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914World.com _ 914World Garage _ Ljet cold start

Posted by: Porschef Aug 8 2015, 07:33 AM

Yesterday I thought I'd take a look at the one remaining issue with my car's running, the cold start up. I have to crank it for about 5-6 seconds before it'll start, and then I have to keep the throttle up with my foot for maybe 30 seconds before it will idle. I can drive it without a problem as long as I don't let the engine try to idle by itself. After a minute or so, it's ok.

It was in the low 70's yesterday, I pulled the cold start vale and watched it's operation as I cranked the cold engine. No fuel came out. Checked voltage at the harness, no voltage. Triggered the CSV with a 9v battery, it clicked open and spritzed some fuel.

I've located a couple wiring sources, but before I go crazy with that, should the CSV even be open at that temperature? I've read that Thermo Time switches rarely fail, and I've checked the AAR, which closes (coincidentally ) around the same amount of time it takes for the car to idle by itself. I've also blocked off the hoses to the AAR, and see no difference.

2056 with 9550 cam. Car runs great once I get past this hiccup.

Any ideas?

Posted by: timothy_nd28 Aug 8 2015, 04:54 PM

The thermotime switch that controls the cold start valve should be inactive with temperatures in the 70's. I can't remember exactly what temperature that little circuit becomes active, but I want to say it's in the 30's?

Do you have access to a air/fuel ratio gauge? I think some tweaking of the AFM may be needed.

Posted by: Dave_Darling Aug 8 2015, 06:00 PM

The CSV should only open while the starter is cranking, and only if the temp is below the low 40s. (Or below freezing, depending on which resource you read.)

--DD

Posted by: Porschef Aug 9 2015, 07:29 AM

Thanks. I do have an AFR gauge, and the engine seems to be enjoying the 13.1 or so reading at idle, and at cruise. If I lean it out anymore, the head temps start to push higher than the 350's that show now at speed.

Really my only complaint is the cold start situation, any time the car cools down it requires a little feathering of the throttle to stay running.