A new challenge. Power loss above 3000 rpm

Brian_Spilsbury

Veteran Member
Joined
Mar 9, 2003
Location
Eden Mills, ON
TDI
2003 JETTA, 2004 JETTA
I blow the carbon out most days on my trip home. It's a nice long stretch and I hard accelerate to 4000 rpm up to about 110 then back off to 80.
Yesterday, it ran as always up to 3000 but then it was like it fell on it's face. Still accelerated but with nowhere near the same power.
I have a Scan gauge set to display boost and it was showing between 180-200 which is normal for my car when it's running well. The ESP warning light came on.
backed off and it ran as well as always for my normal method of driving which is short shifting at 2k. Hit it again and the same thing.
This isn't limp mode, since it doesn't need a key off reset.
I'll check the manifold later today but the propblem has shown up from one day to the next.

Ideas?
 

dadsdiesel

Veteran Member
Joined
May 29, 2004
Location
NW Penna
TDI
'99 NB TDI
I hardly ever drive my wife's NB, but when I did the other day it is doing just like you say (minus the ESP light).

No codes set. I haven't had the time yet to do any VCDS logging, but I am thinking that the intake may be clogged since it has never been cleaned.

I did teach her to WOT it once a day, but her version of WOT is going from 45 mph to 55 mph in 4th gear......

Like you say - it hits a wall at exactly 3000 rpm.
 

Brian_Spilsbury

Veteran Member
Joined
Mar 9, 2003
Location
Eden Mills, ON
TDI
2003 JETTA, 2004 JETTA
and I have no codes, either. I would expect that like the last time my manifold needed cleaning, I would see pressure spikes on my boost gauge.
 

Brian_Spilsbury

Veteran Member
Joined
Mar 9, 2003
Location
Eden Mills, ON
TDI
2003 JETTA, 2004 JETTA
I'll try that on the way home. I'm starting to think I have a fuel issue. It's starting to sputter a bit under harder acceleration but seems smooth otherwise.
Back to looking at fuel lines for restrictions. I spent most tof the spring blowing them out to no avail.
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
I would also look for fuel restrictions.
I would clean out the fuel pickup assembly, if you have not already done that.
Clean the tank.
Maybe drill out the cross piece in the fuel outlet pipe?
Replace the fuel filter?
 

Fiveflat

Veteran Member
Joined
Nov 19, 2010
Location
Sacramento, CA area
TDI
1999 Jetta, 2008 PSD
I had a similar situation with my Jetta, above around 3000RPM. No codes, etc. but it was because of the small leak in my charge air hose. Not low enough boost to cause a code, but low enough to notice...
 

Brian_Spilsbury

Veteran Member
Joined
Mar 9, 2003
Location
Eden Mills, ON
TDI
2003 JETTA, 2004 JETTA
DanG, I still can't help but think I have a fuel flow problem. I have cleaned the pickup out several times and drilled out the one way valve. Because of BIO, I have a bit of sediment but it has never been a problem in 4-5 yrs. Until now, I think.
The Mity Vac comes out the next sunny day, and I'll start putting suction on the fuel lines.
Even though our co-op filters the fuel at the pump, I expect I'm still getting some high temperature gelling at times
 

Corsair

Veteran Member
Joined
Aug 17, 2003
Location
Weedsport, New York
TDI
2002 Jetta GLS TDI 5M
Did you try unplugging the MAF ?
From logs, can you tell if the boost is remaining when the car falls on its face, or is the boost going away ? One possibility is a small vacuum leak that allows normal performance at low demand, but the vacuum reservoir becomes exhausted when asked to maintain high "pull" for extended time. Just a thought.
 

FixItDaily

Active member
Joined
Nov 11, 2018
Location
Washington
TDI
2003 Golf
Same issue here, car kind of falls on its face after 3000 rpm. It’s got new injectors, new 11mm pump, engine has about 30k miles on it... New vacuum pump, new N75, new one way check valve, newer turbo, new exhaust. It’s an 03’ and the car hasn’t been tuned for the .230 nozzles but I’ve been extremely careful, only ever used about half throttle. I’m waiting for my new tune, but even that doesn’t explain the super strong acceleration to about 3000 rpm and then the sudden lull in power. IQ is set at about 5 and the car has a ported and polished head with a stage 2 cam. Not sure what to look at next... I will replace the fuel filter and look again for any vacuum leaks but other than that I just don’t know. I replaced the MAF not long ago.
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
Vcds
Get a log of everything
Report back
Everything else is guess work. Also put an egr gauge on that baby
 

FixItDaily

Active member
Joined
Nov 11, 2018
Location
Washington
TDI
2003 Golf
EGR is deleted, I have a pyrometer that needs to be installed, I also have a Methanol injection system for it. I haven’t run any logs, I don’t want to until I get the new tune and the EGR installed. I also have (for the last 5 months) the Kerma Long Runner intake on the car. Most of the turbo piping is replaced, really just need to get rid of the pancake pipe. The turbo is the Kerma billet turbo. It’s about a year old, but I checked it when I swapped the exhaust and it was nice and tight, the actuator seems to be functioning properly.
 

fatmobile

Veteran Member
Joined
Jul 16, 2019
Location
north iowa
TDI
an ALH M-TDI in a MK2, a 2000 Jetta, 2003 wagon
2.5 BTDC?
At idle?
Thought it was supposed to be 12 BTDC,...
with a pulse detector.
 

Nero Morg

Top Post Dawg
Joined
Oct 19, 2017
Location
OR
TDI
2014 A6 TDI, 2001 Jetta TDI, 2014 Passat TDI
In VCDS monitoring under measuring block 004
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Start of injection: range 12 - 75 = 2 degrees ATDC - 3 degrees BTDC
If it won't rev past 3000 could be MAF related. If it accelerates with no power I'd start by checking the actuator adjustment, the vacuum lines and N75. If those are good look for boost pipe leakage or even (unlikely) MAP related errors. Any fuel (air, diesel) restrictions could also do it.
 
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