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Correct. The ITEC system requires a cranking signal (from the distributor) to energize the fuel pump relay and fuel pump.

BTW for testing/troubleshooting you can bypass the relay by removing it and jumpering the appropriate terminals.

Attached is the ECM wiring diagram for an '88-89 Trooper 2.6 ITEC.
 

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The tube is for the EGR. There are 2 ways to pull the head; since the intake is almost impossible to remove in the vehicle, pull the intake and exhaust manifold together with the head. You'll need a strong helper or engine hoist/comealong. To make the assembly a bit lighter, remove the exhaust manifold. Probably a good idea to pre-spray the EGR tube's nut at the manifold and let it soak for a few days.

One thought, before teardown: any possibility of getting it to run? Even if it runs on 3, you'll be able to check oil pressure, listen for noises, warm up to temp and check for white smoke blowing out the exhaust.

Any signs of water in the oil or oil in the radiator? That's a good indication of blown head gasket or cracked head.

If the gas tank isn't too crudded-up, you may be able to drain it then put fresh gas in. Check for a drain plug, most tanks should have one. You can easily pull the fuel pump and take a peek into the tank. Maybe even replace the fuel pump if it's shot.

Here's a pump kit, built in Japan, for under $30 on eBay:

https://www.ebay.com/itm/KEMSO-340LPH-H ... SwXIhbjjiv

This one should be better than an unreliable Airtex or generic Chinese junk.

On the low compression, I'd still check the other 3 cylinders. If, for example, compression is also down on #2, it's most likely the head gasket metal fire ring is blown between #1 and #2. If only #1 is low, more likely a burnt exhaust valve. Check valve clearance and if it's tight, readjust to .010" and check compression.

It's very common to see burnt exhaust valves on earlier models, since they had production issues. Add a lack of proper valve adjustments by previous owners, and there ya go!

Typically you'll get head gasket and burnt valve failures on cylinders 2 & 3 or 3 & 4, but stuff happens! It'd be good to know what's going on before teardown.

Anyway, just a thought, HTH...........ed
 

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giusedtobe said:
Thanks for the tips. Good advice so I will go ahead and check the other three to be certain instead of going off my memory of how one with a broken timing belt sounded 25 years ago. Not sure if you can get video on here or not but I will see if I can video it so you can hear it. It sounds like a sick pup spinning over.
It may have more than one bad valve (or other problem), sounds like it. If you pull the distributor cap while you're cranking, you can see if the rotor turns. Or I supposed just pull the oil fill cap on the valve cover and see if the camshaft turns.

Got Spark?? :mrgreen:

No doubt, if the timing belt broke, the head's gotta come off. This is Most Definitely an interference engine. If it's only crunched valves, they're easily replaced. Have the machine shop do a valve grind, or quick-n-dirty just lap in the new valves with some Clover valve grinding compound, if the valve seats aren't in too bad of shape. Rockauto has some decent deals on aftermarket valves. Isuzu OEM valves are better, but they are REALLY expensive!

If it's the head or gasket issue, you're gonna have to get that head pressure-checked before doing anything. You can't trust 'em. Last time I did a head, I had to replace all the valves & exhaust guides too. With pressure-checking and milling, it was quite expensive. Coulda bought a new head by the time I was done. Machine shop prices have gone up astronomically since then.

Unless you've got a good buddy with a machine shop!
 

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#1 is at the front and #4 at the firewall. The later-style "heart-shaped" cyl head, along with a change in pistons to match the new shape of the combustion chamber, was mostly for emissions purposes.

However, when you throw one of these heads on an older engine with "flat top" pistons, it does bump up the compression a bit. Conducive to adding performance as per recent posts here.

Sounds to me like you've got burnt valves. Or maybe a combination of burnt valves and a blown head gasket, who knows. Might be productive to ask the P.O. what made him think the head gasket was blown. If it's just poor running (from the low compression), and not overheating/white smoke/fluids where they shouldn't be, then maybe it's just a valve thing.

Very remote chance of piston/cylinder issues but the bottom ends on these are pretty stout, except for the thrust bearing issues we talked about prior. Mostly they suffer upper-end problems.

Here's a brand-new bare head on eBay for $345 shipped:

https://www.ebay.com/itm/Isuzu-2-6-SOHC ... SwjVVV15xO

You'd need to install new valves and build-up the head with the rest of your valvetrain. A good time to add a performance cam, too!

Jerry Lemond is also a good source of parts, you might give him a holler to see if he has any of these heads in stock. Username on this forum: JLEMOND

For a low-buck$ solution, check at http://www.car-part.com

I found a number of '94-97 Rodeo/Passport 2.6 heads around the country, for pretty decent prices. and what you'd get from the wrecking yards would be the entire head assy, valves, valvetrain, cam, etc. Can't hurt to check around, you may find a good deal with one of those. There were a few listed for a '94 Amigo as well, even cheaper.

The newer heads are far less likely to have cracking issues than older ones (such as your '88). ZuZu upgraded the head castings with a better design, when they changed the cyl head style.

And while it may be relatively safe to buy a used/remanufactured newer-style head, NEVER waste your money on a used open-chamber head. You never know when you're gonna get one that's either cracked, or ready to crack. And there's no guarantee that a remanufacturer won't have welded-up one of the older heads, which is just asking for trouble.

Almost time for the autopsy, have fun!
 

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giusedtobe said:
Thanks for the links!

I don't have a shop manual yet, anybody have the bolt pattern for the order you remove and replace the head bolts?
The attached pic shows the installation tightening sequence, just start from bolt #10 and work your way in for removal.
 

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Take lots of pictures! You can also mark with masking or duct tape and a Sharpie. I don't recall having any issues taking off the exhaust manifold, the bolts are fairly accessible. But if you can't get 'em, there's a joint where the exhaust downpipe connects to the manifold, and you can undo the bolts/nuts there to release the pipe from the manifold.

Spray some PB Blaster, Kroil, or other penetrant on the nuts/bolts and let 'em soak for a day or so, it'll help get things apart.

If you remove the hood, you can pull the head straight out of the rig with a come-along or engine hoist. Be sure to make some match-marks by the hood bolts, so you can retain the hood alignment when you reinstall.
 

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giusedtobe said:
Could not get this fitting to budge. Anybody got any tricks here? This is the pipe that runs from the Ex Manifold to the intake manifold.

Also I loosened the head bolts and several were loose already. Unless the PO had already dug in here any idea why several of the bolts would be loose? The ones that weren't loose were not hard at all to break either so I doubt they were torqued down.

Thanks
Alan
Do you have a torch? Heat the heck out of the manifold, then soak a rag in icy water & wrap it around the EGR pipe & nut. That might help to shrink the nut away from the manifold.

You do have to be careful on that hollow nut, to not crush it. A flare nut wrench might help with that. Heating the manifold then spraying with penetrant while it's still warm might help. Watch out, no open flame-age 'cause the stuff is flammable! Keep a fire extinguisher or at least some baking soda nearby, to prevent Bad Things Happening.

Here's some other stuff that might help, CRC Freeze-Off Super Penetrant:

https://www.amazon.com/CRC-05002-Freeze ... 630&sr=8-2

It'll drastically lower the temp which helps to "crack" the part loose, and also allows the stuff to penetrate better. Seems like a good idea & has good feedback. It has a low flash point, so probably wouldn't be a good idea to heat the manifold before trying this stuff. The can says "Extremely Flammable" so I guess they're not joking!

Loose head bolts don't bode well, maybe somebody has been in there and didn't know what they were doing. A sure way to get a blown head gasket/warped head! So maybe that's a lot of the engine troubles.

Check all of the head bolt's sockets, if they're chewed-up you'll want to renew the bolts. Otherwise, they're not Torque-to-Yield, so they can be reused.

You might want to put some ARP Ultra Torque fastener assembly lube on your list of parts, it's pretty good stuff and will help to achieve even head-bolt torques.

https://www.amazon.com/ARP-100-9909-Tor ... B8Y4HNVVYD

You'll want a metric bottoming tap as well, sized 12mmx1.50, to chase the crud out of all the head bolt holes.

G'luck with that EGR pipe, it can be a real bugger! Worst case, maybe you can undo the intake manifold end of the EGR pipe and tie it back out of the way.
 

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If you do end up getting the Exhaust side of the EGR tube busted loose, when reassembling use some anti-seize compound on the threads. That'll keep it from getting stuck in the future.
 

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"Adjustable wrench" DOH!

I don't recall the size, but it's probably something like 14mm or 15mm. Got a combination wrench? Stick it across the flats of the nut and see what fits!

Time for a decent set of metric wrenches if you don't have any, it's pretty hard to work on these with Crescent or other adjustable-types. Sears has good sales, and both Lowes and Home Depot have decent lines of hand tools that'll get the job done.

Here's a good deal on a Sears socket set but there's only 9 minutes left. Hurry!!

https://tools.woot.com/offers/craftsman ... 460a1c0e11
 

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That head is really chewed! Ready for the scrap bin, for sure. How bad are the cylinders scored? Really deep, or just fine lines? Can you catch the scoring with your fingernail? If so, you might seriously think about tearing it down for a rebuld. The block might need to be bored out & fitted with oversized pistons.
 

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giusedtobe said:
I'll have to go back out and look at it in the daylight. I only saw the scoring on #2 shown in the picture but will give a better inspection tomorrow. Couple of novice questions;

Any way you can tell from the pictures or castings etc if this is the OEM head & gasket?

What causes the erosion of the aluminum around the valve seats, spark plugs and that one spot along the gasket?

Lastly, am I missing any fasteners on the intake/ITEC? Pulled four bolts and two nuts off of it. Still stuck tight.

Thanks
Alan
I dunno if there's a way to tell, if you can't find any markings on it (not likely now), the OE gaskets are dark in color and some of the aftermarket ones are more red/orange, but that doesn't mean much.

That type of erosion might be from steam (water leaks in the combustion chamber), or really bad detonation. The one where the fire ring seals, is from combustion pressures leaking past the steel ring, and "undercutting" the softer aluminum head in the process.

Does the block's sealing surface look OK? You'll want to scrape it with a really sharp razor blade. I've used paint scrapers in the past with success and Wal-Mart has some pretty cheap ones, just pick one up and a set of extra blades and you're good. It helps to spray a bit of light lube on the block when you're scraping, makes it go a bit smoother.

Don't use those Scotch-Brite discs that you chuck into a drill motor; the abrasive goes everywhere. When you're cleaning the block, stuff a small piece of rag or paper towel down the oil passages in the top of the block, that'll help keep any crud outa there. Be sure to pull them out when you're done! Turn the crankshaft so all of the pistons are down in the cylinders, then stuff shop rags or paper towels in the cylinders to help keep the crud out of them, too.

Of course if you end up tearing the block apart all that'll be a moot point!

There should be (2) fasteners per cylinder on the intake manifold. So (8) total. I don't recall having any issues with my Spacecab 2.6 other than they're a Beetch to get at!

I did read on another thread that it's a bit easier to pull the intake off the head, if you remove the upper half of the ITEC manifold assembly first. Then you can get at all the bolts better. Be sure to make diagrams and/or take lots of pictures!

This thread has a few tips for getting that pesky intake busted loose:

https://forum.planetisuzoo.com/viewtopi ... take+upper

HTH..........ed
 

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giusedtobe said:
I was afraid of that on the studs! So that leads to another stupid question; are the studs bottomed out? I assume they are otherwise you'd have to measure how far they need to protrude. I know this is a really stupid question but this entire process is OJT for me as this is the first head I have pulled.

Any need to use anti-seize on the studs when they go in the new head?
As O.P. suggested you can double-nut the stud, lock those 2 nuts together using 2 wrenches, then torque on the inside nut (the one closet to the cyl head) and back out the stud without damaging it.

Stud extractor tools also do that job nicely and here's one at Amazon for around $14 that would do the trick:

https://www.amazon.com/Performance-Tool ... B01GGV1UWI

When you reinstall studs, use the double-nut method. The stud will bottom out on the middle "shoulder". They probably don't really need lube when screwing them in, but it certainly won't hurt and likely they'll go in a bit more smoothly.

BTW most studs are shorter on one end, IIRC the short end of the stud screws into the head. Just take note of how they go when you take 'em out, and make sure they go back the same way.
 

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First things first, before you pull the balancer, you can remove the outer V-belt pulley. It bolts to the inner face of the balancer with (3) bolts IIRC. That'll get it out of your way and give you more room to work. Did you pull the radiator? That gives more space, lessens the chance of dinging it, and you'll need to test and/or replace anyway.

On the block, most of those darker markings you see are "imprinting" from the head gasket. Not a real big issue, long as there isn't any raised material left on the block.

What I would worry about is whether the block has any big pits, erosion, or depressed areas. Hard to tell from the pics but check especially where the fire rings of the head gaskets sit. Also concentrate on that area where the "steam cutting" took out the head and gasket.

If you have a mechanic's pick (or even a sharp nail will do), drag the pointy end of it across the block surface. You should be able to feel any rough spots or serious depressions, or other discontinuities in the block.

Especially if there are any low points right where the head gasket fire rings are sealing, that's gonna cause problems.

On the pistons, yeah one looks like it was "kissed" by a valve. You could hand-work that down to the base metal so it's not sticking up where it can get red-hot and then cause detonation.

The other piston that's deteriorated on the edge, I'd bet that's the one where the gasket was leaking and the aluminum was eroded away. The upper part of the piston is quite thick, so there's no worry about breakage or anything like that. I would work that one, too with a file etc to smooth out any sharp edges. Use a vacuum afterwards to suck out any debris that might have gotten down the side of the piston.

Things I'd be most concerned about: the block sealing surface and scoring in the cylinders. If you've got heavy scoring that catches your fingernail (or that mechanic's pic) pretty hard, then that's the type of damage that'll cause oil consumption and declining compression.

Guess this engine has had a hard life! But hey, at least the thrust bearings sound like they're good!
 

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p.s. Nix on air tools to clean the block, it just spreads abrasive material all around in places where it shouldn't be.

Safest method (and pretty effective) is with a razor-blade scraper. A wide scraper is cheap at Walmart, pick up a cheap set of extra blades while you're at it. The wide blade has less of a tendency to want to dig in.

I like to use Marvel Mystery Oil as a lube when I'm scraping. It gives a nice, smooth scrape-o-the-razor and smells nice, too. Just buy a quart bottle and a pump spray dispenser, and you're in business.

WD-40 or other similar light lubricant will also work as well, but IMHO the MMO does a better job. It's great to use for busting cylinder glaze as well.

https://www.walmart.com/ip/Allway-Glass ... thena=true

Vacuum out the cyls after scraping.

Make sure the oil and water passages are free of debris as well. You can keep a lot of crud out of those by stuffing shop rags/paper towels down below the surface of the block (so that the razor won't catch them when you're scraping).
 

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Unless the depressions are really deep, a .005"-.010" skim cut of the block will probably clean it up. With a new head, you shouldn't have to worry about the head/block "sandwich" being too thin. Yes, there is a spec for that, because when you take material off of one surface or the other, it will change the cam timing a bit (brings the cam closer to the crankshaft, which affects the length of the timing belt and changes cam timing).

As long as you stay within the spec for that measurement, you'd be ok. There are metal shims that would go between the block and the head gasket to correct an out-of-spec condition, as well. You'd seal that shim to the block with Kopper Kote spray or similar. But not to get ahead of ourselves!

You'd have to get hold of your local machine shop to see what their rates are for rebuilding a short block such as this. But I'd expect that as long as the crankshaft thrust surfaces are in good shape, the engine should be very rebuildable. Probably your highest cost would be machining the "deck" (surface of the block). Unless of course you need to bore it out, then there's charge for that and for swapping the old rods onto new, oversized pistons.

Maybe one of the other Trooper Dudes here running 4-cyls can chime in on rebuilder sources, I'm not so up on that. Jerry Lemond might be able to help in that area as well.

There's also another guy who has tons of ZuZu parts, by the name of "J - o - h - n - n - y - 5".

Unfortunately due to issues I won't go into here, he's been banned from this site and mention of his name is moderated as well. He has a lot of videos on Youtube with tons of good ZuZu info, and has collected a massive store of vehicles. So if your block doesn't pan out, maybe he's got something for you.

All that being said, one last thing you could do is take a very very straight edge, and lay it perpendicular to the block. Shine a light behind it. If you can see the light thru low spots in the block, that's not so good. The head gasket can seal some slight irregularities, but there comes a point where it's just gonna leak again.

Pretty hard to evaluate from this side of the keyboard, but we're here to help best as we can!
 

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Believe so. Check YouTube and he has his website info there. Or Google his moniker, it should pull up results.........ed
 

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When you pull the engine, the oil pan will hit the cross-member. Pull the small steel pan off the bottom of the engine, and using great care, the oil pickup screen will just slide across the cross-member as you're going out. Same going back in. At least that was my experience pulling the 2.3 out of my '86 Trooper.

Have Fun!!!
 

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The big cast aluminum pan that bolts to the block stays put. Only the small "top hat" stamped steel pan at the bottom of the oil pan sump is required to be removed. The only thing that sticks out of that bottom part is the oil pickup screen. When you reinstall the engine, you could wrap the pickup screen in a plastic bag to keep foreign material out.

One other possibility, is to drop the front differential carrier at the frame brackets. This is usually required when pulling a GM V6 out of Gen I Troopers.

There are (2) quite large bolts per side that hold the differential mounting brackets to the frame, and the bolts go thru large rubber noise-and-vibration-isolation bushings with a metal tube (spool) in the middle. I used a good air-impact wrench with the compressor pressure turned up, and was able to bust them loose. As long as the rig isn't a rust-belt creature, the bolts should come off and then the diff and cross-member will drop down a bit for more clearance.

Kinda 6 of one, half-dozen of the other. The oil pan bolts are way easier to remove but then the pickup screen is hanging out.

Hope that helps.......ed
 
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