PD Surging at Certain RPM's

FordGuy100

Veteran Member
Joined
Apr 13, 2011
Location
Silverton, OR
TDI
2004 Jetta TDI
I have been noticing lately that if I am just cruising along, in any gear above 2nd (3rd, 4th, 5th) and my RPM's are ranging from 1750-1950, the car surges. At first I thought it was because of rain, but today it was dry and it was doing it. The roads were all fairly flat, but honestly I think some were slight uphill, while others were slight downhill. If I go above or below those RPM's, there is no surge. This only happens when at a cruise, not accelerating, or decelerating. Car does not make any funny noises during this either.

Kinda weird that it only happens at certain RPM's. I was wondering if it was motor mounts, as perhaps maybe I get slack in the drivetrain, and then it kinda jolts?

Advice, or comments?
 

FordGuy100

Veteran Member
Joined
Apr 13, 2011
Location
Silverton, OR
TDI
2004 Jetta TDI
Also let me add that these "surges" are very brief. If you were driving 60mph it feels about the same as hitting a 6"-1' diameter puddle and hydroplaining for that split second. Sometimes it does it once every 5 seconds, other times it feels as though it does several ever 5 seconds.
 

yatzee

Top Post Dawg
Joined
Jan 4, 2004
Location
Montreal, Qc
TDI
see sig
do you have a VCDS? If yes, you could graph out group 11 to see if the 'surging' shows in the turbo readings
 

FordGuy100

Veteran Member
Joined
Apr 13, 2011
Location
Silverton, OR
TDI
2004 Jetta TDI
Seems to happen the most when coolant temps are 140-170 degrees on the factory gauge. Kinda makes me think EGR as perhaps as the engine heats up to operating temp, it starts closing EGR valve?
 

FordGuy100

Veteran Member
Joined
Apr 13, 2011
Location
Silverton, OR
TDI
2004 Jetta TDI
Negative. I pretty much ruled that it's a combo of bad starter/fuel pump not working. Gotta love high mileage cars lol
 

FordGuy100

Veteran Member
Joined
Apr 13, 2011
Location
Silverton, OR
TDI
2004 Jetta TDI
I have determined the in tank lift pump is in-op. I came to this conclusion because when I turn the key on, fuel does not flow to the filter. Found this out the hard way doing a filter change. When 20+ key cycles nets no more than a few dribbles (probably from the cranking more than anything and the tandem pump?) I think it's safe to say it's the in tank lift pump.
 

Nutsnbolts

Vendor , w/Business number
Joined
Nov 1, 2001
Location
Weare, NH
TDI
2000 Jetta, Silver Arrow
In addition, the PDs in general are very susceptible to fuel starvation. If the filter is clogged even a little bit, it will make these engines run poorly. Without a working lift pump in the tank, any little bit of restriction in the system will wreak havoc.

-Rich
 

FordGuy100

Veteran Member
Joined
Apr 13, 2011
Location
Silverton, OR
TDI
2004 Jetta TDI
I'm half wondering if its fuel related, but then I tell myself its not.

Another observation today. It wont do it until it is at about 130* coolant temp. Once it reaches operating temp (190*) it will only do it for a couple additional miles, then it wont do it anymore. Much more noticable going up inclines, which I assume is due to the additional load put on the engine, and then those random stutters.
 

FordGuy100

Veteran Member
Joined
Apr 13, 2011
Location
Silverton, OR
TDI
2004 Jetta TDI
VSDS is about two or three weeks away, until then I will just keep posting my observations as a baseline for me to remember lol.
 

PDJetta

Top Post Dawg
Joined
Nov 6, 2003
Location
Northern Virginia
TDI
'04 Jetta GLS TDI Pumpe Duce Platinum Grey w/ Leather
I would replace the in-tank lift pump and then re-evaluate after that. Also replace the fuel filter if it has more than 20,000 miles of use on it.

--Nate
 

d-man

Veteran Member
Joined
Nov 15, 2008
Location
alberta
TDI
05 jetta PD
Get the pump changed and a new fuel filter, if the car runs you can do it yourself just make sure the tank is half to quarter tank of fuel left. pump is under the rear passenger seat.
 

FordGuy100

Veteran Member
Joined
Apr 13, 2011
Location
Silverton, OR
TDI
2004 Jetta TDI
Filter was changed 200 miles ago. Thats how I figured the in tank lift pump wasnt working. After 20 key cycles there was hardly any fuel in it....
 

PDJetta

Top Post Dawg
Joined
Nov 6, 2003
Location
Northern Virginia
TDI
'04 Jetta GLS TDI Pumpe Duce Platinum Grey w/ Leather
I bet if you change the dead lift pump, that the surging will be gone.

--Nate
 
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