2004 LeMans TPS adjust vaulue?

[Guest ratchethack]

Dave, on a day like today, you should be out riding! Me, I'm trying to get some mandatory reading done so's i can get out in the mountains, dammit...

 

Well, I think we're splitting hairs a bit on how to index. I tend to go with what the experienced Pro's recommend as long as it doesn't seem too far out of line with what makes sense to me. If what the Pro's recommend is also easier and more convenient, it approaches "no brainer" territory in my book. I agree that the closed-throttle 150 mV technically should be the "gold standard", as there are less variable factors in the mix this way, and I'd certainly get a "zero degree" reading before doing a custom map as a reference point. But in my case, since I seem to lack any justification for an alternative map to the one I've already got, and Todd's method evidently works as well for me as for those who follow his recommendations (I reckon there's quite a few by now), I'm a happy camper.

 

As far as sticking with what the factory intended, this flies out the window as soon as you install a PC III, never to return, and it gets further and further away over the horizon as you stack up other modifications. Most of us (myself included) are running quite a list. Matter of fact, I reckon if I stuck with what the factory intended, I'd be a pretty sad pup.

 

Thankfully many can disagree on this point and evidently still get good results.

[dlaing]

Nobody is splitting hairs.

I think we are all agreeing

and yes I should be out riding and seeing if I can get 40MPG!!!

But I am at the keyboard ignoring house chores...and breakfast

[Guest ratchethack]

Nobody is splitting hairs.

OK, you threw down the gauntlet. Now I'm gonna pick it up.

 

So now I hafta do a "reverse" measurement and see what my closed-throttle setting is. What do you bet it's within +30 mV of 150 (~180)? I'll call this splittin' hairs. If it's over ~50 mV away from 150 mV, it's not splittin' hairs. Fair enough?

 

EDIT: Zoot, alors! I've been confounded! You win. It seems there's nary a hair to be split! I read 303 mV.

 

This won't change my method, however. I'm sticking with the twin philosophies that a little rich = a safety cushion, and as long as she runs 100%, gets decent mileage (~40 mpg last I checked) the plugs read OK (grey-tan and mildly sooty on the flame shadow side), it's mostly free from ping with 91 RON gas, and she pulls like a tractor on steroids cleanly throughout the rev range - what else is there? I reckon she's in "perfect" tune.

 

Interesting exercise, though. I'll run it by Todd next time I see him.

 

Thanks for the challenge, I learn something new nearly every day around here.

[dlaing]

This won't change my method, however.

67023[/snapback]

I agree, your method is fine for what you are doing.

I am sure Todd also zero'd your PCIII map, so you should be fine.

But the map he loaded will interlay best with your bike if you are tuned exactly as was the bike that that map was created on.

Perhaps that is splitting hairs relatively.

Luhbo and I are on a different track with TuneEdit.

I had Todd measure my TPS at idle once, with wire piercing probes, and we got a reading of 260mV at idle...months later I got around to soldering in some test wires and my reading now is 165mV disconnected and something around 500(I forget) at idle.

I don't know if we mis-probed or it shifted, but some of it was because my bypass screws were too far out (from trying to get a smooth TB balance from idle on up)

I suspect if your reading today was correct, something is a little off, like your valves are too loose, or your bypass screws are too open.

But knowing you, that is probably not the case, in which case I have no answer...maybe you did not back out the right side set screw all the way

[Guest ratchethack]

I suspect if your reading today was correct, something is a little off, like your valves are too loose, or your bypass screws are too open.

But knowing you, that is probably not the case, in which case I have no answer...maybe you did not back out the right side set screw all the way

Naaaaah, I'm running my valves at .006 and .008. Air bypass screws were set properly balancing the TBs, something like 1 turn out and 3/4 turn out. I took out the RHS idle stop screw and disconnected the idle advance to get my reading.

 

Yep, Todd zeroed my map. Can't imagine he'd ever omit this.

 

In terms of setting the TPS, there's definitely a signficant difference between stock and PC III. I'm starting to suspect that the PC III requires 150 mV more voltage across the entire range of the TPS. I put an inquiry in to Todd, will advise.

[luhbo]

....

In  terms of setting the TPS, there's definitely a signficant difference between stock and PC III.  I'm starting to suspect that the PC III requires 150 mV more voltage across the entire range of the TPS.  I put an inquiry in to Todd, will advise.

67033[/snapback]

 

If your PC was a valid and independent working ecu, then you could probably do what you like. I can do so with my My15M of course. When I tell this unit "Zero means 300mV" then it works with 300 mV as basis. No problem. But I should very carefully engrave this value somewhere I will always be remembered to. If I forget it and then by whatever reasons adjust the TPS back to 150mV or 450 the whole map will be useless.

 

The PC works different as you know. Beeing a piggyback solution it can work only as good as the ecu below it.

 

Tweeking the TPS basic setting to be on the rich and safe side and then "rucksack" the PC to enrich even more to be on the even more secure side, well, I cannot see any positive logic behind this. Maybe there are other reasons. Who knows.

 

BTW, we have winter here, so I'm not missing a good day for riding while I'm sitting here typing...

 

Hubert

[dlaing]

Air bypass screws were set properly balancing the TBs, something like 1 turn out and 3/4 turn out.

67033[/snapback]

I think some consider proper to be 1/2 turn out.

I am guessing next tune-up you might try 1/2 turn out, up the idle a little, but stay below 1200rpm, balance with bypas screws as last resort and average them out to 1/2 turn, set the TPS to 500mV, and re-zero the PCIII....That should make the de-linked TPS reading get closer to 150mV, and I would guess your map might overlay better.(Yah, I am splitting hairs on how much better)

But talk with Todd first

When you zero your map, also make sure that WOT reads 100%.

[Alex-Corsa]

If your PC was a valid and independent working ecu, then you could probably do what you like. I can do so with my My15M of course. When I tell this unit "Zero means 300mV" then it works with 300 mV as basis. No problem. But I should very carefully engrave this value somewhere I will always be remembered to. If I forget it and then by whatever reasons adjust the TPS back to 150mV or 450 the whole map will be useless.

 

The PC works different as you know. Beeing a piggyback solution it can work only as good as the ecu below it.

 

Tweeking the TPS basic setting to be on the rich and safe side and then "rucksack" the PC to enrich even more to be on the even more secure side, well, I cannot see any positive logic behind this. Maybe there are other reasons. Who knows.

 

BTW, we have winter here, so I'm not missing a good day for riding while I'm sitting here typing...

 

Hubert

 

Wow , well I was thinking on a PCIII for my Sporti , but what ist it finnally this unit ? Since it bypasses the ECU (correct?) and has maps isn't it as an ECU unit?

anyway , I'll try following up the topic, though I am confused, Is it really so demanding to get this PC set up or adjusted-callibrated to the machine.

Gruss

[dlaing]

Tweeking the TPS basic setting to be on the rich and safe side and then "rucksack" the PC to enrich even more to be on the even more secure side, well, I cannot see any positive logic behind this. Maybe there are other reasons. Who knows.

67037[/snapback]

Yah, that would be a bad idea, and I suspect the very few negative experiences with PCIII may be caused by just that.

I wish every downloadable map gave the exact state of tune at the time of the mapping.

But as Ratchet says, 30mV difference is not much.

considering that the TPS goes from about 500mV to 5000mV from 0 to 100% throttle, 30mV is somewhere between 1% and 10% of a mapping grid,(~3% if the grids are in 10% increments) hardly worth worrying about.

Worst case scenario on the PCIII might be the grid jump from 0% to 2% throttle where 30mV would represent 15% of the grid....still not that bad as the mixture change there might not be so critical. The jump from 80%to 100% throttle would be pretty negligible.

But on a PCIII USB their are more grids, again, not a problem if you don't have a big jump between grids.

But if we look at the Tune Edit map, which I believe is the actual ECU map, the TPS grids break into what you see here:

which is very different and you can see that IF there was a significant map change from say 1.0 to 1.99, the mV reading becomes more critical....but only if there is significant changes between grids.

The biggest jump I found (at casual glance) in the OEM ECU was at 4500 rpm it jumped from 116 at 27.99 throttle to 156 at 36.73. This is about a 34% change. So if your TPS is off by 30mV, a little over 3% of your grid would be getting 34% too much or too little fuel injector open time. Not necessarilly a problem but not ideal.

If your TPS is off by 100mV, it may be a problem as all of a sudden about 10% of your grid is grossly wrong. I suspect this would be pretty noticeable.

FWIW I am dubious of the need to stay with grid jumps like that, especially since I have Mistrals and an open box. So, I plan on smoothing out my map so it works more like a phreaking carburetor!

[txrider]

As a followup on this neophyte's first encounter with MG FI tuneup here's what I did and the results that ensued-

 

1. Used t-pins in the tps connector to get tps readings.

2. Got baseline readings (415mv).

3. Backed off throttle stop screws both sides and adjusted tps to 150 mv.

4. Adjusted r/h side throttle stop screw tp 465 mv.

5. Closed air bypass screws.

6. Cranked engine, and using a Carb-Stix adjusted l/h throttle stop screw to be even with r/h stop screw.

7. Backed out airbypass screws 1/4 turn at a time until 1000 rpm and equal columns of mercury.

8. Adjusted cross link bar so engaging bar with r/h tb produced no change in r/h throttle stop 465 mv reading.

9. Cranked engine, checked idle on both cylinders with carb stix- almost dead even. Checked at 3000 rpm dead even.

 

Road test showed smoother running and a "happy" engine. And the thing pulls so nice and smooth at 5000 and above I find I am reluctant to ease off the throttle.

Thanks again to Mike and Todd Haven at MPH, Mr. Bean and luhbo. You guys were all a great help.

 

Now, about those forks...

[Guest ratchethack]

Road test showed smoother running and a "happy" engine.  And the thing pulls so nice and smooth at 5000 and above I find I am reluctant to ease off the throttle.

John, your procedure makes logical sense to me, yet it's a different way to do it than any procedure I've seen. Congratulations on your tune-up. There's nothin' quite like gettin' it spot-on with your own two hands.

Now, about those forks...

Hey! There's still an altogether different Pandora's box to open that's just as full of befuddling rocket science, and it also at times appears to be chockerblock full o' mysticism and black art. The good news is, it doesn't yet have ECU control....but I'm sure these days are numbered...

 

I reckon the reason we're into this stuff is that it's just complex enough and stimulating enough to distract our attention from our real responsibilities in life...

[dlaing]

I just re-found this tidbit from Jeff B. on GuzziTechDotCom

the 1.5M ECU is an 8-bit digital system, it takes that 0-5 volt signal from your TPS and chops it up into 256 evenly spaced steps. Each step is about 19.5mv.  So, at each 19.5mv step, the ECU grabs a value off of the fuel table.

I am not sure if that gives a clue on the importance of setting it accurately, but to my mind it implies that in the stock ECU a jump from 1.00%throttle to 1.99 % throttle to go from the first map cell is going to require an increase of voltage of 49.725mV

(assuming 1% change is 2.55 19.5mV increments, 2.55 x 19.5 = 49.725)

And going from 60.73 to 84.56 is a change of 23.83 which if you multiply it 23.83 x 2.55 x 19.5 = 1184.947 which would be much less critical if your TPS is a little off.

But actually I would not be exacty correct as according to Jeff's article the TPS has two different slopes.

I do find it odd that the first ten map position are all under 17%throttle, according to TuneEdit.

But the variations there are also pretty subtle.

[dlaing]

I reckon the reason we're into this stuff is that it's just complex enough and stimulating enough to distract our attention from our real responsibilities in life...

67050[/snapback]

Did you get that mandatory reading taken care of?

I put two hours into the pool of endless chores... but now it is Breaktime

[Guest ratchethack]

Did you get that mandatory reading taken care of?

Nope. Gotta do that now. But I did sneak a nice little ride in while it was nice out....

[luhbo]

...

But as Ratchet says, 30mV difference is not much.

...

 

That's not much, maybe. I'm arguing against sentences like "don't bother about basic TPS setting". That's unprofessional. It's not only that, one could also think that some of the dealers either don't have understood how EFI works (don't hope so) or at least could have something to hide.

 

...Hey! There's still an altogether different Pandora's box to open that's just as full of befuddling rocket science, and it also at times appears to be chockerblock full o' mysticism and black art. ...

 

Here you'll run into exactly the same trap. You may weigh 70 kg, an expert sends you tips how he has adjusted a V11 for a 100 kg rider.

Before you start fiddling with your fork, I'd recommend lots of pasta forks to achieve the index-weight first

Another possibility would be that you sit on the tank instead on the seat. This way you could get the same weight on the front wheel.

 

Hubert