I have a small dilemma. I have a 1987 isuzu trooper II. IT is a 4 cyclinder, with a 2 bbl carb. On the engine itself, it just says ISUZU, no numbers or telling what engine it is. I was told that it might have a 1988 engine. Doing a little research, I found that most 88 engines were fuel injection. Can anyone tell me any physical differences between the two?

You have the 4DZ1 I had that same motor in my 87 Isuzu Trooper II. It is a decent four banger not huge on power or anything but if you have drove it i'm sure that you know about what its like. Try to keep it from overheating the headgaskets don't like that and the usual plugs, wires, and basic maintainence and it should last you a really long time. Is there something wrong that you were trying to figure out or did you just want to know what you had? Check out the FAQ thread on top of the board here if you want to know more about it and tranny's and axle's and other stuff along those lines. Welcome to the PBB :flipoff2: :flipoff2:

The reason I was asking is it runs awesome. I have had it for 2 months and have changed: fuel filter, pcv gasket, air filter, spark plugs, wires, distributor cap and rotor, brake pads, brake rotors(Thanks Greg), battery and just cleaned the carb with some carb cleaner but I still have problems with the tacometer starts jumping and almost stalling on occasion and sometimes it just straight out stalls when coming to a stop. While I am driving, I lose power and it sort of bucks like it is trying but then it kicks back in. It was happening all the time and when I bought a can of carb cleaner and cleaned the outside and inside of the carb, it works 10X better. But I still have the problem of it losing power like it is not getting fuel. I was thinking of rebuilding the carb, since it ran so much better when i used the cleaner.

check your fuel filter again a guy that i'm friends with just had the same problem and all it turned out to be was that the tank was hella dirty and it kept cloging the filter so at 4$ a filter try changing it again and if it runs good for a while then starts doin it again its time to take your tank out and flush it and then reseal it just my 0.2$

It is possible that someone swapped a 4ZE1 2.6L block and head into it. Look on the driver's side of the block behind/under the exhaust manifold and it should have the engine code cast in fairly large letters. 4ZD1 means a 2.3L and 4ZE1 means a 2.6L. The casting is towards the rear, but on the driver's side of the block.

The same code can be found on the back side of the head, but you have to read it using the brail method.

If the truck has been sitting for a while, your whole fuel system could have some junk in it. It works great, until a bit of it finds its way into something important in the carb. Changing the fuel filter is a great start, and you can clean out the screen on the carb. Take off the pipe that goes into the carb from the fuel pump right at the carb. There is a screen inside of that which could be gummed up.

I took your advice and replaced the fuel filter. A few years ago, the fuel pump was replaced with an electric fuel pump. I checked that and it is working fine. The car is still acting on occasion like it is not getting enough fuel. Yesterday, it was running fine and suddenly lost all power and tried to stall. I was going downhill so it did not stall and then suddenly it stalled a few hundred feet down the road. Before it stalled, it backfired a few small fires then let out a loud backfire. It stalled and I had to wait until the next morning. It started but I got it towed, it was only 10 miles and was covered under AAA. Talking to a few people, they are still convinced the carb needs rebuilding because it seems to run fine and randomly act up. Anyway, I have called around, including the dealership and they do not have a carb rebuild kit for a stock carb for an 87 trooper II. They say they can get me just the gaskets. Anyway, I was thinking of just buying a new carb. Actually a weber carb. Any thoughts?

where do u live i have a mpfi set up for the engine its got everything included
just figured i say this incase you wanna go injected insted of carbed pm me i ya want if not its just a thought :cool2:

I took your advice and replaced the fuel filter. A few years ago, the fuel pump was replaced with an electric fuel pump. I checked that and it is working fine. The car is still acting on occasion like it is not getting enough fuel. Yesterday, it was running fine and suddenly lost all power and tried to stall. I was going downhill so it did not stall and then suddenly it stalled a few hundred feet down the road. Before it stalled, it backfired a few small fires then let out a loud backfire. It stalled and I had to wait until the next morning. It started but I got it towed, it was only 10 miles and was covered under AAA. Talking to a few people, they are still convinced the carb needs rebuilding because it seems to run fine and randomly act up. Anyway, I have called around, including the dealership and they do not have a carb rebuild kit for a stock carb for an 87 trooper II. They say they can get me just the gaskets. Anyway, I was thinking of just buying a new carb. Actually a weber carb. Any thoughts?Hi, not to be a pain, but I haven't read anything that conclusively indicates a fuel/carb problem, except that you did write that things seemed improved when you de-gunked the carb inside and out. Anyway, to me, it seems like the symptoms you describe are ignition related. Usually fuel related problems are more repeatable and not so intermittent. For example, if the fuel filter is clogged and fuel supply is restricted, it may idle fine, but not have much power to accelerate or maintain a freeway cruise speed with. Typically, these symptoms will be continuous until the fuel filter is replaced. Your symptoms, however, seem more intermittent. When you say it runs awesome and I still have problems with the tacometer starts jumping and almost stalling on occasion and sometimes it just straight out stalls when coming to a stop. While I am driving, I lose power and it sort of bucks like it is trying but then it kicks back in. and I was going downhill so it did not stall and then suddenly it stalled a few hundred feet down the road. Before it stalled, it backfired a few small fires then let out a loud backfire. It stalled and I had to wait until the next morning. It started but I got it towed,My spider senses tell me there's something wrong with your ignition. Like the fuse for the ignition power is loose, or the ignition switch is bad, or the ignition module is bad, or the ignition coil is bad, or perhaps the pickup coil?

Perhaps I could talk you into a simple test or two? Keep a #2 Philips screw driver (4-5" shank) and a flashlight handy and drive the thing until it craps out again and won't start. Then, check for spark and check for fuel supply. Pull a spark plug wire from a spark plug and run the Philips up the boot so it's in contact with the wire's spark plug terminal. Lay the screwdriver somewhere in the engine compartment so that it's close by ground (not touching), but you can still see the spark jump from the screwdriver shank to ground when you're in the driver's seat cranking the engine over. Or, with the ignition switch off, take a look down the carb throat while you operate the throttle a few times. The carb's accelerator pump should give a small squirt of fuel on every throttle operation (until the carb bowl gets empty). Best of luck!

Thanks Dog. I will check it out and let you know. This car is my learning car to learn more than just basics. Everyone's help is very much appreciated.

Yo Dog, I did both checks and both were ok. I saw the fuel go down and I saw the sparks. Do you have anymore checks? I checked the ignition coil, because I replaced it with the spark plugs and wires. Any other checks to find out whats wrong?

Not to dismiss RudeDog's excellent advice, but I thought I'd add that it could be vacuum related too. I had a lot of trouble with my 86 (same motor/carb setup you have) when I first got it, and it turned out to be the Mixture Control Valve. It is a white plastic barbell shaped deal on the passenger side inner fender. There is a large line going from it to the manifold right under the carb, and smaller line that goes into the maze of vac lines around the carb. In my case, the valve was opening up and sticking intermittantly at first, then constantly. With it open, it leaks a huge amount of vac off through that large line, enough you can hear it sucking air through the bottom of the MCV. You could try pulling the large line from the manifold and capping it off, then seeing if you have the same problems. A quick check might be to just rap on the valve with something when it is screwing up, might unstick it, let you know it is part of the problem, and make it run enough to get you home.

The MCV is part of the emissions system, allows more air in for a short bit when you snap the throttle closed to burn excess fuel better. It will not affect drivability noticably being bypassed, but you should have it hooked up to comply with the law.

A good overall check for vac leaks wouldn't be a bad idea either, but I don't think your intermittant problem would be caused by something like a straight leak. Check over your hoses, spray a little carb cleaner around the carb base and intake manifold/head joint and listen for changes in engine RPMs.

If it is a fuel issue, it would probably be in the carb, junk floating around and sticking in the jets every once in a while.

I did a vacuum check, and all is good. I also checked the mixture control valve and it was already disconnected. Someone at work said to check the negative terminal where it connects to the engine. He said on his car, it was loose and that would cause it to sometimes loose the power like I am having. I checked the cable but it wasn't loosed, just really gunked up. I also checked the positive cable and it was worse than the negative. The one thing that caught my attention is that halfway down the positive wire, it was cut and spliced and they twisted back together and bolted to the wheel well. Could the gunk and crud, or even the splicing have anything to do with this?

I do have one question. I was thinking of switching out the carb just with a new one and get it over with. Someone made a good point that if I switch it out with a weber carb, I will lose all the insane vacuum hoses :) the problem is that my county requires emision testing. Is there a way around that, by not having all the hoses, or will I have to put the old carb in when I get tested then switch it out?

My other question is how hard is it to switch out the carb with a fuel injection from the same make, model and year? I have the option of doing either, just wanted some info on how hard the switch is and what extra things do I need to get to add with the FI?

If you order the Weber kit for the Trooper it will have places to hook everything except the stuff on the air cleaner if you choose. You can get an adapter for the top of the carb to match the air cleaner, and then you could keep virtually everything. I've heard that If your smog inspector isn't checking carefully, he/she might not even notice that the Weber isn't stock, and let it pass right on by. Where I live we don't have testing, so I've never gotten to experience it myself. I don't know what you can get away with. Check out www.carbs.net for parts like the air cleaner adapter.

The reality is that the Weber (if adjusted right, and they are easy to adjust) will burn cleaner than the stock carb, it is just a matter of whether the test station decides that an aftermarket carb will be allowed or not. I think in some states its not as big of a deal as in others, but I couldn't say for sure. You might just go have a chat with the folks at a test station and see what they say. Pick the one in the next town if you're worried about tipping them off. ;)

FI swap is doable, but it would take quite a few parts. A big chunk of the wiring harness, intake and exhaust manifolds(need O2 bung in the exhaust), exhaust down pipe, probably the catalytic converter, computer, in tank fuel pump(perhaps the tank too), distributor, coil, a couple handfuls of relays. If you got a donor rig you would have everything you need. It would take a lot of work though, and it might further complicate things with your emissions testing.

The one thing that caught my attention is that halfway down the positive wire, it was cut and spliced and they twisted back together and bolted to the wheel well. Could the gunk and crud, or even the splicing have anything to do with this?

I would suspect that positive wire. Even if it isn't the cause of your problem, it could be the source of a fire one day. A splice on the main wire to the starter could turn into a big resistance point, restance makes heat, heat adds more resistance, etc. I think I'd just replace it to be on the safe side, but it does sound like it could be part of your problem.

Yo Dog, I did both checks and both were ok. I saw the fuel go down and I saw the sparks. Do you have anymore checks? I checked the ignition coil, because I replaced it with the spark plugs and wires. Any other checks to find out whats wrong? Hey, good progress. I'm fresh back from cavorting with my trooper in the Siskiyous. If the engine won't start, and you pumped the throttle and saw fuel, then I'd say the problem is ignition related. Even if the carb is way messed up, provided no vacuum leaks (per 800XL), if you pump the throttle and get a squirt of fuel, you should still be able to crank it over and get some sign of life, even if it just runs for a second or two and dies. Also, I gather that if you get her running nice, the problem shows up after it's warmed up, and when it dies completely, it will start again after its had a chance to cool down (overnight, like when you got it towed)? If so, that makes me think ignition module, or pickup coil. The fact that it sparks when it won't run sez your ignition is getting power. However, this does not rule out a problem with primary wiring. Some electronic ignitions work poorly under 8 or 9 volts. If there's a faulty power connection, wherever it may be (ignition sw., fuse box, main battery cable, etc.), it could cause too low of voltage supply to the ignition module, resulting in weak spark and messed up ignition timing. New coil you say? Is it an aftermarket "hot rod" coil? I hope your (stock?) ignition module has the balls to drive it. Maybe you could try a known good stock ignition coil to see if things get magically better? If the ignition module isn't already ruined, that is. If the new coil is overloading the ignition module, you might see the same symptoms you're having. Don't get me wrong, I'm not saying your ignition module can't drive an aftermarket coil (if so equiped), I'm saying I don't know if it can, and some engine's modules can't. Anyhoo, just some more things to consider from the back of my brain. Good luck. BTW, is there an ECM on this beasty? If so, any codes? I kind of doubt there is, considering the plethora of vacuum lines and carb as described. Something to try: Verify that it runs and will start (symptom not showing) and figure out a way to starve it from fuel (disconnect the suction line from the fuel pump, or pinch off the hose or something) and let the engine use up the remaining fuel until it stops running. Check and note the ignition timing while someone cranks the engine over. Get a feel for the rythm/cadence of the light flashes. Restore the fuel supply and run the engine until it fails again (symptom is showing). Check the timing while you get someone to crank it over (be careful, the engine may start at any time) and see if the ignition timing appears to have changed or is highly variable, or skips a lot, or doesn't even get the timing light to flash etc. Anyway, just another idea I thought I'd throw in the elevator and see what floor it stops on.

I decided to change the battery cables. The cables were pretty corroded(sp) and the negative wire was spliced and had another negative wire tied to that one and then back to the frame. The positive wire also was spliced, and then just twisted together, it looked horrible. I replaced both of them.
The ignition wire I got was from Autozone. The problem that seems to be occuring the last few days is when I try to cold start it, it wont start at all, but if I take the air cleaner assembly off so the carb is just there with nothing blocking it, it starts right up. I know there has to be a problem with the vacuum hoses. I checked them all, no leaks, I even replaced all of them because most of them were cracked and just looked terrible. The problem is I don't know if they are correct. I have been searching for some sort of vacuum hose diagram but I am not having any luck. There were a few hoses that had a T plug on them but nothing attached to the top part of the plug. I found one plug sort of thing that the hose wasn't connected to. The hoses on this thing are insane. The little plug thing was located on the passenger side on the wheel well. I have no idea what it does, but when i stop up the part where there is no hose, the engines starts to stall a little. Also, my air pump is ceased up but that doesn't have to do with the running of the engine, just the emissions, right?

I must say, I bought this car to learn on, and I have learned more in the last 2 months than I thought I would. Thank you for everyone's comments.

Also, my air pump is ceased up but that doesn't have to do with the running of the engine, just the emissions, right? Right! The air pump being stuck wouldn't mess up your engine running, unless the belt was still attached. Sometimes they get stuck and people just disconnect the belt, and other times, people disconnect the air pump to take advantage of the extra 3/10 HP gain and it gets stuck from non-use. Either way, I wouldn't bother with making it work unless it's required to work to pass inspection (don't mention it, they may overlook it). Some auto MFGs place handy stickers under the hoods of their cars. Belt routing (usually in the case of serpentine belts), tune-up info, and vacuum hose routing. Otherwise, you may take a trip to the local public library. See if you can find a repair manual that shows the vacuum routing diagram. You may also find some explanation of all the vacuum widgets and frazelknackers and how to check for their proper operation. Concerning vacuum as the possible culprit, even if the hoses are routed correctly, if a diaphragm is bad, whatever the diaphragm does wouldn't operate correctly, and there would be a hidden vacuum leak. However, the only vacuum leak I can think of that would be big enough to cause it to stop running while driving, and fail to start, would be something about the size of the vacuum line going to the power brake booster (if so equiped). A vacuum leak, even a generous vacuum leak, usually makes the engine so it won't idle and perhaps will make it so it's hard to start. Usually, a vacuum leak will not cause the intermittant symptoms you described earlier. That is, with a vacuum leak, it's going to run crappy all the time until you get the vacuum leak fixed. With a vacuum leak, it will usually not mostly run great and then occasionally crap out.