Quantity Adjuster-Rough Idle

spanky1

Veteran Member
Joined
Feb 24, 2003
Location
east Tennessee
TDI
Jetta, 2012, platinum grey(6-spd manual)
Hate to start another QA thread, but I've read so much that I'm a bit befuddled.

My 2003 has 263K+ miles. Has had 2nd TB, and within the past year, a new turbo and clutch flywheel. After sinking this money in it, I'm afraid that I'm looking at an injector pump rebuild.

I've use some percentage of bio-fuel for the past 6 years. Anywhere from B100-B5. Last year, I had no source for bio, so I went back to dinofuel for about 6 weeks. Needless to say, I got leaking from my IP seals. Shortly after I went back to biofuel(B25-B50), the leaking stopped, but I developed a very rough idle. However, this only happens when the engine is heated up, never when it's cold. Starting is no issue, and mileage seems normal.

Throughout the years, I've had QA codes that will come and go. Now I have one that I can't clear. Can't remember it exactly, but I think it mentions reaching upper limit-intermittent.

After reading some threads tonight, I did unplug the MAF, and it didn't change anything. According to the VAG-COM, the injector quantity is just under 2 mg/stroke. I maxed out the QA adaptation, value but it had little effect, however it would only let me raise it a few digits over the default.

Should I attempt the hammer mod, or have someone take the IP off? One other thought that entered my mind is that the 6 week leak of diesel fuel got into an electrical connector at the pump. Could this be happening? The idle going from smooth when cold, to bad when engine warms up is a puzzler.
 

94cobra2615

Veteran Member
Joined
Jun 16, 2013
Location
ohio
TDI
2002 Black Wagon
Take the QA cover off and watch the QA needle sweep when you turn the key on and off. Do it over and over and see if it stops or binds up.

Then do it manually with your finger to feel for any rough or binding spots.

Also, check the QA voltages when you turn the key on and also watch voltages when it starts running rough.
 
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