grooveshack26

Re; 87 S4, was cruising in my s4 the other day and it died on a turn, seems to be dead fuel pump since relay is good. Is there more then the one external pump?

Also car has major heat, cannot turn it off and the fan speed for the heat seems to fluxuate, Heater control valve issue?

Thanks for any and all help. Sincerely Rodney M 87s4

Calgary Ole

Heater valves can leak but first do a search on HVAC vacuum as you need vacuum to close the heater valve. (there is plenty of info about this problem)Closeing with a tie to test may give you a quick fix.
Others will chime in but there might be a second internal pump on your MY

Stromius

Welcome! See the sticky email at the top of the forums for lots of good info. You're S4 has only one external pump located at the rear and accessible from under the tank/rear bumper cover. Search for fuel pump replacement and you'll see lots of threads. Be sure to pay the modest membership to get access to information for keeping your S4 up and running.

Calgary Ole

Heater valve is under passenger side airbox, you can close with a tie to test but chances are vacuum is the issue or valve has failed.

IcemanG17

I think the pre 89S4's had only 1 pump....the 89+ had both the main pump and the problematic in tank pump...

My 88 had only 1 pump and when it started to intermittently die it was due to its internal resistance getting too high..its easy to check...just check the resistance between both poles on the pump (ignition off of course).....it should be low......mine would spike and not run...then cool off and run again briefly...

the flyin' scotsman

Is the car still dead? or did it re-start?

If you have a fuel pressure guage what does it read?

Sudden engine stall can be easy but expensive to cure once we know some facts.

grooveshack26

Thus far new fuel pump but still no run! Car has spark as it will run on starting fluid in the air intake but not on it's own. Jumped out fuel pump relay and run pump but will not run car? Rpm guage jumps as it turns over so that it supposed to be in working order for rpm sensor. Pulling my hair out lol, my 5th 928 and only one to leave me on the side of the road!

the flyin' scotsman

Is there fuel pressure at the rail?

Did the brains get a reset?

Mrmerlin

did you check to see if you have wires going to the fitting where the fuel line comes out of the tank?? this indicates an internal fuel pump?? if so then it may be bad due to the internal hose coming apart

John Speake

Change out LH relay for a known good one. Then consider the possibility of LH failure.