ECU F-40 (OEM) vs F-41 (cust satisfaction unit)
ECU
As we all know, the 97 TL1000S was recalled and “customer satisfaction” ECUs were installed. These reduced surging, improved mileage, and unfortunately took a noticeable amount of power out of the engine, according to many owners I’ve talked with. But, many of them felt it was worth the tradeoff, so the surging must have been pretty bad! One would think that it was not necessary to alter WOT settings, but it seems that Suzuki did, and the bike definitely slowed down. I’ve asked and asked and asked around and have never run into anyone who can tell me specifically what was changed in the ECU, or what was done to detune the 1998 TL-S.
The original US 97 ECU has this part number: 32920-02F40
The updated US ECU has this part number: 32920-02F41
Jan 14 2007: AHA! I bought an original 97 ECU.
March 28 2007: Immediately it is obvious it has different fuel mapping than the updated unit. But, my intake is so enlarged, that both are running very lean and I can’t really evaluate it.
I rode it more today going back and forth btwn ECU boxes, but could not run it hard coz its wet.
The F-40 box was soft down low and hesitated when I opened the throttle, also, sometimes after a “blip” the revs would fall really low, then recover. It often seemed about to stall at those moments. Pulling out from a stop, it was very flat with the throttle just cracked open, and again, I nearly stalled it on several occasions simply pulling out from a stop. Initially I thought it was rich, from the throttle blipping thing, but being unable to pull out from a stop, it acted like a bike with a too-small pilot jet.
Cruising along at 3000 rpm it surged, but no worse than my recall box. I realized that if they had different fuel maps, and my PC2 was optimized for the F41 box, this was going to skew the tests.
Finally I took off the PC2 and just ran the OEM boxes, with no powercommander.
Well!
All the intake de-restriction has made it pretty lean at part throttle. With the F41 (recall) box, it was real soft at part throttle, instead of real sharp like it usually is. Snapping the gas made it hesitate and sag a bit before going, unlike with the PC2 attached.
Then I switched to the F40 (original) box
It was so lean at part throttle, that even driving along at 3500 rpm it was hiccuping and backfiring out the intakes. Which was odd, coz now I can feel those backfires thru the gas tank!
Anyhow, DEFINITELY I think the F-40 box is LEANER at part throttle. With the PC2 and enriched setting, the F40 was driveable but still “not right”. Without the PC2, it was so lean I could barely pull out from a stop... or cruise along without banging and backfiring.
So, I dunno what else is different, but the boxes surely have different fuel maps down low.
Given that it *may* be as simple as tweaking a fuel map to fix the driveability issues, I am optimistic that I may be able to use the F-40 box and tune up the low end fuelling with my PC3. If I can get it to drive around OK, without the backfiring and bullshit, then I’ll keep it on and go get it fully mapped for my setup. If I just can’t get it driveable, I will regrettably have to stick with the “recall” updated unit. The F40 really was chore to ride around with- but, remember, my intake is far from stock, so the fuel maps in the stock ECU are way off, now. I still do not know if the F-40 has a more aggressive timing map, but I am hopeful, so, I will try it. I can’t imagine that Suzuki simply “leaned the bike out” or something, to take 4-6 HP off of it. I think there are other changes inside the ECU that accounted for the lost HP. We’ll see!
NOTE!! Bernhard from Germany sent me this link to his page- lots of ECU info there, you will need to use Babelfish or other service to translate
here is a translation of his page, I got help from a buddy in Germany
OK, it dried out finally and I got a chance to ride around with the F40 box. I installed my PC3 and used the map that came in it, the M301-302.djm map (it says “Yosh full exhaust, stock or aftermarket air filter)
And lo and behold, I can drive around like a normal person. Can it be this simple??
Although right at 2500 rpm, it’s still lean- it will occasionally bark or hiccup when cruising along at 2500. So, I looked at the map table
And, what do you know, it’s enriched over stock everywhere except at 2500 rpm, where it’s leaner than stock. I’ll fool with that this weekend, I still need to synch it and set the TPS. Oh my GOD, after years of procrastinating, it’s time to finally do that.
See the PowerCommender3 section for info on that the PC3, as well as some notes on sorting out the PC3/ F40 ECU to make it more drivable.