Engine in high rev

1995 ISUZU BIGHORN
93,000 MILES • 3.1L • 4 CYL • 4WD • MANUAL
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BATAAN DEIRERAGEA
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Hi,

I am working on this vehicle with a 4JG21 engine equipped with an electronic version injector pump.

The issue with this car is the engine stuck in very high rev every time it started without the possibility of controlling it. I am suspecting the injector pump or the ECU but not sure if that's the case due to no manual available.

Further more, it seems not from oil source which may cause runaway engine as the engine stops whenever turning ignition key to off position, if am correct.

Any help to resolve this problem would be appreciated.

Regards,

Bataan
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Apr 5, 2019 at 2:08 AM
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1995 ISUZU BIGHORN ? I don't see this engine in this truck?
Apr 8, 2019 at 12:57 PM
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BATAAN DEIRERAGEA
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These are some actual photo of the truck for verification.

As you can see I have removed the intercooler, front end cover and injector pump in the plan of sending the injector pump oversees for checking and repair but decided to pin point the problem first whether it is actually the injector pump, ECU, sensor or wiring etc. is at fault but this is difficult without proper manual.

The only manual I have for this model incorporates a mechanical injector pump.






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Apr 8, 2019 at 6:05 PM
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BATAAN DEIRERAGEA
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These are some actual photo of the truck for verification.

As you can see I have removed the intercooler, front end cover and injector pump in the plan of sending the injector pump oversees for checking and repair but decided to pin point the problem first whether it is actually the injector pump, ECU, sensor or wiring etc. is at fault but this is difficult without proper manual.

The only manual I have for this model incorporates a mechanical injector pump.






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Apr 8, 2019 at 6:08 PM
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STRAILER
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Does this have a throttle body can I get pictures of that?
Apr 9, 2019 at 11:26 AM
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BATAAN DEIRERAGEA
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Photos taken on intake manifold, inter-cooler and electric valve controlling EGR valve. Looks like no throttle body or anti-shudder valve equipped for this model.
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Apr 10, 2019 at 4:22 PM
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STRAILER
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Do you have a picture of the throttle body?
Apr 11, 2019 at 9:29 AM
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BATAAN DEIRERAGEA
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The throttle body is usually mounted on the intake manifold, if i am correct, which obviously nowhere to be found on the intake manifold. refer latest reply photos. If I'm wrong, please advise where to locate it.
Apr 11, 2019 at 11:07 PM
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It might not have one, the high idle is due to excessive fuel entering the engine at idle. This could be due to a faulty throttle sensor or injector pump, on or the other. can you take pictures of the throttle pedal etc?
Apr 12, 2019 at 10:15 AM
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BATAAN DEIRERAGEA
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Photos taken: injector pump connectors, OBD2 connector and accelerator position sensor, last 4 photos, respectively.
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Apr 12, 2019 at 9:47 PM
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STRAILER
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Yep, I would test or replace the throttle sensor or look for an adjustment. Also lets run the codes to see what comes up.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run down this guide and report back.
Apr 13, 2019 at 11:09 AM
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BATAAN DEIRERAGEA
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Hi,

Sorry for late reply.

Unfortunately no available scan tool is able to retrieve fault code. but I've disconnected the accelerator pedal sensor but still engine rev problem existed.
Oct 23, 2019 at 4:36 PM
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STRAILER
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Lets remove the EGR valve to see if it is stuck open. here is a video to help:

https://youtu.be/DqUCbbKdWf4

Please run down this guide and report back.
Oct 24, 2019 at 10:34 AM
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BATAAN DEIRERAGEA
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Hi,

It's been long since my last post, sorry.

The injector pump just came back from servicing overseas as it is at fault as per agent finding and now problem existed no fuel reaching injector nozzle upon cranking.

Could this be timing setting, wiring connection or any other problem that's causing this?

Regards,

Bataan



Feb 7, 2020 at 1:02 PM
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Yes it can be any of these things. Can you please shoot a quick video with your phone so we can see what's going on? that would be great. You can upload it here with your response.
Feb 9, 2020 at 11:44 AM
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BATAAN DEIRERAGEA
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Hi Ken,

Can you advise me how to set injector pump timing on this vehicle? Seeing this is unlike the one in the manual, mostly mechanical except for the electric fuel cut solenoid, this is electronic version.

Regards,

Bataan





Mar 6, 2020 at 10:38 PM
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Sorry, we don't have that info for this truck engine.
Mar 7, 2020 at 12:30 PM
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BATAAN DEIRERAGEA
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Ken,

Do you know the connection on the pump and what to expect on the multi-meter reading? as I am thinking it might be a simple electrical problem.

Regards,

Bataan
Apr 9, 2020 at 9:34 PM