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Isuzu Trooper



  • I have an 88 Trooper II with the 4ZE1 4cyl engine, which had issues. I rebuilt the engine and installed a new head. The valves are all at .008". I set the crank timing mark on "0°" (zero), set the camshaft gear notch to the arrow on the plate, and I get spark at "0°" with the distributor set at midrange. But I'm not getting fuel injector action.
    When I crank it over it sputters but won't start. The fuel pump is new and it works if I apply power to it.
    If I set the cam sprocket two teeth advanced, the engine will start and run but the distributor is at the extreme retarded position of it's adjustment range, it runs rough and lacks power.
    Can anyone tell me why the FI works then but not when things are set according to the book?
    I also noted that fuse # 8, #10, #11 & #12 get power from the main engine relay but have no power with the key turned on, and the relay is good. Fuse #10 powers the fuel pump relay. Does that energize after the engine starts?
    Does anyone know where I can find a "Theory of operation" manual on the fuel system?
  • Hi Everyone,

    I just purchased a 94 Trooper LS. It needs some TLC as its been sitting for 8 months. I have a few problems I'm trying to collect info on.

    1. I was wondering what the avg. oil pressure reading is at 55mph, as they don't give this in the service manual or on Mitchell.

    2. I have a hesitation when the engine's cold and a whistling sound under med. acceleration(thinking a vacuum leak, possibly related to the hesitation??) I'm wondering if anyone has had a similar situation so I can pinpoint the cause easier.

    3. When shifting from 3rd to 4th the trans shifts and rpm drops, but then it rises about 200-400rpm then drops again to the normal speed (2250@55mph or there abouts). Could this be TCM or band related, the trans operates normally otherwise. I'm not very experienced with computer controlled transmissions.

    I'd appreciate any input on these matters, Thanks
  • atfdmikeatfdmike Posts: 414
    edited February 2011
    Congrats on your Trooper. Oil pressure varies with speed, rule of thumb is 10# for every 1000 RPM. I think there is something in my factory manual that references a minimum at idle and again at 3000RPM. I will look to see. The 3.2 has a real good repuatation as a good motor, but I have heard of intake manifold gaskets needing to be replaced, and your symptoms sound like classics.
    As for the trans, first off, do you know the maintenance history? If not, changing the filter and fluid is a great idea. IT is a GM made 4L30E with as you know, electronic control. One thing you do NOT want to do is get a power flush and fill on the trans unless you know the previous owner had been getting them regularly. A flush seems to be a bad thing as many owners report trans problems after doing so even in trans that never had a symptom. The thinking is that the flush dislodges too much crap and it plugs valves and check balls in the valve body.
    I suggest you get the fluid changed and filter changed and then change it again after 10,000 miles.
    As to your surge in OD, your converter is a locking converter controlled by the trans control module through a solenoid. If you drive with shifter in 3 rather than OD, and there is no surge, then likely it is in the OD circuit. I would change the fluid and filter, and give it a few miles to see if it cleans up the problem. If not, the TCC solenoid can be replaced pretty easily, assuming that is where the problem lies. When you are under the trans, the smaller pan in front of the larger trans pan is the locking converter body added to the 4L30 base transmission to make it a 4L30E. Checking the electrical connections for the trans mode switch located on the trans input shifter shaft and grounds is always a good idea, clean and tighten them, and report back. Also, this link goes to a discussion on the TCC.
    HTH One guys opinion.
  • thanks for the reply, looks like my oil pressure is good, as I'm getting about 32psi @ 2200rpm. thats one less thing to worry about. as far as the trans goes I haven't got around to changing the fluid and filter yet, my buddies own a shop and I have to work around their schedule. I was leaning towards a TCC or connector problem my self but I wanted a second opinion. as for the possible intake leak I'll have to hook up the smoke machine and see if I can locate any leaks. Thanks again
  • I have a 94 trooper with sohc. I just bought it used and noticed that the transmission was not shifting on its own. I changed the fuses and the auto shift began to work, now the transmission light comes on and I lose power. This is not all the time and happens at random intervals.

    Any advise or suggestions? :cry:
  • atfdmikeatfdmike Posts: 414
    Your trans is electronically controlled, so the voltage in your car must be right between 12 and 14 to work right. So you charging system has to be good. The grounds in your wire harness must be clean and secure. You can check the mode switch connector where it plugs into the trans harness too. Just spray connections with contact cleaner and make sure the pins and terminals are straight and clean. These are all common reasons for problems. HTH One guys opinion.
  • Thank you :) I will check it all when I get home from work. I do know that the voltage is reading between 12 and 14.

    I am just really worried that my transmission is going to fall out as I am driving home. I know I might be over paranoid... but I would rather err on the side of caution. :blush:

    Thank you again for the advice

  • auoohh35auoohh35 Posts: 3
    I need a new gast tank for my 1994 Trooper and can't seem to find any online, any ideas?
  • My son has a 91 Trooper and just this past week it wouldn't start at times. We would get the "click click click" noise when turning it over. Tried to jump it, 'nothing'... put the battery on the charger and it charged up within an hour, put it in the troop and nothing. Then an hour later went out and it started right up. He drove 500 miles back to school this weekend and it ran great. This morning he went out after class to start it and "click click click" again....

    Is this something as simple as a battery, now that he is in his college parking lot ???

    thanks so much !
  • fudgiefudgie Posts: 1
    The EMS system closed down the engine---diagnostic machine said crankshaft sensor
    sensor filed down a little--broke down again
    sensor replaced--so back to square one--except--engine wont start now
    question--does the diagnostic machine have to instruct the EMS---to reset itself somehow
    we know that this poor engine has had historic problems--by design
    the cause is probably worn crank bearings--at 49000 thats poor
    but at least the engine should start and idle
  • Hello. I just purchased a 1997 Isuzu Trooper LS with 196K miles. It starts, drives, idles, and shifts great. Before purchasing it I checked the ATF and it was dark brown/black, but there weren't any particulates in it nor did it smell burnt. So I figured that I would just have the transmission flushed.

    I've been advised that I should have the transmission flushed because the ATF is dark (it should be a translucent red).

    I've also been told that I should NOT have the transmission flushed because I run the risk of loosening particles and deteriorating the seals through the process of flushing. This would then lead to having to rebuild the transmission.

    I purchased the vehicle used and I don't have maintenance records. I assume that the transmission was flushed at some point in the past since the mileage is so high (the Trooper would have died before reaching 196K without a flush, right?) Even though I prefer to take preventive measures I am thinking of not flushing the transmission and replacing the filter since it drives fine. If/when the transmission falters then I'll have it rebuilt. Does anyone have any other advice or insight?

    Thanks for your reply in advance and let me know if you need more information to better respond to my post.

  • atfdmikeatfdmike Posts: 414
    I would recommend NOT getting a flush, but rather, have the fluid and filter changed right away and do it again in another two or three thousand miles.

    While a power flush does get most of the old trans fluid exchanged, it also does as you describe. Better to change the filter and fluid gradually. 4L30E transmissions are known to get into the 200,000 mile range, but need regular care to do so.

    Power flushing a trans with that many miles usually proves problematic, and many owners report trans failures shortly after doing it. Since your history is unknown, you don't know that the previous owner ever did it. Rule of thumb with power flushing is do it the first time and everytime if you do it at all.
    HTH One guys opinion.
  • Hey Mike,

    Thanks for your suggestion. Given the concerns with flushing the transmission, are there any concerns about changing the fluid and filter? Conceptually, gradually changing out the fluid makes sense to me rather than "shocking" the transmission with a flush. However, is there also the threat of deteriorating the seals or dislodging particles with a fluid and filter change? Ultimately, I would like to avoid rebuilding the transmission until necessary (it dies). My concern is that a new filter may change the pressure in the transmission which could lead to damaging the seals which would then lead to rebuilding the transmission. Have you ever heard of a transmission having to be rebuilt after a fluid and filter change?
  • atfdmikeatfdmike Posts: 414
    Well, you pose some questions that I don't think anyone can guarantee the result, but let's look at this from the perspective that auto trans need good, clean fluid in order to function properly. In your situation, you know your trans fluid needs changing. When you change the filter and fluid, the reality is that you will be only changing about 3 to 4 qts of trans fluid and the new filter won't increase pressure except that it will allow the pump to suck up the fluid easier. You will still have about 7 to 8 quarts of old fluid in the trans (converter, TCC module, etc;), so there is not that much "shock" as you might think. Each oil change will gradually improve the condition of the oil and hopefully prolong the overall life of the trans.
    HTH One guys opinion.
  • myth1myth1 Posts: 2
    I am turning in my VW Passat lease and am bringing my 2001 Isuzu Trooper out of "mothballs" and back into full time service. It runs great, has spent most of it's days in my carport and only has 63,500 miles. I have driven it about once a week just to keep it limber. I am looking to spruce it up with new car mats. Does anybody know a way to get new OEM Isuzu mats? Can I order them through a still operating Isuzu dealer? If not, how about getting them from Australia or Phillipines?
  • atfdmikeatfdmike Posts: 414
    Couple of ways to go can go to and shop the parts you need and get quotes...if any are to be had....from dealers OR you can try people who bought a lot of the dealership inventory when they shut down North American operations and closed dealers. An email to may help, he has lots of parts, and a dealer in Missouri, St. Louis Isuzu, will dropship direct from Isuzu Japan if the part is available and you buy it through them.
    HTH One guys opinion.
  • I recently had my mechanic replace the timing beltand water pump. Everything is working except that I have some sort of rattle under the hood. I hear it when I go over bumps, when I brake, etc. Could the water pump be loose but still not leak?

    Also, my mechanic is saying that he is having difficulty getting parts for the Trooper. Are parts shortages becoming an issue now that Isuzu is not in the USA anymore.

  • moxconmoxcon Posts: 2
    this might sound nuts but after I had my timing belt changed I heard what I thought was rattling under the hood also but it was actually rattling under the car . I needed a new catalytic converter . I chalked it up to coincidence. But who knows. I sure hope yours is a loose screw instead of a 800 converter
  • dplastdplast Posts: 1
    edited December 2011
    The 4 wheel on demand light is flashing. Just bought the Trooper from a friend and when I bought it he said "the problem was a bad sensor or two or something like that and was expensive and so he just ignored the light". Anyway, living in a Sacramento suburb he never had a need for 4 wheel drive. Where as I bought it to take it out on the desert.

    However, putting it into 4 wheel drive manually works but it just bugs me, that light flashing and wondering what it would do if it all worked properly.

    Any thoughts, thanks.
  • My 2000 Trooper has an issue that when from a stop you can press on the gas and it very slowly starts to accel very slowly and will kick into 2nd gear and finally get up to full speed eventually. Not sure what this is and dont want to start tearing it apart yet until i have an idea were to start. Any suggestions will help. Thanks
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