K-Mech
Senior Member Picogroup
 
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I'm an Autonerd
Posts: 216
Nairobi Kenya
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Hi nerdz. I am working on a VW golf. I don't have much experience with VWs, so I needed to know if this is a problem or not.
The client called me in to find out why it intermittently stalls on acceleration. When she took me on a test drive to duplicate the problem, the symptoms were when you punch it to the floor, it surges 3 - 5 times (almost like injectors turning on and off) then the car stalls. When it stalls, it is a no start for the first couple of cranks.
When we drove back to her house, I put a scanner on it. No codes. Pulled live data then tried to duplicate the problem, but as it usually goes, the car refused to act up with me there. Everything on live data seemed to be OK, EXCEPT I noticed the ignition timing at idle was reading 12 degrees ATDC. I thought, NO, impossible! I've never seen any car fire after top dead center and run as well as this car is running. So I decided to take a pressure transducer reading in order to verify if the computer is lying or telling the truth. Sure enough, the capture below shows indeed the computer is telling the truth (ch1 - Ignition signal for coil #1, ch 2 - pressure transducer in cylinder #1).
I have to go back and look at the car when it acts up again, but I cannot get the timing out of my head. This is the VW 2.0l FSI engine. There is no published data on ignition timing from VW for this engine. Has anyone ever experienced this? This car has no running issues - no popping, rough idling or anything.
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