MPG setting on IP-1.6L diesel

[doonboggle]

Taking my pickup to a VW shop next week for a bunch of things to be addressed ... with one being to retime everything since I took the IP off some time back.  I have it running ... real good I might add for an old 'phart' ... with the 3 marks lined up almost perfectly ... but am concerned that the shop fellow may not keep it in the good mpg range.  Presently getting 52 mpg.

I'm sure the older fellow there knows the proper setting for good mpg ... 'retard' or 'advance' ... but since my brain recently had a 'phart', I would like to use the magical word so that I can impress him.

Most of my driving on my 'new' pickup toy, that I only recently began to enjoy, is on a relatively flat terrain in the outskirts of the desert area in upper Nevada; just south of Reno ... Yerington.  On rare times I may be exiting the valley, where I will have to climb a hill of about 2 miles ... but otherwise, all flat driving.

So should I advise him to keep the timing advanced or retarded ?
And anything else ? ?
TIA

PS:  Yes I have the timing tools and gauge, etc. ... just never used them yet ... and since I had several other items for him, thought I'd just have him do the timing this time.

[theman53]

If you are getting 52MPG I would just stick the gauge to it and make sure you could always come back to that if you ever need to.

[doonboggle]

Well ... it's running rough in the range below 2000 rpm ... low gears ... stop n go ... etc.
So am thinking my 'bumble fingers', in aligning the 3 points, is off a bit to cause this ... and since a lot of my daily driving will be inside the city limits, want to eliminate that.

I realize I may loose some mpg with the new timing setting, but want to plant in his head my request and concern.

If you are getting 52MPG I would just stick the gauge to it and make sure you could always come back to that if you ever need to.

[theman53]

Usually for better performance like what you want then you would want to advance the timing. BUT since it may be advanced too far already I would tell him to set it a 1.00mm for the non turbo. If you know without a doubt it is under 1.00 already then you could tell him to advance it some to get there.
I guess what I am trying to say is too far advanced will run poorly too, but usually it is too far retarded to have the symptoms you have. Especially if it sounds good now(no marbles on plate sound)
Clear as mud?

[doonboggle]

Usually for better performance like what you want then you would want to advance the timing. BUT since it may be advanced too far already I would tell him to set it a 1.00mm for the non turbo. If you know without a doubt it is under 1.00 already then you could tell him to advance it some to get there.
I guess what I am trying to say is too far advanced will run poorly too, but usually it is too far retarded to have the symptoms you have. Especially if it sounds good now(no marbles on plate sound)
Well ... if this is meant to be a clackie-clackie-clackie more than what would seem normal, then there is a marble or 2 loose.  I had one of these, new, in 81 ... and while recall it being the normal rabbit clack-clack-clack, this now sounds like a bit more than what I recall.
Power wise, it seems OK.  Had it out on the road to test the speedo, and was able to get up to 65 without that much of a problem.  Took me a couple of miles ... yes ... but she was climbing all the time; and accelerating is OK as well ... but not smooth in the lower rpms.

Clear as mud?

[Smokey Eddy]

retarding the timing will give you that low end power you're looking for plus i find it will help mileage (although 52 is just fine for an IDI) and advancing will make the pedal seem more responsive and really make the different at high speeds/higher rpm.
im talking very small adjustments.
However there are diminishing returns with this obviously and its real easy to retard too far.

[doonboggle]

retarding the timing will give you that low end power you're looking for plus i find it will help mileage (although 52 is just fine for an IDI) and advancing will make the pedal seem more responsive and really make the different at high speeds/higher rpm.
im talking very small adjustments.
Thanks Smokey.  When you say 'very small adjustments' ... what would that be on say ....... the gauge setting?
I am asking this from the perspective of presumption that the fellow doing the timing will of course be using the gauge process.
However there are diminishing returns with this obviously and its real easy to retard too far.

I'm doing this this way based on the fact that the fellow 'may' come up with other adjustments that need to be done as well.  I am not versed ... yet ... in the finite things, so am going to try and use his settings, etc. as guidelines in the future ... once I get the process implemented with the kit I purchased recently.

[Baron VonZeppelin]

Have him verify that you have all the initial parameters and belt tension set right on the button. And then have him dial the injection timing to spec or no more than .05 mm above (advanced) the stock parameter.

If your truck still has the yellow decal on the passenger strut tower, the injection timing will be listed on it. 81 Truck is 0.88mm with a +/- of .05 variation.

The stock setting, or within .05 advanced beyond spec - is the best place to start. If your compression is good, Inj Pump and Injectors healthy, that spec range will give best MPG and best cold-hot starts on an NA. In my experiences.

Too low can effect Cold (real winter cold) starts.
Too high can effect Hot restarts.

I would ask for 0.88-0.90mm
Belt tension spec is 12-13 units, if he has the tension gauge.

Later on you could tinker the timing once you have had plenty of test hours behind the wheel. And perhaps alter it to address symptoms or faults.

[R.O.R-2.0]

52 mpg and you wanna mess with the timing?!?!?!

i would leave it. and its not like rabbit diesels are power houses.. its not gonna be a night and day difference, thats for sure.

[2strokesmoke]

Hi, I too have a similiar condition,with my 82 Caddy  1.6NA .
Feels like "bucking" or missing in 1st,2nd and 3rd gears. Not as noticable in 4th and 5th gears. Seems to smooth out around 2500 RPM ? (No tach) Also Not as bad under hard acceleration-feels like the engine is powering through it. It is driving me "Nuts" ! I posted a thread on the Vortex (while this site was down) I think I will post here as well. Good luck in curing the problem---and please post if you find the problem ! Thanks !