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

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

[GreenHorn]

When I got rid of the egr, most of the vac lines where removed including the the ac advance. What was left was the turbo boost to injector and brake res to vac pump circiut. With the aircon vac line removed it, made very little noticable difference to the 3.1 when air con is on when waiting at traffic lights. Butterfly in the intercooler inlet is long gone and so has the exhausted cold start valve (been replaced by larger new exhaust pipe when the original muffer rotted out) so all the vac plumbing for these are not needed. Been like this for about 5-6 years now.

[Captcol]

When my engine is cold the ac idle up is good otherwise i get the bonnet vibration at the intersections, but it is not necessary just nice. I have disconnected the vac to the butterfly thing on the turbo side of the intercooler as I have no idea what it does and if it is supposed to have full time vac or what, or how I can remove it without causing leaks.

[MU31TD]

"The vac to the butterfly thing on the turbo side of the intercooler" works together with the exhaust brake for cold start, as far as I know. But it is not needed really in Australia. Point (B) may be left out. No need to block it. I've removed the solenoid (B) on my mate's car completely since I've posted this diagram above.

There is nothing wrong the way it is on the diagram. However you can ignore solenoid marked (B). This way vac line will go from (A) to (D).

Note: Not all engines are equipped with the boost controlled fuel pump. (It allows more diesel with higher boost). Some engines may not have actuator (D) at all! Instead there is another automatic controller that works when altitude changes.

[MU31TD]

I have a stock standard 3.1TD MU in the workshop at the moment. If I get a chance I can draw a diagram and mark all the vac lines as where they go and what color they are marked.

[johneeewalker]

I have a 95 bighorn 4gj2 3.1td.... Coming from vacuum pump on alternator there are two Vac lines. One is fat and one is skinny. The fat one goes to the brake booster. The skinny hose has come disconnected and i cannot find where it goes to. Can anyone help?

[geeves]

It goes up between the alternator and engine and connects to one of the hoses going across the front of the engine.
From there it feeds into several solinoids for the EGR the air con fast idle the SOTF if you have it etc

[Dreti]

Hi.
My lines are all disconnected because mi lasted mechanic.
anybody have a manual for the vacuum diagram for all the lines

[Sjgreer]

Or a hand drawn diagram can also do the job

[Jamieyoung]

Hi can anyone help me please I have a Isuzu bighorn but don't no where the vacuum lines go for the turbo to work if anyone has anyknolage on this would be much appreciated thanks

[Jamieyoung]

Wat pipe goes to the waste gate at the top of the turbo am lost regards jamie