Very limited time these days so I am looking at some probables on isolating the problem.
Car ran flawless up until I parked it 3 days ago.
Got in this morning and it started up and died within a second.
Tried in vain but it would not turn over. Cranks great though.

Once it did kick over and idled only at 2k with some pedal but very rough and then died.

Swapped out the fuel pump relay (not EFI relay). Checked fuses as those were the easy things to do.

Unplugged the MAF and no change.

Unplugged the TEMPII sensor-no change. Resistance checks out.

Unplugged FPR-no change.

But.....If I loosen the front fuel hose which is connected to the right rail the car will actually start up or come very close to starting before dying even though no fuel is coming out of there.

At this time I am possibly thinking the LH is defective though of course no spare is available to check.

Again, car ran great up until now. 86k original miles.

Anything I may be missing?
thanks ahead of time.

 

Generally I think the phase is "relay, relay, relay" and it sounds like you only hit one of the three so I would start there with either different relays or jumpers.

 

if you are cracking the front fuel hose and no fuel is coming out then the fuel pump is not running.

I would check the fuse for the pump, and then go to the pump and see if it runs, and if it is getting power to it.

But again relay relay realy, jumper the fuel pump, LH and EZK relays and try to start as one of the brains triggers the FP relay and if it doesnt trigger it the FP will not turn on.

 

Do injectors click repeatedly when ign is switched on (not cranking) ?

 

#1 thing I always do with any car when it cranks but doesn't start is to jumper the fuel pump to run all the time. All you need is a 1 foot or so long wire with spade terminals crimped on each side. Pull the fuel pump fuse, pull a fuse that is on bus-30 (such as the hazard lights, although 928's don't have one so something like parking lights would do) and connect the jumper wire to the + of both fuse sockets. You should immediately hear the fuel pump start up.

Dan
'91 928GT S/C
'86 928S 5-spd w/LSD *sale pending*

 

Well, it seems to be getting better on it's own leading me to believe the LH unit is faulty.
It will now start and stay on if I keep the revs around 1500 or higher. Dies below that. The car does not run well and does have a bit of smoke (cannot tell which color from inside).

Since the cars runs albeit badly the relays must be fine (swapped them out or jumpered) which leads me to the LH unit.
Runs the same whether the MAF is plugged in or not

Has anyone tried resoldering the LH unit?

 

"Runs the same whether the MAF is plugged in or not"

Could be the MAF. Got any 928 buddies nearby with an 87-95? They can be used to test your MAF and LH.

 

Have to check that out, but it seems the FI relay is working okay.

I checked the coils /wires which seem to be alright.

Nothing really left except for the LH or MAF I suppose.

 

If you start soldering around in your LH you may do more harm than good !

 

Thanks for the tip. I managed to solder 2 of these years past for my 44's and both came out pretty good-lasted for a few years till cars sold.

At this time I am contemplating whether or not I want to go through the hassle of asking someone to swap these out or just load up the car and donate it somewhere.

 

When you switch on igntion, but not cranking, do you here any clicking inside the engine bay ?

 

Thanks John
I just checked yes, I get a series of click when the key is turned to on.
Car will start when cold but very rough a lot of smoke, exhaust smell, with the pedal down, and once war does not seem to want to stay on even with the pedal
thanks

PS, I will post a video here in a few minutes of what it does

 

Here is a short video clip of what occurs.
Engine cold in this as indicated by the gauge. Black soot out the tailpipe

Sad, was looking forward to some canyon driving today for my Sunday drive.

40mb, takes a minute or two to download

LINK TO VIDEO CLIP

 

Ok from your clip it sounds like not all cylinders are firing. Could be a number of things. Spark, fuel, air.
Together with black soot coming out of the tail pipe it might be that your spark plugs are fouled. Can you pull the spark plugs to see what they look like? Black & dry means running rich, black & oily, well, that's another problem. If rich then your O2 sensor (or MAF) might be faulty. Clean up your spark plugs and try again. Pull out the O2 sensor and try again.
(Afterthought: I noticed you fuel is low, that got me thinking that - when is the last time you changed your fuel filter?)

 

Cannot see it being the o2 sensor as the system in is open loop when cold. Fuel filter would be gradual over time. This occurred out of tech blue-immediate.

Perhaps a MAF.