vortech305

I've checked every wiring and its ok, Found out AIC was no working. Replaced it and adjusted and it ran fine until it was suppose to go into close loop, then it rattles and just dies. I cant seem to find the problem. Could it be the O2 sensor? Im gonna use a Snap On Scan Tool, but i cant get ahold of one till next week. If anyone has had this problem or any info please let me know. thanx

vortech305

dont everyone go on and post all at once:nono: :sillylol:

jkris53406

iTrader: (5)

This does sound like an O2 sensor. If it is stuck rich it will lean the fuel until the car dies. Otherwise the only other sensor that could affect the car like that is the temp sensor fooling the computer to think it is running way to hot. this however is fairly unlikely considering it runs fine until closed loop operation. Just my 2 cents. Good luck.

Brian'sIROC

If you have a MAF, that could also be your problem. When my MAF went bad the car ran fine until closed loop. 92 Camaro's didn't have a MAF, but I noticed your sig said TPI swap.

Ed Maher

MY CTS is currently on break right now, my dumb *** managed to break the connector off while messing around under the hood.

Anyhow, i had to take it in to get tires today, so rather than leave it disconnected and the SES light on, or leave in the 'operating temp' resistor i use for cruising (which doesn't letit cold start) i put in a resistor to make it think it was 50'. Figured that would be OK enough to drive, keep the SES light off and still let it start.

Well, in the space of maybe a 10 minute drive to work it was basically fine. In the last 1/2 mile on my way to work though it started to load up really bad from the enrichment. To the point that it stalled and didn't even want to restart and i had to swap in my normal resstor to get across the parking lot.

Moral of the story, a stuck low CTS will work OK enough on a cold engine and then screw you all up when you warm up.


Still, tahts just guessing. Gte it on the scan tool and you shoudl be much better off.

vortech305

thanx guys, the motor is a 87 TPI, I did remove the screens on the MAF and the Coolant temp sensor is about a year old. When i had the Scan tool hooked up it read the MAF's Flow and all, but i dont know if its off specs or not....

vortech305

last TTT

AaronIROCZ

iTrader: (5)

It really doesn't matter how old the CTS is, I had a brand new one for my new engine and it worked once and died, I swapped in the old one and it works great.

vortech305

I have this vacuum gauge and at idle it reads between 300mmHg to 400mmHG(On the gauge at 400mmGH it says "Late on Timing") The needle Fluxiates to 300mmGH - 400mmGH, not rapidly but in consecutives seconds. Could this indicate a vacuum leak?

scorp508

Unplug the MAF completely and see if the symptoms stops. I'll assume the ECM for your '87 TPI works nearly the same as my '87 TPI vette. When the MAF is unplugged it will use a reference chart stored in the ECM PROM. The car can and will run without a MAF signal. If the car cleans up some maybe it is that, if not then I'd move on.

I'm going to guess O2 sensor at this point. I had one that was 3 days old die on me completely without warning. As soon as the car went closed loop the thing freaked out and would buck and fart all over the place horribly. I was stuck about 70 miles from home when it happened which made for a really lousy ride home from the dyno shop. Especially when I didn't know what had happened. I thought I had somehow broke the car on the dyno. Then I noticed one wierd thing that led me to the cause. In a fit of anger I went WOT and the car pulled hard and clean to 6300 like it always does. This made me say WTF a few times. I tried it over and over. Every time the TPS was moved enough to put the car into WOT mode the thing ran clean. Ah ha!!!!!

If you can keep the car running long enough try this test. Get it in closed loop and get it onto the street and go WOT. If the car pulls like a motha' then you've solved it. In power enrichment mode (WOT) the O2 sensor is completely ignored by a TPI engine and it runs strictly on hard coded values in the PROM.

Give it a shot if you can.


p.s.

If you get ahold of a scanner soon this is what I saw on mine to verify it was the O2 sensor. In open loop the O2 sensor moved around a little like it should before closed loop when the ECM isn' reading off of it. As soon as the car warmed up and got into closed loop the O2 sensor stayed at 9 and didn't move. Not one single value did it budge. So at that point I knew the O2 sensor was fried. At idle in closed loop your O2 sensor should be looping through 900 to 0 over and over again (or is it 1000 to 0, doesn't matter you get the picture).

vortech305

Thanx man, i'll def. look into it. I was told that maybe the cam is bad cause of the reading with the vacuum gauge. I pray to *** that this isnt the case. The car isnt streetable yet, since its awaiting a t-56. Judging by the Air/fuel meter the car is running "RICH". I did order a O2 sensor from a 91' ZR1(3wire heated O2 sensor) and plan on using that. Once thats installed, im gonna put the timing right on tap and go from there. I'll def. do and check out what you referred. I just hope this isnt anything mechanical.

vortech305

Just wanted to let you guys know that the 02 was bad, I replaced it by converting to a 3 wire heated O2 and problem was as good as gone. Of course with my luck it'll prob. return within a week.

scorp508

Good job.