Cold start & Hot start issues

[ybn533]

Hi,

It seems that almost everyone with 911sc will have these issues.

First of all, I'm not a pro mechanic and far away from being an expert,I only know to read and do some statistics.

I read a lot in this forum about these problems and it seems that the hot start problems are really easy to fix and the must common solutions are the Fuel Accumulator and next step is the fuel pump check valve. I'll say that these two are the leading problems for hot start issues. Am I right on this so far?

Now, about the cold start issues I haven't got to conclusions yet. can you say from your knowledge which parts are the common failure that causing the cold start problem?

I know that you prefer to check in a step by step procedure but I think that this can help everyone who is not an expert and want to get a quick knowledge of the common parts that are causing these problems.

so let see what do you think:

Hot Start problem: (start with the must common)
1. fuel accumulator
2. FP check valve
3. ?
4. ?
5. ?

Cold Start problem:

1. ?
2. ?
3. ?
4. ?
5. ?

[Paulporsche]

Ahead of both lists would be to FIRST ensure that all ignition components are functioning properly.

Then I would verify that there are no vacuum leaks.

After that, I would verify the fuel and control pressures.

Then I would start the other component tests.

After years of reading posts on this BBS, troubleshooting my own car, and lots of help from Pelican members, it seems to me that the most common reasons for poor cold starting (once the above verification is done) are failures of the Warmup Regulator, giving, usually, either a too high or, sometimes, a too low cold control pressure, which results in poor cold starting.

After that, the Aux Air Regulator can have an effect.

The cold start injector is another, though not too often, possible culprit.

Poor hot starting can result from the above items to be verified, the 2 components you mentioned and a malfunctioning WUR, resulting in a too lean or rich hot start condition.

It SEAMS that rarely vapor lock is an issue w/ these cars.