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Another 91 for me

81K views 212 replies 19 participants last post by  giusedtobe 
#1 ·
I had been looking for a replacement for my 91 since I had done a trans conversion last year. While under there I found more rust than I wanted to deal with. So I set my sights on a late 1st Gen to drop all my parts into and have a good running Trooper. I wanted to get an LS with all the bells and whistles and a 5 speed.
I found this one on KSL.com out of Salt Lake. The Trooper spent a good amount of time in the Portland area and a lot of time being towed behind an RV. The guy told me it was rust free and tip top condition, just a blown trans. It has some rust and the blown trans I think is blown T case. We made a deal and I went and picked it up last week. It had not run for some time as all the pulleys had surface rust on them and the rotors are rusty also. I got it home and stuck a battery in it and in a couple of minutes had it running. Yesterday I pulled the trans and today the plan is to pull the engine. I am putting the drivetrain out of the rusty one into this one. I had built the engine up a few years ago and it only has 10K on it. The replacement trans if coming from the rusty one also, as I have had no issues with it since I put it in. All of this has to be done in time for my Moab trip in early May. I have my work cut out for me that is for sure. Here are a couple of picts.
 

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#102 ·
The timing is set and fuel has been replaced, cannot find the bolts for the hood, only been off for 6 months so that is no surprise. Going to head out for a quick road test soon. First stop is to get more fuel!
 
#103 ·
By now you should have several cans and cups of various sized nuts and bolts to dig through :mrgreen:

Sounds like today will be an enjoyable day finally !! Have fun Hess !!

As far as the name , you just called me by my last name so all is well :D

Just don't call me late for supper ..
 
#104 ·
Eh pussinboots........SHUTUP.

He likes to be called pussinboots more then anything else Dick. Congratulations....with the timing set, & new fuel let us know it's running smooth as butter.
 
#105 ·
Well guys........It runs awesome! I put about 75 miles on it today, made 2 runs over the pass north of town and never dropped out of 5th. It dropped to 55 on the steeper section but that is like making history for me. Elko is at 5000 feet and the pass is 6200 feet I think. I know it a hard climb in the semi. Oil pressure steady at 55 and the temp right where it needs to be. Not so much as a hiccup or should I say it... nor a drop of oil on the ground. I'm telling ya that is history right there. So to say the least I was feeling all sorts of Isuzu love today. So I came home, took the wife to lunch. Then I cleaned the front seats and carpet a bit, changed the oil, put in the front driveshaft and cleaned the windows.
I read somewhere that I should change the injectors to the 3.4 instead of the 2.8's I have in there now. It ran well enough for me with no CE lights... so don't fix it if it ain't broke kind of a thing?? I have a set of brand new flow matched 3.4 injectors around here somewhere.
On yeah and I have lots of bolts around here, but I only found 1 hood bolt, wierd. I am going to go out to the scrapyard tomorrow and see what I can find out there. My donor trooper is still out there and I saw an old Mitsubishi pickup out there too.
 
#106 ·
:cheers: . Great news. Sticking with it worked out. Going over "the pass" had to be the ultimate test. Down here, the only "climb challenge" we have is the 200 ft high Skyway Bridge, but it will let you know if you don't have enough power. Dennis
 
#107 ·
You mean 4.3 injectors? Probably worth it to try them out to check the differences in performance and economy.
 
#108 ·
Sounds like you finally got er dialed in !! Is that a stock intake or has it been altered ? Just wondering for the power and performance comparisons ..

Awesome to hear it's running so well now !!
 
#109 ·
Thanks Brad, the manifold has been bored out, I bought it that way years ago from a member in Las Vegas. It was also on the dead 3.1

Paul, no I believe I ordered 3.4 injectors when I bought them. Currently running the 2.8 ones.
 
#110 ·
hessmess said:
Thanks Brad, the manifold has been bored out, I bought it that way years ago from a member in Las Vegas. It was also on the dead 3.1

Paul, no I believe I ordered 3.4 injectors when I bought them. Currently running the 2.8 ones.
That's interesting...to my knowledge the 3.4 never came with a throttle body...maybe they are from the 2.8 or 4.3 and specifically adjusted for a 3.4? If so, I'd be interested in knowing where you got 'em.

I very hazily still remember what it was like to drive a trooper with a hopped up 3.4 swapped in. What a difference it was! I had a trooper with a 2.8 and 31's and then briefly had one with a 3.4 and 35's. The 3.4 felt like it had "normal car power" which was like an unknown feeling in a trooper :D I've got to bit the bullet and make the time to swap mine in.
 
#111 ·
paulevans76 said:
hessmess said:
Thanks Brad, the manifold has been bored out, I bought it that way years ago from a member in Las Vegas. It was also on the dead 3.1

Paul, no I believe I ordered 3.4 injectors when I bought them. Currently running the 2.8 ones.
That's interesting...to my knowledge the 3.4 never came with a throttle body...maybe they are from the 2.8 or 4.3 and specifically adjusted for a 3.4? If so, I'd be interested in knowing where you got 'em.

I very hazily still remember what it was like to drive a trooper with a hopped up 3.4 swapped in. What a difference it was! I had a trooper with a 2.8 and 31's and then briefly had one with a 3.4 and 35's. The 3.4 felt like it had "normal car power" which was like an unknown feeling in a trooper :D I've got to bit the bullet and make the time to swap mine in.
Well now you are making me wonder myself, but I swear I ordered the injectors for the 3.4, I bought them off of Ebay, flow matched and all that stuff. I am going to have to find them this weekend and I will post what I find. I put another 25 miles on it today, to and from work. It is running great and the power is, for a Trooper, fantastic. Glad I did this. I only paid 600 bucks for the engine, but I had to round trip Reno to get it. That was almost 600 miles over the weekend. My dead 3.1 was a Las Vegas trip and that one is closer to 1400 miles over a weekend. Yeah I live in the middle of nowhere Nevada.
 
#113 ·
I should say an Isuzu but I have a decent 07 F150. I bought it with 500 miles on it and it now has 55000 on it. I can't even remember the number of times I had it in Portland when the kids were at PSU. I even bought my first Isuzu engine up there from a recycler and brought it home. Got hosed on that one.
 
#114 ·
Well back to the fuel injector question. I am wrong on it being a 3.4, it is the 4.3. I went out and found them and the paperwork. Bought them off of Ebay. Still don't know if I want to put them in. I think I will just wait a bit for now.
 
#115 ·
hessmess said:
Well back to the fuel injector question. I am wrong on it being a 3.4, it is the 4.3. I went out and found them and the paperwork. Bought them off of Ebay. Still don't know if I want to put them in. I think I will just wait a bit for now.
Are you having any issues with "lean surge" on cold startups? This is the most typical problem when upgrading to a 3.4 and using smaller injectors. When the engine is in Cold Start mode, it's richening the mixture based on a pre-determined "map", mainly according to input from the Engine Coolant Sensor (ECS or ECT).

If that's not enough fuel for a larger motor, the ECM won't know the difference 'cause it's not reacting yet to the O2 sensor's signal. One way to compensate for this is to increase fuel pressure which will result in more spray out of the 2.8 injectors every spray-cycle.

The other way would be to install the 4.3 injectors which fuel more per spray-cycle than 2.8 injectors, for any given fuel pressure.

If you're not lean-surging, maybe your fuel pressure happens to already be on the higher end of the factory's adjustment range.

The other issue is, at full throttle the 2.8 injectors can only physically flow so much no matter what. Even at 100 percent they wouldn't flow as much as a 4.3 injector. So, it's possible to go lean at the top end, on a 3.4 engine with 2.8 injectors.

If you haven't noticed this, maybe it's enough fuel. Or at a higher altitude, it's already running rich enough. About the only way you could tell for sure would be to have a laptop running WINALDL, hooked-up to the ECM, and taking full-throttle data points while driving. I'm not deeply knowledgeable with the finer points of tuning with WINALDL, but as I recall you'd be looking for the values associated with "fuel trim" amongst others.

If the ECM is running the 2.8 injectors at full cycle at WOT, that's not really good either.

Last thought, it can't hurt to install the 4.3 injectors; the worst that can happen is a bit of a rich idle with cold starts, but once the engine is fully warmed & in Closed Loop, the ECM will control fuel ratio and only inject as much as the engine needs. So if you ever plan to tow or run the engine hard, better to have extra fuel available instead of fuel starvation at the top end.

HTH..........ed
 
#116 ·
Ed, that is the kind of information that I was looking to get. I don't have any cold start or idling issues. It fires right up and fast idles and then starts to drop like it should. No surging. But I live at 5000 feet so that may be why. I have a heated O2 sensor waiting for me to get to it, off the old Trooper. I have noticed that when getting on the freeway and going through the gears that I think it feels like it is lacking in the power area. But on a uphill on ramp I can still be at 65 by the time I get actually on the freeway. I do have the pressure set at 13 psi and that may be why too I don't have idle issues. I downloaded Winald today and windows 10 opened it. That was one of my worries as there doesn't seem to be any upgrades since 07. I will hook that up and see what it all looks like. I had not thought about maxing out the 2.8 injectors at freeway speed. If the weather holds tomorrow I may have to drop them in.
 
#117 ·
Well not to much to report on this week. I had a multitude of CEL lights and tracked that down to the fact I forgot to hook up the ground strap on the back of the engine. That seems to be gone now. I have put about 350 miles on this junkyard engine and it is running good. I don't see any leaks and that is a first for me. I spent yesterday stripping parts off of the donor vehicle before it gets crushed. I pulled the shackle lift off and part of the front end that had the newer CV axles on it. I had to mount a better spare also. I have a set of tube bumpers that I have been cleaning up and getting ready to install. I also have a factory hitch to install at the same time. I have a brand new set of sliders that need to go on also. I need to snap a few pictures so you guys will believe that I actually have a trooper. One of these days!
 
#119 ·
Yes sir, there will always be something else to do on it. I fueled it up today as I was worried if the fuel gauge was anywhere near right. It seems to be darn close. I had about 1/3rd of a tank with 225 about miles on it. It took 14 gallons and it worked out to 15.6 MPG. That is what I would call good. Most of the driving is 12 miles of freeway and then back. With some in town mixed in. 75 MPH on the freeway. This engine is still running great and no fluid loss and better, no driveway spots. My 08 Tahoe leaves spots!
 
#120 ·
That's impressive considering your rpms are higher and all ... My in town driving kills me ..

Need to see some fresh pictures of the machine :)
 
#121 ·
Yeah I keep saying I am going to post pictures, need to get that done. Looks like the emails are working again!
 
#123 ·
That was funny, cracked me up! The 3.4 continues to run well, just a bit over 1000 miles to date, no oil usage or coolant problems. Started up at 0 degrees. I have future plans but it is just to cold to work on it more. I have front and rear Smittybuilt bumpers painted up and waiting, and the rock sliders are ready also. And I do need to post pictures.
 
#124 ·
Gonna throw a few pictures up hopefully.
 

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#125 ·
Here is a few more, had to resize them. :lol:
They are not lined up like I want but that is not important
 

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#126 ·
I don't have anymore that are new to post, thought I did. So I guess I will have to get a few more and then after the bumpers and sliders, get a few more then. Doubt if anything will happen until after Christmas.
 
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