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914World.com _ 914World Garage _ Oh dear-here we go again!
Posted by: porschefile2010 May 26 2016, 07:49 PM
I needed your help before and now we have a new issue. I have just about had it with the ongoing problems.
Mine is a 75, 2.0 with original FI. I dropped a valve seat and gave it to my garage to repair the head and replace all the valves. It all went back together and fired and ran but only for a very short time as all the cylinders ran rich and fouled the plugs.
So my take on this is that it can't be the injectors as they are not all likely to fail at the same time.
Perhaps it is something in the system that makes the injectors fire continuously? So could that be trigger points?
If you could give me any ideas as to why all the plugs might foul I will start looking at each one until I nail it.
Thanks Guys.
Richard 
Posted by: catsltd May 26 2016, 08:31 PM
I needed your help before and now we have a new issue. I have just about had it with the ongoing problems.
Mine is a 75, 2.0 with original FI. I dropped a valve seat and gave it to my garage to repair the head and replace all the valves. It all went back together and fired and ran but only for a very short time as all the cylinders ran rich and fouled the plugs.
So my take on this is that it can't be the injectors as they are not all likely to fail at the same time.
Perhaps it is something in the system that makes the injectors fire continuously? So could that be trigger points?
If you could give me any ideas as to why all the plugs might foul I will start looking at each one until I nail it.
Thanks Guys.
Richard
My guess its a vacum leak.
Head gasket maybe.but for sure something is leaking,or not sealed right.
My FI had same problem with fouling plugs,but forgot what caused it.
I just got my 1.8L working like a new car,and clutch blew apart.
These cars take more patience than anything I have ever done.
Posted by: r_towle May 26 2016, 08:32 PM
Sounds like when your valve seat dropped it may have blown too much back pressure through the intake and took out the MPS.
See if the MPS holds a vacuum....
Posted by: porschefile2010 May 26 2016, 08:34 PM
Sounds like when your valve seat dropped it may have blown too much back pressure through the intake and took out the MPS.
See if the MPS holds a vacuum....
Hmmm. There's a thought. I have a spare MPS so I could change that out and see what happens. Thanks
Posted by: 76-914 May 27 2016, 08:03 AM
Agree with Rich or the MPS is unplugged.
Posted by: The Cabinetmaker May 27 2016, 08:34 AM
Plus one on the mps
Posted by: Tbrown4x4 May 27 2016, 08:59 AM
Sounds like when your valve seat dropped it may have blown too much back pressure through the intake and took out the MPS.
See if the MPS holds a vacuum....
Hmmm. There's a thought. I have a spare MPS so I could change that out and see what happens. Thanks
Just put a hose on it and see if it holds vacuum. If the diaphragm is blown, the ECM thinks the engine is under full load and goes rich.
Posted by: Tom_T May 27 2016, 12:42 PM
Hi Richard,
I just sent you an email on this & the other info. you wanted before.
Again for those reading on here, if you've got a shop doing your work for pay who cannot diagnose & fix these issues, then you need a different shop more familiar with 914/411/412/Bus with the 2.0s IMHO! 
I mention the MPS noted above + FPR & ECU + bad rebuilt injectors possibilities, as well as possible problems if that D-jet was used & modified on your prior 2.4 that came on the car.
Tom
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Posted by: Dave_Darling May 27 2016, 02:52 PM
MPS would be the first thing I would check, along with its hose.
Fuel pressure would be the second thing.
....Actually, in my car it'd be the other way around, because I have a fuel pressure gauge permanently mounted in the engine bay... 
After that, I'd be looking at the ignition system.
--DD
Posted by: porschefile2010 May 27 2016, 04:19 PM
Thanks to everyone. That'll keep me busy for the weekend. Appreciate all your advice.
R 
Posted by: Samuelrocky May 27 2016, 11:29 PM
The cold start valve malfunctioned on my 73 2.0 which caused extreme rich fuel mixture. Unplugged it and the car ran normally.
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