Isuzu SUV Forum banner
1 - 9 of 9 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter · #1 ·
Hey guys! I'm brand new to your forum and first of all I would like to greet all of you Trooper/Isuzu-enthusiasts.

I bought my '91 Trooper I 4 months ago and since then started a big restoration project with him.

I made huge process already but now stumbled over a problem where I am slowly but surely getting crazy and frustrated.
The trooper has a really bad starting behaviour (cold and warm). When I start the engine the motor runs only for 1-2 seconds then dies again. Giving him some gaspedal hits nearly has no effect (even if I push gently or full throttle). It seems he is not getting enough fuel if you ask me.
After 4-5 starting procedures he mostly comes to life (often followed by backfiring). If he is finally running the engine behaviour seems to be quite normal (just sometime a small shaking)... If I "play" with the throttle he's showing sometimes smaller backfiring. If I turn the engine off I am getting the same behaviour as before.

Until now I already replaced the spark plugs, fuel filter, air filter, checked the whole air system, cleaned up the throttle valve, replaced 2 year old fuel, replaced all vacuum hoses in the engine bay, checked and corrected valve clearances and I had put fuel injector cleaning substrat into new fuel but nothing had solved the problem.

Did someone of you maybe heard or had similar problems?

My last left-over assumptions are fuel injectors, fuel pump, bad ignition timing or a faulty ignition cable / dirty distributor cap...
What do you think? I really hope to find some good answers here because I have so many open project-ideas I would love to follow.

Thanks in advance!
ghost
 

·
Registered
Joined
·
868 Posts
What motor do you have in it? Also, what is the fuel pressure reading at the motor?
 

·
Registered
Joined
·
10,176 Posts
Two POSSIBILITIES: Bad fuel pump, or bad alternator. The alternator has a special circuit that powers up the fuel pump relay after it starts (this is an accident safety feature). There is a way to jumper the F.P. relay, maybe in the "Hall of Fame" section. Only way to check F.P. pressure on a 2.6 is to add a Tee fitting to the fuel line. Dennis
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #5 ·
could this also be related to my next problem that I don't pass exhaust-gas check? CO-value was at 0.7 before I had renewed the catalysator and lamda sensor. Now it is at 0.5 but I need to bring it down to 0.3 to pass it. If you are standing next to the car you really can smell intensity of exhaust gas and fuel so it seems to me when he is running he is much too "rich" on fuel at the fuel-o2-balance
 

·
Registered
Joined
·
10,176 Posts
Fresh plugs and properly adjusted valves, Check. You might double check that the ignition timing is EXACTLY where Isuzu recommends it. Too advanced or retarded and emissions will increase. Many think that if you advance th etiming and it runs better (they usually do) the emissions are lower. This is false. The specified timing and settings are for least amount of emissions, NOT best running. I've had a few cars where I could adjust timing (after emissions inspection) and get BETTER gas mileage and performance. Make sure that timing is right. One other thing. These engines are known for also having the timing mark on the crankshaft pulley (harmonic balancer) slip and not be accurate. The balancer is two pieces, an inner hub and the outer ring. The ring can slip. if you suspect it has slipped, pull the #1 plug, (maybe all the plugs) get a long screwdriver or rod, insert it into the plug hole and rotate or rock the crank back and forth until the rod is at its highest point (there is a certain amount of swing while the piston is at TDC, but this will be close). If mark is at or near zero, your balancer is probably accurate. Dennis
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #7 ·
Thanks Dennis! Very good advice. For sure I will need to check ignition timing and furthermore also plug wire electrical resistance value.

The balancer advice I need to deep dive into it because at the moment I don't understand it completely 😅.
But nevertheless thanks alot for your tips!
 

·
Registered
Joined
·
10,176 Posts
Inner hub on balancer. The outer ring (with the mark) is bonded to the hub by a rubber substance (for lack of official term). Sometimes the rubber separates or slips and the outer ring may move which moves the timing mark. 2.6 engines are known for this, and the earlier 3.2s had the same problem. The balancer on my '94 3.2 slipped so badly that if I turned on the headlights and A/C, the belts would stop turning.
If you find it is accurate, I suggest making a mark from the center hub to the outer ring (I used white paint on mine). this way you can immediately tell if it does slip. Dennis
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #9 ·
So I've made the jumper as mentioned in **********'s video (
) and there was something interested I've noticed. At Johnny's mentioned jumper position 1 the engine didn't start at all... but with position 2 where the fuel pump is running all the time the engine started immediately without problems and furthermore my oil-pressure warning symbol did not light up anymore (with the relay installed I get the warning symbol slighty illuminated in the dash-panel... this turns then out after some time when the engine is running...)
Already replaced the two oil-pressure sensors here as well (one sitting at the bottom of the engine block and one is connected next to the oil filter) but this had no effect to the oil-pressure symbol.. unfortunately my oil-pressure gauge still did not show a pressure more then 0 when the engine is running
 
1 - 9 of 9 Posts
Top