92-95 CPI - Failed emissions test, many codes, missing info

Hello everyone,

I have had my 88 s10 with the 4.3L in it for just over a year now. It runs great, but has a rough idle, that almost likes to stall some times for a split second, then picks back up. The year of the engine is unknown.

I have replaced plugs, wires, cap, rotor, FPR, Fuel pump, fuel and Air Filter, Battery since I have owned the truck. For the whole time I have had it, I randomly get a SES light flicker on here and there, or stay on straight from key on. Sometimes I won't have it at all.

I have recently failed my etest of the HC @ idle. Here are my results.

40 km/h test

type limit Reading Result

HC ppm 95 73 Pass

CO % 0.53 0.04 Pass

NO ppm 1048 388 Pass

idle test

type limit Reading Result

HC ppm 200 211 Fail

CO % 1 0.22 Pass



I have ran my code test and this is what I get.

22 tps sensor signal voltage low
34 map sensor signal out of range, low
37 TCC brake switch circuit error (my brake light sticks, I got rid of this before)
43 knock sensor or electronic spark control circuit fault
45 oxygen sensor rich exhaust

I have had the knock sensor code for quite sometime, and had it before when problem solving other issues, so I picked up 2 new ones to replace today. How ever when I went to take the driver side one out, the inside portion of the sensor just spun in its outer casing. So what the hell do I do now to get this one out? Also, where does the blue wire that runs from both of these senors go to? Just so I have an idea where to trace it.


Also, I was told that there are 4 o2 sensors on this engine. One past each exhaust manifold, one before and after the cat.

Now maybe it was just the person who put the engine in and did all the custom work before I purchased it, but there is only 1 o2 sensor just before the cat. What will this affect in terms of the computer controlling variables, and what can I do about this?

I tested my TPS sensor a couple months ago and had a .6 to 4.3V rating, and never had a MAP code. I will have to retest these sensors and post the results.

Thanks

Hello everyone,

I have had my 88 s10 with the 4.3L in it for just over a year now. It runs great, but has a rough idle, that almost likes to stall some times for a split second, then picks back up. The year of the engine is unknown.

I have replaced plugs, wires, cap, rotor, FPR, Fuel pump, fuel and Air Filter, Battery since I have owned the truck. For the whole time I have had it, I randomly get a SES light flicker on here and there, or stay on straight from key on. Sometimes I won't have it at all.

I have recently failed my etest of the HC @ idle. Here are my results.

40 km/h test

type limit Reading Result



HC ppm 95 73 Pass

CO % 0.53 0.04 Pass

NO ppm 1048 388 Pass

idle test

type limit Reading Result

HC ppm 200 211 Fail

CO % 1 0.22 Pass



I have ran my code test and this is what I get.

22 tps sensor signal voltage low
34 map sensor signal out of range, low
37 TCC brake switch circuit error (my brake light sticks, I got rid of this before)
43 knock sensor or electronic spark control circuit fault
45 oxygen sensor rich exhaust

I have had the knock sensor code for quite sometime, and had it before when problem solving other issues, so I picked up 2 new ones to replace today. How ever when I went to take the driver side one out, the inside portion of the sensor just spun in its outer casing. So what the hell do I do now to get this one out? Also, where does the blue wire that runs from both of these senors go to? Just so I have an idea where to trace it.


Also, I was told that there are 4 o2 sensors on this engine. One past each exhaust manifold, one before and after the cat.

Now maybe it was just the person who put the engine in and did all the custom work before I purchased it, but there is only 1 o2 sensor just before the cat. What will this affect in terms of the computer controlling variables, and what can I do about this?

I tested my TPS sensor a couple months ago and had a .6 to 4.3V rating, and never had a MAP code. I will have to retest these sensors and post the results.

Thanks

You nee to work on map and tps sensor problem first.
Always confirm good vacumn to map sensor.

On knock sensor is thre a 9\16 nut close to where it screws in?

If not vise grips or chanel lock piers work good.

88 only uses one 02 sensor.
Knock sensor blue wire goes to ESC module.
[electronic control module]

I don't see a nut near it, other then another Temp sensor thats not plugged into anything.

There is no way I can fit channel locks into there to grab it well enough. I was thinking of putting a self taping screw through the outtershell into the center, and then undo it.


The ESC the big rectangle box mounted by the brake booster? I'm trying to understand how they used the 88 ESC on a completely different engine. What does it actually do?

I notched the plastic holes on my TPS and adjusted it back a little bit. I get a .45 to 4.34 reading now which is better. And made sure that my throttle fully opens and closes. The cruise control was preventing it from reaching WOT by about a 1/4 from the plastic shield. But since mine doesn't work and I would never use it, I disconnected it out of the way.

I don't see a nut near it, other then another Temp sensor thats not plugged into anything.

There is no way I can fit channel locks into there to grab it well enough. I was thinking of putting a self taping screw through the outtershell into the center, and then undo it.


The ESC the big rectangle box mounted by the brake booster? I'm trying to understand how they used the 88 ESC on a completely different engine. What does it actually do?

I notched the plastic holes on my TPS and adjusted it back a little bit. I get a .45 to 4.34 reading now which is better. And made sure that my throttle fully opens and closes. The cruise control was preventing it from reaching WOT by about a 1/4 from the plastic shield. But since mine doesn't work and I would never use it, I disconnected it out of the way.

ESC box is usualy on fire wall wired to dist.
It controls spark advance.

On knock sensor it may be best to leave old one there as it screws into water jacket on block.

With a pipe fitting welder to a angle iron it can be mounter soled to block or heads.
Some 4.3 v6 enven screw them into back of head.

Be sure to repair map sensor problem.
That can cause engine to run real rich or lean but usuall rich.

There should be no tempt sensor near knock sensor.
Knock sensor screws into lower middle of block where block drain plug used to be.

You must be thinking of another engine then.

There is a temp sensor right above the knock sensor on the driver side between the 3/5 cylinders. I pulled it in order to get channel locks on the knock sensor, and was able to replace both of those today.

Timing has been checked and fine. We adjusted the TPS a little bit (position) for a better reading. It now reads .55 to 4.45V and runs the engine alot better. Knock sensors have been replaced the the SES is now gone after pulling the terminal off for 30 seconds.

Theres a couple odds and ends I have to take care of like cleaning the EGR valve and add my cold air intake along with some new valcum lines.


The truck runs a lot better, how ever the shifting on it is where its losing its power. It seems like the engine revs up but does nothing for a second or two untill it kicks in gear in the low end or from mid power to an instant WOT. Also, it seems like the tranny hangs at a high rpm between some shifts. Fluid level in it is fine, and its clean.

You must be thinking of another engine then.

There is a temp sensor right above the knock sensor on the driver side between the 3/5 cylinders. I pulled it in order to get channel locks on the knock sensor, and was able to replace both of those today.

Timing has been checked and fine. We adjusted the TPS a little bit (position) for a better reading. It now reads .55 to 4.45V and runs the engine alot better. Knock sensors have been replaced the the SES is now gone after pulling the terminal off for 30 seconds.

Theres a couple odds and ends I have to take care of like cleaning the EGR valve and add my cold air intake along with some new valcum lines.


The truck runs a lot better, how ever the shifting on it is where its losing its power. It seems like the engine revs up but does nothing for a second or two untill it kicks in gear in the low end or from mid power to an instant WOT. Also, it seems like the tranny hangs at a high rpm between some shifts. Fluid level in it is fine, and its clean.

Good luck and let us know how it goes.
Getting the engine running good may help transmission.
The shold be a pressure cabel adjustment on throttle body to adjust and fine tune shifting.