88porsche928

This is an update from a previous post summarized and i still have problems.
Heres the situation and what I have done.
One day after running the car for two minutes it simply died.
Spark plugs showed spark.
spark plugs replaced
LH-ECU was repalced "completly unnecessary the original still worked"
Internal fuel pump replaced "i epoxied the boss back in no leaks"
External fuel pump replaced "known for not working"
fuel filter replaced
almost all the relays , really any relay that had anything to do with ignition or fuel was replaced
all fuses where replaced
I still cannot get the 928 to start. the orginial fuel pump was bad becuase when i jumped the relay the first time it made a thud sound and now you can here is flowing. Why is this not working? The LH-ECU was replaced with a rebuilt one from JDS porsche. So its good. does any one have any clues or suggestions.

Mrmerlin

start at the battery clean every thing looking for corrosion then the hot post the clean all of the fuses and the relays make sure the correct fuse/relay is in the correct position

88porsche928

mr merlin, will do once their is daylight

Mrmerlin

Also remove the computer connections next to the CE panel and inspect the pins for corrosion

Tails

Also remove the engine earth connection and clean both ends, clean the area where it attaches to the body and the engine block.

Tails 1990 928S4 Auto

Leon Speed

Just to make sure, are the spark plugs getting wet when you try to start it? Did you verify this after you replaced the fuel pump?

Landseer

Its interesting how various dirty grounds throughout can disable one of these cars. I'd not believed it, had I not experienced it myself. Same with the ignition switch. Seems to be fine, but turns out not.

Tampa 928s

Did you check your crank sensor?

Mrmerlin

he said it was getting spark so the CPS should be working, but it also could be weak so that is another possibility but do the elex parts first

John Speake

Recheck you have spark from both distributors. Then check if the plugs get when after cranking for a few seconds. Let us know what you find.

What was done to the car imediately before it refused to start ?

88porsche928

orginally i had thrust bearing failure and a used engine was put in it. the car ran for a week after getting it back from the mechanic. then one morning i just started it up. it ran for two minutes and died. im going back out in a minute to do more troubleshooting.

tveltman

The engine has oil in it, right? My buddy got his 944 back from a wrench and the guy had not tightened the oil drainplug. Engine siezed on the drive home .

Lizard928

Stan is correct, if there is spark the CPS should be OK.

I would recommend replacing it regardless though as they are getting to an age where it should be done.

The other thing which has not been mentioned is if you have checked for voltage/pulses at the injector plugs. It is possible for the wires to fray and touch together which would stop your injectors from working.

I would also verify that the LH relay is actuating. I say this because the LH relay is switched by the EZK. If there is a problem in the wiring the EZK will still fire but the LH will not.

Tampa 928s

Pick up a noid lamp available at any auto supply store. Hook it to one injector connection and see if it lights when turning over. This tells you if your injectors are firing, the old harness one can short out very easily taking all the injectors out.

Landseer

NAPA, Advance, Autozone and Pep Boys here had no idea what a noid light was. Maybe you will be more lucky than me.

Don't be discouraged. try an independent parts store that carries Lisle brand.