1990 Isuzu Trooper HELP

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1990 Isuzu Trooper HELP

Postby Trooper1990 » Mon Aug 14, 2006 6:22 pm

Hello to all,

I am a newbie here. I own a Isuzu Trooper 1990 4cyl manual tranny. After I start the engine idling is ok and RPM is also ok but afterward like 5-10 minutes driving my rpm goes up and down like you are stepping on the gas and letting it go fast and many times. afterwards RPM goes high and remains high while temperature is high( i know this part is normal so water can circulate) can anyone help me with this problem? I love my car and would really like to fix it.

Nay help would do.

Thank you all
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Postby BigRed » Wed Aug 16, 2006 10:01 pm

Congrats on your New Old Trooper. They are classic, tough, reliable -- if you take care of them.

Sounds to me like you need to do the following:

1) Drive to local auto part store BUY HAYNES MANUAL
2) Look in troubleshooting section ENGINE SURGES AT IDLE

Could be an overheating issue. Change thermostat and drain, flush, replace hoses + fluid. Buy a new 2 core radiator from radiator barn (search google).

The only way to take care of your truck is to do everything diligently.
Replace plugs, cap, rotor, wires, air filter, fuel filter -- when recommended
Adjust valves every 12K
Every two years new belts and adjust timing
The way I solve problems is by doing routine maintenance. That way I am aware of what has been fixed, which parts are new, and therefore which parts would not be a source of the problem. If you are on top of your maintenance, you just get better at diagnosing your truck.

Sounds like overheating. THese trucks will overheat, so upgrade to bigger radiator and overhaul the cooling system, couldn't hurt.

$.02

Roste
'96 Acura SLX. 144K. 3.2 SOHC, Auto, White. Stock all around for now.
'98 Rodeo S. 147K. 3.2 DOHC, 5sp, Red, Rancho 5000's, 2" lift, OME 913 - SOLD
'90 Trooper. 126K. 2.6L, 5sp, Red, Rancho 5000's - SOLD
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Postby soopertrooper » Wed Aug 16, 2006 11:28 pm

you need to clean your throttlebody and ck. your idle air control valve (IAC)
cleaning fixed mine and only cost me a can of carb cleaner.
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good point

Postby Skeletor » Thu Aug 17, 2006 7:24 am

soopertrooper wrote:you need to clean your throttlebody and ck. your idle air control valve (IAC)
cleaning fixed mine and only cost me a can of carb cleaner.



I know a few owners, who had similar problems,and it was
fixed this way.....oops, gotta go, Elvis is at the door...


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Engine Surges at Idle

Postby Trooper1990 » Fri Aug 18, 2006 6:34 pm

Thank everyone for the welcome !!

Yup, I did buy a can of Carburator cleaner. Here is what I did:

1. Removed the air filter and the whole air intake so you can see the intake for the carburator.
2. Sprayed the whole intake manifold with the cleaner, cleaned it with a toothbrush and wiped it dry with a clean cloth. (did this like 4 times to remove gunk).
3. And then I saw that a part of the mechanism for (attached to the gas pedal line is crooked and bent) so I adjusted it and made it straight.
3. cleaned everything up again, dried and then sprayed WD40 allover to prevent rust on the springs.
4. My idle did go OK and the revving stopped but for a while and then I was driving it found out that the revving (which goes up and down is still ther) specially when the engine gets hot (i.e. the temperature gauge goes beyond the middle lin, and then the engine revs up to compensate and circulate the water. Afterwards the engine would idle dwon slowly when the water have already circulated and the heat dissipates.

I am thinking that my thermostat is broken, is it ok to run without the thermostat? What are the pro's and cons? Is it also hard to remove and change the thermostat? or this situation is ok and normal that my temp. gauge will go up that high but eventually go down ? I dont want to have a blown gasket or something the like.

Sorry, newbie here and just learning to DIY my trooper (which I really love)

Thanks !
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Postby tractorking » Fri Aug 18, 2006 7:04 pm

super easy to do the T-stat, maybe 5-10mins and $5-15.
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Postby Hack » Sat Aug 19, 2006 11:36 am

The 2.6 has a belt driven fan. It is designed to increase the idle when the engine is hot. I have driven mine with the AC on in 100+ temps this summer and have never had the temp gauge go past verticle. If your's is doing that it definitely sounds like a cooling problem. Better get it fixed because the heads on that motor are prone to warping due to high temps. I wouldn't just remove the T-stat. That engine is designed to have one. In fact, if you replace it be sure to get a genuine Isuzu part. Some users have reported problems with some of the after market

Personally, I'd start with a good cleaning of the radiator. Sometimes mud and leaves get caught in the gap between the radiator and the AC cooler cutting off the air flow especially at idle. The next thing that I would try would be a good cooling system flush. After that if you still have overheading problems check to see that you are getting good flow. You can usually tell by feeling the top radiator hose, just be careful not to get burnt.

By the way, how is the timing belt? Do you know when the belt was last changed? If not, the belt can be inspected by removing a few bolts and bending back the plastic cover. If the belt looks worn, replace it. A busted belt will do a number on the valves. Most usually change the water pump (and belt tensioner) when they replace the timing belt.
Mario

Trail Truck: 2001 Amigo 4x4, Auto, 3.2L, Rear LSD, Front Aussie Locker, HD Torsion Bars, 2" Lift, BFG M/T KA2 33x10.5R15
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RIP: 1989 Troop 2.6L 5spd --- Stripped of all good parts. Body and rotted frame sent to the crusher.
RIP: 1999 2WD Amigo, Engine Blown by Daughter #2. Parted out. Sent to crusher.
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Heating

Postby Trooper1990 » Mon Aug 21, 2006 2:16 pm

Yup, there is good flow of coolant to the engine. I will change the thermostat just to be sure this weekend. I dont want my heads to be warped and have a blown head gasket due to this problem.

Timing belt is ok and water pump is new, so the only hting I am thinkoing causing the problem might me the thermostat is not opening correctly.

I hate when my temp goes hiigh pas vertical cause I know my engine will not feel good when this happens. I will DIY it this weekend. Hopefully everything will beok then.

This morning it still went a little bit after vertical but afterwards it went down slowly, dont want this to happen again.

Will post results afterwards !

THANKS SO MUCH and HAPPY TROOPING !
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Postby Troopy89 » Mon Aug 21, 2006 3:38 pm

If you go to radiators.com they have a trooper radiator for 108 bucks shipped. I just got one and it is great looking and works great. The fins in my radiator on my 2.6l '89 were disitntigrating on the side that faces the ac cooler. You might want to just get a new one at that price like I did. I also did the water pump and timing belt & all the drive belts when I did my headgasket 3 weeks ago.
My trooper did the up and down surge thing for awhile 8 years ago when I first got it and I found a loose vac hoses and replaced all of them with new hoses and zip tied them all, the problem went away after that.
So far I have 86 miles on my head gasket job and troopy is idling like it is 1989 again!
BTW Its not good to run without a thermostat.... but you can in a pinch if it is imparitive to get where your going in the desert.

........Good luck and check out both sides of that radiator...
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Idling Problem

Postby Trooper1990 » Tue Aug 22, 2006 3:52 pm

I will do all of your advises this weekend, remod change all vacuum hoses, cause a lot of them are rotting out and brittle. Remove and change the thermostat also do a radiator flushing, clean my radiator (by the way it is already brand new). I just cleaned my whole throttle body with cloth toothbrussh and a carb cleaner, worked ok my idling went down and normal only when it gets hot and then it surges up and down afterwards when the temp goes down the idling is ok again so by the way of elimination.....wlaah the problem might me the cooling system of the engine.

One more favor guys, do you have a picture of the vacuum hose placement for a 1990 trooper 4cyl manual, no aircon. I found out just now that some of that one or two hoses are missing one is for the carboin canister and another loose one that I do not know where it goes.

Thanks all !!!!
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Re: Idling Problem

Postby DogMeat » Tue Aug 22, 2006 5:51 pm

Trooper1990 wrote:One more favor guys, do you have a picture of the vacuum hose placement for a 1990 trooper 4cyl manual, no aircon. I found out just now that some of that one or two hoses are missing one is for the carboin canister and another loose one that I do not know where it goes.

Thanks all !!!!


huh? the "wiring" diagram for the hoses should be under the engine hood.
if you still need one, i'll take a pic of it later today.

also, if the hoses are dry rotten, replace them all.
2.6L 1990 pup w/t 31" M/Ts
plays well with others.
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Postby Hack » Tue Aug 22, 2006 6:02 pm

No need to take the photos. They have already been posted http://www.planetisuzoo.com/articles.ht ... ose_Photos
Mario

Trail Truck: 2001 Amigo 4x4, Auto, 3.2L, Rear LSD, Front Aussie Locker, HD Torsion Bars, 2" Lift, BFG M/T KA2 33x10.5R15
RIP: 1988 Troop 2.6L 5spd, Stripped and sent to crusher
RIP: 1998 4WD Rodeo, Auto, 3.2L. Ruined by Daughter #1, stripped and sent to crusher
RIP: 1989 Troop 2.6L 5spd --- Stripped of all good parts. Body and rotted frame sent to the crusher.
RIP: 1999 2WD Amigo, Engine Blown by Daughter #2. Parted out. Sent to crusher.
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Postby onetouch » Tue Aug 22, 2006 6:09 pm

This might help.

http://www.asashop.org/autoinc/feb98/techtips.htm

I replaced the valve with one from a yard & the surge went away.

Jim
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Postby tractorking » Tue Aug 22, 2006 8:33 pm

Hope this helps 1990 4cyl
I can get a better one if you need it.


Image
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Postby bendorfold » Tue Aug 22, 2006 9:33 pm

Auto Zone has a bunch of info at there web site. It looks a lot like Chilton style information.

http://www.autozone.com/servlet/UiBroke ... 183ab2.jsp

Pulled this image from above link.

Image
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mine - 1989 Trooper, 2.6L, 5-spd Manual, 170,742 miles, Stock - SOLD
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Postby tractorking » Wed Aug 23, 2006 2:47 am

Is there supposed to be an idle set screw with the EFI 4cyl
is so mines missing but I assumed it was computer driven.
:?
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Postby Hack » Wed Aug 23, 2006 10:16 am

Yes, there is a set screw.
Mario

Trail Truck: 2001 Amigo 4x4, Auto, 3.2L, Rear LSD, Front Aussie Locker, HD Torsion Bars, 2" Lift, BFG M/T KA2 33x10.5R15
RIP: 1988 Troop 2.6L 5spd, Stripped and sent to crusher
RIP: 1998 4WD Rodeo, Auto, 3.2L. Ruined by Daughter #1, stripped and sent to crusher
RIP: 1989 Troop 2.6L 5spd --- Stripped of all good parts. Body and rotted frame sent to the crusher.
RIP: 1999 2WD Amigo, Engine Blown by Daughter #2. Parted out. Sent to crusher.
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Postby tractorking » Wed Aug 23, 2006 4:23 pm

No wonder mine has alsways idled a little low, hmmmmm
ill have to do something about that.

Why would anyone take it out, or could it just rattle loose.
Its never been there since Ive had it. :roll:

sweet, maybe this will smooth everything out real nice!
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Postby onetouch » Wed Aug 23, 2006 6:25 pm

That is odd.

The set screw is factory set and sealed with paint.

Disturbing the setting of the screw is very seldom necessary.

Strange that the thing would just fall out of there. :?

Jim
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Red-2 91 Trooper, 2.8, 5 speed, acquiring stuff.

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Postby Hack » Wed Aug 23, 2006 7:40 pm

Perhaps someone adjsted the screw too much and it worked its way loose? Unlike many computer controlled fuel injected engines, the 2.6L is designed to be adjusted manually. That is what the dealer did to correct a high idle on my Troop.
Mario

Trail Truck: 2001 Amigo 4x4, Auto, 3.2L, Rear LSD, Front Aussie Locker, HD Torsion Bars, 2" Lift, BFG M/T KA2 33x10.5R15
RIP: 1988 Troop 2.6L 5spd, Stripped and sent to crusher
RIP: 1998 4WD Rodeo, Auto, 3.2L. Ruined by Daughter #1, stripped and sent to crusher
RIP: 1989 Troop 2.6L 5spd --- Stripped of all good parts. Body and rotted frame sent to the crusher.
RIP: 1999 2WD Amigo, Engine Blown by Daughter #2. Parted out. Sent to crusher.
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Postby onetouch » Wed Aug 23, 2006 9:19 pm

Quite possible.

When I was going through my idle woes, I first cleaned up my vacuum lines which were a mess.

Helped, but not all that much.

I then replaced the thermal valve, which got rid of the hard surge I was having.

I then checked out the tps, fast idle soliniod, and on and on.

Still had crappy idle, to fast, some surging.

I finaly broke down & took the throttle body loose with all those annoying little hoses that are such a pain to get back and pulled the head with the manifold on it and put it on the bench to get a good look at it.

It was a couple of loose bolts on the intake manifold.

New gaskets, put it back together & problem pretty much solved.

Still not perfect though.

I'm guessing wear on the throtle valve it's self, or maybe the tachometer.

Some days it settles in at 850 idle, other days 950.

cant seem to hit that majic 900.

Cant really tell a difference listening to it.

Anyway, good idle, no surge and I never touched the Idle screw because the factory manual basicly said dont mess with it.

Jim
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Postby Grumpfrompahrump » Wed Aug 23, 2006 9:52 pm

BigRed wrote:Could be an overheating issue. Change thermostat and drain, flush, replace hoses + fluid. Buy a new 2 core radiator from radiator barn (search google).


If in fact you are overheating, it means that it is acting normal. The thermal vacuum valve is supposed to give you higher idle as you get hot.

It addresses it in the Haynes manual, page 160. "The fast idle system improves cooling when the engine is hot by allowing additional air into the common chamber. The system consits of a thermal valve that senses coolant temperature and a fast idle solenoid that controls flow to the common chamber."

HOT = MORE AIR = FASTER IDLE

I puchased my 88 brand new in Mississippi while in the Air Force. As hot as it gets there, the idle did this all the time, and I brought it back for warranty work (I thought). They assured me it is normal, and even allowed me take another unsold Trooper for a long test drive. It was the same. Even now, the times I go to Death Valley in the summer, my idle takes off! I was just there in July.

I agree to check your cooling system. If it is just running hot because it over 100 degrees, I'd say it is normal. Try taking it out in the evenings when it is cooler.
Steve
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Postby tractorking » Thu Aug 24, 2006 3:34 am

Here s a pic, I can get a better one, but this is where I think it belongs.
I tried but its super tight so I wrapped a zip tie through so the throttle wouldnt go all the way down.

Image
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set screw

Postby Trooper1990 » Thu Aug 24, 2006 2:22 pm

Yep, picture is correct the idle set screw is right on the spot the arrow sets, a little weird thou if you said it was not there ? probably it has fallen out when someone adjusted it ???

Thanks everyone for posting all the pictures for the vacuum hoses I will be changing all of them this weekend and I will be happy to report all the results !

I will change the thermostat also, guys can you give me more inforamiton about the solenoid stuff and the idle sensosr thing ?

Thanks a lot !!!!
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Postby tractorking » Thu Aug 24, 2006 4:56 pm

Ok thats good to know, I thought it was a vacuum leak or a vavle adjustments that was causing my low and soomtimes eradict idle.

I tried several approaches to getting a screw back in there and its just too tight of a spot. I have to do a valve adjutsment sometime soon so Ill wait till I pull everthing off and then replace it.

I wrapped a nice piece of zip tie trough the hole so the throtle would not go all the way down, that seems to help slightly. I always wonderered why it idled a little rough. :D

Oh and short or replaceing all the vacuum hoses, I have been going through and clipping the cracked and brittle ends off and then refitting them with the fressh cut rubber. Adding a zip tie to everything seems to have helped my truck run just a tad bit smoother..
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