Tweet
Hi folks, new here. Here is what I am working with:
1991 Isuzu Trooper, 5-speed. I swapped the 2.8V6 out with a 3.4 from a 1995 Pontiac Firebird. While the motor was out, new cam, new timing, new pushrods, roller rockers, etc.
Then I got a bored out intake from 'betterthanyou' and installed it. Also got a 4.3 throttle body on top and a 4.3 injector pod from a seller on eBay (note, this might be part of the problem).
Following betterthanyou's instructions from here:
I set the idle speed and TPS minimum voltage. I drove around like this for months, with little trouble. Then it was time for emissions. I realized that my idle speed was a little high (like 1200-1300) and I wanted to lower it to the "proper" range before I got my emissions checked. So I went through the process of adjusting the idle and TPS minimum voltage again. This time around, I could not get the TPS minimum voltage to set and it was VERY hard to get my idle down to even 1000 RPMs. After this, I also started throwing CELs indicating "Throttle Position Censor Voltage Out of Range" or something like that.
So, I have been struggling with this for a while now. About a month ago, I worked on it a little more, and I seemed to get the idle to stabilize even though I could not get the voltage even close to .50. My voltage reads out more like .7-.8. During the process I did change out the MAP sensor and also the TPS. Same issue.
This morning it was chilly, got up early, started driving the Trooper and it was sputtering and the idle was all over the place, surging high then dropping really low and it died about 4 times within the first 2 miles. Once it warmed up, it seemed a little better but this was the worse its been in a while.
So, I am wondering about what I can do. Of the top of my head I am wondering:
1) Is the 4.3 injector pod I got off eBay bad? When I got it, I did get a rebuild kit for it and it looked fine and performed well for some time.
2) Is there something wrong with the idle set screw and spring causing this problem? No matter how much I turn it one way or the other, I just can't seem to get the idle down to around 800 where I want it.
3) Getting the voltage to where it should be seems pretty much impossible at this point. I've notched the screw holes on the TPS so I could rotate it more, but its still not even close.
So, where do you guys think the problem is coming from? This morning with all that trouble I got no CEL, it just drove like crap. I was thinking maybe a vacuum leak, but wouldn't I likely get a CEL if that was the case?
Any suggestions? What parts should I start throwing at it first?
Thanks all!!!
Bart
1991 Isuzu Trooper, 5-speed. I swapped the 2.8V6 out with a 3.4 from a 1995 Pontiac Firebird. While the motor was out, new cam, new timing, new pushrods, roller rockers, etc.
Then I got a bored out intake from 'betterthanyou' and installed it. Also got a 4.3 throttle body on top and a 4.3 injector pod from a seller on eBay (note, this might be part of the problem).
Following betterthanyou's instructions from here:
I set the idle speed and TPS minimum voltage. I drove around like this for months, with little trouble. Then it was time for emissions. I realized that my idle speed was a little high (like 1200-1300) and I wanted to lower it to the "proper" range before I got my emissions checked. So I went through the process of adjusting the idle and TPS minimum voltage again. This time around, I could not get the TPS minimum voltage to set and it was VERY hard to get my idle down to even 1000 RPMs. After this, I also started throwing CELs indicating "Throttle Position Censor Voltage Out of Range" or something like that.
So, I have been struggling with this for a while now. About a month ago, I worked on it a little more, and I seemed to get the idle to stabilize even though I could not get the voltage even close to .50. My voltage reads out more like .7-.8. During the process I did change out the MAP sensor and also the TPS. Same issue.
This morning it was chilly, got up early, started driving the Trooper and it was sputtering and the idle was all over the place, surging high then dropping really low and it died about 4 times within the first 2 miles. Once it warmed up, it seemed a little better but this was the worse its been in a while.
So, I am wondering about what I can do. Of the top of my head I am wondering:
1) Is the 4.3 injector pod I got off eBay bad? When I got it, I did get a rebuild kit for it and it looked fine and performed well for some time.
2) Is there something wrong with the idle set screw and spring causing this problem? No matter how much I turn it one way or the other, I just can't seem to get the idle down to around 800 where I want it.
3) Getting the voltage to where it should be seems pretty much impossible at this point. I've notched the screw holes on the TPS so I could rotate it more, but its still not even close.
So, where do you guys think the problem is coming from? This morning with all that trouble I got no CEL, it just drove like crap. I was thinking maybe a vacuum leak, but wouldn't I likely get a CEL if that was the case?
Any suggestions? What parts should I start throwing at it first?
Thanks all!!!
Bart