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Discussion Starter · #1 · (Edited)
1993 Isuzu Trooper S SOHC 3.2L Manual Transmission, no mods, almost everything is stock. I have had this car for 8 years after my sister basically drove it in to the ground, and I have been slowly fixing it up as a long time project. I love this car and I try to take really good care of it, but with no one around to teach me anything about cars, I have had to teach myself everything I know. So I apologize for my lack of knowledge.

There is a large mountain where I live to get to the closest city, and I used to be able to ride up it in 4th gear at 70 - 80mph and roughly 4.3k revs at 70. After the tranny swap and gasket replacements, I can ride the hills only in 3rd gear at 4.5k - 5k revs and at 55mph - 60mph. I don't want to push the engine too much because it's so old and has between 450k - 550k miles on it (odometer is broken so this is a rough estimate) and blow the motor until I can open it up and rebuild it. I like this car, I know it's a lot of work but it's done me good and these lines of cars earned the title Trooper.

A little back story and information on the big repairs, I have replaced the transmission from another trooper I found on Ebay, not sure if it was a SOHC or DOHC, but it was the same year Trooper that it was pulled off of. Had a "get what you pay for" mechanic install it who was a good friend, but the other work he helped me with was basically trash (he pretty much ruined my exhast system and had to put a new line on in a couple of places, and I need a new muffler even though I just got a new one 3 years ago) so I know I need to go through and recheck any of the work he's ever done on the car (thankfully it wasnt much). I have replaced a few other things like the valve cover gaskets and spark plug seals, power steering pump, radiator, serpentine belts and timing belt, fuel pump, fluids, spark plugs, ignition coils, cleaned some of the engine of old leaked oil, intake manifold, throttle body, etc. The easy stuff. Couple of things that need attention is the suspension, long axle (cv boot is busted open), and maybe the u-joints, also the poor thing has a loud popping noise on the passenger side when I turn the wheel too far in motion (like u turns), so I gotta be careful there. Steering column has a busted boot, like, just a cacophany of things that need attention I'm slowly getting around to, but I figure the info could help.

Everything else is basically stock except the vacuum booster hose that's suppose to be molded, not sure if it makes a difference but Jerry is in the process of finding me one, as of right now it's just a heater hose connecting the lines. The car is running almost better than ever, especially since I got it, however the only thing I have realised, and can think of right now, is a significant change in powerloss going up hill.

Where do I start diagnosing to find the problem? I have looked in the forums but I feel it's just such a specific situation that asking the Isuzu experts is the way to go. Any information is helpful. Thanks in advance!
 

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1989 Trooper R/S
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Not sure about the brake booster vacuum line make-up on the Gen. 2 Troopers, but on the Gen. 1's there is a one way check valve that is part of the line itself and if missing could be a large vacuum leak.
 
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I would start with the fuel filter, you didn't mention that it has been replaced. When I owned my 1987 Trooper I noticed one day while going up a long hill near my home, that I had to push the throttle all the way down just to maintain my speed. The Trooper was going slower and slower until I finally crested the top. I had never changed the fuel filter before and when I did, I noticed immediately how heavy it was in my hand. After replacement, my Trooper's power was restored and I never had any problem with that hill again.

Good Luck!
 

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X 2 on the brake booster "one way valve" (they also prevent a backfire from destroying your booster diaphragm) and on the fuel filter. Dennis
 

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Discussion Starter · #8 ·
I would start with the fuel filter, you didn't mention that it has been replaced. When I owned my 1987 Trooper I noticed one day while going up a long hill near my home, that I had to push the throttle all the way down just to maintain my speed. The Trooper was going slower and slower until I finally crested the top. I had never changed the fuel filter before and when I did, I noticed immediately how heavy it was in my hand. After replacement, my Trooper's power was restored and I never had any problem with that hill again.

Good Luck!
Actually I have replaced it, but I have a shifty family. Last time I replaced it was about 14(?) months ago around last year, but I'm not sure. However I'll check it out, good idea!
 

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It's just a little check valve that slips inside the brake booster vacuum hose. Often just about 6" to a foot from the booster, sometimes appears as a bulge in the hose. Sometimes marked. Dennis
 

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Discussion Starter · #12 · (Edited)
It's just a little check valve that slips inside the brake booster vacuum hose. Often just about 6" to a foot from the booster, sometimes appears as a bulge in the hose. Sometimes marked. Dennis
So like this but actually inside the hose? If so I do not have one.
Arm Font Gesture Gas Tool



EDIT: Did some research on this one way valve and I definitely do not have one. I also don't have the molded hose, and after looking in to it, a heater hose is more likely to collapse under pressure (or lack thereof in this case) so I just need to grab one online, at an autoparts store, or through Jerry if I can't find one that fits. I'll give an update if replacing this makes a difference.
Not sure about the brake booster vacuum line make-up on the Gen. 2 Troopers, but on the Gen. 1's there is a one way check valve that is part of the line itself and if missing could be a large vacuum leak.
 

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Discussion Starter · #13 ·
EDIT: I am referring to the part names on my vacuum diagram here Font Gas Paper Paper product Document


I went to check my pcv valve and the whole thing came apart pretty easy, not sure if that's suppose to happen. My revs don't bounce anymore since I replaced my valve cover gaskets and spark plug seals, but I think the pcv valve can reduce power? My egr valve and the egr backpressure valve have never been replaced as well, could this a possibile diagnosis? Right now my plan is that I'm gonna replace my fuel filter just incase it caught anything, as well as my pcv valve just incase.

Heres the crankcase (the part that goes in the crancase through the valve cover) side of the pcv valve:
(as you can see the gromet has buildup on it, but the rest looks fine)
Wood Household hardware Gas Auto part Automotive tire

and the other side:
Wood Gas Auto part Composite material Metal
 
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