3 bar map sensor upgrade?

danielhf

Veteran Member
Joined
Mar 27, 2007
Location
Dallas, TX
TDI
None anymore...
Recently my car has been running into a few strange problems after my new tune (RC3+):

Once the car warms up it performs beautifully. It effortlessly sustains 21 PSI. If I go beyond that, let's say 25 PSI, the car hits a brick wall. I lose all ability to accelerate and can only hit a new maximum of 6 PSI or so, while pouring smoke and watching the EGTs climb a few hundred degrees.

Upon turning off the car and restarting it, everything's fine and back to normal. I do not have a huge lead food problem, so I don't run into the 25 PSI range very often, so I really only encounter this problem once a week, if that.

As this is, what I believe to be, the situation known as "limp mode," I believe I have covered most of the bases.

1) I installed a new N75 two months ago
2) With the new PD150 turbo inlet pipe that I installed 2 weeks ago, a new MAF was installed

This only leads me to believe one thing, either my new N75 or MAF is bad, or I need to install the 3 bar map sensor. Are my conclusions sound? Any better ideas or suggestions?
 

Ed's TDI

Top Post Dawg
Joined
Jan 30, 2001
Location
Victoria, BC, Canada
TDI
'01 Bora and '97 A4 1.8T Quattro (future TDI conversion maybe?)
You may want to get some Vag-com logs to see what your "requested" vs. "actual" boost looks like because it seems your ECU is shutting things down because it's not liking what it's seeing (or not seeing if it's your MAP sensor).
 

Rub87

Top Post Dawg
Joined
Dec 10, 2006
Location
Belgium
TDI
Ibiza '99 90HP
Normally if you want to run more then 22.5psi of boost you need a 3bar MAP..

You experience the limp mode caused by overboosting, maybe the vnt vanes are stuck.. remeber if you are now running 21psi of boost and you swap in a 3 bar map you will be running 28psi if you don't remap the ecu to work with the 3 bar map..
 

jsrmonster

Veteran Member - TDIClub Enthusiast
Joined
Apr 22, 2002
Location
Red Lion, PA
TDI
15 Golf SW DSG, RC3 piped, 99.5 Jetta Rocket PD150 6spd 4motion, 2000 ASV110 RC6 "Silverbullet" 5spd Race Car, 2003.5 Cummins QCLB 4x4 "Blue Monster" Jeep CRD juiced, MB Sprinter van juiced up
Hi Dan,

You may want to lengthen the vnt actuator rod 2 turns on the nut. This will give a bit more return spring force on the vnt trim ring. Check it with a handheld vaccume pump, should be around 5-6" Hg cracking vaccume. Check before and after and let me know.

Check for vaccume leaks and boost leaks, this can run the duty cycle very high too causing limp in 3 sec. A boostvalve can help too if you are an agressive driver and stab the throttle alot (w/automatic).

Get me some vaglogs too please, 001, 003, and 011, then 001, 004, and 011 for wot blast (don't need high speed run, just 100% duty cycle for 4000 rpm) Shut down can also occur if IAT gets too high, this gives same fault as overboost. I can eliminate the boost limitation byte, and charge air overtemp limitation, but it is there for hardware protection on street tunes.

Jeff
 
Top