from my Doctor (Dr. Evil) on the electrical trouble shooting. I hope to get to the bottom of this soon.

I'm going beezerk.

I feel like I'm driving the Titanic!

 

Went to leave work today and started the card. Fired right up as usual an then quit as if I just turned the key back off. Will not even run now. Looks like the "Dr." is going to make a house call. Good thing he is on call now.

Time to do some voltage checks!

 

Abbreviated version:

Thought it was the ECM. Bought one. Installed.

Acted up with new ECM installed for about 5 minutes. Then all of the sudden it ran fine. I chose to drive 20mi. home. No problem. Drove to work the next day and started acting up again. Quit at work.

Called Gordon Killebrew. Discussed. Think possible grounding problem. Time to chase the disappearing electrical problem.

This will be the death of me!

 

If not by your car its gonna be by me

 

One way or another!?

 

Gotta love these kinds of problems. Check my injectors/ECM posts. It is very frustrating when you can't figure it out!!!

 

Well, I DUNNO!

Took Grape8 to the operating room(had no problem getting there). Tried periodically over a few days letting it run to get it to act up. Nothing! Went over a couple of nights ago and began exploratory surgery. Could not duplicate the error. We decided that maybe through some divine intervention it had been cured by a miracle!
I also had discussed a battery angle before hand so I had a new battery to put in it as well. We tried the trouble shooting before the battery install. The only thing that stood out to me is that there seem to be some signs of bad battery at one time or another and the grounding post had moisture inside of it. Regardless, I put the new battery in and I've been driving it ever since. Waiting for it to leave me stranded.

Wish me luck!

 

Here we go!

After replacing the battery, the doctor (EVIL) noticed that some damaged may have occured to some of the plastic coverings around the battery. Being late + my frustration = Let me just drive it and see. Well, it seemed to run fine for a while but then began having problems again. I stopped to see some friends one day at lunch as it began acting up again and we went back to the battery area again. This time in the daylight, we were able to see that a part had been all but destroyed by corrosion. Hmm! What does that go to? Another breakthrough was that the weather in the last 2 months has been mostly dry for long periods of time. I noticed that the only time I had problems was immediately after I washed the car. Very interesting! A couple of days later I disassembled the whole side where the battery is and inspected all the wires. The wire that had the connector that was destroyed just so happens to be the 12v wire that feeds the ECM. When I tried to take the connector apart, everything basically crumbled in my hand. Once I had all the plastic removed, the actual connector was corroded beyond belief. This could definately by the source. I removed the connector all together and soldered (sp) the ends together, covered them with automotive silicone, and then covered with heat shrink. I have had no problems since and the true test came 2 days ago when I drowned the car at the car wash. The battery area is exposed through the side vents on the body and I'm sure that is why it would act up when the car was washed or exposed to heavy rain or morning dew. I have been the most optimistic about this fix because of everything involved. I will try to post the pictures later of the connector.

Thanks to all for the imput and I hope that we all make a mental note as to what caused all this mayhem. Especially since the battery issue seems to be issue with C-4s as well as C-5s. The proximity to important wires plus the leaking of the side post battery.