SC acting weird

JoeF · 03-30-2002, 12:17 PM

This just started happening. Up until now this car always started right up with just quick turn from the starter. In the past 2 days, after starting normally then driving around for a while, I shut the car down, go to restart it anywhere from 1/2 hour to 2 hours later and the car needs to be craked a long time or a few times to start. I also have to give it a little gas. Then it will start slow and kind of take about 20 -30 seconds to get up to a steady idle. It isnt that normal start up. This does not hsappen every time I restart it, only after the car has sat a while after runnig it that day. The car runs great other wise. Is this an issue?
JoeF

hilandscott · hilandscott's Garage

Sounds like you are experiencing something equivalent to either vapor lock or lack of residual fuel pressure in the lines after cooled down a little. I don't know the prevalance of vapor pressure problems in Porsches, but the CIS system is also designed to keep enough fuel pressure in the lines after running. Troubleshooting the fuel, such as accumulator, check valve might be a place to start. I did a search of the web for CIS and found sites a while ago...

Joeaksa · 03-30-2002, 12:33 PM

Joe,

Since its not summer in NJ just yet, wonder if your fuel pump is giving up the ghost or another reason for low fuel pressure.

Have seen this happen in summer where your fuel is vaporized in the fuel lines after the car sits for a while but it should be too cool there now for this.

Joe

Al S · 03-30-2002, 05:19 PM

Exactly the same thing happened to me on my 83SC.........I first changed the check valve at the fuel pump (didn't help), then the fuel accumulator - Voila! Problem solved . It's usually one of these culprits. Basically the CIS loses residual pressure during shut down making start up difficult. Thankfully, a cheap and easy fix.

JoeF · 03-31-2002, 04:22 AM

Thanks for the info guys, I will check these out and let you know.
JoeF

ronb · 04-02-2002, 06:56 AM

I am having the same problem - starts fine if cold or hot, will not start easily if warm, ie has cooled down for 30min - 2 hours. Very "choked" start then after several long cranks, then needs help from throttle to stop from stalling. In addition to the fuel accumulator, should I be replacing check valves, is there more than the one at the fuel pump? Where else to look for residual pressure related issue?

Superman · 04-02-2002, 08:24 AM

The fuel pump check valve is cheapest and is a very likely suspect. Fuel accumulators go bad less than people think. The other place fuel pressure can be lost is the injectors. Fuel may dribble out the injectors while it's sitting.