IP fueling adjustment

[92EcoDiesel Jetta]

Do I have to remove the chrome ring (circled) to adjust the fueling screw? Do I pry it off or does it unscrew? Is c.w. more fuel and c.c.w. less fuel? The ring does not look scratched up so does that mean it's never been screwed with?

[Rabbit on Roids]

the ring is a limit. if you want more power, just take the limiting collar off. turning the fuel screw in = more fuel = more power = less mileage.

[airhead]

You just pry it off. You should be able to give the screw a quarter to half a turn in even with it still in place though.

[rabbitman]

I can blow huuge black cloud and I've never removed the collar.

[Rabbit on Roids]

i could always get a pretty good black cloud fro mine, but after i removed the collar, i could make THICK black clouds. not just a light haze, or a pretty good puff.. i can fill the road up with black goodness when i really get on it. oh man, when i run it on WMO it smokes even better. doesnt have quite the power on WMO, but its basically free.

[92EcoDiesel Jetta]

Unlike most here, I want to tune it for economy- i.e. NO BLACK SMOKE!

[rabbid79]

The collar on the fuel screw in my '79 Rabbit was not only crimped on, it was also spot welded in 2 places.  It may take a little more than a screwdriver to remove it.

[airhead]

Well if youre going to be reducing the fuelling, you shouldnt need to remove it at all because you'll be unscrewing the screw.

[Pre95]

I can blow huuge black cloud and I've never removed the collar.

2nd that. I am interested in seeing where others have the fuel load adjustment set. Currently I have 2 threads before I hit the collar and I wouldn't go any further (already @ WOT I have a light haze, I have had it up a bit more before but just causes more smoke, no gain in power, on my 1.6 N/A). I am also running the worlds oldest injectors (248k and still squirting) so when I swap those out next weekend I am sure I will need to go back in and turn the fuel down a bit.

If your looking for less fuel, you'll be backing the screw out as what was said above. And as what was already mentioned my collar is tack welded in 2 spots and looks like it's on there pretty good.

To adjust the fuel, loosen the 13mm fastening nut while holding the screw itself with a flat head screwdriver. Pay attention to where it's at currently, and make your adjustments 1/8th of a turn at a time between test drives. Once the nut is loose the screw should move quite easily. Be sure you hit some hills on your test drives, if you have it set too far out it will seem OK when driving around on flat ground until you hit an incline (no power).

Word of advise: Have a new 5mm x 2mm metric o-ring handy. When I started tuning my rabbit the fuel load adjustment o-ring was worn and began leaking diesel after a few tries. It's easy to replace the o-ring if it starts leaking, just pull the screw all the way out, pop off the old one and toss on a new one, I used the 13mm fastening nut as a stop so I would know where the screw sat before removing it.


Happy tuning!

[92EcoDiesel Jetta]

I haven't fooled with it yet. I assume the collar is on there from the factory as an anti tampering device? How is the collar secured? Is it threaded on? pressed on? crimped on? crimped and welded on? Once the collar is removed, is it trashed -to be discarded or can it be re-used?

[Pre95]

I haven't fooled with it yet. I assume the collar is on there from the factory as an anti tampering device? How is the collar secured? Is it threaded on? pressed on? crimped on? crimped and welded on? Once the collar is removed, is it trashed -to be discarded or can it be re-used?

The collar itself really isn't the problem with adjusting. It is a factory stop put in place so you cant turn the fuel so far up it floods the heck out of itself (I guess some turbo guys would need to remove it for tons-more-fuel?). Mine looks crimped on to hold it in place, then tack welded to really make sur eit isn't going anywhere.

When you loosen the 13mm nut you will see the collar has no affect on the tuning of the load adjustment screw. If you have the fuel set to where the collar hits the 13mm nut and you still dont have enough power, something is definitely wrong (I am guessing injectors or water in your fuel?)

[92EcoDiesel Jetta]

Pre95, thanks for the info. As I remember, I think the collar is right up against the lock nut. I do get some smoke at WOT, but it is not black. When I have time, I will play with it. I've been busy installing a tach (a real tach with  mag pickup on the crank pulley).

[92EcoDiesel Jetta]

I left the collar on as suggested and loosened the 13 mm nut and backed  out the 6 mm adjust screw. Tried a few settings till I got it to not smoke at all on WOT and not lose any acceleration at the same time.  I'll see if my mpg improves. Thanks for the inputs.

[Rabbit TD]

Unlike most here, I want to tune it for economy- i.e. NO BLACK SMOKE!

Ahmen, If I want tons of smoke and lousy mileage I'll get a Kenworth

[Pre95]

I left the collar on as suggested and loosened the 13 mm nut and backed  out the 6 mm adjust screw. Tried a few settings till I got it to not smoke at all on WOT and not lose any acceleration at the same time.  I'll see if my mpg improves. Thanks for the inputs.

How the heck did you manage to maintain your acceleration but reduce the fuel? Mine is quite touchy, any changes to the load adjustment and the acceleration is directly affected (and quite noticeable). Insight appreciated, still trying to figure out how to properly tune this ol girl...