Does the 710n twist apart and open up like other DVs? I am trying to diagnose a boost issue and want to examine the internals.

 

i believe you will have to cut it open

 

Thanks for the reply. I was hoping that would not be the case.

Let me expand on the issue and maybe someone will provide insight.

Symptoms: Before I installed a boost gauge, I thought I noticed somewhat of a performance dropp off. After I installed the gauge I began to notice intermittent loss of boost. I start my car up and everything seems to be fine. I spike at 15psi and maybe am not holding boost quite as long as I should, not sure because the problem somehwhat coincides with the installation of the gauge. I drive around for a few minutes until the max boost drops to like 5psi. AFter that I can not get above 5psi. I checked the codes and they seemed to indicate a problem with the n75. Upgraded to the n75j but the problem persists. Now the boost will drop to like 7-8psi max. If I turn my car off and wait awhile, the boost returns to the 15psi level. After a few minutes of driving the maximum drops back down to 7-8psi.

It could be a boost leak but it seems unlikely since the boost will hold for awhile. My thought is that the DV works for awhile until the car reaches max boost, then it gets "stuck" open and limits the boost level.

DOes this analysis make sense? Is it more likely the DV or a boost leak or something else? I dont want to spend $100 on a new DV unless I am somewhat certain that it is the problem.

 

Sounds more like a bad/dirty MAF causing limp mode.

Codes would be good.

 

do you have the code(s)?

 

Address 01: Engine Labels: 4B0-906-018.lbl
Part No: 4B0 906 018 Q
Component: 1.8L R4/5VT G 0005
Coding: 07251
Shop #: WSC 06335

2 Faults Found:
17965 - Charge Pressure Control: Positive Deviation
P1557 - 35-00 - -
18010 - Power Supply Terminal 30: Voltage too Low
P1602 - 35-10 - - - Intermittent
Readiness: 0000 0000

I recently disconnected the battery which should account for the second code. The first code is the one that I have seen before.

17965/P1557/005463 - Charge Pressure Control: Positive Deviation

Possible Symptoms

Reduced power output
Limp mode
Possible Causes

Boost Pressure too High
Hoses/Pipes incorrect connected, disconnected, blocked or leaking
Charger Pressure Control defective
VNT (variable nozzle turbo): nozzles stuck
Solenoid Valve for Boost Pressure Control (N75) defective
Possible Solutions

Check Hoses/Pipes to/between Components
Check Solenoid Valve for Boost Pressure Control (N75)
Check / Clean / Replace Charge Pressure Control
Check / Clean mechanism for variable nozzles

I will clean the MAF tonight since it is easy to do.

Can I disconnect the MAF completely to see if it is related to the problem?

 

Yes, you can run with the MAF disconnected, and the car will run on "default" maps. If things get better, buy a new MAF.

 

agreed, i tried the whole cleaning the MAF deal and it didn't work out, its a faulty part and needs to be replaced if its causing a CEL.

 

I unplugged the MAF and ran the car with the preprogrammed settings and everything seemd to be good and I didnt trigger limp mode. I cleaned the MAF and connector and plugged it back in. Did a couple WOT runs with the vag-com logging block 002. Numbers didnt look too bizarre but I hit limp mode again. I now know that the MAF is bad or I have leak behind the MAF. Either way I expected to get some help from the vag-com but the numbers are pretty much what they should be. I will do some more logging tomorrow too see if anything pops up. In the meantime, I'm looking into buying a remanufactured MAF for $85, compared to $235 from the dealer and $135 for the Bosch OEM replacement. I will post back when things get figured out.

Thanks for the insight.

 

MAFs are pretty common on vortex, I've bought 2 in the last couple months, paid $40 shipped for the first, $45 shipped for the second.