frustrated

88/89 S4 Drives fine for about 30 minutes and then suddenly cuts out. after that it will start but cuts out more frequently. Felt like fuel starvation. checked fuse and no current across it, changed that and fuel pump relay. starts fine again but still cutting out and the fuel pump relay is getting hot. Fuel pump works fine if I bridge the relay socket but is buzzing quite loudly.
It also seems there is no power on the ECU side of the relay when it cuts out.
Would anyone like to hazzard a guess as to whether its the ECU or Fuel pump?
Both are relatively new. about 12 months old.

linderpat

Is it an auto box car?

WallyP

These are common problems, and the fixes/tests are free...

1) Carefully clean all of the battery terminals, especially the medium-sized red wires on the positive terminal. These feed the ECUs, fuel pump, etc.

2) Swap the LH Relay (XXV) with any working "53" relay in the panel, such as the horn, back-up lights, etc.

3) Swap the EZK Relay (XVI) with any working "53" relay in the panel, such as the horn, back-up lights, etc. Don't worry if it looks different because it has a fuse tester built in - it is just a "53" relay at heart.

frustrated

Um yes it is an auto, 4 spd ??

frustrated

ok thanks will try the other relays and terminals.

risaac928

Good luck, keep us posted this will make an interesting read. Heck you never know when this might happend to my old girl...scary.

linderpat

Besides what Wally said, one thing hot stalls are sypmtomatic of are thrust bearing failure, which affects post -84 auto box cars primarily. Do a search for the many threads dealing with this topic. Hopefully your issue is one of the common and simplke things Wally pointed out.

John Speake

Check for spark when it cuts out. Does the tach flicker when you crank imedaitely after it stops ?

frustrated

Hi John. Tried to phone you about it around noon.
the computer readout flickers but thought that was just a low battery.

frustrated

oh jeeze, could that be my clanking when braking to a stop downhill that i still havent found a cause for. have changed shocks, pads, discs and bearings. (which needed changing anyway).

the flyin' scotsman

Whats the battery history? Is it secured properly?

frustrated

Battery and connections are fine. dont think it would be the thrust bearing as it runs smoothly until it shuts down. There are no ecu faults showing on the Spanner
The other matter of the clanking from the front is only after having driven for a while and braking to a stop or braking downhill.

the flyin' scotsman

ok.............did you swap the relays?

Has the flex plate pressure been released?

Whats the fuel pressure?

RED SHARK 1990

Hello mine used to start and runs fine ,but after warm up it will start to shut down....has that been changed?

John Speake

I was in the garden so missed your call :-( Have you checked for spark when it dies ?