I've completed all the tune up tasks and have run through all the FI components (stock D-Jet from a 72 1.7L) and here's my scenerio:

THE GOOD:
-Pulls well, fairly strong throughout the entire RPM range (really wakes up around 4K due to the cam)

-Idle's nearly perfectly @ 1K RPM when warm

THE BAD:
-Idle "rolls" and sometimes stalls when cold after the AAR closes up (runs approx 1700 RPM w/AAR open - as it is supposed to).

-Pinging occurs @ highway speeds when attempting to accererate around 3200 to 3400 RPM's. - especially in warmer weater. I can "drive around" this pinging but I built the 2056 so I would be able to drive, not tap dance... I always run premium gas to keep the pinging to a minimum but really want to eliminate it for good.

-The exhaust has a bit of "popping" on decel. Sounds kinda cool (in a Harley sort of way) but tells me the mixture is not correct - I can't remember if this infers the air/fuel mixture is too rich or too lean...

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MY THOUGHS ON FIXES AND QUESTIONS TO YOU's EXPERTS:

-I'll need to adjust the MPS to accomodate the "fast cam" but which direction should I start adjusting first? How large of increments should be made per adjustment? -----> Note, I have 2 MPS's, both of which have been bench tested and proven as good. One of which I'll leave @ stock (so I can always come back to factory setting), the other which I can tweak til my hearts content.

-Has anyone who's running this setup deviated from the called for 29PSI fuel pressure? I could get it to run a bit richer throughout the entire range by bumping up the fuel pressure but it I'm only having probs under certain driving conditions so I'm hesitant to do this...

-Advice on adjusting the MPS?? Is it possible to adjust it too much in either direction and break it? These things are getting hard to find & I don't want to find myself hunting for one...


OH, a couple last notes - I have printed and read (over and over) PB Anders D-Jet write up. Also, I don't have a CO meter or Dyno. Those devices are to get it near perfect - I just need it workable...

If you've read all this, THANK U! I promise to pay back the advice gods by posting my own knowledge via this board and in person when possible...

-Pete

What numbers are on the MPS's? If you have a 037 install that as its richer than the 043. Thats why you are pinging, too lean.

Mine set up with a stock 043 runs about 14.7 to 1 and its too lean at cruise.

Took some adjusting using a LM1 meter to set it to 13.7 to 1 for cruise.

WOT is set by the big machine screw backing it out until 12.5 to 1.

How to do it by ear? pretty effin tough or near impossible! Adjusting the outer screw alittle bit swings the mix alot.

You have to adjust it by using a O2 sensor set up.

Sorry, go to a dyno shop after you set up a MPS by removing the epoxy and cafefully removing the WOT stop. That is not easy to do without destroying the stop or the threads so go slow.

Apprec the reply. I'll check the numbers tonight. Also, one of the MPS's (the one currerntly on the car) actually doesn't have the outside screw (the one w/the epoxy) - only a narrow hole w/the inner screw.

The spare MPS (that still has the stock setting) has had the epoxy removed and the outer screw is a little scored. Looks like I'll need to get the outer screw "unscored" or rob an outer screw from one of the old broken MPS's laying aournd...

If you are running a MPS wihout the WOT stop set you will blow the diaphram as its unsupported and travels too far cracking.

A scored or one will a hole drilled in it is ok, its just a Bitch get the screw out without proper purchase on the screw with a large screwdriver.

To remove the WOT I first heat the MPS really hot at the WOT witha heat gun to cook the epoxy and the threads. Then screw it in until iit stops. With a dental pick I remove all the epoxy out of the threads and slowly work hte WOT stop out and in to clean out the rest picking with the dental tool as I go. Takes about 15 to 30 minutes of goofing around with it to finish with the screw to get it out.
Now you can adjust the inner/outer screws that set the idle/cruize mix with a meter or at the dynoshop.

Cool - I'll need to get a tap & die to sort out the slight scoring which occurred in removing the outer screw. Oddly, the MPS that has been on the car for a looong time is VW # 022 906 051A; Bosch # 0 280 100 019

Hmmmmm

early 1.7L either 914 or 411

The tap to clean out the threads is pretty trick and I had to order one as its metric and 1.0mm fine threads.

Good luck finding one.

You are running rather lean probably in the 15 to 1 range...

Pete: Go down to the local motor cycle store and get some B9ES, they are a real cold plug. That will help get some of the heat out of the heads. When you get it running cool enough to foul them you can go to a hotter one.
Geoff is the man when it comes to adjusting the MPS. He gave me a lot of insight. If you have to do this hole thing by reading plugs it will take you forever. It took me mounths and I bought the LM1. To start with it would be nice to know where the full stop screw is (how deep).
By messing with this you stand a chance of over heating your motor.....
If you really want to do this I'll look into my notes and see if I can fine where Geoff tripped me out.
:PERMATGRIN: Joe

To simplify things - If you are able to clean up the outer screw area (I can provide pics if you'd like) I'd be more than happy to send it your way as I've read that you were in the business of rebuilding these suckers in the past. Happy/willing to pay you fair rate for your services. I won't be laid up if I send it to you b/c I'm running "OK" now but want to have one that can be properly dialed. The MPS I'm running on now is the earlier type which doesn't even have an outer screw - only a narrow hole to adjust the inner scre....

Whatchya think?

Hadn't heard of B9ES before. Apprec. I'm thinking of getting an LM1. Can they be found for under $300? How does it read the air/fuel mixture? Does it have a sensor that "sniffs" the exhaust?

LM-1 goes for $349 LM-1

or you can go with the LC-1 which can be read from a gauge or a laptop computer

I have both and they use a sensor that read from the tailpipe or better yet from sensor installed in the exhaust.

I may end up just buying a LM1. Figure that if I pay a shop for Dyno time and/or O2 meter time I'm probably shelling out $150 to $200 - and thats a one time deal. With that amount I'm half way to a new LM1!

We'll see how the summer progresses...

-pt

I could send you a MPS adjusted close to what your setup needs and then you fine tune it at a dyno.

every motor is alittle different unless its totally stock.

the only MPS's without the WOT machined stop plug are the Type 3 ones! Yikes

Before you start messing with the MPS, crank fuel pressure up to 35 and put
about 300 ohms of resistance in the head temp wire. I have the same setup and never needed to adjust the MPS. I have an adjustable one and have never been happy with it. If you are up for a drive, come down to Bucks County, PA and try both of my MPS units.

I may just take you up on that. I'm tied up for a couple weeks but will try a couple things and may just make the 87 mile drive in your direction!

-pt