tdaaj Posted June 19, 2007 Report Share Posted June 19, 2007 have an 89 trooper, 2.6, 5spd, and am having trouble getting it to idle correctly. any way i can check the throttle positioning sensor? was told it might also be the maf sensor too. is this possible? i'm also running a cone style k&n air filter that is in need of cleaning also. any ideas would be helpful. also, engine is a 91, i just replaced the head gasket about 250 miles ago. i replaced the egr about 2 years ago and the idling problem was there beforee i did the head gasket. i've replaced both maf and tps, maf was used out of a running vehicle. tps was new. this is a fuel injected multi? port engine. any ideas? i've also replaced the airfilter. Quote Link to comment
datsunaholic Posted June 19, 2007 Report Share Posted June 19, 2007 The TPS is tested with a multimeter- you just check each terminal and ensure it makes contact at different spots (usually they're just a multiposition switch, though some systems had switched to a potentiometer so it would only have a couple terminals and have a ohm range. But I don't think Isuzus used that type). Normally, poor idle (and no other obvious symptoms) on those is simply a case of air hoses that are cracked/ leaking or not sealed well. Essentially, ALL air has to go through the MAF, so you're looking for a leak between the MAF and the throttle body. A leak causes the system to go lean, but at higher air flow (off idle) it doesn't show up. Quote Link to comment
Icehouse Posted June 19, 2007 Report Share Posted June 19, 2007 91 is OBD 1, you should be able to check the codes on the ECU without a code reader. Nissan has a flashy light, I'm not sure about your trooper. You FSM should have something about it. Is it a ruff idle or just low? You should have an idle air control valve, on the valve there will be a adjustment screw, if you idle is just low you can bump it up there. You should also have 8" or more inches in-between the k&n/maf and your throttle body, if it is less it will get a bad reading. I would check the ECU for codes first, if it says everything is A OK I would check for vacuum leaks. When was the last time it had a tune up? I always do a full tune up before diagnosing any EFI problem. Quote Link to comment
datsunaholic Posted June 19, 2007 Report Share Posted June 19, 2007 It's a '91 engine- the trooper is a '89. Last I remember it was rough as in the engine vibrated at idle (like it was running on 3 cylinders) and inconsistent. But it's been a while since I've been in it. Quote Link to comment
tdaaj Posted June 19, 2007 Author Report Share Posted June 19, 2007 its still acting the same doug. i've tried just about everything, but i'm sure its something i missed it idlesbetween 400-2500 rpm. Quote Link to comment
Icehouse Posted June 19, 2007 Report Share Posted June 19, 2007 Check the FSM for codes and get back to us. Quote Link to comment
71-521 Posted June 20, 2007 Report Share Posted June 20, 2007 factory service manual... Quote Link to comment
tdaaj Posted June 20, 2007 Author Report Share Posted June 20, 2007 yeah uhm, about that.......... Quote Link to comment
Icehouse Posted June 20, 2007 Report Share Posted June 20, 2007 you don't have the service manual!!! ThThey have it on CD Quote Link to comment
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