Fuel pump question

[pj027235 10]

Hi,

I have a 2.0l 16v 9a which will start and then immediately cut out. I am thinking this is a fuel supply issue and so have been reading up on the fuel pump(s).

Question 1, why are there 2 pumps? Q2, why does the external pump prime? is it pressurising the system? Once it has primed does it stop running?

Any info much appreciated,

Phil.

[Harrier 1]

It sounds like you possibly have an imobilser fault,assuming you have a later car with the chip in the key,

[pj027235 10]

Yes this is a possibility. The immobiliser on the car immobilised the ignition several years ago. When I find the problem I will update here. Thanks for replying.

[britpop95 0]

My fix to this issue on my vr in remove the lower plastic surrounding the steering wheel grab hold of the big wireing harness and give it a little wiggle . I've had Bo issues since.

[pj027235 10]

Yes I see that ignition switches can be problematic...it's going to get looked at today.

Cheers.

[britpop95 0]

Little tip for the ignition switch 😋 it is held in by microscopic screw , put a little bluetac on your screwdriver to hold the screw steady, it goes in at a really awkward angle . I had my head resting on the break peddle . Plenty of huffing and puffing should get it sorted.

[pj027235 10]

Ok....immobiliser completely and wiring back as original. I've checked both fuel pumps and they seem fine although I can't hear the one in the tank. Tried starting it this evening. I turned it over for about 10 seconds, it fired once or twice but would normally be up and running straight away. Had a quick look at the plugs and 3 were wet one was black, sooty but dry. I'm starting to think it might be an ignition problem as fuel is obviously getting there.

Any suggestions welcome,

Phil

[britpop95 0]

Obvious check I know but are you getting good spark on all 4 plugs ? From what your describing it does sound very immobiliser related , let's the car fire then kills the power within a second or 2 . Also a problem a had once was that the little pressure valve on the fuel rail had vibrated loose and caused rough idle almost to the point if cutting out. Easy to check, it's on the drivers side of the fuel rail and it's a small Allen key .

[pj027235 10]

Update:-

The car had a toad immobiliser which has now been completely removed and wiring restored to original....made no difference. The problem is that the car is massively over-fuelling to the extent that it simply won't run. So I started to look at the metering head and the associated electrical gizmos screwed to it. Found that there was no power supply to the MAF potentiometer which is supplied by the ecu. Then found that there was no power to the ecu. I traced this to a badly crimped wire on the back of the ruse/relay block, which was also plugged in to the wrong connector or plug. I made good the connection to the fuse block...ecu now powered. Car will now run but mixture is still very rich. I returned to the MAF potentiometer and it's output voltage is way out of spec. I managed to get the pot off and can see that the electrical track inside is very worn. Although it is worn it is still working so tomorrow I am going to re-adjust it's position on the side of the MAF unit to try and get it's output voltage within spec.

[easypops 8]

Try unplugging the electrical plug on the 5th injector, mine was faulty on my old valver, constantly overfueling......I ran it unplugged for years without any problems

[pj027235 10]

Update2:-

Original MAF potentiometer too worn to get any reliable and steady output volts....well it has done 235k. Now have a new MAF from a stealers, the pot output voltage is out of spec but the car is running fine. I'm not sure why the pot has such an influence on the mixture, but I would be delighted to know if someone knows the answer.