'83 SC runs for a minute, then...

[kosmonaut]

Hi all. Guess I'll be starting off here with some problems, but I've been lurking since I bought my first 911 in May. It's a US model that has done 155k miles. Imported to Norway from Cali around eight years ago. It was fairly cheap due to the mileage and lack of maintenance, but it's solid and was running fine. Been catching up on maintenance on it. Changed oil on the transmission and engine, oil filter, fan belt, air filter, brake pads, spark plugs and distributor cap.

A month back we went on a three day roadtrip with a big group. After a few hours the engine just cut whilst driving. We weren't getting spark on the coil. No luck getting it to fire back roadside, so we hauled it to the campsite. Long story short, a guy showed up with a spare CDI box and it fired right up. Didn't run well on low RPM's, but it got us through the two days of driving and back home.

Since then I haven't been able to drive it. It starts right up, but idles at around 1700 rpm for a minute. Then it drops to 4-500 and it runs really poor, not firing on all cylinders. First I thought it was the spare CDI box that was bad (it became a spare since it originally died on the owner, but then worked again later). I sent mine to Parts Klassik and got a mint one in return, but the issue remains. With my old box it needed to rev for five or six seconds before starting up when cold, then idle was pulsating for a while before running like it should - so I assumed that this had been a warning of the failing box. Now it seems like there are more issues.

Any input would be great. I've inspected the green wire which seems fine, adjusted distributor timing and swapped back the old distributor cap. Going to swap back to old plugs and try a different coil. I'm dreading the CIS system and vacuum leaks, but I'm guessing that could be next on the list?

Pardon the lengthy post. Here are a few pictures:

[Flat6pac]

80-83 has the lambda box under the passenger seat. There is a relay next to it, originally marked VW part. Change that relay because if defective it mimics the warm up regulator being defective and it’s inexpensive..
Bruce

[garment]

+1 on this. I had the same issue, new relay solved it.

Originally Posted by Flat6pac

80-83 has the lambda box under the passenger seat. There is a relay next to it, originally marked VW part. Change that relay because if defective it mimics the warm up regulator being defective and it’s inexpensive..
Bruce

[kosmonaut]

I'll try that, thanks!

[GothingNC]

Make sure you get the relay from our host.

I wasted $12 picking up one from the local auto parts store.

[kosmonaut]

Wow, that sorted it. Thanks again!

@GothingNC: For sure that makes sense on some parts. But with shipping and a 25% import tax plus fees it would make for one ridiculously expensive relay that I'd have to wait a week to get. Last night I literally cycled up to a store and paid $5 to pick it up.

Cheers!

[GothingNC]

Glad it was a cheap fix :-)

[mikedsilva]

Originally Posted by Flat6pac

80-83 has the lambda box under the passenger seat. There is a relay next to it, originally marked VW part. Change that relay because if defective it mimics the warm up regulator being defective and it’s inexpensive..
Bruce

Bruce to the rescue again! Where would we be without guys like Bruce!

[al lkosmal]

Nice fix Bruce...experience is all!