Weird Startup issue on 81SC

[Downerman]

So normally my 81SC starts with a quick blimp to the starter. No gas...nothing. Idles up and then when warm settles down perfectly/ Cold.....hot it does not matter.

This morning @68 degrees I hit the key and fires up for about 1 second then nothing. Try again...same thing. Try about 6-7 times with same result then suddenly it fires up like regular. I did notice that the OXY light was staying on during this but then again, maybe it didn't have enough time to shut off. Very weird. To be clear after it fired up the OXY went out and I warmed it up. Ran up the road a few times, idled in the garage for maybe 3 minutes and drove it into town. About an hour in and another back home. Ran perfectly. Did some reading and it doesen't sound like a O2 issue but man, sure has me stumped. Anyone experience this?

Dave

[tirwin]

Intermittent issues are so frustrating because... well... they are intermittent.

When I hear that I tend to think along a couple of lines.

1) Something is failing. The most common thing is CDI. Especially as daily temps get hotter, you’re getting to a temperature failure threshold faster than when the air is cooler. Classic symptom is it fails when it gets hot and starts working again after cooling off.

2) The condition that causes the problem is erratic. Fuse or relay has some corrosion. You hit a bump and jostle something that is loose. That kind of thing. Check fuses, relays and grounds for corrosion. I had a cracked fuse holder once. It had split enough that the fuses would get loose and cause all kind of erratic behavior. Maddening. Only found it when I went to replace it with an ATO style fuse panel.

I doubt OXY system has anything to do with it. Likely red herring. There is a counter that is supposed to be reset when the O2 sensor is replaced after it’s service life (30k miles? I don’t remember). It doesn’t affect the running of the car AFAIK.

[zje]

I had intermittent starting issues when my green distributor pick-up wire was failing. If you move/manipulate the green wire while the engine is running and it starts to stutter or run poorly, that's a likely culprit. It's a pretty easy test, so might be worth checking out.

[T77911S]

I may be wrong but looking at the diagram the O2 light is not really tied into the function or operation of the O2 sensor or system.
the light looks like it comes on based on mileage.
it gets power form the ALT, and mileage from the speedo.

spin fuse 18. could be bad connection

[OsoMoore]

I had issues with my fuel pump relay that plagued me for a few years. Eventually I bought the more expensive ones and haven't had trouble in a few years.

Next time it won't start and you have some extra time, do a check on the basics: Fuel, Spark, Air.

A little searching will give more details than I can elaborate on right now, but there are some good posts on it.

[ago85carrera]

Originally Posted by OsoMoore

I had issues with my fuel pump relay that plagued me for a few years. Eventually I bought the more expensive ones and haven't had trouble in a few years.

Next time it won't start and you have some extra time, do a check on the basics: Fuel, Spark, Air.

A little searching will give more details than I can elaborate on right now, but there are some good posts on it.

+1 on suspecting the fuel pump relay. I had pretty much the same experience several times (when hot and cold if I remember right). Figuring that the moment of combustion was on fuel from the cold start valve followed by nothing, I replaced the relay and have gone a couple years without incident.

[Downerman]

Hey thanks for the info. I pulled the red relay and the connections were really clean but figured I would toss an old relay that I had in my Porsche box. Not sure what the difference is between the black and red one but until my next Pelican order at least I have that.

Again, my thanks.

Dave