classic1275cc

Hello all

long story short I have a mk2 that I have replaced the fuel pump on (pt.no 38309) from intermotor as well as cleaned out the tank and given it a tart up, spending ages blowing and vacuuming any debris out the tank

put it all back together and using a fresh battery the car starts but dies after approx 4 seconds, occasionally rough idles Indefinitely until you stroke the accelerator pedal and it dies, and sometimes you can start it a it will rev roughly for a short time before dying

It has the classic fuel pump relay issue or black box issue not supplying power to the pump but it has been like this for in excess of 8 years and the fuel pump had been run off a battery

my questions are

1. Is there a procedure for getting air out of the fuel lines?

2. would incorrect polarity on the pump cause this? I.e. just enough fuel to run but not keep running (I say this because the pump is clearly marked positive on one terminal but the small terminal, and in my experience the large terminal on anything like this is the positive, not the small?)

the car had been stood for 5 years being started occasionally always fired right up but last winter the fuel pump died (could here it stop short you after connecting the pump battery)

thanks for your time and any input

classic1275cc

Took the low pressure pipe off from tank to fuel pump expecting to get the 10l of fuel I put into to come racing out into my bucket... not a drop... should come gushing out right ?

is it possible that my blowing around in the tank with an airline hose getting rust out out has dislodged something in the internal baffle / float or what ever is in the tank?

OAP Pete

You have the wiring correct on the new pump, the 4 seconds running tells me your running on the 5th injector only, if the wires were wrong way round there would be "Zero" pressure, and the 5th injector wont work as its on the main pressure line...looks like more Fuel needed ?...as you say the pipe off !!...no fuel..?....just to add, normal COLD starting on "KE " system, 5th starts engine....pressure Actuator take over in Increasing pressure in the system to give good running , and Fast Idle control takes over the Idle while warming up. Peter.

classic1275cc

So when I take the low pressure line off at the back of the fuel pump and blow into it I head bubbles then when I take my mouth off I get a gush of fuel out (catching it Into a bucket) and then something seals off inside the tank and I get no flow?

does anybody actually know what mechanism is inside the tank? Somebody on here must? why would it behave like that

it’s not a blocked breather because nothing comes off even with the filler cap off

OAP Pete

What I believe is happening is these Pumps do "Suck" when running, have to say back in the day when I changed Pumps , cars were nearly all over Half full, I feel when your Pump is running it is on full pressure, Easy check hear....Remove the pipe on the 5th injector, place in a large Safe container as I recon your see full pressure, then unplug the Pump relay, with a short wire Bridge out Terminal "30".. with Terminal "87". the wire colurs your bridgeing.... "Red"...&....Red/black..tracer..... Pump will run now all the Time..i feel it will fill the container, Peter

classic1275cc

Finally got her to go after

brimming fuel tank
new fuel filter (recon it was a bit waxed up from VERY stinky old fuel)
touch of oil down the bores for maximum compression as it had been flooded

and it coughed into life!