PD Golf
Member
I want to preface this by saying that I am not blaming anyone for my car's issues. Jeff Robertson (of Rocketchip) and Jon Hamilton (of Jon's Automotive) were more than helpful and very generous with there time trying to resolve this issue. The only reason for mentioning their names is so readers can know the caliber of the experts helping me with this issue(s). They identified the fuel contamination issue, weak lift pump and the bad MAF. These were all apparent problems that needed to be (and since have been) resolved. They were limited to trying to diag a car with obvious issues that could not be resolved at that particular time and therefore ran into a dead end for further diagnostics. I'm only posting this info to brainstorm for possible diag tips and/or solutions...
Here is what I had just before any recent changes were made: 2005 Golf (PD, BEW), thru exhaust, egr delete, new VNT 17, RC1+, 2.5 bar map. Car ran great, smooth power, no surging, no over boosting, ran at a max of 17-18 psi, egt's were happy (and still are).
What was changed: Went from a RC1+ to a RC2 w/ a 3 bar map. Due to a 30psi spike after the RC2 and 3 bar map was added, we had the actuator adjusted to the recommended spec 4-5" to 17-18" of vacum range as it was out of adjustment (although there was no lag or spike with the VNT17, RC1+ and 2.5 bar map). The N75 valve was swapped back/forth with another to eliminate this as an issue- existing one seems ok. Vacum lines were checked for correct connection and vacum system holds good vacum (no leaks). The MAF was unplugged to eliminate this as the issue. The lift pump was replaced as it's pressure was low and it could almost not be heard when cycling the key. (with an ear next to the pump)
Other discovered issues: Per the PO001 code the car has thrown in the past and per Jeff's VagCom logs, the MAF was known to be bad. The MAF was replaced. The car also had contaminated fuel. There was gasoline in the diesel. Of course, the tank was drained and the good fuel was added.
The result: Car spikes upwards of 30 psi. The boost surges bad. It seesaws back and forth from 25-30 at WOT. At times, the boost will even suddenly peg the gauge at 35 psi for a split second. With the cruse set a 70mph, the car runs at 20 psi. Seemed unusual at a very low load on almost flat road. The car is even making massive amounts of boost (20-25+ psi) at as little as 1/4 throttle while driving like a grandma at speed as little as 30-40 mph... I swear the boost gauge moves almost like the tach while driving the car nice and easy. Once you get to the desired speed and begin to maintain that speed, it seems that the boost is all or nothing and it kicks back and forth. With the slightest touch of the throttle, the boost will go from 0 to 15+ psi (up to 30 ish) depending on how much more throttle you demand. Like an on/off switch.
This is the only self diag I have done myself- to confirm that it was not an actuator or turbo vane issue, I checked the vacum going to the actuator by placing a vacum gauge with a tee fitting inline with the vacum line that goes from the N75 to the turbo. The vacum fluctuates with the boost. So, it does not appear that anything is sticking with the actuator or turbo vanes (new turbo) and instead it is being demanded.
If anyone has any knowledgeable info please share. I would like to continue to attempt to resolve this issue.
Here is what I had just before any recent changes were made: 2005 Golf (PD, BEW), thru exhaust, egr delete, new VNT 17, RC1+, 2.5 bar map. Car ran great, smooth power, no surging, no over boosting, ran at a max of 17-18 psi, egt's were happy (and still are).
What was changed: Went from a RC1+ to a RC2 w/ a 3 bar map. Due to a 30psi spike after the RC2 and 3 bar map was added, we had the actuator adjusted to the recommended spec 4-5" to 17-18" of vacum range as it was out of adjustment (although there was no lag or spike with the VNT17, RC1+ and 2.5 bar map). The N75 valve was swapped back/forth with another to eliminate this as an issue- existing one seems ok. Vacum lines were checked for correct connection and vacum system holds good vacum (no leaks). The MAF was unplugged to eliminate this as the issue. The lift pump was replaced as it's pressure was low and it could almost not be heard when cycling the key. (with an ear next to the pump)
Other discovered issues: Per the PO001 code the car has thrown in the past and per Jeff's VagCom logs, the MAF was known to be bad. The MAF was replaced. The car also had contaminated fuel. There was gasoline in the diesel. Of course, the tank was drained and the good fuel was added.
The result: Car spikes upwards of 30 psi. The boost surges bad. It seesaws back and forth from 25-30 at WOT. At times, the boost will even suddenly peg the gauge at 35 psi for a split second. With the cruse set a 70mph, the car runs at 20 psi. Seemed unusual at a very low load on almost flat road. The car is even making massive amounts of boost (20-25+ psi) at as little as 1/4 throttle while driving like a grandma at speed as little as 30-40 mph... I swear the boost gauge moves almost like the tach while driving the car nice and easy. Once you get to the desired speed and begin to maintain that speed, it seems that the boost is all or nothing and it kicks back and forth. With the slightest touch of the throttle, the boost will go from 0 to 15+ psi (up to 30 ish) depending on how much more throttle you demand. Like an on/off switch.
This is the only self diag I have done myself- to confirm that it was not an actuator or turbo vane issue, I checked the vacum going to the actuator by placing a vacum gauge with a tee fitting inline with the vacum line that goes from the N75 to the turbo. The vacum fluctuates with the boost. So, it does not appear that anything is sticking with the actuator or turbo vanes (new turbo) and instead it is being demanded.
If anyone has any knowledgeable info please share. I would like to continue to attempt to resolve this issue.
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