HELP PLEASE - Fuel problem

[Kool68]

Gday all,
I have this mongrel fuel problem with my petrol NH 3L v6.
There's no fuel getting to the engine (plenty of spark).
I just spent crap loads of money putting in a new fuel pump & fuel filter which didn't change a thing. The mechanic showed me the ECU - it was fried. I went to Imlach's & got a reco ECU & put that in, STILL NO FUEL.
This car is worth about $4000 & I've spent at least $6000 in repairs in the last 12 months (I know, stupid me. I did plan to keep it at the time, now I cant get rid of it fast enough).
Could anyone PLEASE give me advice on what to try next?
The fuse box under the bonnet has no marking as to what fuse is for what, but the RACV guy tried all them & said they're ok, but I'd still like to replace the fuel pump one anyway, just in case. Do you know which one it is?

Thanks in advance,
Adam

[Aussie_Dan]

Have you unplugged the connector from the fuel pump and checked for voltage when ignition is on?
Dan.

[Kool68]

Have you unplugged the connector from the fuel pump and checked for voltage when ignition is on?
Dan.

Thanks for the reply Dan.
Yes I just did that now. No voltage to the fuel pump connector when the ignition is on.

[Aussie_Dan]

Okay, sounds like you are on the right track with a fuse or wiring fault then.....
Do you have a workshop manual of any kind for your car that has wiring diagrams?
If you have a diagram, I don't imagine it would be too hard to trace a fault in the fuel pump electrical circuit....
Dan.

[Kool68]

Okay, sounds like you are on the right track with a fuse or wiring fault then.....
Do you have a workshop manual of any kind for your car that has wiring diagrams?
If you have a diagram, I don't imagine it would be too hard to trace a fault in the fuel pump electrical circuit....
Dan.

Thanks Dan,
Yes I have a Melway manual. In the diagram it shows 20amp fuse to ECU to fuel pump. But the problem is I have no idea which fuse it's referring to.
I guess I'll just have to change them all & see what happens?

[Aussie_Dan]

Thanks Dan,
Yes I have a Melway manual. In the diagram it shows 20amp fuse to ECU to fuel pump. But the problem is I have no idea which fuse it's referring to.
I guess I'll just have to change them all & see what happens?

Does the wiring diagram show you which pin on the ECU connector accepts the feed from the fuse? You could use a multimeter to work out which fuse it is. Remember that muost cars have fuse boxes both under the dash and under the bonnet.
If you can identify the right pins on the ECU connector, probably a good idea to check continuity of the wire from the ECU to the fuel pump also, considering you have confirmed that you get no voltage there.
Also check that you have an earth on the other pin at the fuel pump connector.
Dan.

[dolphin]

just check to see if this model has a fuel pump relay. i know the NM does as i had this same problem with no fuel to rails and it was the relay at fault.

[Kool68]

just check to see if this model has a fuel pump relay. i know the NM does as i had this same problem with no fuel to rails and it was the relay at fault.

I think you're right. I called Knox Mitsubishi & they said it's probably the fuse or relay. But with no writing on the lid of the fuse box (under the bonnet) I have no idea which one is which.

Does anyone have an NH that could send me a picture of which one you think it is?

[usrichards]

Hi Kool 68

Just grabbed the owners manual for my NH 93

Has all the fuses & relays listed, but no mention of a specific fuel pump fuse or relay.
There is one relay Labeled as 20amp M.P.I (dont know what this is) ?
It is 3rd relay down on L/H side of under bonnet box standing at side of car.

Hope this helps

Al

[usrichards]

Just googled M.P.I appears it is related to your fuel pump.
Could be the one you need to check.

Cheers Al

[Kool68]

Hi Kool 68

Just grabbed the owners manual for my NH 93

Has all the fuses & relays listed, but no mention of a specific fuel pump fuse or relay.
There is one relay Labeled as 20amp M.P.I (dont know what this is) ?
It is 3rd relay down on L/H side of under bonnet box standing at side of car.

Hope this helps

Al

Thanks heaps, That helps alot. But I don't know if we have the same fuse box. I've attached a pic of mine I just took. Is this the same as yours?

Cheers,
Adam

[usrichards]

Yep same box, 3rd down on left, blue. Two on angle then next one..
Hope this helps
Al

[Aussie_Dan]

MPI probably means Multi Point Injection?

[Kool68]

Yep same box, 3rd down on left, blue. Two on angle then next one..
Hope this helps
Al

Thanks heaps Al.
I tested that fuse & it's fine & there's power getting to 1 pin with the ignition on, so I guess it's back to the drawing board.

[goldnugget]

Under the bonnet you will find a wiring harness on the passenger front wall with 2 leads that go nowhere and probably have a fake plug on them...one will be an orange sort of color...this is the timing over-ride, the other black one should be a single lead with a black wire (white trace), if it has a cover on it, take it off (being careful, it will have a push thing on it before you can remove it)...take a piece of wire (perferably with aligator clip) and bridge this to the positive terminal to the battery intermittently. There should be a small spark when you do this and you should hear some pressurisation in the fuel line...this is a manual overide of the fuel pump...if it makes no noise or spark then it could be a couple of things...let me know.
You dont need the ignition on to do this.
Check this and then we will go from there.