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-   -   problems with '74 2.7 (http://forums.pelicanparts.com/porsche-911-technical-forum/139079-problems-74-2-7-a.html)

vintageairs 12-10-2003 06:25 AM

problems with '74 2.7
 
i guys!
i need some help.

i took my car to the shop because i was experiencing loss of power, backfiring, and it was hard to start after sitting for a while. i had to use the hand throttle to start it every morning, but sometimes had to crank it as many as 10 times before the rpm's would even out and it would hold an idle.

after i got it back from the shop it ran like a dream and started on the first crank every time. the shop said they had to simply adjust the cis.

now, a few days later, i have the same hard start problem. now it takes 5 attempts and them my car seems like it has loss of power for the first few mninutes. then it weems to be fine. this hard start problem is driving me crazy for months. maybe something vibrated loose in the last 100 or so miles? any ideas?

thanks in advance,
josh

TerryBPP 12-10-2003 06:59 AM

Might be your WUR. Look in the archives for a test procedure.

vintageairs 12-10-2003 07:03 AM

i had to idea that my car had a WUR. Are you sure? why would it have worked fine after i picked it up, then gone faulty a few days later?
thanks for your help,
josh

fintstone 12-10-2003 07:29 AM

Your car will always need to have the hand throttle engaged somewhat to start unless the engine is hot. Turn the key on for a few seconds before turning to start to build fuel pressure.

vintageairs 12-10-2003 08:13 AM

i always use the hand throttle when the motor is cold. i have no problem with the hand throttle, but it is still hard to start these days. it worked great using the hand throttle when i got it back from the shop just a few days ago.
thanks again,
josh

IROC 12-10-2003 08:28 AM

Strangely, I took my car in for the same problems you describe years ago and the shop simply "adjusted the CIS" and gave it back to me. It started a little better, but ran like crap otherwise.

I finally gave up and decided to fix it myself. It ended up being the warm-up regulator...

Mike

vintageairs 12-10-2003 08:30 AM

are you guys sure i have a warm-up regulator?...or am i goi9ng crazy this morning. my '74 has no smog or oxygen sensor.
thanks again,
josh

TerryBPP 12-10-2003 08:36 AM

All CIS cars have a WUR (Warm Up Regulator). Its pretty easy to remove and test. I don't know why it would be fine then go bad but stranger things have happened. If you know someone that has a used one you can borrow just try it out.

vash 12-10-2003 08:37 AM

are you handy with tools? the CIS system is not strange voodoo. it is actually pretty easy, get a book and the guage system. no sense guessing what it is. but if i had to, it is the WUR. what the WUR will do when the car is cold, is to lower the pressure to the fuel distributor plunger (1.5 bar). that way, the air sensor plate can move up with less resistance allow more fuel, which means a richer mixture. as it warms up, the pressure builds up, and leans out the mixture. that is why the WUR is always somewhere that is in close contact with the tempurature generated by the engine. look at the driver's side of the engine on top.

cliff

vintageairs 12-10-2003 08:49 AM

thanks guys. i certainly do have a WUR. i will take it to the shop tomorrow to have them check it out.
thanks again,
josh

fintstone 12-10-2003 08:54 AM

Yes, you have a WUR. look to the back, left side of your engine between the intakes. It is the thing with several wires and vacuum hoses attached. Could be your problem. Also the cold start valve is a possibility.


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