'83 Woes

Iwishshewereded · 11-23-2009, 08:59 AM

Hi all, I am working on my boss's '83 Carrera. It did not idle for long after starting and he replaced the fuel pump on the advise of a "911 mechanic". The problem still persists?
Basically, once started, the idle gets weaker and weaker. If you try to give it any gas it backfires and soon dies. It will restart but repeats the problem? HELP!

I would appreciate any advice. Thanks, Mark.

Dueller · 11-23-2009, 09:13 AM

Is it a Carrera or an SC? '83 was SC. 84-89=Carrera. CIS or motronic f/i? If SC check to see if pop off valve or airbox is leaking.

Superman · 11-23-2009, 09:17 AM

Dome light fuse?
Frequency Valve Relay?
Beyond that......auxilliary air valve.......fuel pressures......

Paulporsche · 11-23-2009, 09:20 AM

Mark,

You have some reading ahead of you. If you search your symptoms you will find there is a lot of info here re CIS start and run problems. CIS was used through MY 83.

A CIS fuel pressure gauge is required to measure your fuel and control pressures. The WUR (warmup regulator) controls these pressures and it is very common that this component goes out of spec, resulting in the symptoms you described.

The Auxiliary air regulator (AAR) is necessary to keep revs up during warmup.

Vacuum leaks are also common problem areas, resulting in start and run problems.

The Bentley manual for SCs, this site, and Jim Williams' website all have a lot of info on the CIS.

If the car is an 84 or later, then it would have the Motronic systam, which operates differently.

T77911S · 11-23-2009, 10:50 AM

here is the most important question.

Iwishshewereded- i gotta know more, or does the name say it all.
i think this might be the best name i have seen so far

Iwishshewereded · 11-26-2009, 06:52 AM

Thanks for the info. I will go back there after the weekend and start working through your suggestions. He has an old Haynes manual, but it is not useful for trouble shooting. Thanks again for the help...I am sure I will need more of it! (Oh the username. If you ever met the delightful, vemon-filled trollup who married my neighbor and forgot to mention it, you might ask "Why so few adjectives Mark?")

Iwishshewereded · 03-25-2010, 07:48 AM

Ok...it's an '82 SC. Does that change the original advice? Sorry for the delay, other projects, and the sunshine is coming so the Targa needs to work. Thanks in advance.

Forza · Forza's Garage

Here's a CIS primer:

CIS Primer for the Porsche 911

Iwishshewereded · 03-25-2010, 08:32 AM

Thanks! I will inspect the lines to the warm up regulator first. I checked the price...ouch. The fuel pump was replaced recently but not sure about the filter? Mark.

vash · vash's Garage

it may help to indicate where you live. if you were near me, i would drop by for a look-see. then after checking out the trollop, i would help on the car.

has the air fuel mixture been checked? is it good?

wjfk32 · 03-25-2010, 08:42 AM

Sounds like its not getting fuel.... Possible fuel head gum-up if the car has been standing and not running... Try some marvel msyt. oil....

Good luck

T77911S · 03-26-2010, 06:37 PM

it sounds like when it starts, the aux air regulator (AAR) is working. it is raising the idle, or making it idle since there is something else going on, then as it warms, it lowers the idle as it should. but something is making it idle too low, and causing it to backfire, both of which can be a very lean condition.

i would look for air leaks and check fuel pressures.