924Board.org

Guest · Posted: Sun Jan 16, 2000 9:19 am Post subject:

From: Rodolfo Bonnin
Email: Rbonnin@admin.fsu.edu
Date: 1/16/00
Time: 10:19:02 AM

Hi. I have a 78 with 40,000 and it does not like to start while the engine is warm. It has no problems starting cold as well as hot. However, once the engine begins to cool off, it has a tendency to act as if it's flooding. The engine cranks, then turns off immediately and refuses to start up. Then it takes many cranks to finally get it started. Once I am able to start it, the engine sputters as if one or more of the injectors aren't working. Then after about 5-10 seconds the engine smooths out and it runs great. Also, while the engine is in the cooling of stage (about an hour after it stopped running), there is a strong odor of gas. Which contributes to the notion that there might be some type of leak somewhere. The car has been taken to a local Porsche specialists who have conducted pressure tests with the system. However, the car continues to have difficulty starting while it is warm. The injectors were also pulled and checked and they are fine. There are no visible leaks at this point. If you have any ideas or experiences with this type problem, please give me your commentaries.

Thanks in advance, your response is appreciated.

Guest · Posted: Sun Jan 16, 2000 9:20 am Post subject:

From: Michael J. Brown
Email: 924martinirossi@email.msn.com
Date: 1/16/00
Time: 10:20:36 AM

Sounds like everything was checked. Make sure the fuel pump has the check valve on it. This valve keeps pressure in the line for around 1/2 hour after turn off.

Guest · Posted: Wed Jan 19, 2000 2:38 am Post subject:

From: JManu from FRANCE
Email: jean-manuel.toussaint@univ-rouen.fr
Date: 1/19/00
Time: 3:38:35 AM

Hi,
my car have exactly the same problem. According to Rick maclaren, the problem may be due to the temperature control.
see below his advice (I don't have tried yet, but soon...) :

(1) Wrap the starter in a heat resistant fabric
(2) Ensure that the Porsche heat shield, a piece of tin, is properly in
place.
(3) Re wire the Battery to starter, alternator connections - All of
them. New wires.
(4) Replace VW Thermofan switch, and
(5) Replace thermostat. Ensure the switch and thermostat are rated for
the same temperature. Your starting problem should go away.

I hope this may be of help
Jean manu

Guest · Posted: Fri Jan 21, 2000 11:23 pm Post subject:

From: nick d
Email: nickd_bebop@hotmail.com
Date: 1/22/00
Time: 12:23:32 AM

Also- take a look at the fuel accumulators. Mine had this same hot
start problem that was caused from leaking accumulators (you have
two unlike later cars), this keeps a residual pressure on the system
after you shut it off to avoid vapor lock. And yes you can get vapor
lock at any ambient temperature. Sounds like your mechanic checked
it all, but just to make sure. I had a fuel smell too, one of accumulators
was actually dripping. They are located next to the fuel pump.

Good Luck,
-nick

Guest · Posted: Thu Feb 03, 2000 1:46 pm Post subject:

From: Llion
Email: llinhughes@hotmail.com
Date: 2/3/00
Time: 2:46:27 PM

Same problem different solution.
I had vapour lock on my 1980 924. my solution (which has worked up to now) was to wire a push switch into the 5th injector circuit. If it wont start i now manualy select the 5th injector and lo and behold it starts

Guest · Posted: Thu Feb 03, 2000 2:11 pm Post subject:

From: wesley m
Email: suprhack@hotmail.com
Date: 2/3/00
Time: 3:11:30 PM

Llion,

Could you tellme how you did this? Is the 5th injector your refering to the coldstart valve?

Thanks
wes

Guest · Posted: Wed Feb 16, 2000 3:31 pm Post subject:

From: Llion
Email: llionhughes@hotmail.com
Date: 16 Feb 2000
Time: 16:31:04

Sorry for the delay in replying.
Yes I was refering to the cold start injector,
If you look at the wiring diagram you will see that the injector has a permanent live feed and that
the injector is "turned on" by the thermo switch by switching to earth.
If you break into this wire and run a cable into the passenger compartment to a push switch (I was able to use the front headlamp switch) and then to earth.
When (not if) the car does'nt start the procedure is as follows.
Turn the ignition on and engage the starter. Press the push switch Usually for only a matter of 2-3 seconds and it starts.
If you do this mod take care with the wiring and ensure that you pick up the correct wire at the injector
Good luck
Llion

Guest · Posted: Sun Feb 20, 2000 2:04 pm Post subject:

From: llion
Email: llionhughes@hotmail.com
Date: 20 Feb 2000
Time: 15:04:49

Sorry wesley when i re read my reply spotted mistake, please read headlamp switch as headlamp washer switch

Guest · Posted: Mon Mar 13, 2000 5:51 pm Post subject:

From: Robert Middleton
Email: robert_middleton@talk21.com
Date: 13 Mar 2000
Time: 18:51:24

Lots of esoteric explanations I see but practical experience matches best with hackers who have attacked the hot start injector. I bought a hot start relay fix which did not work but in essence pulses the hot start relay, to no avail. Allowing manual intervention (switch in cabin) when difficulty is encountered gives a successful (if embarassing) start within 5 attempts. Also beware of sticking fuel pump relay (whack relay board while cranking the engine)listen for high pressure pump over-run after failed start attempts.
I seem to have little E-mail replies so in case my address is getting scrambled it is robert_middleton@talk21.com
Keep cranking you 924 owners
Bob