Intermittent ECU & fuel pump relay

[MisterT]

After a few false starts this season, most recent being a failed fuel pump relay, I got a chance to take the WARP DRIVE machine out for a proper run for the first time this afternoon .

2 new relays arrived earlier this week, and after fitting them the fuel pump whirred into life just fine. Set off, running out of town about 25mph and the car felt really good, smoother than it has done for ages (its just had a 12k service, brakes and tyres as well). Even the notorious low speed shunting seemed better. It performed overtaking manouevres like a jet on after burner

Then, just as I rolled into Stamford running at about 25 - 30 mph the car started to misfire and behave like its out of fuel! It wasnt, tank is over 3/4 full.

Fortunately I hadnt pushed the ECU and wiring back in place above the battery box and so I could hear one of the relays on the ECU loom dropping in and out in time with the misfire! Unfortunately I dont know which one it was, my guess is the one in the blue socket as usually the one in the black socket takes a few seconds to drop out after the car is turned off, but I cant be sure.

Not wanting to get stranded by the roadside again I made a rapid detour and headed back home, and apart from a couple of small hiccups it didnt occur again. Great, an intermittent fault! They're always a bugger to cure.

Any suggestions on what might be the cause, and what I should check, would be gratefully received. I have a hunch bad earthing may figure in this but unsure where the earth points are that I should check!

[mongoose]

Its worh checking the connectors in the relay holders.They can bcome loose and/or corroded.

[Guillotine]

or earth!

[robspoff]

My fuel pump cut on and off, causing missfire, and in the end, a motorway breakdown, because fuel pump would not run. I got home by by luck because by dropping the main CPU agains the footwell floor the fuel pump ran. When I got home after taking antistatic precautiuions I carefully pushed the main CPU chip back into its socket base. It was not until later when Mark Adams went to fit one of his Chips, he said my chip had again 'moved' out a bit from its socket on the PCB. He then said that several Griffs were fitted with a very cheap socket. As part of his install he insisted on going away for over an hour and soldered in a gold plated socket base before fitting his chip. The fault has never happened again. This may not be your cause but might be worth checking.