Warm start up problem.

[sabeo.m]

Hey guy's i had another start up problem after driving my car for about an hour today for the second time. The first time this happen to me is when i first purchased it and drove it from the PO to my house. I shut the engine off to open up my garage door and then when i went to put the car into the garage it didn't want to start up. So, i contacted the PO and he said that i had to press down on the gas peddle a couple of times to get it started because he stated that the car loves a lot of gas. But, this action can't be normal or is? So I did and it started right up after about 20 minutes of trying to start it. Today was most embarrassing because i ran into the store as i returned i found a very new 996 (yellow) parked right next to me with the owner talking on his cell phone, i jumped in my car ready to rev my little monster and Nothing, just the starter turning over! Well, the butt hole in the 996 just smirks and tears ass out of the parking lot, i knew he wasn't a fellow pelican! Both times my car was parked on a bit of a incline. I recently fished a tune up job so i figured this problem might of dissipated. I'm thinking i need to replace the fuel accumulator, fuel pump, oxygen sensor or CD unit? What do you guys think? Couldn't find a thread on this subject or i could of missed it... THANK U!

[herr_oberst]

I don't know enough about these cars to qualify to help you other than to tell you that you are probably experiencing a Hot Start problem, rather than a Warm Start problem (or a Cold Start problem) and maybe it would be better to begin your search that way. My car had a Warm Start issue that manifested itself after the car had been driven enough to get up to temp (220 or so) and then let sit for a couple of hours - it cranked really hard till it finally started; but if I just went into a store and came right out, no problem starting, and in the morning, no problem. I finally solved it by replacing the fuel pump check valve. Having said that, my research taught me that these problems are fairly common and some very smart folks on this board have posted a lot of information about all three.

Might be as easy as a fuel filter.

Good luck.

[sabeo.m]

Thanks herr, i just recently change the fuel filter as well. I will check under hot start and see what i come up with. I will also investigate the check valve suggestion...

[Gogar]

+1 for accumulator OR fuel pump check valve. These things help keep the fuel pressure UP for a while when you turn your engine off. If they're not working, the pressure goes down and the fuel will have a greater chance of vaporizing from the heat, making for a hard start.

[Mike Stanko]

I'm in the midst of investigating a restart problem on my '83 SC. It's identical to the problem that herr_oberst had. I just bought a Bentley 911 SC service manual and it contains a wealth of info on the CIS system. If you can get your hands on a copy, I think you'd find it most helpful for troubleshooting your problem.

Here's some web accessible info that might help you...

http://members.rennlist.com/jimwms/CIS/CIShome.html

I've been told that diagnosis starts with measuring the system fuel pressure. See what I was told in my recent post...

'83 SC Warm Restart Problem and Questions

Keep (me ) posted on what you find. Good luck.

Mike

[Paulporsche]

As others have said, you should check your fuel pressures, especially your warm control presure. The most likely parts at fault are the WUR, check valve and fuel accumulator.

Mike or Sabeo.m: Please let us all know what happens after you run the tests. Even though previous threads and knowledge suggest the solution to your problems, it is good to get the results into the data base.

[sabeo.m]

Thanks Mike and Paul. I never had a problem starting cold. It starts instantly cold, damp and wet outside. I'm gonna start by replacing the accumulator and go from there. Mike, thanks for the links you provided...

[jannova]

I have a nearly identical problem on a '78. Starts fine except when hot. My first step was going to be to replace the check valve. But need some help on figureing out where it is? The Pelican part which fits into the outlet side of the fuel pump-connects to high pressure line banjo fitting is just a hollow connector, not a valve, although listed as one in other model years. I suspect valve might be on the fuel distribution end but don't see anything obvious on engine or Pelican part diagram. Thanks.

jnova
Illinois
'78 911sc targa

[sabeo.m]

jnova, I will try to find the location in my Bentley service manual and i will get back to you. I also thought it could be the check valve but insisted on changing the accumulator first then go from there... Have any pic's of your ride? where in IL, are you? I'm in Chicago, welcome to the board!

[SCWDP911]

What about rough idle after a hot restart... drive it for a half a mile or so, and runs fine. Drive for 100-200 miles. Shut off. Get gas. Retart, low and rough idle again, having to coax it along with the gas a bit, drive down the road a half of a mile or so, adn back to normal. In fact, after driving that 100 or so miles, come to a stop, and idles fine. Problem only occurs after restart...

This happened to me tonight on the way home from Palooza. Oil Temps normal the whole time, and it was a very pleasant day out (70's).