Starting a 1979 with 5 speed manual

My recently acquired 1979 928 has the following starting symptoms:

Unless started within the last few hours, the car will not start on the first crank. On the second crank, the engine barley catches on a few cylinders and then builds up rpms to around 1500 over about 5 seconds. During the next 20 seconds, the rpms drop down to around 900 rpms. After a few seconds at 900 rpm, the idle is smooth and the car will drive away easily.

My first guess was a fule check valve but this car does not have one. Befoe I buy more parts, does anyone have a suggestion on what could cause these symptoms?

Thanks,
ewm

Is the fuel filter clean/new?

Try cycling the key to on, wait a few seconds, then off, repeat and cycle key on again, do it a 3rd time and then try starting and see it it is any different. If it is better then it is fuel related.

My car dose not have a fuel check ball to my knowledge and if it dose it dose not hold pressure bast 10-15 seconds of turning the key off.

Maybe it is dirty injectors? is there a way for you to connect a fuel pressure gauge into the line for testing purposes?

Brad

Thanks for the response.

The fuel filter is new. The injectors may be dirty but the cars runs extremely well once started.

Does anyone use injector cleaner additives in the early 928s?

Some may use cleaner.
I just ordered a set for $165

My first quick (unrefined) thought is that a ;79 would be a CIS system, and have an additional cold start injector that connects to the top front of the plenum. At least that is my recollection for how my '80 Euro S was setup.

So, if your problem is at start up, perhaps that "extra" injector is not functioning properly and not providing the extra fuel the car requires when cold.

Stan.Shaw@Excell.Net;5623 wrote: My first quick (unrefined) thought is that a ;79 would be a CIS system, and have an additional cold start injector that connects to the top front of the plenum. At least that is my recollection for how my '80 Euro S was setup.

So, if your problem is at start up, perhaps that "extra" injector is not functioning properly and not providing the extra fuel the car requires when cold.

Yes, hard starting on CIS cars is very often the fault of the cold start injector. It's the first place to look.

Do you have a copy of the 928 Workshop Manuals?