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Old mysteries with this FSI

gladdyppp

New member
Location
California
Car(s)
2007 VW GTI
Ever since I checked my cam follower, cold starts have been long and sometimes refuse to start the first crank. Ive checked the cf, maybe I put it on wrong, even replaced it. Still rough startups throughout the day. I've read old threads trying to pinpoint the issue here. People have changed: lpfp, hpfp, coils, plugs, carbon cleaning, yet the issue persists. What is the ACTUAL culprit here? I don't want to change all of these parts if they won't fix the issue. If somebody has seen the better days of this problem, please put it here on how you have solved it.
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
Mine doesn't start every time the first time I attempt cranking it. I now hold the key in the ignition position a bit longer than usual. Mine has new; HPFP__LPFP__fuel pump control module__injectors__6.6 bar fuel filter__plugs__coils__recent valve cleaning. And nothing has helped. I didn't replace all of those for solving its start-up issues. The fueling bits were done for resolving a low pressure issue from the LPFP at high load and revs...and for having a low specified pressure target from the HPFP at full throttle. Plugs and coils were swapped for the plugs being due and the coils had 150k miles on them.

I have recently read a post in the MKVGolfGTI UK forum. The owner, also was having start-up issues, who'd just done the timing chain and tensioner service, posted his start-ups are now crisp as it once was. I have yet done the cam timing service on mine, as I have planned on doing it at 160k miles. It has 157k miles at the moment. But I am hoping the start-up issue is resolved when I do the cam timing service. This may be something for yourself to consider...and would include; new chain & tensioner__new N205 rings__new N205__cleaning the N205 pick-up screen in the chain cover__disassemble and clean, or just replace, the cam phaser unit on the end of the exhaust cam.

There are more possibilities E.g.; runner-flap valves malfunctioning__throttle-body valve malfunctioning__other sensors may be reporting inaccurately to the ECU__fuel pressures are suffering__and who knows what else.

Fuel pressures and delivery may be the more likely cause, and it may require a thorough fuel pressure diagnosis. You'll want to conclude that the injectors, LPFP, fuel filter, injecotors and pressure limiting valve (FPRV) on the rail aren't the cause for fuel to escape from either the low or high pressure sides. This is one video link I share, which shows one determining where the system is losing pressure;
It basically is done so you disregard what the sensors are reporting...for they may be at fault as well. The gauge pressure can be compared to sensor data to verify they are reporting accurately or inaccurately to the ECU.
 

gladdyppp

New member
Location
California
Car(s)
2007 VW GTI
Mine doesn't start every time the first time I attempt cranking it. I now hold the key in the ignition position a bit longer than usual. Mine has new; HPFP__LPFP__fuel pump control module__injectors__6.6 bar fuel filter__plugs__coils__recent valve cleaning. And nothing has helped. I didn't replace all of those for solving its start-up issues. The fueling bits were done for resolving a low pressure issue from the LPFP at high load and revs...and for having a low specified pressure target from the HPFP at full throttle. Plugs and coils were swapped for the plugs being due and the coils had 150k miles on them.

I have recently read a post in the MKVGolfGTI UK forum. The owner, also was having start-up issues, who'd just done the timing chain and tensioner service, posted his start-ups are now crisp as it once was. I have yet done the cam timing service on mine, as I have planned on doing it at 160k miles. It has 157k miles at the moment. But I am hoping the start-up issue is resolved when I do the cam timing service. This may be something for yourself to consider...and would include; new chain & tensioner__new N205 rings__new N205__cleaning the N205 pick-up screen in the chain cover__disassemble and clean, or just replace, the cam phaser unit on the end of the exhaust cam.

There are more possibilities E.g.; runner-flap valves malfunctioning__throttle-body valve malfunctioning__other sensors may be reporting inaccurately to the ECU__fuel pressures are suffering__and who knows what else.

Fuel pressures and delivery may be the more likely cause, and it may require a thorough fuel pressure diagnosis. You'll want to conclude that the injectors, LPFP, fuel filter, injecotors and pressure limiting valve (FPRV) on the rail aren't the cause for fuel to escape from either the low or high pressure sides. This is one video link I share, which shows one determining where the system is losing pressure;
It basically is done so you disregard what the sensors are reporting...for they may be at fault as well. The gauge pressure can be compared to sensor data to verify they are reporting accurately or inaccurately to the ECU.
Sheesh man. How long have you had this start up issue? I wonder if it's been brought up to VW back then...
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
It's just been going on for maybe 1.0 to 1.5 years now.
 
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