Landseer

This might help a little.
https://rennlist.com/forums/928-foru...fc-relays.html
and this
https://rennlist.com/forums/928-foru...ound-long.html
Bottom line is to try the 3way jumper.

dprantl

An L-jet 928 that starts cold then dies immediately? Sounds like it could be the cold-start injector.

Dan
'91 928GT S/C 475hp/460lb.ft

chewy8000

Let me supply a little more info as well. I have a Air fuel pressure gauge hooked up on the rail and it's reading 30 psi when it starts up like it normally reads so it's definately getting fuel pressure which would pretty much rule out the fuel pump atleast. I'll try the relay jumper, maybe if the relay is bad it's cutting off the pump after a few seconds? I HATE electrical issues it's the one thing I can't deal with. I guess the 928 is the wrong car to own if your like me. I also gave it a light shot of ether which did absolutelty nothing to remedy the problem.

dprantl

If the car does not start/run when you spray ether for 2-3 seconds into the intake, you do not have any fueling problem and should focus on the ignition system.

Dan
'91 928GT S/C 475hp/460lb.ft

chewy8000

Ok I'm at the shop and just went through all the tests in the WSM. Bridged the fuel pump same problem bridged the injection relay same problem. I climbed in and noticed to my surprised the connector has somehow popped off the Auxilary air valve!!! Thinking I had finally found the problem I went to start it and nothing changed same start up for a few seconds and stall. WTF! I checked the resistance on the auxilary air valve which is suppose to be 40-75 ohms and it's reading 17 ohms tops. I jumped the fuel pump with the valve hooked up and the door hasn't moved at all stuck in the 3/4 shut, even sprayed it with WD-40.

Could this have died and is causing the start/stall? Could the connector have been loose and when it fell off somehow shorted the regulator? Please help I have got to get this 928 out of my buddys garage almost at the point where I need to tow it.

chewy8000

Any help would be greatly appreciated.

Tempermental

This sounds pretty darn close to what I'm experiencing with my 82 l-jet

With MK's suggestion of the 300ohm tempII jumper (though he has 400 in your post) and the landseers link to the old thread about the Y ignition relay
- my car starts for a few secs and stalls

With the above and a pulled AFM electrical connector - my car will run -badly, not like I can even get it out of my own garage.

So our issues are kind of related - I've ordered a new temp II.

Landseer

Guys, are your ground wire terminals clean? Especially the ones above the CE on the firewall & the big cable linking block to frame beneath passenger side? Also, the one(s) on the right side of motor I think under the cam cover, about midway down the engine.

Also, brain power comes from hot lead on battery, the little cable.

Also, regarding vac, any breaks in 8 boots or the vac connectors at base of throttle body?

Don't underestimate the possibility of these being responsible.

Lizard928

Did you follow my suggestions?

Have you tried to hold the throttle open when starting? Partway, all the way?

And have you jumpered the L-Jet relay using a piece of wire with 3 ends to jumper the relay properly?

chewy8000

I have done all of it.

-cleaned up all grounds
-tested resistance of temp II (fine)
-tested resistance of cold start injector (fine)
-test thermo Time switch (fine)
-three way jumper on injection relay (fine)
-two way jumper to fuel pump (fine)
-checked for voltage at all connectors and everything checked out

Only problem I ran Into was the auxiliary air regulator check in at 17 ohms. Normal operating ohms are 40-70 and its not even close. Do these go bad? Could this be it? I ordered one to rule it out.