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Engine in high rev

Tiny
BATAAN DEIRERAGEA
  • MEMBER
  • 1995 ISUZU BIGHORN
  • 3.1L
  • 4 CYL
  • 4WD
  • MANUAL
  • 93,000 MILES
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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Friday, April 5th, 2019 AT 2:08 AM

17 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,313 POSTS
1995 ISUZU BIGHORN? I don't see this engine in this truck?
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Monday, April 8th, 2019 AT 12:57 PM
Tiny
BATAAN DEIRERAGEA
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  • 10 POSTS
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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Monday, April 8th, 2019 AT 6:05 PM
Tiny
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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Monday, April 8th, 2019 AT 6:08 PM
Tiny
KEN L
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Does this have a throttle body can I get pictures of that?
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Tuesday, April 9th, 2019 AT 11:26 AM
Tiny
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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Wednesday, April 10th, 2019 AT 4:22 PM
Tiny
KEN L
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Do you have a picture of the throttle body?
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Thursday, April 11th, 2019 AT 9:29 AM
Tiny
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.
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Thursday, April 11th, 2019 AT 11:07 PM
Tiny
KEN L
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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?
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Friday, April 12th, 2019 AT 10:15 AM
Tiny
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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Friday, April 12th, 2019 AT 9:47 PM
Tiny
KEN L
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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.
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Saturday, April 13th, 2019 AT 11:09 AM
Tiny
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.
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Wednesday, October 23rd, 2019 AT 4:36 PM
Tiny
KEN L
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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.
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Thursday, October 24th, 2019 AT 10:34 AM
Tiny
BATAAN DEIRERAGEA
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  • 10 POSTS
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
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Friday, February 7th, 2020 AT 1:02 PM
Tiny
KEN L
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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.
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Sunday, February 9th, 2020 AT 11:44 AM
Tiny
BATAAN DEIRERAGEA
  • MEMBER
  • 10 POSTS
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
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Friday, March 6th, 2020 AT 10:38 PM
Tiny
KEN L
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Sorry, we don't have that info for this truck engine.
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Saturday, March 7th, 2020 AT 12:30 PM
Tiny
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
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Thursday, April 9th, 2020 AT 9:34 PM

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