89 S4 No Start
#1
Rennlist Member
Thread Starter
89 S4 No Start
I have searched and used the troubleshooting guides and have not been successful in resolving the no start.
I did an intake refresh with new/rebuilt injectors from Roger. new knock sensors, CPS sensor, throttle position sensor, Idle stabilizer, greg brown fuel lines and all hoses. The car started and ran well before the intake refresh but the flappy valve did not function due to vacuum leak.
There is no hint of starting and I have done the following:
- Checked all connections
- Checked fuses
- Check fuel hoses for leaks by bypassing fuel pump relay (no leaks)
- Ignition on I hear fuel pump for a couple seconds
- Ignition on I hear click for EZK
- Crank engine - no tach movement but I have the digital dash so I am not certain if that is normal
- Swapped CPS sensor with old one but tach still not bouncing and still no start
What have I missed? I suspect something on the intake refresh was not done correctly but I can't seem to find it. This is my 3rd intake refresh so I am not completely new to it.
I did an intake refresh with new/rebuilt injectors from Roger. new knock sensors, CPS sensor, throttle position sensor, Idle stabilizer, greg brown fuel lines and all hoses. The car started and ran well before the intake refresh but the flappy valve did not function due to vacuum leak.
There is no hint of starting and I have done the following:
- Checked all connections
- Checked fuses
- Check fuel hoses for leaks by bypassing fuel pump relay (no leaks)
- Ignition on I hear fuel pump for a couple seconds
- Ignition on I hear click for EZK
- Crank engine - no tach movement but I have the digital dash so I am not certain if that is normal
- Swapped CPS sensor with old one but tach still not bouncing and still no start
What have I missed? I suspect something on the intake refresh was not done correctly but I can't seem to find it. This is my 3rd intake refresh so I am not completely new to it.
#2
Rennlist Member
Thread Starter
Well that was embarrassing.... I switched the CPS and Throttle position wires. Corrected that and the car started on the first flip of the key. Now I'm kicking myself for 3 days of troubleshooting other systems!
Time to go for a drive!
Time to go for a drive!
#4
Team Owner
FWIW get a roll of blue painter tape and label each connector as you take them apart.
Remember it could be months before the engine is back together,
and swapping the connectors will be the last thing you check.
This goes for noobs and olds we all will forget
Remember it could be months before the engine is back together,
and swapping the connectors will be the last thing you check.
This goes for noobs and olds we all will forget
#5
Rennlist Member
Thread Starter
The car ran great..... Drove it around several hot starts, now it won't stay running.
When it catches it goes to about 1K RPM and the it is like someone pulls the plug and the car dies. The tach no longer bumps when starting... let it sit and it will fire again but then die.
Any ideas? I am hoping someone has experienced this, I am not looking forward to going back in.
When it catches it goes to about 1K RPM and the it is like someone pulls the plug and the car dies. The tach no longer bumps when starting... let it sit and it will fire again but then die.
Any ideas? I am hoping someone has experienced this, I am not looking forward to going back in.
#6
Rennlist Member
Thread Starter
well it appears my pressure regulator has failed in a most spectacular fashion. Lots o fuel in the vacuum system and when I mighty vac it fuel fills the mighty vac. I hope it didn't explode with pieces of diaphragm going to my new injectors. I think I am going to replace all the dampers at the same time, 27 years is a pretty good run, sigh another $500.
Still not sure this would cause a start and then stop but they need to be replaced so I'll start there.
Still not sure this would cause a start and then stop but they need to be replaced so I'll start there.
#7
Team Owner
2 dampers and a fuel pressure regulator
NOTE the FPR and front damper look the same,
make sure the right part goes to the right place or it wont start
NOTE the FPR and front damper look the same,
make sure the right part goes to the right place or it wont start
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#8
Rennlist Member
Thread Starter
Regulator and dampers replace. Nice to have a proper running 928! Now onto the fuel tank leak. I've been reading all the nightmares around removing the in tank pump to replace the seal.