Low speed surging - updated

[stewardc]

Is Stanadyne an auto parts store item?    Course it still begs the question of why the car ran fine with a stock pump but surges & possibly requires this additive with the performance pump...

The operative word is "performance". A performance car needs high-test fuel.

[burn_your_money]

GM is one of the many vehicle manufactors that recommend/acknowledge the stanadyne additive. You may be able to get it there?

[Baron VonZeppelin]

Jettage, if you can't find Stanadyne - you probably can find PowerService Diesel-Kleen.
AutoZone, AdvanceAuto, and WalMart all stock it.
I never see Stanadyne anywhere around my areas.
Different regions have different offerings.

If you find Diesel-Kleen, get the one in the GREY/GRAY JUG.
It has Slik Dezl fuel lubricant AND Cetane Boost.
I run it in every tankful.
Costs about $1 extra per 10 gallons to use it.
Higher cetane will increase your MPG and HP.

The ATF dose would be good idea right now too - Hey it worked for Stewardc.
It could work for you. Sure as he[[ won't hurt anything.

[Jettage1]

Baron, thanks for the suggestion.  I did see Stanadyne in the Parts Place catalog, IIRC.  I'll look in my local stores to see what may be available here.  It may wait a while, though, as the car is now resting while I decide my course of action about the now-leaking head gasket. 

I should fix it myself to save the $400 labor, but don't have much time.  Hmmmm.  Only money right?  

[burn_your_money]

Fix it yourself. If you already know how to do timing it's cake.

[Jettage1]

Fix it yourself. If you already know how to do timing it's cake.

Thanks for the vote of confidence  .  Unfortunately my "to do" list is long and time is short.  I still may do it anyway - just have to clear off some other things first...

[stewardc]

Revised update

The surging never went away, it just got much less, but it's still there.

[Rabbit TD]

Fix it yourself. If you already know how to do timing it's cake.

And most importantly you will know it was done right and not have to wonder, did they do this or that?  I'd put studs in it while you have it apart if you don't have them yet with the labor cost you save.

[stewardc]

Update

I ran out of Stanadyne and ran a tank of regular diesel through it. It jerked like crazy in the bottom 3 gears at low speeds. Almost drives me crazy.
Just got some new additive, now to see if it makes a difference again.

[stewardc]

One of the local guys just suggested that. He had a TDI do this, and the dealer enrichened the mixture to solve the problem. Next tank I'll try that.

[stewardc]

There isn't any "enriching the mixture" on an unthrottled diesel other than pressing the accelerator harder or less hard.  If you try to adjust the mixture, the engine just spins faster or slower.  

Residual pressure adjustment can affect the governor and timing and so being slightly out of adjustment (enough that varied fuel viscosity from additives could adjust it) can cause the surging.

IMHO, More fuel at a given throttle setting at a given rpm = enrichment. It's the term used by the VW Master Tech when he described his fix on my TDI Beetle. Some say tomaytoe, some say tomahtoe.
I personally believe it has nothing to do with the viscosity of the fuel, and everything to do with the cetane rating of the fuel. I know that, when I go to another province that has tested-better fuel, there are no issues with my engine, nor were there with my previous TDI.

[catlin_cava]

where do you get your fuel in NS?

[stewardc]

IMHO, More fuel at a given throttle setting at a given rpm = enrichment.

You can change the amount of fuel for a given pedal position, but you cannot increase the fuel for a given rpm without that rpm increasing.  It just doesn't work that way no matter what your "Master VW Tech with 80 years of experience and 17 medals of awesomeness pinned on him by the fuhror himself" happens to say...  Glad to hear he was able to fix your TDI.

Some say tomaytoe, some say tomahtoe 

[stewardc]

where do you get your fuel in NS?

ESSO or Irving - it doesn't matter because it all comes from the old crappy Esso refinery in Dartmouth.

[stewardc]

I simply said that turning the screw gives more fuel at any given pump throttle setting and RPM. You are saying exactly the same thing, but in different, and slightly confusing, terms.
Enough, OK