924Board.org

Guest · Posted: Mon Jul 09, 2001 10:12 pm Post subject:

From: steves
Email: stevey9@hotmail.com
Date: 09 Jul 2001
Time: 22:12:34

I finally have my 77 924na running good after 2 years of work rebuilt engine, rebuilt tranny, and new paint. But i have a starting problem. It will start after 30 sec or so of cranking over. I think i have one of the three fuel problems...

1) Leaking injectors
2) Back check valve
3) Or bad fuel accumulator

How do i check each one to see if thats where my problem is?

A guy here has started having road races on an old airport runway with a cone course i want to start going and see what the car and i can do.

Thanks for the help
Steve

Guest · Posted: Mon Jul 09, 2001 10:48 pm Post subject:

From: Ian
Email: themechanic@talk21.com
Date: 09 Jul 2001
Time: 22:48:25

Have you tried freash fuel and a filter.

Guest · Posted: Tue Jul 10, 2001 9:43 am Post subject:

From: Vaughan
Email: vscott77@nospam.hotmail.com
Date: 10 Jul 2001
Time: 09:43:47

Second Ian's comments; you can check if the injectors are leaking if you pull them and crank the engine to spray the fuel in a jar - look at the pattern, and see if they shut off fuel flow sharply when the engine stops cranking or continue to dribble fuel.

Wouldn't hurt to put some injector cleaner (Chevron Techron) in it... after changing the gas...

Guest · Posted: Tue Jul 10, 2001 1:15 pm Post subject:

From: JoeD.
Email: porsche
Date: 10 Jul 2001
Time: 13:15:59

Since the injectors are so inexspensive for this year I would get a new set for the performance gain anywhoo ... I did after battleing hard starts and sputering and things like that .

JoeD.

Guest · Posted: Tue Jul 10, 2001 1:16 pm Post subject:

From: larso
Email: l_porsche@hotmail.com
Date: 10 Jul 2001
Time: 13:16:50

how does the car start once its hot? does this only occur when its cold?

I third the gas and filter...but 30 seconds is a lot, so my guess is that you do have problems with somethign else other than just gas...if you can do the gas first though that is the best so you don't reck anything up like the fuel pump, and so you eliminate one thing for sure..

Guest · Posted: Tue Jul 10, 2001 4:53 pm Post subject:

From: steves
Email: stevey9@hotmail.com
Date: 10 Jul 2001
Time: 16:53:14

I have a new fuel filter on and i use 97 octain gas and have put in 3 tanks this summer alone so I know it's not either of them.

steve

Guest · Posted: Tue Jul 10, 2001 5:13 pm Post subject:

From: larso
Email: l_porsche@hotmail.com
Date: 10 Jul 2001
Time: 17:13:59

usually bad gas, from my experience, still starts the car fine, but it smokes and stinks.

SO next test i would do is a pressure test, do u have fuel test gauges....u can buy them at auto stores if u don't...

does the car start when hot?

Guest · Posted: Wed Jul 11, 2001 7:08 am Post subject:

From: steves
Email: stevey9@hotmail.com
Date: 11 Jul 2001
Time: 07:08:50

it doesn't make much of a difference if the car is hot or cold when trying to start it. it
may take alittle long when it's hot though. i did the button cold start thing and it seems
to help alittle.

steve

Guest · Posted: Wed Jul 11, 2001 3:12 pm Post subject:

From: Ian
Email: themechanic@talk21.com
Date: 11 Jul 2001
Time: 15:12:25

Is the cold start system working correctly? If you pour a bit of fuel in the intake does it fire imediately? After cranking (before it starts) are the plugs wet?

Guest · Posted: Wed Jul 11, 2001 3:23 pm Post subject:

From: Ian
Email: themechanic@talk21.com
Date: 11 Jul 2001
Time: 15:23:38

Is the cold start system working correctly? If you pour a bit of fuel in the intake does it fire imediately? After cranking (before it starts) are the plugs wet?

Guest · Posted: Wed Jul 11, 2001 3:36 pm Post subject:

From: larso
Email: l_porsche@hotmail.com
Date: 11 Jul 2001
Time: 15:36:40

the button cold start thingy will nto be needed when you fix the problem.

Bascially I would get the pressure gauge on the car to find out what it is. It's probably the accumulator or the WUR. It could be a combination of things. I don't think it is the check valve in the pump as the main problem, because your car does not start when cold...the check valve only makes a difference when the car is hot, because of back pressure and all that stuff that doesn't matter until the car is hot with fuel all over in the system.
What about directly after you turn off the car? like say you run the car for 10 minutes, turn it off, and 2 seconds later try to start? It should start up right away without the cold start valve...how is the mixture? is it set ok?

Guest · Posted: Wed Jul 11, 2001 10:13 pm Post subject:

From: steves
Email: stevey9@hotmail.com
Date: 11 Jul 2001
Time: 22:13:34

yeah if i let it run for 10 mins and shut it off then try to start it again it will start right up no problems. the car starts easier whens its cold but still takes some cranking over. where would i hook up the fuel pressure gauge?

steve

Guest · Posted: Sat Jul 14, 2001 12:24 am Post subject:

From: larso
Email: l_porsche@hotmail.com
Date: 14 Jul 2001
Time: 00:24:47

ok well it definately sounds like a pressure problem!! (most fuel issues are so no big surprise eh?)

Well the Haynes explains all the pressure tests u can do i think....do u have a gauge and stuff??

But my honest guess here is the Warm up reg or fuel accum. Maybe teh fuel accum shot and won't hold a bit of pressure until you get it runnin, or maybe the WUR is jacked (haven't taken one apart, don't know what goes on them....)

u have the haynes? I don't wanna repeat how to test the fuel pressure if its already in the haynes....(someone is borrowing mine now anywho!)