Ragtop 99

iTrader: (7)

When I swapped, I did not swap the harness. I turned off the A4 codes in Edit and use a funky gear ratio to account for the VSS differences.

Have any of you done the swap without swapping the harness reflashed your PCM to an M6 configuration? I'm looking to see if there are any known issues before flash mine.

tici

iTrader: (1)

You can modify the A4 harness. It's only about clutch pedal switch, cruise control switch, reverse lights and trunk opening mechanism. You can connect the reverse lock solenoid to the stop lights. Skip shift: you'll have to tune it out or add a resistor to simulate the solenoid.

Programming: the PCM will think you are always in park and timing won't be according to the usual timing table.

Ragtop 99

iTrader: (7)

I've already done the swap and hooked those up. The only thing not hooked up was the reverse lockout which I wired to a button on the shifter.

Right now the computer thinks I only use A4 gear 1 or 2 as read by ATAP. I'm assuming that 1 is nuetral as it only reads as 1 when I'm at 0% or .4% TPS and below 25 mph. My ignition timing when stopped corresponds to the P/N table. The rest of the time it reads gear 2. My ignition timing while driving corresponds to the the normal high octane table.

What I want to know is what will happen if I flash to an M6. Will it not pick-up what gear I'm in? This is pretty tunable, but the throttle cracker and other tables may not be really usable for me.

pekkaz

Interesting... I'm about to start the swap.

Sounds like it's workin like it should. I'd guess the M6 pcm behaviour is just that. When moving it's in-gear and when stopped P/N tables are used but I'm just guessing. PCM probably could figure out the gear from vss and rpm though.

You didn't wire P/N switch or a4 wires in any way ?

tici

iTrader: (1)

I have now a M6 program and Atap reads 1sr gear all the time.
Strange that it sees 2nd gear when using the A4 program: the signal of which gear comes from the tranny connector and is not a function of rpm, MAF, MAP or whatever...

by the way: how is your mileage after the swap? mine is worst! OK, now it's cold and I only drive short trips (2x 10 miles a day). Is it just the driving style? should I keep the rpm low as with the the A4?

Ragtop 99

iTrader: (7)

ATAP reads "2" which in fact may be first gear, unless P/N normally reads as "0".

I'll take a look at the temps when it was reading "1" for the gear. I use a wierd FTC between the time the car first switches to closed loop and FTC enable kicks in. Part of the problem seems that using my MAF makes it worse, so I may try to go MAFless or get rid of my SLP MAF and get a stock unit.

My city mileage hasn't improved much, if any since the swap. Highway mileage has increased at least 25%. It has been a bit of a tuning challenge with Edit. I just got HPT and hope that it will make things easier.

Probably the only other challenge I have is if I run hard through a gear and then push in the clutch above 4000 rpm to coast. The car just dies. It is probably fuel cut-off kicking in, but I don't have the problem at 3000 rpm so I'm trying to figure out what the cause could be. Maybe something in the throttle cracker tables???

12secSS

iTrader: (30)

The PCM will always read "1" even if it is in Park, Neutral, Reverse, or Drive, only A4 will actually progress up to the higher gear (4). There is no "0" gear, the ECM doesn't depict the other "gears" (PRND), it really doesn't need to. The ECM uses MPH to differentiate from a stopped condition to a moving condition. This for example is used to switch from the Park base timing table to the HO/LO timing tables, once you exceed the value it will remain in the Main Spark tables until you go below the MPH limit. By flashing the ECM to a manual setup, you will only need to reference the VSS signal for the ECM to function properly. There is nothing else the ECM would be concerned about with an M6. As for logging (from what I recall) you will only see "1" as the current gear.

tici

iTrader: (1)

Before getting the M6 program I contacted a couple of knowledgeable tuners asking about modifying the A4 program... They all said that with an editing software you only see a little part of the tables and that you need the complete program to have the car running properly.
In the 98 there are also possible safety issues (TCS, airbag...) so I decided to don't even try to use the A4 program.
I asked Carputing and they sent me a M6 program to fit my VIN, year and calibration number. Using HPT is should be easier.

With the A4 and Atap I saw 1st gear in R, P, 1 and N.
2, 3 and 4 are the result of what the tranny is actually doing. There are swithces in the tranny that tells the PCM what gear is currently active. Strange that you have "2nd" now that the A4 is gone...

Why don't you just reflash the PCM? Here I haven't find any garage able to do it because of the new transmission, but in the States it should be easier...

Ragtop 99

iTrader: (7)

I know I've seen tables (maybe throttle cracker or follower) than have differing values by gear some go 4th, some go 6th. Do these tables not apply to M6 or does it just use values in the gear 1 column?

Assuming my speedo works, is there anything special I need to do to "reference the VSS signal" ?

Thanks

12secSS

iTrader: (30)

That is a very good question. If I recall correctly, the computer uses the VSS signal and compares it to the RPMs, then it looks up the gear ratio table and can figure out what gear the vehicle is currently in. This then helps the ECM figure out which table to use (ie: 1st, 2nd ... 6th). I don't know how if figures out reverse though, or if it even does.

You pretty much have it configured if your speedo works. The VSS is used in a lot of tables, from what I recall Ken and Keith telling me.

I did a manual swap for a buddy of mine, but I can't remember if anything needed to be change table wise. I do recall I was able to swap the VIN without a problem. HPTuners has a Trans Type selection where by you can select Automatic or Manual, but I am not sure how that functions, since it is a "new" feature.