Disappointing MAC11 update
cody at 5000tq.com
cody at 5000tq.com
Thu Sep 4 05:15:29 PDT 2008
Where does the 034 get it's signal?
1. You'll have to get creative with the wiring, but yes any standard
coil will work. You have to be carefull with Porsche coils to make
sure it's not from a car with capacitive discharge ignition (little
box in the left side of the engine bay with lots of heat sink fins on
it) - those coils are for CD ignition only. Whatever coil you use just
make sure you keep the Audi coil's darlington transistor (little round
silver thing mounted to the coil bracket). I'd recomend cutting the
built-in wiring off a known bad coil and wire that to the new coil so
you can still use the stock Audi coil wiring plug.
2. I've got a 7A flywheel on my 'fast' MC engine that has been spun to
8500rpm with no issues.
3. The way I usually set the sensor depth on other cars where you
can't get there is with a tiny bit of glue, glue a small aluminum
crush washer of the proper thickness to the bottom of the sensor then
put it in place until the washer is touching the flywheel. When you
turn the flywheel it will knock the washer out of the way. DONT USE A
STEEL WASHER. The aluminum washer gets disintigrated quickly.
-Cody
Quoting Rick Houck <rhouck at neo.rr.com>:
> MAC11 updateAnother update: no change.
>
> My bright idea today was that my engine monitor system (Innovate
> Motorsport #LM-1 with RPM and aux inputs adaptor) was triggered by
> the MAC11, and that might be causing some problems, but that proved
> to be wrong. The RPM signal to the monitor comes from the fuel
> 034EFI ECU, not the ignition ECU, so disconnecting it did not have
> any effect on the backfiring.
>
> Ben, unfortunately I scrapped out the MC flywheel long ago as never
> to be needed, but the 7A flywheel has only one pin on the engine
> side (I have a spare for comparison), with no other holes for pins
> There are two on the tranny side, but I understand that these were
> needed only by the factory for something. No pickup for those anyway.
>
> I have verified continuity from the two flywheel sensor plugs to the
> ECU connector to identify the proper connection, but did not ohm
> check the sensors themselves (but I have used two different sets
> with same results). I forgot to check clearance from sensors to the
> flywheel teeth and single pin before reassembly.
>
> The coil seems to be a valid suspect, but I am on my THIRD one! I am
> now out of Audi coils, and will have to try something else.
>
> Questions to you fellow do-it-yourselfers:
> 1. Can I use any standard can coil for a test. I have one from an
> old Porsche project that is still good. Any BTDT?
> 2. can anyone confirm that the TDC pins are in fact in the same
> place on both MC and 7A flywheels, just to reassure me that the bad
> fairys didn't move it and fill the hole?
> 3. a rough measurement of the depth from the sensor mounting surface
> to the pin looks like more than what is called out in Bentley
> (0.060"?), but it is hard to get a good depth reading down there for
> comparison to the sensor. Guess I should verify this, right? Yea, I
> know...........
>
> Thanks again for the help. What a great place to bounce ideas.
> Rick
>
>
>
>
> ----- Original Message -----
> From: Ben Swann
> To: rhouck at neo.rr.com
> Cc: 'Ben Swann'
> Sent: Wednesday, September 03, 2008 9:45 AM
> Subject: MAC11 update
>
>
>
>
> Rick,
>
> With exception to the possibility of the pin on your flywheel
> being different than the stock MC-1 flywheel, everything else is
> straight-forward. You basically set the timing up statically as per
> timing-belt installation followed by setting the distributor dead
> "in-window". That means with flywheel at TDC/0 mark hash lined up
> with bell-housing pointer - that should correspond to #1 piston
> being at its topmost of travel (meaure carefully with rod) and if it
> has not slipped, the front pully should line up with TB cover
> dimple or oil pump pointer - although I would not use this as a
> primary reference since these do invariably slip.
>
> Then the cam sprocket should be aligned with rear hash mark at the
> cam cover gasket and watr pump locked down to tighen belt. Then
> the distributor is rotated so middle of rotor is pointing to the
> hash mark on edge of distributor. The number 1 plug wire will be
> at the hash mark. Set it and forget it. No timing light is used -
> maybe to see if getting a spark, but I usually just ground the
> number one plug for that test. If spark - then ignition is working
> - move on to diagnosing fuel issue.
>
> The above does not rule out bad wires, cap, rotor or coil, but
> lets you know that the timing is set correctly. There is no
> adjustment of timing that can be done short of a remapped chip.
> Timing may retard for various reasons during operation - IAT high,
> knock detectoed or other sensor input, but usually not enough to
> even be noticable - certainly not what you describe. Usually if
> there issignificant retard, a code will be set and should be pulled
> prior to engine shutdown as MAC-11 is volatile whereas MAC-14 and
> 3B retain codes until they are cleared.
>
> As far as I recall, although the 7A flywwheel is a different
> thickness, etc. the pins are in the same place with repsect to TDC
> as the MC and 3B flywheels. The 7A uses the same timing
> synchronization method as the MC-1, MC-2, and 3B engine control
> units and the glywheel sensors need to be present and providing a
> good signal. You may want to verify they are the same - I may have
> one to compare as I'm in middle of a swap and pulled my 7A.
>
> Any problems with distributor out of alignment or signaling
> problem with hall or flywheel sensors will generate a code. 4444
> means that everything is checking out good - except that you may
> have the wires in the wrong places in the cap - no start or
> backfiring.
>
> See ****comments below after your questions.
>
> Ben
>
> [Date: Tue, 2 Sep 2008 22:39:27 -0400
> From: "Rick Houck" <rhouck at neo.rr.com>
> Subject: MAC11 update
> To: <cody at 5000tq.com>
> Cc: quattro at audifans.com
> Message-ID: <001901c90d6e$48c65190$6401a8c0 at rick>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=response
>
> Thanks to Cody and everyone who offered ideas. I went back in the
> garage tonight and confirmed a few last details. Here is what I did
> (some for the umpteenth time):
>
> 1. installed brand new plugs-no change
> 2. installed used distributor cap and plug wires from another
> motor-no change 3. changed entire distributor with good used one and
> new rotor- no change 4. checked firing order and correct rotor
> rotation, then flywheel, pulley, rotor marks and #1 plug wire to
> make sure - all correct and lined up 5. re-indexed plug wires off
> one position in either direction - no start 6. checked for codes -
> all well (4444) 7. attached timing light and looked for mark on
> pulley and flywheel - NO SHOW!!
>
> 8. Reved motor while watching other visible marks on flywheel and
> pulley - they advanced gradually until I got around 2400 RPM then
> the light quit firing everytime as the engine missed and backfired.
>
> *** Sounds like you had it to the point where you can declare
> ignition good. Again, if the engine starts and runs, then ignition
> is OK. Nothing else to do. Move on to fuel or compression issues.
>
> 9. rotated distributor after it was running to verify that it ran
> better and reved almost like normal - same as before, it did, but
> would not re-start if left in that position 10. unplugged knock
> sensor to see what would happen - no change 11. swapped RPM and
> crank position sensor connections - no start
>
> *** I got these mixed up once and drove me crazy. To verify you
> have the sensor wiring correct, it is a good ide to use a VOM and do
> round-robin continuity check on both flywheel sensor wires, and
> knock sensor as they all use the same colored wires. Basically you
> measure continuity ( 1K?) while sensor connected at firewall, then
> confirm correct sensor by disconnecting it - then mark as per proper
> color code. I received a wire harness that had the color code
> bass-ackwards for the knock sensor and one of the flywheel sensors.
>
> 12. pulled starter to verify that no teeth are damaged or missing
> and that the flywheel pin was still there - teeth showed only minor
> signs of stupid engagement while engine running sometime in the past
> and the pin was there, and no other holes (with a missing pin) were
> found 13. Decided to give up and drink a full keg to drown my
> misery, but didn't have one.
>
> My conclusion:
> I think all the individual parts are working properly but the
> timing pin is in the wrong location. All of my last 9 years of track
> events with this MC1engine and 7A flywheel performing beautifully
> are just a figment of my imagination, or a bad fairy came and
> modified my flywheel between run groups. I'm at a loss to understand
> it now, unless something has been retarding my timing just enough
> to offset the incorrect position until recently.
>
> Questions:
> Shouldn't I be able to see the TDC "0" mark on the flywheel with
> the timing light at idle (I think so), or on the front pulley?
>
> *** Not really - timing belt just does not work for this type of
> ignition setup - all you see is a flashing light.
>
> Is there any way I could have installed the 7A flywheel off one
> hole? - I don't think so, but I just went until all the holes lined
> up for the bolts without trying the next position.
>
> *** No holes are drilled to be idiot proof.
>
> How do I find the correct position for the pin, so I can hopefully
> redrill and install it through the starter opening?
>
> *** unless pin sheared off, the pins (2 of them) should be there
> or you will not location of pin where there is a sheared off pin.
> You'll need to drill it out and install a new pin. I know - easier
> said than done.
>
> Can I simply pull the pin sensor while the visible mark is on the
> "0" and mark that location, or is there an offset of a few degrees?
>
> *** Pins are not at TDC on the flywheel, but are more like 60
> degrees and offset by 20 degrees - no these are not exact.
>
> Thanks again to everyone.
>
> frustrated Rick]
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