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1989 Isuzu Pickup 4WD 2.6 5sp
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Hello all,

I recently bought an 89 4WD 5sp Pickup. It has the 4ZE1 with the I-tech. Body, frame, bones are in great shape (AZ car with no rust). The test drive went great and she's got some pep and shifted fine through all five gears. I then drove it back home from Tuscon to Phoenix (about 120 miles) at around 65 the whole time. Truck did great (from what I could tell). I got her home, backed it in the driveway and made room in my garage.

About 30-40 min later I fired her up and when I gave her revs there was a pretty horrible squeal. I couldn't tell if it was a belt, bearing, or what. So I turned it around and squeal-ily pulled it in to the garage. She also dumped some oil while briefly parked after the hour and half drive. It was passenger side about even with the axle.

When I start the truck up now there's a bit of a vibration (I don't remember if that was always there). The passenger mirror vibrates pretty good.

So now it's 2.5 weeks later and I'm ready to dive in. I've done a bunch of research on the 4ZE1, watched all of *******'s Youtube videos, bought a physical FSM and have a pretty large hit list.

I'd like to know what is the best order to knock everything out?

Here's what I'm thinking for priority:

  1. Remove radiator and fan[/*]
  2. Tighten timing belt[/*]
  3. Inspect harmonic balancer (maybe caused the squeal?)[/*]
  4. Adjust valves[/*]
  5. Adjust timing[/*]
  6. Replace plugs[/*]
  7. Replace oil,trans oil,diff fluid[/*]
  8. Inspect/replace belts[/*]
  9. Inspect/replace vacuum tubing[/*]

Would you do it differently? Is there something that I should be prioritizing higher? I have a large list of other things but I want to get the engine straightened out first. I bookmarked the great thread, "Reliability mods" too.

Thanks much!

Oh and this is my 2nd Isuzu. We also have a 2000 Trooper 5sp that my 16yo son is now driving. It's been a beast! This forum has been great.
 

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Unless you have a trustworthy record of when the timing belt was replaced, it would be recommendable to replace the belt.

Some would also recommend that you re torque the head.
 
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1989 Isuzu Pickup 4WD 2.6 5sp
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Discussion Starter · #3 ·
mudoilngears said:
Unless you have a trustworthy record of when the timing belt was replaced, it would be recommendable to replace the belt.

Some would also recommend that you re torque the head.
I don't have such a record so I'll replace it. Do you have recommendation on suitable brand? Will torque the head while I'm in there too. Thanks!
 

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Start with a compression test. Then adjust the valves and retest - or adjust he valves first. 2 adjacent cylinders with zero or low compression MAY be a blown head gasket. If you pull the valve cover to adjust valves, take a torque wrench and 10MM allen bit and pull the final value torque on the head bolts in sequence (re-torque head bolts)
IF you have to do a head gasket: 1. only use a genuine Isuzu head gasket, or a Felpro head gasket. For best results, take the head to a shop and have it redone. Some of the earlier heads were prone to cracking.
When doing the head gasket (or if it checks out okay) a Gates timing belt is good enough. I have replaced several Isuzu and Subaru belts and Gates worked for me.
The oil leak COULD be: (easiest to most difficult) oil filter gasket, oil pressure sender (less likely), oil filter adapter block gasket, oil pump seal (less likely - usually a front seal looking kind of leak) there is an oil gallery in the center of the lower intake where it bolts to the head. The gasket can leak there.
There are a ton of other "New Isuzu owner" checks, we'll cover those after you get the engine situation sorted out. Dennis
 

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re: oil leak
Also, check the 1/2 moon rubber thing (damn, can't think of the word for it) at the rear of the head and the distributor o-ring(s). Both known to leak.

Mike
 

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Discussion Starter · #7 ·
gruff54 said:
re: oil leak
Also, check the 1/2 moon rubber thing (damn, can't think of the word for it) at the rear of the head and the distributor o-ring(s). Both known to leak.

Mike
Appreciate the tip. Thanks MIke. I'll look there as well. I'll be able to dedicate all day tomorrow to start tearing into the truck. Will report back.
 

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Don't recall seeing the picture on the original post. Sweet looking truck. Dennis
 

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oil filter adapter block gasket,
 

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I also recommend removing the EGR and cleaning it with carb cleaner, mine had enough build up to make the truck run a little funky.

Here's the method I used.

Also, cool truck. I'm a little jealous of the smokers windows and rear sliding glass that the early year pickups got. Also they seemed to have gotten rid of the fold down arm rest bench seat at some point too, not sure if yours has that.
 

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DSUZU said:
Don't recall seeing the picture on the original post. Sweet looking truck. Dennis
Thanks! It had the factory 31" tires but currently has 29". I'll be replacing them. I think that means I have the 4.56 gears too.

Tentin said:
I also recommend removing the EGR and cleaning it with carb cleaner, mine had enough build up to make the truck run a little funky.

Here's the method I used.

Also, cool truck. I'm a little jealous of the smokers windows and rear sliding glass that the early year pickups got. Also they seemed to have gotten rid of the fold down arm rest bench seat at some point too, not sure if yours has that.
Excellent. I'll take a look there as well. Thanks! Yea I love those triangle windows and rear slider too. The interior will be getting attention once the engine is sorted. I'm going to attempt to remove all the custom wiring, a-pillar gauge cluster, etc. I read that I can replace the cluster with one from a Rodeo that has all the gauges and tach. I'll add some late model buckets and some kind of center console.

01717_7yt6ZW9jVww_0t20CI_600x450.jpg
 

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The cluster has to come from a 4 cylinder pickup or Amigo. All the 4 cylinder Rodeos had just a speedometer. A replacement bench seat OR buckets can come from a Rodeo. Your truck should already have the threaded holes for bucket seats should you choose that option. Dennis
 

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DSUZU said:
The cluster has to come from a 4 cylinder pickup or Amigo. All the 4 cylinder Rodeos had just a speedometer. A replacement bench seat OR buckets can come from a Rodeo. Your truck should already have the threaded holes for bucket seats should you choose that option. Dennis
Will definitely start the hunt for Amigo or Pickup. They're pretty hard to find around here. Here's the thread I found where a member was able to swap in a V6 Rodeo cluster. Was your experience different than his? I'm hopeful the Rodeo will work because those are readily available on eBay for like $65. :D

Will look for Rodeo buckets! Good to hear the threaded holes are present. I'll look for them.

Here is a pic of where oil seems to to be dripping (not sure how are far up it originates):

oil-drips.jpg
 

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Compression is done and seems to be looking ok:

1 - 130
2 - 115
3 - 120
4 - 120

However, I have a fuel leak. So I haven't adjusted the valves yet, assuming this should be the highest priority fix. I wasn't able to get a visual of a leak dripping out, but the insulation around the fuel lines seems wet. There's also some other wet areas. Here are some pics but I'm really not sure where to start. I figure the I-tech might be a culprit too? The previous owner told me the truck sits a few days then the fuel leak happens. But after it runs it "seals up" and doesn't leak. When I bought the truck there was no fuel leaking whatsoever. I was searching for it and it wasn't leaking. It's been sitting two weeks now since I bought it.

Here are the pics of what/where I think the fuel leak is coming from. Looking for any advice or tips on how best to address this. Thanks again!

Pic 1: The drips

  1. main puddle of fuel [/*]
  2. smaller puddle of fuel [/*]
  3. dripping from diff cross member [/*]

fuel-leak-1.jpg


Pic 2: Undercarriage

  1. Fuel line insulation is wet with what I think is fuel [/*]
  2. This thing was very wet [/*]

fuel-leak-2.jpg


Pic 3: Fuel line to I-tech

  1. Line seemed dry [/*]

fuel-leak-3.jpg


Thanks again for any advice. I've tried to annotate the images with numbers so that I can convey what I'm seeing easier. Let me know if there something else I should do.

Cheers!
 

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Discussion Starter · #15 ·
Going to replace the injector o-rings. My problem is just like the one described in this post. Anyone have any luck with this eBay kit?

I suppose I should take the intake off and inspect before buying parts. Will inspect FPR too.

EDIT: I've visually confirmed a leak is at at least two injectors. I'll get the rebuilt kit. **********'s video of the intake removal does not sell this job as a fun one, lol. "GODDAMNNITT!!!!" <-- quote from video
 

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1. Check those hoses and make sure they are EFI rated fuel hose.
2. I used an injector O-ring kit from Autozone. You DON'T have to remove the upper (common) chamber to change the injectors. My build thread, around page 30 shows where I pulled my injectors, found and cleaned the individual injector screens, cleaned them myself, tested them myself, and all w/o removing that top chamber.
3. be very careful installing the o-rings and injector seals. The tiny upper rings can pinch and leak, the bottom seals cam fall out. Install, HAVE A FIRE EXTINGUISHER HANDY start and check for leaks. Let it sit and cool off and recheck for leaks (see my fire picture near the end of my build thread)
4. AFAIK, the V-6 instrument panel should NOT work. The V-6 tach should be different, and the V6 speedo may not be correct ratio Dennis
 

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Discussion Starter · #17 ·
DSUZU said:
1. Check those hoses and make sure they are EFI rated fuel hose.
2. I used an injector O-ring kit from Autozone. You DON'T have to remove the upper (common) chamber to change the injectors. My build thread, around page 30 shows where I pulled my injectors, found and cleaned the individual injector screens, cleaned them myself, tested them myself, and all w/o removing that top chamber.
3. be very careful installing the o-rings and injector seals. The tiny upper rings can pinch and leak, the bottom seals cam fall out. Install, HAVE A FIRE EXTINGUISHER HANDY start and check for leaks. Let it sit and cool off and recheck for leaks (see my fire picture near the end of my build thread)
4. AFAIK, the V-6 instrument panel should NOT work. The V-6 tach should be different, and the V6 speedo may not be correct ratio Dennis
That is great news not having to remove the chamber! I'll check your thread. I edited my last post before realizing you responded. Thanks again and, yes, I'll have a fire extinguisher on the ready.

EDIT: Found DSUZU's post on removing the rail without having to remove the chamber.
 

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Ten days later and the injector repair kit I ordered should be here today or tomorrow. Yesterday I hit a couple of junkyards hoping for spare I-tech components but no luck. Got an antenna, washer fluid reservoir, and fuse box cover. Oh and I grabbed the battery strap of a 2nd gen Trooper that'll I try to modify to fit the pickup.

My current priorities are (in order):

  1. Injector seals[/*]
  2. Adjust valves[/*]
  3. Adjust timing[/*]
  4. Tighten timing belt[/*]
  5. Replace fuel filter[/*]
  6. Replace fluids[/*]
  7. Inspect/replace belts[/*]
  8. Inspect/replace vacuum tubing[/*]

I have an ever-growing to do list for everything else. I'll start a build thread.

Here's the 94 pickup that I picked. Recovered a 12mm box wrench from under the air filter :lol:
IMG_0620.jpg

IMG_0634.jpg


Optimus Prime pedal mod?
IMG_0631.jpg
 

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Got the injectors out without removing the chamber! Thanks again for the tips. I noticed some things...

  1. The leaky injector had a jacked up seal [/*]
  2. The leaky injector is not same as the other three and was stuck in the rail[/*]
  3. Will replace hose on fuel rail with EFI rated as suggested by DSUZU[/*]

I found a post that recommends an injector cleaning service and shaggy had success. So I'm going to send my three correct injectors for cleaning. Can anyone recommend a source for a replacement? OEM refurb would be great if possible.

I have no idea how these would relate to compression but here are the injectors. 1 to 4 is left to right in this photo.

1 - 130psi
2 - 115psi
3 - 120psi
4 - 120psi (this is the odd one and was stuck in the rail)

IMG_0703.jpg

IMG_0686.jpg


Some other things I noticed now that I've started removing stuff:

  1. All of the injector connectors were missing the metal retaining clip[/*]
  2. TPS connector missing and replaced with spade terminals (same for coil)[/*]
  3. Throttle body coolant nipples are rusty[/*]
  4. Throttle body and chamber seem excessively dirty [/*]

IMG_0663.jpg

rusty-nips.jpg

carbon-intake.jpg


Lots of wiring seems to be missing connectors. I wonder if the original engine was cut out in haste and replaced with the current one. I'll try to locate the serial number and find out.

Pretty stoked to finally get some progress!
 

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