Old guy Old Rabbit---both Happy.

[lyeinyoureye]

Edit-If the fuel is injected after the piston has started moving down then more work will be done compared to it igniting before the piston gets to tdc and doing extra work pushing the piston down. The downside is that pressure isn't as high, so the fuel doesn't combust as well. Since Hagar is running a turbo, he's artificially increasing the pressure above NA levels, which reduces any loss in pressure that would result in a NA engine when retarding timing. Best of both worlds so to speak...

Another WAG is that any increase in air above a certain point doesn't help out with combustion efficiency, so the retardation of timing is the next logical step to better fuel economy. A positive side effect is less diesel knock, like Hagar said.

[coke]

In my experience, retarding the timing has always increased fuel mileage somewhat. The highest i've gotten in my 90 jetta is 48. My dad got higher, probably driving 40mph or something. But when I have it advanced, my fuel mileage goes in the gutter. Im just trying to get to a point where my economy is around 48mpg consistantly and my smoke is minimal.
So hagar, refer to my post before this and let me know what you think.

[hagar]

coke : and All .--- if you are not towing boats and campers ----you are on easy street , with a Rabbit.----WHY ? --cost per mile. or Km.--read my lips.--EH ? ---Bunny Bondo shows the way.

Bondo ? yes a 1984 1.6L Turbo Rabbit.----she is "TUNED" for complete combustion right now --in ECO mode ---but for POWER ? --turn on the LDA . ---wow ? at least 100 HP.---I hagar have NOT needed to use the LDA for years. , and we drive in BC: Kanada. , no hills ? . -------Now for the "ADA" ? can it be used ? I think so. ( Bunny Bondo--will try for 120 Miles on a gallon Imp--in 2006)

My UK and Amerikan friends -- NOT using "Metric"----will come back to haunt you SOON.---read my lips.

1013.25 millibar is the "Krauts" standard for calibrating the VW on a "ADA" ----and it , or the LDA together with the governor and so on ---combines to move the "Control Collar". ----what is the highest Rabbit Road in the world ? ---say it is ---31.0 inches of mercury ? EH ?.--that is small change , for a LDA.---BUT for a "ADA" ? --it is significant.----work it out ?.

---say 29.7 inches of mercury is Zero. ? EH then at 1000 feet will be about ---28.6 ? EH ? Mark Shepherd say something. --if I am wrong , it is a clerical error.----gimmi metric anytime..

more later.

hagar.

[coke]

So hagar, I am assuming I should retard the pump to the smoke/fog point, advance it a tad, and turn the fuel screw out till it wont start and turn it in one turn icrements until it does, and i'll be in mileage land?

[hagar]

coke : tell me the numbers of the FLOW testing. and the cold start knob pull test.----then I can be of more help.

in general with a good pump ---we advance as much as we dare ---that makes for more power and mileage.
and less smoke.

Oh and email me a blotter test.

hagar.

PS : I have serious medical problems right now.

[coke]

No need for a blotter test, my oil is as dark as ink, and it stays that way even after an oil change. I've never seen clean oil in this engine. I have it advanced quite a bit now, but my mileage sucks. low 40s. even lower sometimes, averaging 38-41.

I dont have the ability to do the flow test, but im a good judge of numbers and the cold start lever pull test appears to be normal. I'd say around 10-15 pounds engine off, and 2-3 pounds engine on. What else do you suggest?

[libbybapa]

-

[coke]

I tinkered with the idea of an alternate fuel pump, just in case my pump is in fact worn. Hagar, is the flow test libbybapa mentioned the one you are referring to? If it is I can do that no problem. Very easily.

As for the pull test, like I mentioned. 10-15 pounds not running, 3-4 maybe 5 pounds running. It seems to be comparable to yours.

I may actually try an external fuel pump and see if that helps.

Libbybapa, did you ever have a chance to test the mechanical fuel pump that goes to the blocked off int. shaft port?

I have noticed something, maybe someone can shed some light on this. When my car is warm, and I start it without glow plugs, it starts after 4 cranks or so. If I pull the cold start lever out, which mechanically advances the timing 2.5 degrees, it starts great. So I'm beginning to wonder if the internal advance mechanism is in fact not working like it should be.

[hagar]

coke and ALL : you should be so lucky as to have Andrew in Flagstaff AZ on your team.

I have known him for years ---and have followed him getting better and better on VW Diesels. and read my lips --he is getting GOOD.-----by the time he gets to 75 (like me) ----WOW.

Ask him what I am talking about --(he knows) ---then he will translate. -- As you can all see above.

BUT coke your little cutie needs a LOT of TLC. --IMHO. and BLOTTER test is very important.

Bunny Bondos pull-test ? 10 to ! --good reading. Yours may be 2 to 1 ----test it again HOT. ------remember NOT to panic ? -EH ? --we have lots and lots of real neat tricks on the back burner..

hagar never rules anything out or take anything of the table. ----WHY ? ---PO's I never believe what they say.
When I first stumbled in to Dan's forum -----someone cynical said "Free information is worth NOTHING" ---oh yeah ? I beg to differ.-----but sorting things out is important.
I have a must read list on Jacks and Dan's-----saved me a bundle or two.

In signing off coke ---remember to buy 450 gram of ParoWax. ---I know Maine USA it will get cold very soon.

hagar.

[coke]

hagar, reference the blotter test, I assume your talking about an engine oil blotting test. Like I said, there is no reason. Its as black as ink, its never clean, ever. The only thing I can think of is I've been running synthetic oil and its cleaning all the other sludge out. Which is likely.

The cold start pull test: It pulls significantly harder with the engine off than when on.

Weird starting: Car starts great if I let the plugs warm each time. If I pull the cold start it always starts without the plugs after being warmed up. Leads me to believe my pump is actually severely worn and the internal advance isn't working as it should, though I can't say for certain. I don't know enough about pumps. What else do you suggest? I may be able to get a more definitive pull lever / cold lever test coming up. You mentioned the flow test. I'll review the article and see what that entails. And the blotter test, well I can tell you now its black as ink even directly after changing the oil.

Im trying to get my hands on an external pump to see if that helps with the starting problem.

[libbybapa]

-

[coke]

I was thinking that but I can't advance it any more. What I was theorizing is that the cold start is a mechanical advance, and therefore it was advacing 2.5 degrees to where it should be, but the internal advance in the pump isn't allowing it to. I'm going to mess around with my car today, im going to attempt to time it while its running and see what effects it has. Pump timing, that is.

[hagar]

coke and ALL : if the blotter say "TOBYS BUTT" --we have a problem. -----to find it is Apple pie ---but it takes a fair amount of baking. ------we methodically test ---EVERYTHING.

Under "Hillbilly- TUNING" is a simple procedure for getting a handle on "BLOW-BY" -----that will show if top piston rings are broken or stuck -----a very common thing on Rabbits. -in North Amerika.

hagar.

[coke]

I'll do the flow test tomorrow hopefully. And play with my timing on the pump. I have a lot to do tomorrow. But I'll see what I can manage. I have the flow test figured to .625 liters in 90 seconds, thats just over half a litre, should be easy to measure.

hagar, where in Canada do you live, exactly?

[hagar]

coke IMHO your Jetta is in bad need of attention.

So when you do a new accurate pull-test --at the same time test as follows : Listen real carefully at idle ---and pull and push cold start knob. If there is no difference --it is a good pump. A LOT of difference ? --a BAD pump.---Normally the engine speeds up when pulling.
All this is wasted if you did not install BRAND NEW nozzles. recommended 293 ---I use 193 .

The cold start --is only a small cam pushing directly on timing piston.. On Bunny Bondo at idle the piston is no longer touching cam. --so ? it has NO effect on engine. 1.25 degrees on Roller Ring is a small move.

hagar.