Engine shstdown after 5 seconds
09-11-2004, 10:05 PM
#1
Rennlist Member
Thread Starter
Engine shstdown after 5 seconds
Started the engine in the racecar today. 
Sounds good but 
it only runs for about 5 seconds then the fuel pumps shut down. I am thinking it is some kind of safety related feature. A few of things that could be related/causing it are:
No airbags (they blew due to the crash prior to my ownership)
Inertia sensors not connected
No brake fluid/pressure
ABS brain not connected
Any ideas would be appreciated.
Sounds good but it only runs for about 5 seconds then the fuel pumps shut down. I am thinking it is some kind of safety related feature. A few of things that could be related/causing it are:No airbags (they blew due to the crash prior to my ownership)
Inertia sensors not connected
No brake fluid/pressure
ABS brain not connected
Any ideas would be appreciated.
09-12-2004, 01:37 AM
#2
Burning Brakes
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Have you have double and tripple checked the wiring for your fuel cut-out switch, but on the other hand I wonder if it would run for as long as 5 seconds if this would be the problem. Anyway, I have seen this as the source to the type of problem you have numerous times.
Does your car have (or previously had) an alaram system with some kind of imobilizer function ?
Very common problem and a PITA to find.
I don't think the airbags could cause this kind of problem, at least I never heard of such thing.
Have you deactivated your airbags with a bridge connecter (not using the right word here), it's a 928.xxx.xxx.xx part that you connect inside the console. If not, it's probably good doing that to "outrule" anyhting airbag related.
Inertia sensors, is this air bag sensors in the front ?
My car starts with very low brake fluid pressure, a light comes on and I can hear a beep signal, but it starts.
ABS system, I don't know.
Only safety things that would shut down the fuel pumps that I know of is fuel cut-out switch and imobilizers, could be a wiring issue as well, fuel pump relays etc.
Does your car have (or previously had) an alaram system with some kind of imobilizer function ?
Very common problem and a PITA to find.
I don't think the airbags could cause this kind of problem, at least I never heard of such thing.
Have you deactivated your airbags with a bridge connecter (not using the right word here), it's a 928.xxx.xxx.xx part that you connect inside the console. If not, it's probably good doing that to "outrule" anyhting airbag related.
Inertia sensors, is this air bag sensors in the front ?
My car starts with very low brake fluid pressure, a light comes on and I can hear a beep signal, but it starts.
ABS system, I don't know.
Only safety things that would shut down the fuel pumps that I know of is fuel cut-out switch and imobilizers, could be a wiring issue as well, fuel pump relays etc.
09-12-2004, 09:48 AM
#3
Justin,
Probably is the air bag system controller. The ignition system power control does run through the air bag controller and I believe the controller will shutdown the engine in the event of an air bag deployment.
This is why you need the Porsche air bag delete bypass connector if you are not going to use the air bags.
I installed this bypass connector when I installed a non-airbag steering wheel, it came with the wheel. The bypass connector is just a jumper wire connecting the ignition circuit input/output wires to the air bag controller. If you look at the factory wiring diagram it shows the bypass connector option and you could simply make your own jumper.
I am not sure but I think the air bag controller ignition cut-off is probably not in the engine run circuit until after the starting cycle is completed and may be why your engine runs for a short time.
Mike
Probably is the air bag system controller. The ignition system power control does run through the air bag controller and I believe the controller will shutdown the engine in the event of an air bag deployment.
This is why you need the Porsche air bag delete bypass connector if you are not going to use the air bags.
I installed this bypass connector when I installed a non-airbag steering wheel, it came with the wheel. The bypass connector is just a jumper wire connecting the ignition circuit input/output wires to the air bag controller. If you look at the factory wiring diagram it shows the bypass connector option and you could simply make your own jumper.
I am not sure but I think the air bag controller ignition cut-off is probably not in the engine run circuit until after the starting cycle is completed and may be why your engine runs for a short time.
Mike
09-12-2004, 10:32 AM
#4
Rennlist Member
Thread Starter
The car ran before before we started taking it apart but it was intact, ie the airbags were still in the car as well as the original wheel and airbag sensors. The airbags were blown and it ran. Where is the bypass connector for the aibags located in the car?
09-12-2004, 10:36 AM
#5
Rennlist Member
Thread Starter
The car did have an aftemarket alarm system but I removed it. They had tapped into one wire but I reconnected it. I think it might have a factory alarm system as well. In the right floorboard area under seat there is a controller that has a 928 part number that has "alarm" printed on it.