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Isuzu Trooper



  • k2rmk2rm Posts: 205
    My "check TOD" comes on after driving several miles while in TOD. I pulled the code and it gave me a "code 31."

    If I stop and start the engine immediately after I get this code, it will not go into TOD, but the "check TOD" and wheel indicator lights will keep flashing.

    If I let the engine cool, I can shift into TOD without any problems, but again, after several miles of driving, I will get the flashing "check TOD" light again.

    Any ideas?
  • atfdmikeatfdmike Posts: 414
    I don't think that the oil is part of this problem. There are two possible sources of oil that I know of. ONe is that the valve cover gasket is allowing oil to seep into the plug tube, which can be fixed by replacing the cover gasket. The alternative is if the tube itself which is pressed in the head is leaking, then the tube has to be replaced. I have never done the latter, but Isuzu has a bulletin out on it for 2nd gen troopers.
  • atfdmikeatfdmike Posts: 414
    Everyone has an opinion, but in my experience, some pumps may be intermittent due to bad connections or grounds or due to internal wear and failures. A fuel pressure gage on the fuel tap at the tap by the firewall will tell you how much pressure is in the rail. If the pump is bad and not working, of course the trupr won't work at all. The pressure regulator is often at fault for poor idle characteristics and hard starting. That is why there is a bulletin out for that too. The regulator can be bad and still permit the engine to run, just not as well as it should.
    Identify the fuel relay on the RH fender well and remove it to allow you to put a jumper wire across the hot terminal to the fuel pump terminal. This will allow you to turn the pump on (with the ignition preferably) and pressurize the fuel system. If you are not handy and familiar with electrical troubleshooting, you may want some help to do this. Then you can be sure the pump is on when you try your initial start up and see how the engine starts. If it fires right up, and does so the next time you cold start, then your fuel system is losing pressure but your pump is fine. The gauge will tell you if you are losing pressure too fast by watching it after you shut the truck and fuel pump off after running it, and see if it falls. It will fall but it should do so very slowly, like over a several hour period. If it happens fairly fast, then the next place I would check would be the fuel regulator:first remove the vacuum line to it and see if fuel come out of it when the fuel pump is on.....if it does, it is bad and has to be replaced. If no fuel comes out, then it gets trickier, because you can change the regulator but it is a bit of work to do so and see if that makes a difference. It is about $50 bucks last time I did one. You also should replace the O rings at the same time. As I said before, if there is a check valve in the system at the tank that could be my last check. I just don't know if it exists but I suspect it does for safety reasons if none other. Maybe a search of this forum and others will help on that one. Good luck. One guys opinion.
  • well today i went throught all of that at a mechanics shop. the pressure is great. everything looks great. the spark plugs are sitting in a little oil, but i dont think thats the problem. we are thinking that there might be a leek in the tubes attached to the fuel pump area that is not allowing the full initial blast of fuel at first. my mechanic explained it as the tubes coming out of the fuel pump. so after an hour of him diagnosing everything we really couldnt pinpoint anything, he suggested giving it that half key turn, wait repeat method to allow fuel to fill and then start, for a couple days and if it fires up everytime, but not when immediatel started, then he wanted to take the fuel tank and insides apart to examine. sounds good but your mention about the regulator seems to really pinpoint my problem. not only is it a delayed start of 5-10 seconds but once started, it putts and chokes unless i give it gas, but once i do it runs great. still not sure, about to make a move but dont want it to be for nothing, what do you think, fuel regulator, or bleeding hose in fuel pump area? thanks-jes
  • also a side note. all the pressure readings were where they should be and with the engine turned off, the pressure remained 4 options. 1- new super spark plugs you had mentioned in a article. 2- fix valve cover gasket to stop oil buildup, which may cause not enought spark to fire gas up right away.. - 3 replace regulator. 4- most unwanted to do/ drop fuel tank, check pump and hoses for bleeding, which im not even sure how to do. what options do you think i tackle first. thanks-jes
  • matausmataus Posts: 43
    I do believe you're right. Do you know how I would ajust the fuel air mixture? :confuse:
  • atfdmikeatfdmike Posts: 414
    The fuel air mixture is not adjustable unless the ECM is reprogrammable. I think I would look for what might cause the fuel air mixture to be bad. Is the TBI body clean, is the air filter clean, Is the Mass air flow sensor (or equivalent working or at least clean (there are special cleaners for these, do not touch or use alternative) The injectors getting a good signal (there are checkers that plug in to the connector to verify signal to injector...when you remove air cleaner you can see TBI, the injectors have the wires going in to them). How about codes...not all codes keep the CEL illuminated all the time. The ECM stores codes for quite a while.
    Let us know what you find!
  • atfdmikeatfdmike Posts: 414
    Well.....I am no expert, and changing the fuel regulator requires some work, but it does do a couple things that could also help. You may wish to consider whether or not you have an intake gasket leak. Sometimes they will cause problems particularly with cold engine. If you change the regulator, you have to remove the upper intake....on DOHC that is upper and intermediate intake, just to get to regulator. We are talking several hours anyway. I am not sure on SOHC engine. It is only a little more work to remove the lower intake (injectors housed in it) and just replace all the intake gaskets.
    This is a lot of work, but easier (I think) than looking at the fuel pump. When you tested did you see any loss of pressure over 15 minutes or so? I generally look to the obvious first, and since Isuzu makes mention of the fuel regulator as a cause for slow starting, I would start there. I have often thought about putting a direct push on type switch on the dash that would allow you to energise the pump at will so cold starts are not a problem. Most car companies have a longer run time than Isuzu for the pump at start.??????
    I agree that if oil was deep in tube then you might get shorting of spark current, but not a little at bottom of tube. One guys opinion.
  • ok so say it is the fuel regulator that is causing this. then when im driving down the road or if ive had the vehicle running for any period of time longer than five minutes. if i turn the vehicle off and then start if back up, it fires right up, no matter how many times i do that. again only when the vehicle is sitting for a long period of time. does it have this delayed start up. would a faulty regulator still allow that
  • or better yet to figure this out. i am able to locate the regulator for 45 bucks at oreilys auto parts. what can i do to check to see if the regulator is shot. what signs does it show, except for the obvious ones that i am facing. or should i just start with tackling this project and go from there.
  • atfdmikeatfdmike Posts: 414
    It is pretty hard to give you direction, but when you did the fuel pressure test, did you give the fuel system some off time and watch the guage for leakdown? If it is leaking down, often it is fuel regulator. I really suggest that you search a couple of the Isuzu forums for "fuel regulator" and maybe "check valve" and see what you come up with. I have suggested the most often quoted items to look at but that does not mean the cause could not be elsewhere. PlanetIsuzu is another great forum I check on too.
    good luck, one guys opinion.
  • cgb678cgb678 Posts: 1
    I have a 97 Trooper, when i put the key into the ignition and turn on the electrical systems, everything works fine. I continue to turn the key to engage the starter and I hear a loud click...everthing dies, starter does not engage and all electrical systems shut down. If i remove the key and wait a minute and put the key back into the igintion the electrical systems come back on but the clock and stereo have reset... still no start. Battery is new and fully charged. The starter was replaced last year. Any thoughts?
  • yes it definatly seems to be the regulator, because i have heard from people that normally once a fuel pump goes bad, it stays bad. in other words i dont think that if the fuel pump was bad it would give me such a hard time starting and then work great while running. so im quite sold it being the regulator, plus like you said, if isuzu is saying to replace the regulator from slow starting, then it must be a common issue. thanks i will check out that other site also
  • nope it wasnt the regulator. i changed it today with a new one and the problem continues. as i sat thinking about this problem, the trooper will fire up right away if ive been driving it, and if its been sitting for a half an hour will fire up after about 4 seconds. but if i let it sit overnight it takes alot to get it going. the mechanic had tested the pressure but not for a long period of time. so lets just say that it doesnt sound like the fuel pump because it wouldnt have pressure or be working at all, or over time stop working. so if it;s not the fpr and the pump is fine, then it would seem that there is some bleeding in the line somewhere. as i am not a mechanic firsthand i dont know anything about how or where i would begin with finding the bleeding. the mechanic said that 85% of the line is metal except for whats in the pump area. Is that right? do i want to pull the fuel tank down and look for bleeding there along with just changing the pump at the same time?
  • I have a 95 trooper that i recently crashed, i replaced the passenger side fender but i need the fender flare, with mudflap! It ruins the look of it and i can't find one anywhere!! Does anybody know where i can find one or does anybody have one on a parts trooper? Thanks
  • If anyone is contemplating this one, I did it myself in about three hours. You need a torque wrench and some parts of it are a pain, but it takes about three or four hours. At least for a DIYer.

    I followed directions I found on planetisuzoo.

    I had had a CEL for a while and surging idle. My mechanic told me it was the MAF sensor, but that didn't seem right to me... then I started hearing the engine whistle. Dead giveaway.

    It hasn't run this smoothly in a long time.
  • It's weird how easy it is to find the fender, and how hard it is to find the flare. Is this part still available from the dealer? Others speak highly of St. Charles Isuzu, and I know they mail-order parts.
  • okay, update on my failed startup progress for those interested. my 94 trooper with 168,000 miles runs strong, when its running at least. i have had trouble starting it, especially when its sat overnight or for a few hours. it will turn over but not start up. everything is well maintained, new/ filters, oil, pvc valve, fuel pressure regulator, fuel pump and strainer, fuel filter, spark plugs, well basically you name it ive just about did it. and it still will not fire up, and now its gotten quite bad where i think im going to trash my starter by cranking on it so long before it fires up. i tested my fuel pressure, and over time it looses pressure, but not much, i think that there is a leaking fuel injector and it is flooding my spark plug out, and when i try to start it takes a good minute to burn up that excess fuel, but once done, fires right up and if i turn the trooper off and then back on it will fire right up everythime, once chambers are cleaned and dry.
    so i let the vehicle sit overnight and in the morning pulled all spark plugs out and smelled them all over and over. I found that one spark plug reaked of gasoline, so hopefully my theory is right and its a leaky fuel injector that is flooding the system and is the final cause to this problem. tommorrow i begin the replacement process. i will respond with a conclusion.- jes
  • Howdy folks,
    after the rains this last weekend, I went out to my trooper to discover that the passengers side floor were soaked with water. It's coming in thru the blower motor. I took the garden hose and soaked the windshield and the flow started again. I loosened some of the screws mounting the blower motor, and quite a bit of water came rushing out. Is this a pretty common problem ?. I've had the Trooper for several years and this is a first. Any suggestions as to what to do to rectify this problem. Thanks for any input. John
  • gahlgahl Posts: 7
    a word of advice to any who may think they need to replace the fuel pump in your Trooper - go to the passenger's side of the gas tank & find the electrical connector at the side of the tank - twice now - on two different Troopers I thought the fuel pump was shot - it looks like a well sealed connection but use a small screwdriver to open the snap & pull the connector apart - push it back together & there is a good chance it will now start - sure beats a new fuel pump install
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