Another VK45 timing question.

[StarPD]

In another thread, one of the members here advised me that timing CAN be changed on the VK45, but it must be done with a CONSULT II.

So I asked my dealer's service supervisor if he'd bump the timing on my 2005 Q45 by two degrees to 14 degrees BTDC.

When the car was returned to me, the tech put a small adding machine type printout slip from the CONSULT II in my cupholder. I can't find it now, but as best I can recall, the only number on it was a "2", which I thought strange at the time. The service supervisor states that is all it will display, the amount increased. Since then, I notice that the pedal seems a little "soft" and power seems down a little, the exact opposite of what I expected, and mileage is slightly down.

In my long experience working on cars, bumping timing a small amount by 2 degrees isn't counterproductive, but rather improves power, throttle response, and mileage, albeit only a small amount. It's usually a minor tweak, rather than a major improvement, but every little bit helps. My experience has been that a series of small improvements will accomplish as much or more more safely and efficiently than attempts to make major changes which can sometimes compromise other factors.

I'm wondering if the tech or the CONSULT II actually REDUCED the timing by 2 degrees, or worse, dropped it to 2 degrees BTDC rather than increasing it by 2 degrees from 12 degrees to 14 degrees.

I'm taking it back in Wednesday to have him re-check it.

Any thoughts or comments from anyone familiar with CONSULT II and re-setting ignition timing on VK45?

I appreciate any input I can get before I take the car back to the dealer.

Thank you for any help.

[ScottJackson]

can't help you on specifics, but yes, advancing the ignition timing should have made it more "peppy" if nothing else.

[StarPD]

After driving for a few days,I determined that the throttle felt like it was attached by a rubber band. I know, it's "drive by wire", but that's what it felt like. I thought somehow the timing was retarded rather than advanced. Took it in and had the dealer check it, timing was 14 degrees, exactly as I aked them to set it. I had it returned to stock 12 degrees.

Now it drives like it used to.

Damfino why 2 degrees additional advance would cause this, but it did.

I'm wondering if something in the CONSULT II or in the ECU changd some other parameters when the timing was changed.

It would be interesting to see if one of the techs here that has access to a CONSULT II and an F50 could play with this issue and give us a report. The whole thing seems strange to me, and completely counter to my many years of experience working on and playing with high performance cars.

[Q451990]

That's interesting... I wonder if the ECU was compensating for the timing adjustment somehow? The only other idea is that maybe the timing adjustment added enough spark knock that the knock sensors/ECU were reducing your timing advance back well below the stock 12*BTDC?

Without having the ability or access to datalog a few WOT runs, I don't know that it will be easy to figure out...

Heath

[StarPD]

That's interesting... I wonder if the ECU was compensating for the timing adjustment somehow? The only other idea is that maybe the timing adjustment added enough spark knock that the knock sensors/ECU were reducing your timing advance back well below the stock 12*BTDC?

Without having the ability or access to datalog a few WOT runs, I don't know that it will be easy to figure out...

Heath

I really have no idea. This experience runs counter to my many years of working on cars. That's why I hope soneone with access to a CONSULT II and an F50 could investigate and enlighten us. Somewhere, somehow,thers' an answer. I just don't know what it is.