4GJ2 vac lines diagram

[MU31TD]

Does anybody have vacuum lines diagram for 1994 model Isuzu MU 3.1 TD 4JG2 belt drive.

I recently did a top end rebuild on 3.1 4JG2 1994 model. Replaced turbo and removed EGR. During the rebuild we accidentally pulled some Vacuum hoses off solenoids near air intake pipe above on the passenger side. The hoses were all dried and cracked so I replaced them with new ones.

I was sort able to guess connection for most of them. But need to double check if I got them all right. The manuals I found online only have 1999 models onwards.

Also there is a one-way valve in one of the lines. I don't remember which way should it go.

[MU31TD]

Or a hand drawn diagram can also do the job

[wairarapa]

I am having the same problem aswell

[geeves]

they are the same as the 4jb1
It sounds like egr valves so the hoses are optional

[MU31TD]

It's much easier then I though it was. The vacuum line from the vacuum pump is needed if there are solenoids. Block it off if all solenoids are removed.

Since I remover EGR and exhaust throttle those solenoids and actuators were obsolete. I left one solenoid for A/C RPM regulator. The one that increases RPM when A/C compressor is working. Very helpful on a hot day or in traffic. Hence one vacuum line from pump "E" to that solenoid "F" and another line from solenoid to actuator on fuel pump "G".

The boost lines run from intake pipe in between turbo and intake manifold (basically where air is pressurised by turbo) "A" to the vacuum actuator on same intake "B". If vehicle is equipped with boost actuated fuel pump then there would be a T-joint from "A" to run to an actuator on fuel pump "D" as well.

I just happen to have a boost gauge. So I have a second T-joint from "A" to the gauge.

[marroke]

isuzu bighorn 2.8 tdi i got problem i ned a diagram of the ruber hoses from intercoler ishecction pum etc
the are all disconected
i live in indonesia and is imposible to find someone how know about this engine

[arsnik]

plumb it straight from intercooler/cross over pipe to the injector pump and block off the alternator one

SIMPLE

[geeves]

For a basic engine you only need the pipe from the intercooler if you have one or pipe between the turbo and inlet to the top of the fuel pump.
If you have aircon you also need a vaccum line between the back of the alternator where it T s into the larger line to the brake booster and the solinoid on the front of the injector pump.
If you have working emissions gear you need the same line to also go to the plastic thing next to the fuel filter and the other 2 connections on this connect to the 2 valves on the inlet. I dont know which is which

[MU31TD]

This is a rough drawing of what I did on my 3.1 Turbo.

Since I blocked off EGR and removed all the lines and solenoids, I don't have a faintest idea how the lines would go.

Also the Vacuum Pump is on the rear of Alternator.

vacuum diagram.JPG

MU31TD wrote:It's much easier then I though it was. The vacuum line from the vacuum pump is needed if there are solenoids. Block it off if all solenoids are removed.

Since I remover EGR and exhaust throttle those solenoids and actuators were obsolete. I left one solenoid for A/C RPM regulator. The one that increases RPM when A/C compressor is working. Very helpful on a hot day or in traffic. Hence one vacuum line from pump "E" to that solenoid "F" and another line from solenoid to actuator on fuel pump "G".

The boost lines run from intake pipe in between turbo and intake manifold (basically where air is pressurised by turbo) "A" to the vacuum actuator on same intake "B". If vehicle is equipped with boost actuated fuel pump then there would be a T-joint from "A" to run to an actuator on fuel pump "D" as well.

I just happen to have a boost gauge. So I have a second T-joint from "A" to the gauge.

[Captcol]

The fast idle for the a/c is just below the throtle cable on the Injector Pump, towards the rear