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Discussion Starter · #1 ·
seems like the engine idles fine the first start up of the day. Then if I have to stop, it either idles high (1500-2000rpms) or idles low (500-600) and sometimes stalls which is odd because it is automatic. 1989 isuzu trooper SE 4cyl 2.6L. Showing multiple stored DTC and the light comes on very intermittently.

DTC12=normal, communication made
DTC32=EGR failure
DTC44=lean fuel mixture sensed.

A little more background, many vacuum lines are split, so I've replaced a few and am just going to replace them all and clear codes just in case this is the problem. I also found a hose not even connected to a vac switch on the drivers side fender near MAF. A split vac hose could be my idle problem. Another was split at EGR which could very well be my EGR dtc. The only real concern I have is a fuel smell. The computer is detecting a lean mixture and when I fuel up, I can smell fuel. I don't understand why. I have checked the fuel supply at the engine and don't see anything leaking, lines appear to have pressure, and I just ran sea foam hoping that would help. I'm really hoping this is a fluke and clear up when I replace the vac lines.

The reason for this thread is informational, I checked the forums to see if there was something common about this or even to find out what these codes meant and couldn't find anything. Hopefully this will help other trooper enthusiast. I will update once vac lines are replaced.
 

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Discussion Starter · #2 ·
so far it is getting better. i've been tracing lines and replacing them. i ran out of line so wasn't able to replace all but the idle is improving. there are only a few old lines left and i'm worried once they are replaced, it will not fix it. if thats the case, next step for me is an intake manifold gasket. my thinking is the troop is getting extra air at the intake that isn't registering with the maf and that is why it is getting that lean code. its a matter of vacuum leak i think. another development is a fuel smell. everytime i fuel up, i smell fuel in the cab. it goes away after a while. but it came about while i was at the dunes idleing on a steep grade (potty break on a tree with my little boy). i thought it was maybe the filler tube at the gas tank, but i checked it after fill up and it was fine. so i'm wondering if its the actual connection at the filler.
 

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On my Pup the gasket on the top of the fuel tank where the pump is, started leaking. It leaks a bit when full on a slope, as I run the tank down it gets less and less. And I agree you have a vacuum leak also. Try and spray some WD 40 around the gasket area, if you change the idle then you found the problem. This is how I found an intake manifold vacuum leak on my V6 Trooper. And I had surging idle and high RPM. Still haven't fixed it but I know where the problem is now.
 

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Discussion Starter · #4 ·
thanks hessmess, I'm still working on it. I got most of the lines replaced and i have no more surging, also found a missing line on the egr valve and put one on. The lean code went away too so now no more codes. The only thing now is for some reason, if i start it one, its ok. then say i park, then start up again, it idles at like 400 rpms until it warms back up then it runs fine. I just don't have enough time or i'd do a full top end reseal. Plans are to do head gasket, timing belt, water pump, ex manifold and hopefully header, intake manifold, and hopefully cam. Maybe a little homemade port match also, but i will have to wait until summer. I live in florence, oregon and have no garage. how does the cam in your 91 do for ya?
 

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My cam in the 91 did help. But I had a well worn 2.8 and replaced it with a slightly built 3.1. There were so many changes at one time on that engine that I don't know what was the best mod. I haven't worked on it this winter. I blew a soft plug on the way home about a month ago and just haven't touched it since. I have a heated garage but I have been doing a complete remodel on my bathroom so I have no space to put it in there. Plus I have the Pup that I really like to drive so I use that as my DD.
As far as the cam in the 89 Pup, I think it is the way to go to increase bottom end, (cam) At about 3000 RPM it seems to loose it get up and go compared to the lower RPM. But by the time I am setting about 72 MPH so I can live with that. I really wanted the cam for low end stuff in the mountains and I am very happy with that. I am making plans to go back into the 91 and reseal the intake and fix the soft plug. I am hoping that that little sucker really comes to life once I get the vacume leaks stopped. It gave me a hint once or twice after I built it and it was impressive.
 

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Discussion Starter · #6 ·
say no more. i work, go to school, and have two YOUNG kids. my troopers come last also unfortunately. i really like my 2.6 and believe i am getting decent power out of it but I'd just like a little more. I think for me it seems kind of opposite, unless I'm absolutely haulin at about 3000+, I bog down. I'm playing in the sand, so there isn't always enough room to get up that kind of momentum. Makes me hesitant to tune it for certain situations because I'd like it to remain versatile. If I had it my way, I'd purchase a spare 4ze1 and build the daylights out of it, but no garage =(
 

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Discussion Starter · #7 ·
found the fuel smell in case anyone else has the same problem. in the filler neck which can be accessed by removing the trim inside on the right rear quarter panel, there is a main larger diameter hose that drains into the tank and one that shoots off the side. the one that shoots off the side was not even connected, after reconnecting, smell is gone. still have idle issues. will continue to hunt.
 
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