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Discussion Starter · #1 ·
Hello Planet Isuzu!

I've finally gotten around to rebuilding my 1990 Trooper! It's a 2.8l V6 automatic. My parents bought it and used it as a daily driver when I was a kid back in 90's. It's been sitting at my Grandfather's farm and hasn't been turned over in about 4 years. Luckily we put sheets down over the interior, so other than a few old wasp nests it isn't too bad! My plan is to get it running enough to drive it about 50 yards into his barn so that I can have a covered place to work on it (Nashville summers can be unpredictable). Once I've got it in there, I'm going to completely rebuild the motor, with new gaskets, seals, hoses, and any other parts I find that need replacing.

Body is relatively good shape, and mostly rust free. It definitely will need to be painted. Frame has some rust, but nothing a wire wheel and some rust converter won't clean up.

Trans fluid was apparently replaced at some point because it's still cherry red. Oil has no signs of water or coolant. Radiator was dry as bone, but we filled and are going to monitor for leaks.

When we last left it 4 years ago, the fuel pump was shot. We dropped the tank and replaced that, but the old filler neck has hardened. Waiting on some 2" flexible hose to get that replaced.

As far as my experience goes, I've done some light work on engines before (O2 sensors, valve cover gaskets, thermostats on some mid 2000's BMWs and GM trucks) but I'm looking to learn a lot fully tearing this thing down.

Any advice for things I should do before turning trying to turn the car over for the first time in 4 years? I plan to replace the oil and fluids (as much as I can without the car running), but is there anything else I should do before I throw a battery back in and turn it over?

I'll get some pictures when I'm out there later this week.

*Edit: I'm also posting all over the place trying to track down the 90/91 Workshop manual. I would be willing to buy them straight up, or if someone has a set they would like to keep but aren't using, I would be willing to pay to ship it to me, scan OCR and index it, then ship it back to you. I could post the pdf to the forum so everyone could have access to it.
 

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Howdy, sounds like you've got a good plan. What I'd suggest is, before you start the engine or turn it over, pull the fuel pump relay and also the fuel pump backup relay. Then crank over the engine until the oil pressure light goes out and/or you get an indication on the oil pressure gauge.

That way at least you'll have some oil pressure before starting the engine, rather than starting it absolutely dry. I'd say pull the distributor and prime the oil pump, but that's a fair amount of extra work and you're going to rebuild the engine anyway.

On the rebuild, I'd recommend you get a crank kit for a 3.1/3.4 (RWD iron-head 3.1s and 3.4s use the same crankshaft) and pick up a set of pistons meant for a '91 Isuzu Pickup 3.1. The 3.1 crankshaft is a "stroker" compared to the 2.8 crank, and you can have a machine shop press the 3.1 pistons (which have the correct wrist pin height to go with the stroker crankshaft) onto your rebuilt 2.8 rods. This turns it into a 3.1 and you'll really appreciate the extra low-end torque.

You're probably gonna have to get the 2.8 crank machined anyway, and buy new bearings. So might as well, for very little more $$$, make some engine improvements while you're in there.

More than likely you'll need to have the block bored oversize, and it won't be any more expensive to have them bored to the exact specs for the 3.1 pistons. Typical overbore is around .030" and that gets you a displacement of "3.2". More cubes are always an improvement!

Something else to check before moving the rig is the condition of your brake system. You don't want to have a sudden stop 50 yards down the way, into the barn! That would be in-corn-venient. :twisted:

If you're not going to run the engine very long, and just drive right over to the barn, you shouldn't have to worry about "burping" the cooling system. It'll take longer than that short trip to get the engine warmed up enough to burp the air out. If you do idle the engine for a significant time before moving, you'll have to jack up the front end and let the engine warm enough to get out any entrapped air. A Lisle Spill-Free funnel is a great tool for doing this. Otherwise it tends to get a bit messy.

Under $26 at Amazon, and there are cheaper no-name knockoffs that will probably do the job as well. Check out the reviews for more info.

https://www.amazon.com/Lisle-24680-Spil ... B00A6AS6LY

There's an Isuzu 2.8 V6 shop service supplement repair manual on eBay, but they want $175! Like gold!! :shock:

https://www.ebay.com/itm/373576912685

Another Golden Book is by Tom Currao, "How to Rebuild Your Gm V6 60 Degree Engine" Excellent manual, if you could find one. They are out-of-print and copies are quite expensive. Never know, you could run into one in a 2nd-hand book store.

https://duckduckgo.com/?kl=us-en&q=How+ ... key&ia=web

Hope that helps, and Welcome to the Planet! Keep us posted on your progress, and post a few pics when you get a chance.......ed
 
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Discussion Starter · #3 ·
I appreciate the advice Ed and will definitely pull those relays and build a bit of pressure. I also plan on checking the brakes out, as it on top top of a hill right now and I will need them in a hurry. Worst comes to worst I can throw some tow straps on it and walk it down with my truck.

3.1 crank and pistons sounds like a nice simple way to get more power. I'd like to do bigger tires eventually, and I don't think the ole 2.8 would appreciate it much. 4l30e will be able to handle it, but should I do any cooling system upgrades like a double pass radiator, etc?

I managed to track down a 1990 Trooper shop manual and the electrical troubleshooting supplement. Per the 6 antique auto literature companies I called in desperation, the 90 and 91 Trooper manuals are hard to find and sell almost as soon as they list them. I also got a 90-93 Trooper and Rodeo 4l30e supplement as I plan on cracking the trans open as well. I will get to work scanning them in once they arrive so other 90/V6 owners don't have to go through the PITA that is tracking down one of these shop manuals.

On another random looking way too far down the road pipe dream, has anyone thought about swapping the radio and the instrument cluster? I don't see any reasonable way to go double din, but I think one of those flip out single dins could work if it was up where the instrument cluster is now. Just some food for thought.

I'll have pictures and updates after I get back to work on it tomorrow night.
 

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Discussion Starter · #5 ·
Trans cooler is a good idea, would probably help with longevity of an already old trans. Do you think there would be clearance issues with the grille? I believe the A/C condenser sits in front of the radiator, and from my understanding the trans cooler would have to go in front of that.

Heat index has been over 100F out here this past week, so I'm more committed than ever to A/C hahahaha.
 

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Purty Dang Hot!

I've always wondered if a synthetic transmission oil would improve the longevity of the 4L30E.

Maybe something like Amsoil, or? It wouldn't be cheap, but then replacing the durned thing ain't cheap, either!
 

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Discussion Starter · #8 · (Edited by Moderator)
Pictures at long last:

You can see my fuel tank skid plate poking out under the side. Any recommendations for clearing out the bolt holes on the frame?
r1.jpg


Right headlight is totally rusted out, left is starting to so I imagine I'll need to replace those. Clear coat is gone on about 60% of the car, but I wanted to cut my teeth on auto painting any way. Can't decide between going back with the classic blue and pewter, or a charcoal grey. The grey would be convenient because I could just go black on all the faded chrome colored plastic. Nostalgia is a thing so we shall see. But that's a problem for another day. Windshield is toast. Bumper is a bit bent but not too bad.
r6.jpg


Right rear bumper is very dented. Wheels are in solid shape, but the tires are dealing with 20ish years of dry rot. They're pretty much all cracked all the way around on both sides, but by some miracle they're still holding some air. Will need to be replaced before they hit the road.
r4.jpg


All things considered it looks pretty good under the hood. Radiator needs to go, obviously everything rubber as well. I'm considering switching to an electric radiator fan, but I think I would need a thermostat with a temp sensor to kick it on. Any advice on that would be appreciated. There are a few hornets nests that add a certain rustic charm, but probably will probably need to be removed. All in all a good starting point.
r3.jpg


Not pictured: two dead robins that found their way in through the passenger side trunk panel that we left off 4 years ago when we first started messing with the fuel pump. My Dad put a layer of carpet and padding down over the original after I assume we tore it up as kids. Front passenger seat still has the stain from the red crayon my brother left in it one summer while we were in Home Depot. More nostalgia. New carpet layer is not glued down so it will be easy to remove. There's a commercial flooring company that's down stairs in the building I work in, and I plan to get some funky patterned carpet scraps from them to redo the carpet. Seats are in decent shape, but I've got some plans to recover those and add some open cell foam and fans for ventilated seats. If you've never been in a car that has them, they are life changing in the summer. Interior needs work for sure, but isn't toxic waste level bad. Smell: A classic "musty." 6/10.
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Fuel tank is mounted and all hooked up.

Disconnected the fuel pump relay and backup relay, hooked up a battery with some jumper cables, and turned it over for probably 30-45 seconds until the oil pressure light went off per Ed's recommendation. It definitely sounded sluggish turning over, but great to know it built some pressure and isn't locked up! If the plugs are okay, I think she'll start right up. Hopefully it doesn't start spewing fluids once the combustion gets going.

I decided not to throw any gas in it just yet, as I want to make sure the the fuel line in between the inline fuel filter and the TBI is clear of old fuel before I start pumping anything in there. My plan is to disconnect the fuel lines at the TBI, and turn the motor over until I see fresh gas coming out. Is there anything I need to do other than just disconnect the fuel lines?

I'll step my picture game up going forward, more in progress work pics and such.
 

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Well, there's a bit of a project! It'll be nice when you're done.

I see you have A/C, be sure to retain any shim washers you find behind the pump, when you unbolt it. They're there for a reason! Note the number and position of the shims.

On the skid plate holes, maybe they can be chased with a tap. If they're too far gone, a Heli-Coil insert or a Nutsert might work.

Geoff has a good writeup on his site about electric fan conversion, check it out. IIRC you'll use a Camaro 3.4 water pump because it's shorter.

My '90 LS is the same color and the clear coat is in bad shape as well, from years outside. I'm thinking of a repaint too. They are getting to be worth quite a bit as a collector's car, and IMHO well-worth preserving with new paint. Going to practice on the hood with my new buffer and some serious compound, to see if I can get it looking at least a bit more presentable than it is now.

You might not want to run the starter the length of time it could take to pump out the fuel tank. Probably burn the starter up. There should be a drain plug on the tank, try that.

You can also make the fuel pump run continuously without running the engine. There is a black wire with red stripe that lives under the fuse box in the vicinity of the fuel pump relay. It's a "Test" lead, and if you run a #12 or larger jumper wire from the Positive terminal of the battery to the Test lead, the pump will run. It bypasses all relays and controls for the fuel system.

I've attached a diagram showing the fuel pump electrical system and Test lead. You could disconnect the fuel line at the fuel filter (passenger rear side, inboard and up by the frame). Then direct any the discharge to a convenient container.

HTH...........ed

.
 

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Discussion Starter · #10 ·
Much appreciated! The tank is empty at the moment, I was just going to turn it over until clean gas comes out, not a whole tanks worth!

I'll see what I have laying around wire wise, and if I have a enough I'll test it that way. But I'm not too worried about the starter, it's on my list to replace as well.

Good tip in the A/C, I don't know really anything about them. Definitely waiting for my manual to arrive before I dive in!
 

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Ed Mc. said:
I see you have A/C, be sure to retain any shim washers you find behind the pump, when you unbolt it. They're there for a reason! Note the number and position of the shims.
Shims where the compressor mounts? I'm confused on this one. Is this the case on the 2.6 as well? Thinking about reviving my AC and I do not remember any shims.

Thanks
 

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giusedtobe said:
Ed Mc. said:
I see you have A/C, be sure to retain any shim washers you find behind the pump, when you unbolt it. They're there for a reason! Note the number and position of the shims.
Shims where the compressor mounts? I'm confused on this one. Is this the case on the 2.6 as well? Thinking about reviving my AC and I do not remember any shims.

Thanks
Some of the GM rigs had a problem with serpentine belt vibrations and the factory TSB directed the A/C compressor to be shimmed for better alignment. The shim(s), if any, would have been between the compressor mounting bracket and the cylinder head. Mostly applicable to 3.1's but you never know.
 

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TNTrooper90 said:
Much appreciated! The tank is empty at the moment, I was just going to turn it over until clean gas comes out, not a whole tanks worth!

I'll see what I have laying around wire wise, and if I have a enough I'll test it that way. But I'm not too worried about the starter, it's on my list to replace as well.

Good tip in the A/C, I don't know really anything about them. Definitely waiting for my manual to arrive before I dive in!
Well, that should work, then! It shouldn't take much cranking at all to get fuel pumped up to the TBI unit. Or you can prime the system by energizing the Test lead. Might not be a bad idea, either, that way you can check for fuel leaks.
 

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Discussion Starter · #14 ·
I apologize for the delay! Classic busy life scenario.

So I got the fuel pump installed, gas in the tank, and tried to crank the car over. It cranks just fine, and runs if you spray starter fluid in the tbi, but no ignition without the starter fluid. It will run indefinitely and smoothly as long as I hold the RPMs around 2000 and starter fluid is continually sprayed. My hunch is that the injectors are not injecting for some reason.

The fuel pump is audible, and there was pressurized fuel that sprayed out when I disconnected the fuel line at the filter. I replaced the filter, reconnected the line, then disconnected the fuel line at the TBI. When I cranked it with the fuel line disconnected, what I could only described as highly pressurized fuel shot out, so I know I'm getting fuel to the TBI. I don't have any tools to test the psi, but the fuel came out fast so I don't think that's the issue.

I jumped the fuel pump relay to the power windows as another user suggested to by pass the alternator in another post, but still nothing injecting.

When turning the car over, I don't hear any sounds or see any fuel being sprayed out of the injectors.

I'm not an expert with a multimeter, but I did a continuity test on both injectors and the connectors to them. Both injectors show "full" continuity (no resistance), and both connectors show continuity with resistance, but the connectors both have the same level of resistance.

I've ordered a rebuild kit for the TBI, but I'd like to know if my injectors are shot. If they are, I can replace them when I rebuild the tbi, any common issues that would cause the injectors not to fire?
 

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Yeah, sounds like you have enough fuel pressure at the TBI unit to make it run. There is +12V applied to the injectors on the blue-wire-with-black-stripe side, when the Main Relay is energized (by ign switch in Run or Start). The other side of the injector connector is a blue wire for #1 injector and a green wire for #2 injector. Blue and green wires are grounded by the ECM for each pulse of the injector.

With the key on, you can check for power (to ground) on the common "bus" black/blue wire. If you have power, then most likely you're not getting a firing signal from the ECM.

You can test the signal to each injector with a "noid" light. This is connected in place of the injector, and will flash if the ECM is telling the injector to fire. No flashing, no signal from the ECM.

Here's one, under $13 on eBay: https://www.ebay.com/itm/202648871828?epid=1511811466

Here's some good how-to info: https://dannysengineportal.com/noid-lig ... oid-light/

If you find you have a signal, then the injector itself is not firing and likely to be clogged.

No signal, faulty wiring to the ECM or problem with the ECM itself (more likely)

The "cranking signal" comes from the ignition module in the distributor. Since you put a new part in there, not so likely to be the issue. Check for any damaged wiring.

See the attached ECM wiring diagram; check all (5) power inputs to the ECM for a blown fuse.

Hope that helps, keep us posted........ed

.
 

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Discussion Starter · #16 · (Edited)
Finally managed to get back out and get my my hands dirty!

Followed Ed's advice and got a noid light. Flashing looked good on both connectors, so I ordered a couple of new injectors, and a seal kit.

Automotive tire Motor vehicle Wood Automotive exterior Bicycle tire

My well worn throttle body. The connectors & wires had gotten a touch melted from all the starter fluid, so I ordered a couple of new connectors as well.

Motor vehicle Automotive tire Light Automotive exterior Automotive wheel system

Better view of my "well done" wires. I also circled this cracked vacuum connector. Any ideas on the best place to get a replacement? There are some generics from Dorman on Amazon that look like they might work.

Tire Wheel Locking hubs Automotive tire Tread

Working on cleaning up the TBI until the connectors arrive. Didn't look awful inside the injector pods, but there were enough solids that I'm confident it was clogged. I have a suspicion that someone did a seal kit at some point, as the seals came off with relative ease. If the motor runs once everything is buttoned back up, I'll at least give the engine bay a good washing, if not the whole car.

I've also been keeping an eye out for headlight assemblies since mine are both pretty rusted out, and I managed to find a couple of the Depo ones on ebay for $75 a piece. I wish I liked the look of the round headlights, but I just can't bring myself to change them from the squares.

If I don't have much luck with the Depo's, I may 3D print some kind of bracket to hold generic 7x6's, or a set from a Chevy C1500. C1500's are split, but look like they would be close to the same size as the factory squares if they were mounted together.
 

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On that plastic/rubber vacuum line at the TBI, IDK if there are aftermarket replacements. You'd probably have to go to the GM dlr and look up parts for a '90-or-so 2.8 Blazer or S10. Or maybe one of the Dorman hoses you found can be made to work.

I had one of those at my carbon canister; I just cheated and cut the cracked rubber off the plastic line. Then used a chunk of rubber vacuum hose for the end, as a "splicer". Not as purty, but it works and no leaks! That definitely is a big leak , so fixing it will really help.

Ok, just poked around Amazon etc and found these Dorman soft-ends for plastic hose:


Didn't even know those are available, looks like they'd work pretty well. That package has an assortment of sizes and likely there's one to replace your cracked fitting.

If you scroll down and check out the other suggested products, all kinds of neat related stuff shows up. Wondrous!
 

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Discussion Starter · #18 · (Edited)
New injectors did the trick! It started right up once I got the new connectors and freshly sealed TBI bolted back on. No knocks and it held steady at around 1000-1100rpm idle for 10 minutes before I decided to kill it. Where do these 2.8's like to idle? 1100 seems a touch high to me, but I imagine it's been set higher as the injectors and fuel pump wore out.

I ran it through all the gears a few times, and it sounded like it was shifting without issue. I didn't move it at all, as the brakes don't have any pressure and the car is sitting on a hill. So brakes are my next move. Rotors have some surface rust but should be okay, so I was just going to replace the calipers, pads, and soft lines. Anything else I should knock out while I'm down there?

Also those Dorman connectors were too small for that vacuum line, so I will have to go back to the drawing board.

The weather-stripping/seals on the smoker windows has hardened and shrunk on both sides, any idea where I could track these down or and alternative for them?

And sorry for the lack of pictures, my phone died on the way over, so I just left it inside charging.
 

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Idle speed should be closer to 750 rpm. A number of things can cause the fast idle, from cranky IAC to faulty thermal sensor (the one screwed down to the center of the intake manifold, forward of the TBI), vacuum leaks, or just needing a readjustment of idle speed and TPS voltage. I've posted the procedure in the past, if you search on "IAC and TPS" it should come up. I'll repost it here if you like.

If the rotors pass muster, then your plan for replacing calipers, pads, brake lines should be ok. If the front rotors are bad, you'll have to pull the hubs completely off, then you might as well do ball joints while it's down that far. Any rig over 150,000 miles will probably have worn ball joints. But you can always put that off until later, if you don't have to pull the hubs.

Last thought, if you do end up having to replace the front rotors, do the "Big Brake Mod". Gen II Troopers (and later Rodeos & Passports) have a larger-diameter rotor that will fit a Gen I ('88-'91) Trooper and, with a later-style caliper, give you a significant increase in breaking power. And a twist to that mod, revealed earlier this year, is that you can use a double-piston caliper out of a 2005 or so Colorado, for even better braking performance. The Colorado front calipers bolt right up.

Let me know if you'd be interested in doing that, and I'll post the links for you.

Glad the injectors did the trick, it's not always that simple. Happy Wrenching!.............ed
 
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