fuel pump problems?

[laz11]

I have been having starting problems intermitendly with my 4.3. Twice now I have gone to start it up over a period of fairly constant use over the past two days; ignition fine and the motor turns but it doesnt fire up. The common trait has been that the fuel pump whine continues rather than stopping after a few seconds once the ignition is turned. Both times it has happened when the car has not long been standing from a run. Once I leave it for half an hour or so it fires up fine? No other running problems. I'm planning on taking it to the garage but thought I would see if anyone can shed some light on it.

Cheers

[GreenV8S]

Those symptoms ring a bell, this happened to me earlier in the year. The fuel pump ran continuously and the engine would crank over but wouldn't fire. In my case it cleared after I switched off and on a couple of times. For the pump to run continuously, either the relay has stuck (which wouldn't prevent the engine from starting) or the ECU has gone bonkers. I figure it was the ECU.

[griffter]

The fuel pump 'prime' is timed, not related to pressure in the fuel rail, and as GV8S says, is controlled by the ecu.

I'd try resetting the ecu, either by disconnecting it - or more preferably the battery, leaving for >30 mins, and then reconnecting.

[laz11]

Thnaks for the replies. I have had a chat to the garage and they think it could be a blockage in the fuel pipe? Suggested draining the tank. Funny thing is that the problem first started after I filled it up with petrol...standard unleaded as per usual. However that was from a Star filling station...I nearly always use a better grade so that should teach me!

[GreenV8S]

laz11 said:

Thnaks for the replies. I have had a chat to the garage and they think it could be a blockage in the fuel pipe?

This does not make any sense at all, and it sounds to me as if they are guessing without understanding how the fuel system actually works.

[red griff 500]

I agree with GreenV8S. I think you should definitely try re-setting the ECU - It's much easier to unplug it rather than mess about with disconnecting the battery. 30 seconds disconnect time should be ample.

[wadesnj]

I agree with the ECU reset. Even after just cleaning the stepper motor, the map on my 500 was massed up to the extent that I had no idle - the engine just died. I unplugged the ECU for a minute or so, and had a nice steady 900 rev idle again. Steve Heath recommends it, so I should have known no to ignore the bible!

[laz11]

Just thought i'd see if anyone had any other ideas: I have unplugged the ECU and plugged it back again and still wont start. Ignition on fine then the fuel pump noise is continuous and the motor turns but doesn't catch? Checked all fuses so could be the fuel pump relay?

[GreenV8S]

laz11 said:

Just thought i'd see if anyone had any other ideas: I have unplugged the ECU and plugged it back again and still wont start. Ignition on fine then the fuel pump noise is continuous and the motor turns but doesn't catch? Checked all fuses so could be the fuel pump relay?

I have a nasty feeling your ECU is fooked.

[laz11]

GreenV8S said:

I have a nasty feeling your ECU is fooked.

Go don't say that I have only just had a new one put in due to bad running problems!! Actually I have just been on the phone to Paul at Austec and he reckons changing the 2 relays will probably solve the problem...apparently they can easily become troublesome. Let's see eh!

[GreenV8S]

Fingers crossed for you, but fuel pump running continuously implies either an ECU fault or a wiring/relay fault, and a wiring/relay fault which left the pump running continuously wouldn't prevent the engine from starting.

[rfisher]

Talk to your ECU

www.pistonheads.com/sales/54383.htm

[simon.b]

Could also be your immobiliser, If you have the META system fitted. You said it occurs after being stood for a few minutes after a run and this sounds like mine and others variation on the hot start problem.

The META immobiliser has three internal circuit board relays that don’t like getting hot, one for the starter, fuel pump and ignition. Either one of these can become problematic independently of the other two. I’m not sure if an ignition failure would cause the pump to run on, but who knows what the ECU see’s when this situation occurs.

There is a straight forward way to check this, by-pass the immobiliser ignition circuit, unfortunately I’m not the best person to advise on how to do it. I would recommend you get in touch with David Beer of Mod-wise he had this problem and should be able to help.

To fix it, move the immobiliser off the transmission tunnel to a cooler location behind the dash, there’s a few miles of wire provided to do just this and mines been no problem since I moved it.

Cheers,

Simon.

[david beer]

Laz, have you seen the thread on the Chim forum about such stuff ? Might be of interest.

[laz11]

Thanks for all the help chaps. Having changed the relays and still no joy I have left the car with Tower View who are getting their electrician to check it out and also they will look at any faults coming up on the ECU. They are the closest to me and tbh not my first choice. Although I have a courtesy car so can't complain! Will let you know the results!
Laz

[lazyitus]

laz11 said:

Thanks for all the help chaps. Having changed the relays and still no joy I have left the car with Tower View who are getting their electrician to check it out and also they will look at any faults coming up on the ECU. They are the closest to me and tbh not my first choice. Although I have a courtesy car so can't complain! Will let you know the results!
Laz

Laz - did you find the problem ?

[geoffvalenti]

I'd have hoped so, by now

[lazyitus]

geoffvalenti said:

I'd have hoped so, by now

Me too.

I'd like to know what was causing the problem.

Laz !