CIS Gurus: Lay-up issues

[Adam]

I haven't really driven my '76 911 very much lately.

It sits in the garage and gets occasional use on weekends. We're in the winter months and while it doesn't snow, I avoid driving the car in the wet, so I haven't used it for some time.

It's now sat around for some 5 weeks or so. I drove it last night after fitting my new seats (another thread coming later) and I found it just wouldn't idle at the lights. It surges until the revs drop too low and it quits. I had to keep revving it or it'd die. If I'm pulling up at the lights, I've gotta keep on the gas to keep it idling, or it stalls as the revs reach idle. I don't have power brakes, so it's not really a safety issue (unless I've gotta punch it away from trouble).

It always gets better with more regular use, but I'm thinking of tightening the nut on the hand throttle and using that for warm-up, which I've never had to do before. It's always been a car that you could fire up and drive straight away.

Can somebody walk me through troubleshooting this issue? Does it sound like it's the WUR? What does it look like and how does it work? Should I just replace it? I doubt it's a vaccuum leak, as the car runs great when it's warmed up.

Thanks!

[RoninLB]

I'd start with Techron and maybe some fuel stabilizer if it's only driven a few hundred miles this winter. and it takes about 10-15mi to stabilize the engine and oil... assuming the mechanicals and fuel mix are ok that'll give you a clearer pic.

[dd74]

I think your car is mad at you for not driving it, Adam. Classic P-car hissy-fit. You know, they're a lot like women - don't pay attention to them and they become stand-offish.

Apart from that, have you tried just stepping into the accelerator hard? Will it rev to redline? Do a techron treatment, and possibly check your spark connectors. And then, just drive the hell out of it. She'll fall asleep well loved.

[Adam]

Heh.. it runs fine, but just doesn't idle well on cold starts.

It runs real strong and is fast as ever, just grumpy at being woken up.

Ron - Thanks! I'll try some Techron and maybe an octane booster.

[Aussie]

Maybe the cold start injector is not working properly.

Like on my car also..

[Jim Sims]

Cold start injector only functions while the starter is turning over; it has nothing to do with the idle, cold or otherwise. I would suspect the WUR but without a CIS pressure gage harness and some readings one is just guessing. Jim

[Aussie]

Cold start injector only functions while the starter is turning over

Probably explains why mine is sometimes hard to fire, but once started is fine.

[RoninLB]

Originally posted by Adam Chaplin

Ron - Thanks! I'll try some Techron and maybe an octane booster.

NO.. not octaine booster..

"Techron and maybe some fuel stabilizer"... meaning a can of fuel additive to prevent the transformation of your fuel into crap from sitting around to long in the gas tank and fuel system. Pelican should have Staybyl, sic. Marine stores should carry these additives for winter lay-up also. There was an old factory winter storage tech bulletin put out a bunch of years ago. If you are interested and can't find it I can scan it into 2 pages of big bits.

[Doug Steinel]

My CIS will surge until it stalls if the mixture is too rich. Have you checked the CO level? Mine will idle fine at at 3-4%. Get to 8% and it surges.

[Adam]

Well, it's nighttime here. It's approx 4ºC and lots of fog. (winter)

I just took the car for an hour-long blast through the mountains near my home. It seems to be running fine! It's due for an oil change, so I might take it to a family friend who has a gastester and a hoist.

Ron - I'll look around for a fuel stabilizer and let you know. Many thanks.

[Paulporsche]

Try leaning the mixture in 1/32 or 1/16 turn increments. Usually by 1/8 turn that would cure it. 1/8 seems to correspond to about 1% CO.

If that doesn't do it, check out your control pressures, WUR, AAV and vacuum leaks.

Let us know if this works.