Car failing to re-start, relay changed,Ecu Fault?

[bhpjon]

Morning Folks, I've got another interesting one for you, When the car is cold there is generally no problem with starting, but after it has had a bit of a run (He,He,He)the fuel pump is not being energised.Twice i have taken it to electrical specialists and twice it has made a fool of me (eg worked perfectly). I bought a new fuel pump relay to try and cure the fault but it made no difference.One of the electrical people i took it to said it could be the ECU at fault (or presumably the wiring from Ecu to relay, or relay to pump)I have thought of lagging heater pipes in the footwell and lagging the Ecu to prevent it getting warm but other than that i am stumped, all contributions gratefully recieved!!

[Flintstone]

Hate to sound depressing but these symptoms sound exactly like a problem I had earlier this year and yes, it was the ecu.

You could do what I did though and replace a few other things before splashing out on an ecu rebuild. Swop the fuel pump etc, see if that cures it. Or is this the dreaded TVR hot start syndrome (which I have never experienced touch wood and whistle turn round touch the ground make the sign of the evil eye)?

If you want I can lend you my spare fuel pump.

Edited by Flintstone on Wednesday 4th October 11:11

[pupp]

Try bridging the immobiliser circuit for the fuel pump... it's one of three 'cuts' that the immobiliser imposes and they can fail independently of each other (normally it's the starter channel that plays up), and faults are often temperature dependent.

[GreenV8S]

Also check the condition of the inertial cut-out, and the wiring loom at the back of the car in the vicinity of the pump - it's quite exposed. If in doubt, put a fused supply direct from the battery to the pump. If the problems all immediately go away, you know you 'just' need to track down a problem in the pump control circuit and can rule out more general problems in the ECU, ignition circuit etc. If the problem is just in the pump control circuit, the wire for the direct supply also gives you a convenient way to get home.

Edited by GreenV8S on Wednesday 4th October 13:09

[bhpjon]

Thanks guys, theres a lot to chew on there, i was looking at having the ECU changed for a megasquirt this winter, (if i can ever get in touch with 'Trackcar' again!) so it looks like this would be the correct avenue to go down. Funnily enough the problem came to light after the man came to fit a new alarm. When i called them to come and look at it (after having not started for a week, the car erupted into song,first time!!!!)

[bhpjon]

Flintstone said:

Hate to sound depressing but these symptoms sound exactly like a problem I had earlier this year and yes, it was the ecu.

You could do what I did though and replace a few other things before splashing out on an ecu rebuild. Swop the fuel pump etc, see if that cures it. Or is this the dreaded TVR hot start syndrome (which I have never experienced touch wood and whistle turn round touch the ground make the sign of the evil eye)?

If you want I can lend you my spare fuel pump.

Edited by Flintstone on Wednesday 4th October 11:11

Thanks for that i may well take you up on it!!

[that daddy]

if you ring around there are companys that do a benchmark/simulation test on your e.c.u in saying that this one maybe a bit old.worth a try and its not expensive either.

[bhpjon]

Just had Ecu diagnosis done, but nothing showed up and true to form couldn't make the mistake replicate again.I've just added to 'Ecu relay buzzing' www.petrolheads.co.uk/gassing/topic.asp?t=294757&f=8&h=0 with the full tale as this seems to be along the same lines .