F451

Hey guys,

Can you ID this part for me? I was hunting down an irregular idle problem and noticed the black rubber end on this part was torn, on closer inspection, I tore it even more, and I see what look like bare wires. It's all still attached though.

Upon trying to start the car, it turns over, but won't fire. So now I have two issues, no start, and possibly irregular idle still.





Thanks,

Ed

ps: checked the manual and PET but could not find it.

F451

More details:
Car was running fine previously. Steady idle.
Blue check valve on brake booster is clogged (car was running fine).

Went in the other day to swap orientation of water heater valve. Airbox off.

Put it back together, irregular idle: starts up fine, idles around 850 steady. Drive for a bit, it goes up to 1500 and stays there. Off throttle it may dip down to almost zero, but doesn't stall, recovers up to 850, or 1500, depending.

Today it stalled twice off throttle. Besides irregular idle, it revs and runs nicely.

Tried to do some simple troubleshooting:
Disconnected battery.
Pulled airbox.
Discovered disconnected vacuum hose to four way connector near brake booster. Concluded this must be the idle problem as this was connected prior to working on the water heater valve.



Then I noticed the torn edge on the mystery part, and when I touched it to give it a closer inspection, it seperated and I could then see the bare wires, or what look like bare wires.

Put the airbox on, connected the battery.

Turns over, no start.

Any tips or troubleshooting procedures would be greatly appreciated.

Thanks!

danglerb

AFAIK that goes to a second crank sensor that maybe was used at the factory or dealer, but no place else.

Wild Bill

Look elsewhere for your problem, as this is just a test port.

IMHO you may have dislodged another vacuum line or this is just a coincidence and your idle stablizer valve is giving you trouble.

F451

Can the isv cause a no-start situation?

There are some good no-start troubleshooting procedures I can look into, but with the idle problems I was just having, I'm wondering if the isv could cause a no-start sitch.

Thanks guys. -Ed

Wild Bill

Ed,
Sorry, I mis-read your posts... No, I doubt a faulty ISV would cause a no start situation. Short of continuing to guess about what you could have dislodged, it sounds like it may be time to go back to the basic diagnostics... spark, fuel and timing, then apply what you've learned to the mix.

Bill

F451

Cool, thanks Bill. I really think the idle problem was caused by the disconnected vacuum hose - may be wishful thinking, but I'm clinging to that for the moment.

For the no start, I'm going to start with the infamous relays and go from there with the basics. And thinking it over today, I remembered that the external fuel pump was buzzing a bit and I was wondering if it was going out.

The last two times I drove it, yesterday and today, it wasn't buzzing and I was wondering about it.

So, I'll be checking to see if the fuel pump is working too.

F451

Bingo! Fuel pump relay! Switched it out with the horn relay, started right up.

Thanks to the listers for continuously pounding this drum in the no start threads. Also thanks to 928 Specialists for posting their most excellent relay and fuse diagrams online, helped me big time. Printed it out, one copy for the glove box, one copy to go with my manuals in the house.

https://www.928gt.com/t-8788fuse.aspx

Idle has returned to normal, I'm sure it was the disconnected vacuum hose, but will confirm that the idle is steady when I take it out for a spin in a bit.

Also have relay #XXII, Reverse Light Bridge(5-Speed), jumpered. What the hell is that about? I'll get a replacement in there to see what's up.

I'll report back on the idle.

Wild Bill

Glad to hear it Ed. I'm betting the idle is cleared up too.

On a 928, never assume, don't forget the basics and always check those relays, relays, relays!

ATB,

Bill

PorKen

As the name subtly implies, 5-speeds get a bridge. Contrast with automatics, which have a relay in that position.

F451