Four door 2001 Chevy Blazer 4.3 V6 RHD UK model.

I've had intermittent non-starts the past few months, lots of cranking and wont start, then leave it for a few hours, come back and it starts ok. It might work ok for two days, then not work for a week.

First thing I done was bypass the passlock system, but I was never convinced this was actually the issue here. Anytime I deliberately left the immobiliser active the car would start and then die after a couple of seconds. In my problem here the car wouldnt fire up at all, not even for a second. But if I spray carb cleaner or petrol into the throttle body I can make it start for a few seconds, so it's not a spark issue, its a fuel issue.


I changed the fuel filter as I had one lying around, and for 7 days afterwards it worked 100%. I also ordered a fuel pressure gauge in the mean time.

The gauge arrived and I tested the car - 62psi on ignition on not started, when started she would run at 55-60, and hold 50+psi for ten odd minutes when engine is shut down.

Confident that we had it sorted, I took it into town. When I came out of a shop and it wouldnt start! Stranded I had to get a lift home, then I returned several hours later and it started first time.

When I got home I stopped the engine, and it wouldnt restart - I tested the fuel pressure - this time reading zero. Again I sprayed carb cleaner into the throttle body and it started for a few seconds then died again.

So I tested the fuel pump relay, and it's working, and there is 12V going to the '30' terminal all the time, and when I turn the car on there is 12V going to the '85' terminal.

I wired 12V into the prime test terminal and the pump does not run. I jumpered across 30-87 and the pump does not run.

Now I decided to remove the tank and test the pump itself. I spent a few hours removing it last night, and I applied 12V to the grey wire terminal of the plug on the pump and earthed the black wire and the pump runs 100%.

Now this is where I think I've found the problem. I got two long bits of wire and tested for continuity. There is no continuity between the '87' terminal and the grey wire terminal on the fuel pump plug at the rear of the car. Also the prime terminal has no continuity with the grey wire terminal at the back either.

The purple wire for the gauge gives me 5V good enough at the rear plug, its just the 12V that isnt coming through to run the pump. My fuel gauge is working ok.

So my question is this - is it just a straight wire from the 87 terminal to the fuel pump or is there something else wrong, also where is it likely to break or corrode? Or will I just run a fresh wire from 87 to the fuel pump?

Cheers in advance
Adam

 

Is the grey wire normally like this. I expected a straight wire from 87 to the pump plug at the rear.

Please help!

What do you reckon of this?

Grey wire exits fuse box from 87 on fuel relay and is immediately joined to black wire. The black wire enters/exits sheathing along with two other black wires. One of these black wires goes to 85 on the HDLP PWR relay (presume this to be headlamp power) and the other black wire joins to the grey one again.

I've traced the group of three black wires through the bulkhead, removed interior trim under the steering wheel and followed them up til they disappear up behind the dash. I will need to drop the dash down to find them. Done that before and it's a pain in the hole.

My UK spec Blazer must have different wiring to the US model :/

 

Anyone guys?

 

I am fighting the same problem, when I get it figured out will post back.

 

I got sorted buddy. Took the car apart and found the problem. Drop me a pm if you want more info. Where are you based?

 

Private doctrine?

 

hi tooth_dr I' think im battling the same problem you discribe and wonder what you did to remedy your issue with blazer.. thanks