Trooper II injector or valve problem

STEVECAB

MEMBER
ISUZU

Hi,
I have a 1990 TrooperII which has developed a complete failure of No.4 cylinder. The problem got worse and worse over a few weeks or so. I noticed a misfire (no engine trouble codes set in ECU) and replaced plugs leads distributor cap etc but still had the misfire. I ran the vehicle for about week then looked at the plugs. No.4 plug looks absolutely brand new, no deposits of any kind. However it is definitely sparking. All other plugs are fine. When I run the vehicle and disconnect plug lead No.4 there is absolutely no decrease in engine revs at all. Although there is definitely a spark at No.4 there seems to be no combustion whatsoever. I'm guessing the injector has died (or maybe the valves are stuck open, but there's no strange noises to suggest a dropped valve). I live in the middle of nowhere in central America and have no compression tester (only a multimeter and timing light). How can I check the injectors (and/or valves).

What do you think, thanks in advance for your time.

Steve

3 Replies

MIKEYBDMAN

MECHANIC
623 POSTS

Well, you can always take the valve cover off and watch the valves work at idle. That should answer your question about valves.
FUEL INJECTOR
Disconnect fuel injector harness electrical connectors and measure resistance across the terminals. Resistance should be 2-3 ohms.
If measured resistance is not as specified, replace injector.
Check fuel injector operating noise using a suitable metal bar or stethoscope with engine running.
If a regular click is heard which varies with engine speed, proceed to step
If a regular click is not heard, replace injector.
DROPPING RESISTOR
Measurement of resistance
Disconnect dropping resistor wiring at connector
Measure the resistance across the center terminal of the dropping resistor side connector and other terminals. Standard Resistance = 5 - 7 Ohms.
If any one of the measurements deviates from the standard value, the dropping resistor assembly must be replaced.

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Wednesday, August 23rd, 2006 AT 5:19 PM

STEVECAB

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2 POSTS

Thanks I'll try iy out

Cheers

Steve

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Wednesday, August 23rd, 2006 AT 6:20 PM

MOONMAN

MEMBER
2 POSTS

I am been trying to get my 91 trooper to work for a few weeks not and haven't quite got it yet, but we were able to check if the injectors were working by actually taking the fuel rail off and cranking it as my brother held the injectors in the rail so they wouldn't pop out. Just make sure that you hook the fuel lines back up to the rail before you crank it, I know it sounds a bit crazy but we could see that all four injectors had a nice clean squirt and were able to move onto other questions. Good luck and be careful.
Ben

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Tuesday, October 3rd, 2006 AT 3:14 PM