Fabio421

OK folks. The saga continues. Two nights ago I posted about how my car stranded me.Thread Here I went back the next morning and swaped out the fuel pump and the car started right up. I then drove it home.

Well tonight it stranded me again. I was actually driving to the same shopping plaza wheree it left me the other night. This time it stalled while I was driving. It was like someone just killed the ignition. I have a feeling that there is some electrical component that is heating up with use and causing this problem. Both times it has happened the car has been running for about 5 minutes. If you let the car sit for 30 or 45 mins. it will start for a few seconds but then dies like the spark has been shut off. There is no sputter, just immediate silence. If the pump was shutting off wouldn't it sort of sputter? I tried to swap my horn relay with the fuel pump relay but it made no difference. I was doing this by memory but those two relays looked different and were marked differently. I have since looked at the chart at www.928gt.com and can see that those two are different. The recommended swap is for S-4 cars. Oh well. I will try it again tomorrow.

Any suggestions are appreciated.

Alan

Do you have an alarm? does the alarm alert work? could it be getting set off?

Maybe the alarm relay is just dodgy? which car is this?

Alan

ZEUS+

Does the tach move when cranking ? Possible green wire to distributor.

Fabio421

OOPS sorry Alan, this is the 84. As for the alarm. I do have the long key so there is an alarm. But the alarm was somehow disabled by the P.O. How does the alarm normaly work/.

ceedee

i remember michael g. was telling me something about the ECU failing after a certain time.
and that one can have it refurbished with more up-to-date components.
i remember one lady had problems with her 83 928 it would not fire. even though it had spark and fuel. did you check the connection behind the right tail light, where the fuel pump lead ties to the car body? i know it is not a place where you would want to check casually, since it most certainly f's up the bottom of the quarter panel.

ceedee

oh so you do have power at the fuel pump leads?
try to take the fuel pump out and run it with 12v directly... forward and then switch for back.
if it is jammed maybe that will dislodge it.
and you'll know too if the pump is a goner then

Alan

The alarm connects terminals Z1 and Z6 with ignition on when it is operating normally - if alerted it does not connect these - so just jumper it together.

For the fuel pump just remove the relay and jumper socket pins 87 & 30 to see if the pump runs (thats the same as the relay active).

Alan

ceedee

or to be on the save side 15 and 87. that only turns on the fuel pump when the key is turned.
but both are jus for troubleshooting

Mike Frye

Question: Would bad gas cause this problem?

I was just thinking that you switched out the fuel pump and it's doing the same (or similar) things. With the change of season maybe you got some crap gas or moisture in there. Somebody recently had issues with something like this and it was thought that it could be sugar in the tank or maybe just crud from when they switch to 'summer blend'.

Maybe if you pump some fuel into a clear jar and have a look at it for water/crap.

Just my .02.

Fabio421

i suppose it could be bad gas, but it was almost empty when it happened the first time and I put 5 gal. of fresh gas in it at that time. So if that were the case it would be diluted now. Also, in my experience with bad gas, the car will sputter before dying. This is like someone just turned it off. I will check the gas. At this point I cannot exclude any possibilities.

AO

Alex, I'll take "Green Wire" for $200.

killingmoon65

The same thing happened to my shark. The car sputtered stalled and would not start. After getting it back home I found a dead fuel pump under the rear tyre well. I replaced it and the engine started and I took it for a test ride. After about 3 miles the car died- just like the ignition was turned off. No sputter at all, just flat. It turned out to be the fuel pump mounted just outside(mine is a 78) the fuel tank. Once I unjammed that pump by reversing polarity( a trick I learned from someone right here on this forum) the car ran as new and has since.
My point is the engine died in a way that I at first thought was electrical and was in fact fuel starvation. Just a thought.

Fabio421

Oh, one more thing. I noticed last night that when I tried to start the car, I could feel the fuel pump relay pulsing. It wasn't just a click like it was activated, it was repeated clicks in a very quick pace.

Just trying to paint as clear of a picture as possible.
I'm off to troubleshoot the car. Wish me luck.

John V

Have you checked relays...XVI in particular?

Fabio421

Preliminary tests are pointing to the fuel injection relay.

It is deff. not the fuel pump relay and I'm pretty sure its not the infamous "green wire".