Hi all,

Forthose who have been following the SAUJP troubles i have been having ....i'm back.

I was starting my car (92 7730 8DSAUJP ) to gather a cold data log to help nail down a rich start condition...well long story short the car fired ran about 5 seconds then died. fuel pressure is zero . Key on no fuel pump is heard.
Data shows ( via TP/RT ) all is well tho Fuel pump voltage is zero. During cranking voltage returns to normal values, BUT inj PW remains at zero!! When cranking stops pump voltage falls back to zero ?? what the heck do i look for now? I really dont think it is the pump? is it?? thanks GTA....

 

reset the ecm and see what happens

or just put the stock prom in and see if it starts

 

GTA, I've noticed that you've been having issues with getting either good burns or having the ECM read the EPROM. One thing to look for is the SES blink at key-on, engine-off. If the SES doesn't blink then the ECM is in limp mode, not running from the EPROM.

At key-on, engine-off the SES should briefly light up, blink off, then stay on solid. To repeat the test key-off for at least ten seconds. No blink off, don't bother trying to start the engine.

As for the fuel pump, it should always run for two seconds at key-on, engine-off. To repeat, again key off for at least ten seconds. It should do the FP prime whether running in limp or from the EPROM.

Without getting a fuel pump (FP) prime at key-on, either the ECM, wiring between the ECM & fuel pump relay, or the fuel pump relay is bad. There is also an inline fuse that will do this. However, this fuse also powers the ECM so won't get the SES either when open.

If you crank the engine long enough the oil pressure switch will close and that will turn on the FP. Which sounds like what is happening.

Some data streams don't report the cranking injector PW. Not sure if $8D does or not.

RBob.