brain help
#1
Race Car
Thread Starter
brain help
I have an 84 auto and need someone of the family to help me test my brain.
I don't want to buy a new one because I don't know for sure if the problem is with the brain.
Can I test the brain in 80-84 928's?
Thanks
I don't want to buy a new one because I don't know for sure if the problem is with the brain.
Can I test the brain in 80-84 928's?
Thanks
#2
Instructor
Join Date: Aug 2002
Location: Charlton, NY
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I recently sent my 86 brain to Part Werk of Chicago to have it tested for free. They sent it to a rebuilder who tested it and concluded that it need repair. I have not yet put it in the car to determine whether the problem is in fact fixed. The cost was $425. Devek will also test it for free. They do not repair, they will sell you a Porsche rebuild for $800. I have since learned that 928 Specialist will also test for free and rebuild.
#3
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I have now installed my $410 brain and the problem persists. Part Werks tells me that there must be something else wrong with the car in addition to the brain. They tried to help but have very limited understanding.
The problem with my 86 5 speed car is that it runs terribly putting out black soot. The problem developed gradually during a 2 hour trip. I can not drive it. I checked out everything (except fuel pressure since i did not have a guage and pulse width since i don't have a O'scope). Since I thought it was probably the brain and they can test it (for free), I sent it in.
After installing the rebuilt brain, the car would not start at all. I have to replace the EFI relay with a jumper in order to get it to run. The relay is fine.
The problem with my 86 5 speed car is that it runs terribly putting out black soot. The problem developed gradually during a 2 hour trip. I can not drive it. I checked out everything (except fuel pressure since i did not have a guage and pulse width since i don't have a O'scope). Since I thought it was probably the brain and they can test it (for free), I sent it in.
After installing the rebuilt brain, the car would not start at all. I have to replace the EFI relay with a jumper in order to get it to run. The relay is fine.
#4
Racer
Join Date: Nov 2001
Location: Glasgow, Scotland, UK
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If the computer's alright then it's probably getting fed bad information. The symptoms sound to me like the MAF (hot wire air flow sensor) could be bad. This is the behaviour that my auto had when it's hot wire broke.
However I am far from expert in this area so wait for a few more opinions!
DaveW
However I am far from expert in this area so wait for a few more opinions!
DaveW
#5
Rennlist Member
Rennlist Site Sponsor
Pull the vacuum lines from the pressure dampeners and the pressure regulator, jumper the fuel pump relay, and check for fuel coming from any of the units. Any leakage requires replacement.
#6
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thanks Wally, that's a great idea.
any thoughts on why i have to jump the EFI relay in order for the engine to run??? you may find the following history useful:
insert jumper, start engine (engine runs poorly), turnoff engine, replace jumper with relay, start engine, engine dies after 2 seconds.
for some reason it seems that the EFI brain is not grounding the fuel pump relay so the pump doesn't run. I am desperate!!!!!!!
any thoughts on why i have to jump the EFI relay in order for the engine to run??? you may find the following history useful:
insert jumper, start engine (engine runs poorly), turnoff engine, replace jumper with relay, start engine, engine dies after 2 seconds.
for some reason it seems that the EFI brain is not grounding the fuel pump relay so the pump doesn't run. I am desperate!!!!!!!