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Jen...bear in mind here. The MPS...is not a swap it out part. It is custom adjusted to each car. There was almost guaranteed...in my book....that that swapping the MPS alone...would not solve your problem.
In the beginning, the factory just set each MPS a basic baseline that ran decent for most cars....kinda like you have now.
This was OK....as who tested emmissions in NEW cars....in 1971-1974 in this country?....no one did. Later, they started paint marking them for different settings within a given part number lot. Thats because the somewhat general adjustment they slapped into the MPS's...had trouble over the years in adapting to the radically different and variable conditions in this country (high altitude, low altitude, hot, cold, humid)....as well as passing emmissions in places like California that were getting stringent.

This is going to be a long post......I suggest you read all of it please.

There are only a few possible reasons why you could be getting too much fuel across the board...all the time.
(1) You have a leaking injector or cold start injector.
To know if any of them are leakng, the engine must be off, the fuel pump pressurized and running and all five injectors must be pulled from their bores to you can view them. Jumper the pump under the front end with a pair of 8 foot wires to the battery. Mind the polarity...it is marked. The pump will run and the injectors can be observed to see if they drip drip drip.

(2) Your fuel pressure could be too high. It should be 28-30 psi.
If you yourself....have not seen the gauge on the car...and observed this to be true....then assume it is incorrect.

(3) You have serious vacuum leaks. If everything I list below...has not been REPLACED by YOU....then it is assumed to be leaking. Bear in mind....that I am not beating on your mechanic...but few people ....anywhere....are qualified to work on D-jet. Visual inspection and sprays and propane ...or whatever....are NOT good enough to say you are vaccuum leak free....and that is what most mechanics do. this car is 30+ years old. ALL...repeat...ALL of the rubber is shot.
First, idle the car with a vacuum gauge hooked to various ports in turn...at idle. First...to th decel valve port if you have one. Then to the acuum advance port. Then to the auto trans port (if you have one). record thsoe numbers. Anything under 10"hg says you have a leak.

Check and replace ALL of these:
Valve cover gaskets...big no kidding here...where is your oil leak?
Oil breather cork gasket
oil breather lid gasket
pushrod tube seals....yes...they lose vacuum...again...wheres the leak?
The O-ring between the TB and the plenum
The injector seals (use CIS seals from an 80 model rabbit)
The 12mm pcv hose (red) that goes from breather to plenum
The two 12mm hoses that go from the heads to the flame trap "T"
The boots that connect the runners to the plenum
The rubber funky elbow that connects to the auxiliary air reg, the plenum and the decel valve. It is bad 100% of the time...and looks normal
the vaccuum retard hose (if you have one)
The disc shaped vacuum diaphram near the TB if you have an automatic
The hoses that go to it and where they connect to the "T" near the plenum
The hose between the MPS and plenum
The PCV valve itself....it is always...shot! read my notes on how to correct for it without violating emmissions....this part is a big leaker!
The hose to the automatci transmission modulator valve...ir you have an automatic
Check the auxiliary air regulator for dead on sealing after 8 minutes.

(4) poor ignition. Get a pertronix ignitor, throw the points and condensor in the trash...and re-time it.

I guarantee you...that if you check all of this yourself.....you will find at least THREE of these have been missed by your mechanic.

Lastly......you come down to the MPS. If all your problem is......is CO....and all else is well, then its possible that your cars engine either has low compression...or has been rebuilt with low compression pistons...and the MPS was not adjusted to compensate. DO NOT confuse good running with corrfect emmissions. The factory advertized CO level.....for the 74 L-jet 412's....was ridiculously low....and contributed to a great many burned engines. The D-jets factory CO levels dropped almost every year in the books. But....the sloppy factory adjustment level....almost never allowed them to pass emmissions.

If you send me a PM....and zip your MPS out to me...I will carefull remove the adjuster plug for you...so you can tune it. Since the MPS is not an emmissions device...removing the tamper proof plug (which was to keep you from messing with it).....does nothing to void emmissions.
I will mark the proper adjuster screw with red sharpy and write on the outside with pencil the direction to turn to lower CO. You can then take the car to your mechanic......tell him/her to set the knob on your ECU to the middle position (12 clicks).....then hook the car up to a sniffer...warm it up....and then adjust the center screw until CO drops to idle levels.

Its that simple. If all else is well...it will probably take about 1/3 to 1/2 turn.

Bear in mind.....D-jet is very very sensitive to improper valve adjustment. The valves must be adjusted to a tight .006 cold. Ideally, they should be checked again when hot...to make sure they are between
.0015 at the hottest point and .0035 average.

If you have ANY vacuum leaks....you can be screwed. Ray

Jen, I noticed in your ad that you mentioned the valve cover gaskets are bad! Replace them, they are virtually free, and could be causing some of your problems as Ray mentioned above! I think you need to get some of your money back from the mechanics you took it to- I can't believe anyone calling themselves a mechanic wouldn't have replaced them!

Ray I appreciate your post, I am printing it off for later. But 99% of it is Greek to me. I don't have the tools you speak of or the testing gear or the vocabulary. That's why I have to rely on mechanics. I went through the list you provided for me last time one by one with Hoodsy. Now this list is different so when I have a few days off and its not pouring rain, I will do more testing.

I made a mistake in thinking that I could mechanically handle a car like this - I had a 74 Beetle and have owned watercooled VWs before and had ZERO troubles fixing and maintainingany of them. This car. however, has got me completely frustrated and I either can't find parts or don't have the time to dedicate to trouble shooting a problem I didn't even expect when I bought it. I thought I was buying a perfectly operating daily driver.

Since it is not insured anymore, it costs me $32 every time I want to drive it for a day, even just a little pop over to the mechanic.

Jen, if you did fine with a vw aircooled beetle, you will do fine with this. 90% of what I am listing...is just replacing hoses and seals. If you can turn a wrench ...even lightly....you will be fine.

Valve adjustment....is a 13mm wrench, a 13mm socket and a feeler gauge. Right at $20. We can help you through all of this. Just stick with us.

Fuel pressure. You can get 98% right...for under $20. You need a simple water pressure gauge from any home improvement store. Just make sure it is not over 60 psi. It must read in 1 psi encrements. Get a brass barb from the same store, some teflon tape, two hose clamps and 3 foot of fuel hose. All of this should set you back ...about $15.

If you crawl under the front end of the car...you will see a two wire plug on the fuel pump. Pull it off and shine a flashlight on the pump. You will see a small + and - marking. Go to the hardware store...or acomputer store and get 20 feet of 14 gauge wire ($5). get some of those cheap red, yellow and blue female crimp on terminals. Make a pair of 10" wires wit ha female terminal at each end. Plug them into teh pump. The one with the + goes to the red side of the battery, the - to the other side.
Before you hook it to the battery, install the fuel pressure gauge into the "t" fitting that sticks out between the injectors on the left side of the engine. Tighten the clamps....connect the pump. You are now checking fuel pressure. Let itrun for 10 minutes to make sure the pump does not spike or overheat. Then turn it off and record how long it takes for the pressure to drop all the way down. Done.

If you want...I can e-mail digital pics with captions of how to open the backof the MPS and what to adjust. We can help you pass emmissions. Ray

Here are the Aircare reports for those that asked. Please note on the one from Jan 28, it appears the printer may have been offline for the diagnostic trace report, so the little graphs don't quite match up where they are supposed to go.

www.diaryofaloser.com/rawimages/jan%2028.pdf
www.diaryofaloser.com/rawimages/oct%2028.pdf
www.diaryofaloser.com/rawimages/oct%206.pdf

Jen

Yep.....it confirms what I thought. You have vacuum leaks and most probably a broken PCV valve mixed in.
Yes, having an MPS thrown in with a slightly different adjustment...made a slight difference, but overall....it is showing that you either DO need to have an adjustment to the MPS (probably to counteract for age of engine and low compression)...or have low fuel pressure.

The vacuum leak is seen...because at idle you are hideously rich. This is what avacuum leak causes on D-jet....unlike carbs or L-jet.....wherin a vacuum leak causes leanness. It tricks the MPS into thinking that the throttle is cracked open.

Yet....at higher (actually midrange rpms as the dyno driving tests are not at highway speed...and you have tall final drive gearing)...you are overyly lean. This is usually because of either fuel starvation due to pressure......or more likely....the higher rpm of the engine at only slight throttle opening.....is able to overcome the vacuum leaks....telling the MPS to pull fuel mixture back. Fix your leaks. Ray

Do you know someone with a CO meter (single-gas exhaust "sniffer")? If so, borrowing one to check the CO reading after doing a modification while still in your driveway would save that $32 per trip (man, and I thought the TNRCC rules here in Texas were screwy!). If not, I can loan you my Heathkit meter since I'm not using it right now, if you're willing. It's not accurate down to the last 0.1% (more like 0.5-1.0% accuracy at the low end), but it'll get you in the ballpark, close enough to pass the limits shown on those Aircare test sheets you posted.

Hey Guys, why does it look from the charts that some of the readings actually got alot worse with the working MPS???? Is that just because of adjustments needed? Is the real problem just vacuum leaks? Could it be the PVC is hooked up wrong? So does that mean her original MPS is actually good? If so please send me the one I sent back! Anyone gonna send me the other MPS's as agreed?? Just wondering? Jen are you still selling your 412 2door or holding till later? I just had seen you listing for I think 3000 Canadian? Bill

Gonna send it out tomorrow, I promise...

Dang I gotta find some time to finish a batch of the diaphrams.

In general, you can have a very slightly cracked diaphram and still have a good running car. It matters leak down time. If its like ...five minutes....then there is every chance that the volume of vacuum in the manifolds will never notcie that. Where a minor vacuum leak will get noticed ...is when you are say...idleing for like 10 minutes and the leak slowly catches up.....and then idle starts to stumble. A quick blip of the throttle will get you back to stable. But.....if this leak is caused by teh diaphram having a very small crack, then sooner or later you must do something cause the crack will eventually finish the diaphram. If its the 0-ring around the chamber....thats an easy fix.

Yes, other than a vacuum leak....the original MPS was most probably good. Like the ECU....its rare to actually have problems with the electronic portion of teh MpS. Its also pretty rare to wear out the barometric chambers. Its generally just teh diaphram. These parts are almost bulletproof. Only when they get wet does it get ugly.

If your car has had the engine rebuilt...even if it was bone stock rebuild...then your MPS needs adjustment. If you have a totally differnt tire and wheel combo....your MPS may need adjustment. If you have an upgraded ignition or fuel pump system...your MPS probably needs adjustment. If your engine is old...and compression is down....your MPS needs adjustment. If you have changed trannys and have different fional drive or gearing...your MPS needs adjustment.

As for the PCV valve....no...you cannot hook it up backwaqrds. But...if you read my threads on the subject...then take a close look at what you have...about 7 of 10 times you will find it worn out. Even when its perfect....the concept behind it for a MPS controlled engine is poor. Yes it works fine....but only with engines whsoe state of tune is basic factory level. What that means....and what I have found, is that basic factory tune was left slightly rich across the board. That made the system less susceptible to odd fluctuations in manifold pressure. It also made have porrer throttle repsone than is possibel with the system and have slightly less available power. Ray

Bill, I have the two cores all packed up for you, but have simply just forgottten to get those out to you. I've had a few minor personal crises to deal with. I will bring them to work tomorrow and get them shipped out. Sorry for the delay, I had meant to ship them out immediately and I am sorry I have not followed through with that.

My original MPS did not hold vacuum. At all. Not even "held vacuum and bled down" but did not hold vacuum in the slightest and I tested this myself with a hand vacuum pump from work.

At this point I have my car listed for sale on a few sites. I am not actively attempting to unload it and so far any interest in it has been minimal, which I was quite prepared for. I am not in a hurry to sell it and am quite happy to let it sit under a sheet leaking oil onto my parking space while I sort out what to do. I have it listed for $3000 because that is what I paid.

I have not had the time or the inclination to pursue this lately. I'm frustrated by the whole process and quite honestly spending my free time testing things I have already had tested to find something that was missed and looking for things that I don't even know what they are doesn't interest me right now. Maybe in a month or two when the weather is nicer, I will be more interested but not right now. I don't have the tools, the testing gear, the time or the inclination.

MGVWfan - thanks for the offer. I'll pass for now.

Like I said before, I appreciate the support all you guys have offered.

Jen, just let it sit for a while. This is one of the things to realize. If you have free time....study the parts...and study the book. You need to familiarize yourself with what the parts are and what their function are.

Also, if your car is leaking significantly anyplace other than the main seal on the flywheel...trhat is generally a vacuum leak source. Any open hole into the crankcase....will mess with the fuel injection. Oil leaks...up to the flywheel seal...are simple nuts and bolts. Easy to fix.

Also, at some point, you need to start doing some of the adjustments we are recommending. You might also realize....that we are not guessing here. Its exceedingly rare that we (as a group and individually) cannot diagnose a D-jet problem...only because both individually and collectively....we have had every problem there can be....and solved it.

A couple of other questions that have not been asked......what is the condition of the wiring system/harness for your fuel injection? If it has splices, cracks or corrosion....that can be a problem. The ground wires (three bundles of two) under the center of the intake on the case centerline, must be immaculate. Also, what is teh condition of tehFI triggerpoints under the distributor?

If you own a cheap voltmeter....a few things need to be checked...and can be easily checked.
(1) read the resistance (ohms) of each injector with the plug pulled out. They should not read over 3.2 ohms.
(2) There are 4 connector pins on the MPS. The outer pair should read about 96 ohms and the inner pair should read about 33 ohms
(3) The trigger points on the distributor can be checked for resistance..without even removing them. You check them by putting one probe on the center pin and one on an outer pin. You check each outer pin as a pair with the inner pin. They should read...ideally...about .9 ohms. They can read as low as .6 or .7 ohms and as high as 1.0 ohms. But the lower the better and the difference from side to side.....should be no more than .2 ohms. So for example....if the left side read .7 ohms and the right read .9...they would be acceptable...though .7 and .8 would be better.

If they read farther off...then you need to clean them. Ask us how or look for threads on the subject. There are many.

Just please rememebr. D-jet is very dependable....when everything is set up right. But, this will never be a car that you get right once and just drive happily away for ages. It is an old system. Unless you get a new wiring harnes , start with new components.....and are very circumspect....there will sooner or later be things that you will have to know to keep it running. You yourself will have to learn these things.....as there are NO D-jet mechanics out there in the business in general.

Its a simple system. Only 23 wires, three sensors and two main switches. But it has some issues. We can help if you want to work with it. Ray

ubercrap wrote:Gonna send it out tomorrow, I promise...

Hey, vwbill, I had everything ready to go, but when I took the package to the post office, I wasn't sure if the return address on the UPS label was yours of the UPS store that you sent it from. Check your PM!

Hey Uber, I sent you a PM with my address but I never received your PM?
Ray thanks for another great info post! It is hard to remember that the Djet was the first Injection system and only has 23 wires! Think of how much easier we should have it compared to new systems with a ton more sensors for drivability!! It is true with just a few hundred dollars you can set yourself up with a lot of test equipment to test a entire injection system and components! I have seen a CO tester in JC Witney for cheap, I think around 150$ or under! A multimeter can be picked up from Radio Shack or Sears for around 20 bucks and a fuel pressure vacuum setup in the same range. I think my combo that is a vacuum pump and gauge setup cost me almost 30$ and you can bleed brakes with it and test vacuum and pressure! I think a timing light is cheap too! I have had mine for years! I know though for a startup cost it can add up but you then have the equipment!
It is true that once you have these systems setup and checked they provide performance and good reliability! It's just a transition from a bug type setup that can be restored outta a catelog! I dont know how they check out with emmission test though! I hope Jen tries to keep her car till she can do some adjustments and more checks! I really think she is so close to success!! How much is it to bring a car in from Canada to here ? Sorry it wasn't easier for Jen and finding a mechanic that could had her going straight from the start! Isnt the Djet a common system also on Mercedes? I just never buy the oh its a 411/412 excuse!! If you are a mechanic you can find vacuum leaks/pressure check/ adj. and check componants! Take care everyone! Bill

Hey thanks for sending the MPS's 412Jen and Uber! Thanks for the Jam also 412Jen!! Looks yummy!
Just a questions to the crew about the MPS and my observations. From testing now quite a few MPS's I seem to have noticed all have tested good for the terminals and terminals to case! The problem seems to be vacuum leaks of varied grades?? From fast leak which can be heard or a slow leak down or not holding much vacuum and slow leak down?? Does this say that rebuilding is a good possiblity? Is the slow leaks a case leak and the big leaks a diapham issue or is it almost always a diapham issue? So can I tell which it is by pulling what vacuum I can get and seeing if the terminal reistance changes? Thanks bill