91DropTopTA

I finally got my scantool in today and now I'm trying to figure out what is wrong with this thing. I need some answers to a few questions if anyone has some ideas.

1. How much is the O2 sensor volts going to move with a good sensor. I know the engine is running rich, but the reading is only staying at 998 and moved once or twice to 988. Is this indicating a bad O2 sensor? I wired in a 3 wire when I put the headers in.

2. Why does the oil temp read -38.6 ? Is it actually reading anything, since there was no oil temp sensor?

3. I have knock sensor 5, and knock sensor retard 4. What does the 5 represent?

I know these are some questions that have probably been asked a million times. I have been wearing the search button out, but I need some help to get the TA on the road. Thanks.

Grumpy

At anytime other then WOT when fully warmed up the Os voltage should swing from less then .3 volts to over .7 volts as the ecm toggle the injector timing to AVERAGE 14.7:1 AFR. If it stays steady at some high voltage, then the engine is very rich or the sensor's died.

Maybe an oditty in the scanner or you have a vette chip in the car.

91DropTopTA

If the car is running really rich will the oxygen sensor voltage not change at all? I initially thought I had a bad sensor because it was stuck at 998 then I turned the fuel pressure down and it changed to 988. It doesn't vary at all, it just stays at 988. I thought it was supposed to vary some as the engine ran, but it doesn't change at all.



It runs great until the thing goes into closed loop. Then it starts to idle very bad and bog on acceleration.

Ok, update. I ran it today, and tried turning the fuel pressure down after it warmed up and went into closed loop. Well, the driveability became horrible. The lower the fuel pressure the worse it ran. So I tried turning it up to about 38. Well then it runs pretty good, but still bogging down low. After I drove it a while it went back into open loop. What will make it do that?

The thing is supposed to be running dead rich according to the 998-980 O2 sensor volts. It is at 480 volts when the engine is off. If the thing is so rich, why am I getting a knock sensor count of 9-12 and only about 0-7 degrees of retard?

I picked up a new o2 to try out, and I'm going to check all my knock sensor connections in a couple of hours when it cools down, but if anyone has any ideas I would love to hear them.

kevinc

Hang onto your old O2 sensor when you swap it out. Abnormally high O2 voltages, although the engine's running lean, are indicative of a poisoned O2 sensor in some cases. If coolant or non-sensor-safe silicon gets on it, the sensor will report higher than calibrated voltages causing the ECM to pull fuel out, causing the engine to run lean and run poorly.

If your old sensor has white, grainy deposits on it, poisoning is suspect. Could just be someone used silicon spray to hose down your intake ducting, or could be as bad as a blown head gasket leaking coolant (which has silicates) into the combustion chamber(s).

87350IROC

iTrader: (2)

Dude, the stock fuel pressure is 45, I would try it at atleast that high.
JP

91DropTopTA

Does anyone know what would cause a code 43 with a brand new knock sensor? I checked the voltage at the wire and got 4.69 volts. I'm getting knock, but what I don't understand is that the block learn is staying about 126-130 and the lean/rich flag bounces between lean and rich constantly. O2 is moving from 0 to 750 and never gets above 750 or so no matter what the throttle position is. Am I getting false knock? I get counts of 8-10 usually with 0 degrees retard until I get into the throttle when it jumps to 20. Is the engine really running this rich, or is something wrong with the knock circuit?

KYL98

My car continued to do that after a poisoned or dead 02 sensor....it made it run so rich. I reinstalled a new sensor, and it actually ran worse. Come to find out, my plugs were completely fouled....couldnt burn the fuel. Try checking the plugs if you havent already. Id go ahead and change out the knock sensor......I think the sensors are "lazy" as they get older, kinda like an old 02 sensor. ALso, check the EST circuit for shorts....or to make sure its working properly. Hope this helps........

91DropTopTA

That's my problem, I put in a brand new O2 and it's working, I have a brand new AC knock sensor I put in during the engine swap. I figured it would run a little rich until I could get a chip made, but I didn't think it would be hitting 20 on the timing retard. My block learn is staying around 128 and the rich lean flags are bouncing between rich and lean. The O2 is running between 750 and 0, but I can't figure out if I'm actually getting knock or getting false knock.