Stumped the 84 928

Ran PERFECT all day, stopped at a store then NO START, kicked once then spun over but no start. I
1. Checked the fuel pump and fuel tank, tank at 1/2 and pump hum when key turned to start (Tried, no start)
2. Checked for spark ZAP! do not ask (tried no start)
3. Pulled the air cleaner (K&N) no problem there. (Tried No start)
4. Called AAA for a tow, and then threatened the car with a trip to the scrap yard.
Turned key and it started.
What the heck is it? I FIXED nothing, did the normal, air, spark, fuel and NOTHING then it starts.

Well sometimes a coil will act like this and start working once it cools off, but you said it had spark, so its not that.

The ignition switch has been know to cause problems but you say you are getting fuel and spark. You need to verify fuel pressure.

it could be the MAF sensor
it could be the LH ECU

we need more details

928mac;7592 wrote: Well sometimes a coil will act like this and start working once it cools off, but you said it had spark, so its not that.

The ignition switch has been know to cause problems but you say you are getting fuel and spark. You need to verify fuel pressure.

it could be the MAF sensor
it could be the LH ECU

we need more details

That is NEW not a rebuild
BOTH ECU's where replaced with Factory New when I had the shake problem and a rough idle.
The COIL is a GOOD thought, yes it sparked BUT did it every time I hit the key?
The coil is NOT a Bosch, it is from the speed shop side, back up for the modified. It was NEW in the box 12 volt 80,000 volt Accell. MAYBE that IS the problem, can order a new one and have Santa drop it off next to the new Sig Sauer.

lrpman;7595 wrote: That is NEW not a rebuild
BOTH ECU's where replaced with Factory New when I had the shake problem and a rough idle.
The COIL is a GOOD thought, yes it sparked BUT did it every time I hit the key?
The coil is NOT a Bosch, it is from the speed shop side, back up for the modified. It was NEW in the box 12 volt 80,000 volt Accell. MAYBE that IS the problem, can order a new one and have Santa drop it off next to the new Sig Sauer.

I am not sure George. I have heard that only the original coils work well but I am not sure if it is a resistance issue or what.
I would not replace it just yet as it is nice to leave everything as is and find that actual problem. if you start replacing things it may fool you and decide to work for another month and then fail at a very inopportune time.

Grounds are a big intermitant issue on these cars. if you have a meter to check some of the grounds at the ECU, look for anything higher then 0.3 ohms. 0.5 is starting to go bad.
Also, if it dose it again, wiggle the key in the ignition switch to make sure that the switch is not starting to fail.
ILL search the coil issue on Rennlist.

All I have found is that a coil either quits or starts to break down and miss fire at high rpm. (not your problem)

The other thing I found is that they say our system is a matched ignition system and it is already great quality that will not benifit from an aftermarket coil other then the bling.

So lets look somewhere else.

Dose it start now?

Brad, his car has the "air-flow controlled" L-Jet fuel injection brain. It has an air flow meter, rather than an MAF.

George, follow Brad's suggestion on checking and cleaning your grounds. Also, if the sudden no-start issue arises again... Listen to see if the fuel pump is still being energized when you disengage the starter. Try to isolate what circuit(s) are impacted when your car does this. Intermittent issues are the hardest to diagnose and fix. It is hard to fix something that is only sometimes broke.

It may be as simple as your fuel pump fuse, #13 I believe, making an intermittent contact. Then again, it could be the "green wire" creating an intermittent spark.