Date: Mon, 29 Sep 2003 12:12:12 -0700
Reply-To: Robert Keezer <warmerwagen@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Robert Keezer <warmerwagen@HOTMAIL.COM>
Subject: Re: The "Other" System: Motronic (long)
Content-Type: text/plain; format=flowed
Ok Here's the basic lowdown on Motronic.
There are 2 versions for VW's from 1993-1999. One is OBD1 (on-board
diagnosis 1) and OBD2.
'96 and later is OBD2.
Motronic manages the engine differently that Digifant. Here is a partial
list of the main features/advantages:
Adaptive - can compensate for changes from wear /fuel quality.
Sequential injection- each injector operates independently- less pressure
drop as only one injector instead of two operates at a time.
Hot wire intake air measurement:
No moving parts eliminates the vane-type AFM. Better compensation at high
altitude.
Crankshaft position timing:
More precise timing by using a timing ring on the crankshaft to relay
crankshaft position info and RPM signal to ECU via a pick-up.
More accurate that using camshaft as in older systems.
Taking TDC and RPM timing signals directly from the crankshaft avoids
inaccuracies from gear-lash or belt drive. Less spark scatter.
Electronic dwell control. Dwell angle and timing advance is controlled by
the ECU.
A good battery/alternator is a required as voltage is one of the inputs that
determines dwell angle.
The coil doesn't energize until the engine is running, saving the coil and
battery voltage loss when radio is turned on.
The distributor doesn't control timing-it it's locked down and never
adjusted. It functions as a camshaft position sensor, and to distribute
spark to the plugs.
Individual spark timing:
The ECU controls spark timing and calculates this for each plug individually
making for very precise ignition timing.
Minor variances such as plug gap and wear can be compensated for . This
translates to mean that one plug may get a slight ly earlier or later spark
to compensate for any variance.
This is one of the adaptive qualities, which information is stored in the
ROM.
More on adaptive engine management: The ECU has various timing maps it
refers to under different driving conditions such as city of hiway driving.
This ensure optimum performance in conditions that are known to affect
performance.
Here is a direct quote on Motronic adaptive engine management from the Bosch
Fuel injection book:
Adaptive circuitry:
"it adapts or learns what is best for you and this engine, which may be
different from the engine tested to develop the basic data for the memory
maps.
If the concept seems hard to handle, think of it in this way: The control
unit looks at the basepulse-time signals during closed loop (closed loop=
all system components functioning properly) The result is less worry about
intake air leaks, as the system adapts to such variations. It also adapts to
the thinner air at higher altitudes., reducing the need for an altitude
sensor.
Idle speed control:
For you this means no more little black box behind the the right taillight.
The ECU manages the idle stabilizer valve in Motronic to '95. '96-later
Motronic uses a special throttle body to control idle and does away with the
idle stabilizer valve.
Knock control:
The Motronic control unit has accurate information on crankshaft position
and firing order so it is possible to determine which cylinder is
knocking(one cylinder usually begins knocking before the others) Further,
circuits operate at such speed that ignition timing can be retarded only for
the knocking cylinder, and advanced for the firing of the next cylinder.
Each knock signal can modify timing in milliseconds.
This is just a basic description of Motronic. As you have seen, it has much
more control than Digifant.
Diagnostics:
Each time you turn the key ON, the computer checks itself.
Then it checks the sensors. Any defects are stored in the fault memory for
later readout by a diagnostic device( VAG-COM ). Motronic up to '95 can read
-out any stored faults as flashing light codes by bridging two terminals in
the DLC(data link connector). A special bridge plug is used for this.
Or , using an interface harness and a laptop with VW's VAG-COM software, you
can view your engines faults on a monitor display and see the engines
condition in real-time as the engine is running.
Pretty cool, huh?
So - the main challenge is to adapt Motronic to replace the Digifant and
Digijet system that runs the Vanagon.
I won't touch upon the AFC for air-cooled system, as Motronic is designed to
manage water-cooled engines.
First a way has to be found to place a crankshaft position sensor either on
the crankshaft, front pulley or flywheel of the WBX engine.
This is a toothed timing wheel found on the ABA crankshaft. The pick-up is
the other component.
If this can be adapted to the WBX, then Motronic is possible.
The other adaptation is the throttle body.
There are three types of throttle bodies for ABA (Golf-Jetta) Motronic.
Two for '93-'95, manual or auto trans, and one for both '96 -'99.
The Motronic throttle body is also the throttle position sensor. An adaptor
plate may be one way to go, as i had to mke one for my upgrade .
Once these two issues are resolved, the rest is plug and play. Sort-of. I
did'nt say it was easy.
One more component that has to be incorporated: A vehicle speed sensor
(VSS).
Road speed is one of the Motronic sensor inputs. The VSS in Motronic cars
also sends the mph signal to the electronic speedometer in these cars.
This signal is is sent from a sensor in the Golf Jetta etc transmission.
Vanagons have a mechanical speedometer so how do you get a road speed
signal?
Well, if you have cruise control in your Vanagon you already have one in the
back of your speedometer.
If you don't , then you can add one from a automatic A-2 speedometer('85-'92
Jetta Golf-Jetta etc)
The tab with the German word "abgriff" is removed and the pick-up is
installed with two screws. The pick-up is marked for wire connecting
polarity and sensor. One wire goes to key-on power, one to ground, and one
to the ecu.
Without this sensor the engine can stall and run rough, as it needs this
signal to facilitate some of the adaptive functions.
If adapting proves difficult of impossible, though I don't think it is, a
way you can have this wonder fuel injection system that runs modern VW
engines is just by installing the engine from a Jetta . Golf etc.
With the Diesel Vanagon engine and transmission hardware, and a '93 or later
Jetta engine, you all set to have a more powerful and efficient engine and
control system.
The aftermarket Tiico South African inline-four conversion is also a
practical installation, but I prefer the North American version from a Golf
-Jetta for these main reasons.
The NA inline four is a true 2 liter block. The SA is a modified 1.8.
Better hardware- there are several deficiencies with the SA brackets, etc.
Better engine management : The US Motronic is fully adaptive. The SA version
sensor, doesn't have a crankshaft position sensor as already described for
more accurate timing( knock and ping is a problem with the SA Motronic.
Other differences are: The SA comes without the O2 sensor wired-you have to
add it.
It isn't plug and play-
The SA Motronic needs to be set -up on a laptop with the VAG-COM.
US Motronic up to '95 has no use or shop adjustment requirements- you can't
tweak US Motronic like you can the SA version.
Again, SA Motronic as ships with the Tiico is not adaptive as the US version
is. This is my personal observation and is not meant to discourage use of
the SA version, just that after comparing both , the US version comes out
ahead as it is self-adjusting.
Also, the SA injectors are'nt as good as the US spec, among others.
Another virtue of using US systems is that they are serviceable by
technicians familiar with the systems in other models.
The SA version is not understood or serviced by the VW dealer, however,
there are shops certified by Tiico to service it.
In my opinion I think when doing a full or partial conversion , going with
what is common and available makes for less trouble down the road.
Any shop with the 1551/2 machine can plug you in to see what's going on when
you have a problem.
Given that you have all components in good condition, these Motronic driven
inline fours are very reliable .
Instead of asking the list what's's wrong with your engine. you can now look
at your laptop.
SO then the only thing left to discuss will be tires.
If you have questions maybe I have answers.. I don't claim to be an expert
at all- I am a student like you and have just finished a Motronic upgrade on
my '95 Golf engine that formerly ran the A-2 or earlier Digifant 2 system.
While it's still fresh in my mind and the behest of John Rodgers i have
spoken thus.
If anyone is the real expert out there please make corrections and /or add
to this discussion.
All ideas are welcome. I am curious to know if Motronic can be adapted to
the WBX .
Maybe this is for some of you die-hard WBX people.
The rest of you can't go wrong upgrading to a newer motor and system.
If you are in the Vanagon for the long term then it may be what you need.
Just as older computer programs became obsolete in favor of improved newer
versions, so also has fuel injection management.
Rather than selling your Vanagon and buying a new car with the system in
place, my approach is to take the newer system and add it to the older car.
And , as we know, it's not a car.
It's a Vanagon.
Just like a sailboat , we just keep them sailing.
All systems go.
Robert K
1982 Westfalia
----Original Message Follows----
From: John Rodgers <j_rodgers@CHARTER.NET>
Reply-To: John Rodgers <j_rodgers@CHARTER.NET>
To: vanagon@GERRY.VANAGON.COM
Subject: Re: The "Other" Vanagon Syndrome, Part II
Date: Mon, 29 Sep 2003 05:36:52 -0500
Robert,
As I recall you mentioned a while back about having Motronic FI on your
vehicle. Don't remember the engine you were referring to. There was some
mention of why it can't be put on the WBX. Something about anti-knock
devices not fitting or something to that effect.
I know absolutely nothing about Motronic and how it compares to the
Digifant. I, and I'm sure others on the list, would really appreciate
it if you would go back through that explanation and also address any
changes that might possibly be made, or would have to be made somehow,
to adapt Motronic to the WBX. Digifant FI becoming obsolete is a concern
of mine, as the AFM's are a weak spot in the system, and are getting
harder to get, and more expensive all the time.
I have another 2.1L WBX engine, a basket case, that I would like to
rebuild with counter weighted crank, fully balanced etc, and all that
jazz, and if there were some way to adapt the Motronic FI, and it
required machining work, etc, to accomplish it, I would like to look at
the possibilities before I get started.
Thanks,
John Rodgers
88 GL Driver
Robert Keezer wrote:
>Aha!! Harald, this is the same thing that plagued my Vanagon on a 45 day
>road trip to the east coast and back. You have a bad air flow meter.
>That's
>my guess.
>
>I thought it was all the things you are going thru-- fuel pump, fuel
>quality, a clogged tank.
>
>When I got back to Seattle, I bought a good used AFM and the problem was
>gone.
>
>This bucking, cutting out,and stalling is very classic AFM syndrome. It
>isn't likely that it fuel supply related or even qualiity.
>
>Most if not all underground fuel storage tanks have been replaced but I
>wonder where all the dirt in mine came from.
>
>I had my gas tank out yesterday and no matter how many gallons of gas I
>rinsed it out with, dirt was always present.
>So a new one is on order soon.
>
>I had a cutting out problem before I changed my fuel injection system
>to a
>newer version.
>
>Well guess what- the cutting out and stumbling is still present- so I
>am now
>pretty sure it was the dirt in the 18 year old tank.
>
>
>Turning off the engine and then restarting resets everything -this is
>typical of AFM syndrome.
>
>And I seem to remember you have a new AFM and the capicitor, so waht
>gives?
>
>Well when the AFM goes out, the capacitor does nothing to help -my
>experience .
>
>For this reason I changed to the FI system that has no moving parts.
>Unfortunately not available for the WBX, only '93 and later VW's. All
>it has
>is a little wire that gets hot, and the ECU increases injector time as
>the
>wire cools from increased air volume of acceleration.
>
>So , instead of a flap and a wiper, the changing restistance of the wire
>cooling is the signal the ECU reads .
>
>Also this is not affected by air density like a mechanical flap is.
>Better
>high altitude compensation.
>
>I should'nt have mentioned it since you are a WBX guy but unless somone
>revisions the WBX fuel injection system, it is becoming a obsolete ,
>without on-board diagnosis which may have been nice to have right
>about now.
>
>I did'nt know about the Vanagon list in '97 when I had the AFM
>problems- it
>sure would have saved me the trouble of changing three fuel pumps.
>I read about the bucking syndrome in the archives.
>
>Try changing the AFM at a shop or junkyard .
>
>Robert
>
>1982 Westfalia
>
>
>
>
>
>
>
>
>
>
>
>----Original Message Follows----
>From: Harald Rust <harald_nancy_vw@YAHOO.COM>
>Reply-To: Harald Rust <harald_nancy_vw@YAHOO.COM>
>To: vanagon@GERRY.VANAGON.COM
>Subject: The "Other" Vanagon Syndrome, Part II
>Date: Sun, 28 Sep 2003 16:48:33 -0700
>
>>From http://autos.groups.yahoo.com/group/vw-camping/
>
>After spending many days touring the Yellowstone
>geysers, wildlife viewing, photographing the Grand
>Tetons, and driving hundreds of miles in the parks at
>8,000 feet, it's time to go back home to Washington.
>In the parks, the vanagon runs perfect, and
>our confidence has returned.
>We exit Yellowstone at the north entrance, and
>proceed on to Livingston, Montana, and there top
>off with Exxon premium and get back on I-90 west.
>After 50 miles on the highway, it starts all over
>again, bucking, backfiring, loss of power, as
>if someone back in the engine compartment cut
>the fuel supply off.
>We are 800 miles from home, and there are some big
>mountain passes in front of us, and it's
>becoming very nerve-wracking.
>We pull over once again, move all the things onto
>the camper floor, and open up the engine compartment.
>Start up the waterboxer, and now it confounds us
>by idling really nicely again.
>Back on the freeway, after another 60 miles or so,
>it starts stumbling again. After a very long day
>of slow driving, we limp into Butte, Montana
>with 35 mph and the emergency flashers blinking.
>Camp at the KOA. In the morning we buy a new fuel
>filter at a store, and replace the old one
>at the KOA.
>(for good measure, also put in the spare coil.)
>I cut open the old fuel filter, which
>is also fairly new. Hardly any dirt in it.
>The paper element looks just fine.
>There are a few water droplets in the fuel,
>but nothing that should make the vanagon stop running.
>People blame a lot of problems on bad gas.
>I was always skeptical of that, because the other
>cars seem to run ok on the same gas.
>The vanagon isn't that different, or is it?
>So if it's not bad gas, what is it then?
>The symptoms are always a leaning out of the fuel.
>So finally we realize it could be clogged fuel
>injectors. Maybe clogged or worn fuel injectors
>are more sensitive to reformulated gas containing
>ethanol(?)
>Maybe that's the reason some vanagons seem to
>run better on certain brands of gas.
>In Western Washington our vanagon always
>ran great on the cheapest regular gas.
>Maybe the heat of all-day freeway driving makes the
>varnish deposits in the fuel injectors stick(?)
>Stuck fuel injectors is something that we hadn't
>thought of up until that point.
>Our injectors have been replaced once, but are
>about 9 years old with 110,000 miles on them.
>Never really added much detergent to clean them
>on a regular basis.
>So we drive down to the gas station mart, and
>stock up on 5 bottles of Techron additive.
>The guy behind the counter comments on how
>expensive the stuff is, and that's why he rides
>a bicycle.
>So we start by pouring 2 bottles of Techron in
>the fuel tank. Get back on the freeway, a little
>later the vanagon starts bucking once again.
>Another 100 miles later, the bucking becomes
>less severe, and sometimes I'm even able to
>keep up with traffic on a uphill grade.
>At the next fill up, add more Techron.
>By the time we reach Idaho, the vanagon runs
>really great again, and the stumbling totally
>disappears. We drive all the way back home
>without any problems.
>Still with all this, we don't consider the
>problem fixed. It's probably time to replace
>the fuel injectors, or at least, take them out,
>and send them in for ultrasound cleaning or something.
>Some research shows that European car fuel injectors
>are more sensitive to sticking than domestic.
>So it looks like we'll be replacing the fuel
>injectors soon, even though the vanagon is
>running really well again right now.
>Harald
>'90 westy
>
>
>__________________________________
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>
>Robert
>1982 Westfalia 1987 Wolfsburg
>
>_________________________________________________________________
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>
Robert
1982 Westfalia 1987 Wolfsburg
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