LMM timing limiter and pilot issue

[bballer182]

What would happen if you left the pilot on and commanded the pulse width down to 1 uS which is virtually off. so you could use the pilot on timing table to get the timing desired? Would that work as a work around?

[camcojb]

What would happen if you left the pilot on and commanded the pulse width down to 1 uS which is virtually off. so you could use the pilot on timing table to get the timing desired? Would that work as a work around?

You can zero out the pilot tables and it still shows 240 US and 3.5 mm3. I tried going down to .1 and it still had 240 US and 3.5 mm3. When you zero out even the 0-30 mm3 pilot and pilot 2 tables (which shouldn't even be working at 105 mm3 and wot) then you can get the US down to 150, still at 3.5 mm3 pilot. There is no way I can find to get it down below that, other than to not allow more than 1 pulse in the fuel pressure area, but then you lose your timing.

Oh, I also tried negative pilot since 0 didn't work and I noticed it was available in the limits. That doesn't work at all, cut my timing back to 6.5 degrees total at wot.

Jody

[vortecfcar]

Jody,

I don't know how Rob has scaled your boost tables, or if you're still using the desired boost tables, but you might try rescaling your boost sensor if you think the timing limit is boost related. Of course this is only a 'solution' if Rob isn't using the desired boost tables.

Nick

[camcojb]

Jody,

I don't know how Rob has scaled your boost tables, or if you're still using the desired boost tables, but you might try rescaling your boost sensor if you think the timing limit is boost related. Of course this is only a 'solution' if Rob isn't using the desired boost tables.

Nick

thanks for your input Nick. He has the sensor max voltage set as high as EFI Live allows (5.10 volts). Is that what you meant? Looks like he still uses the desired boost tables.

Jody

[vortecfcar]

My thought was that if he were only using the vane tables to tune the turbo, he could rescale the MAP sensor so that it reports a lower manifold pressure than actual. This under reporting could potentially help avoid a boost related timing limit (which I thought you were alluding to).

On second read through, it looks like you struck out on a boost related timing retard.

Have you tried setting the timing on the pilot to coincide with the main pulse? You might also try setting the main pulse table to 0uS from 0-10mm3 when fuel pressure exceeds 150 MPa. I suggest this simply to eliminate the pulsewidth tables we have access to with regard to possible usage for the pilot PW calc.


Nick

[camcojb]

My thought was that if he were only using the vane tables to tune the turbo, he could rescale the MAP sensor so that it reports a lower manifold pressure than actual. This under reporting could potentially help avoid a boost related timing limit (which I thought you were alluding to).

On second read through, it looks like you struck out on a boost related timing retard.

Have you tried setting the timing on the pilot to coincide with the main pulse? You might also try setting the main pulse table to 0uS from 0-10mm3 when fuel pressure exceeds 150 MPa. I suggest this simply to eliminate the pulsewidth tables we have access to with regard to possible usage for the pilot PW calc.


Nick

I have not moved the pilot timing (didn't know you could), but I have zeroed out all the pilots from 160 mpa up. This does change the pilot from 240 US to 150 US, and picks up 2-3 tenths in et, but still does not shut the pilot off.

Have you ever got the pilot to go off on an LMM without changing the fuel pressure max pulses allowed table (B1021) to 1? I zeroed everything on my old combo and could only get it to 150US and 3.5 mm3. I can get the pilot to 0 with the B1021 table, but then lose my timing.

Then again, maybe the 150US is a glitch in the software and it really is off, as the truck definitely picks up; you would think going from 240US to 150US would help much if at all. This still means there's another timing limiter at the high boost ranges a twin runs, because even with it at 150 or 240US it won't go past 26.3 degrees on my truck. We also did a full flash of another OS, same results.

Jody

[OSUBeaver]

Have you ran it at the track Jody? What were your times and trap speeds? Just curious if they are congruent with mine.

[bballer182]

My thought was that if he were only using the vane tables to tune the turbo, he could rescale the MAP sensor so that it reports a lower manifold pressure than actual. This under reporting could potentially help avoid a boost related timing limit (which I thought you were alluding to).

On second read through, it looks like you struck out on a boost related timing retard.

Have you tried setting the timing on the pilot to coincide with the main pulse? You might also try setting the main pulse table to 0uS from 0-10mm3 when fuel pressure exceeds 150 MPa. I suggest this simply to eliminate the pulsewidth tables we have access to with regard to possible usage for the pilot PW calc.



Nick

That's what i was trying to say.. while the ecm can still command a certain mm3 for the pilot the actual pulse width would be zero so that the ecm thinks it's using the pilot but there is not pulse for the pilot in actuality?!?

[camcojb]

That's what i was trying to say.. while the ecm can still command a certain mm3 for the pilot the actual pulse width would be zero so that the ecm thinks it's using the pilot but there is not pulse for the pilot in actuality?!?

setting the pilot pulse to 0 doesn't zero out the pulse; it still shows a 150US pulse width. The only way to get the pilot to be zero is shut off the extra pulses in the fuel pressure section; but then it won't go over 22 degrees of timing.

[camcojb]

Have you ran it at the track Jody? What were your times and trap speeds? Just curious if they are congruent with mine.

no, but it's not going to run with my old combo yet. My old stock turbo went 12.75 at 108.4 with 70 psi in the tires and no track prep at all. That same combo datalogged 0 to 100 mph in 11 flat. It also showed 0-108 mph at 12.7, so pretty much dead on with what it did at the track.

I use a dead end road for datalogging, starting at the same spot and going the same direction every time to eliminate variables. So far the twin setup is .6 to .8 of a second slower from 0-100 mph than my old combo, so I'd bet on it not being equal to what I had.......... yet.

I did get the timing up to 28 degrees by asking for 30 and raising the max limits. But the pilot is still on at 150US (then again it was the same with the old combo datalogs). I'm running 3100-3200 pulse like the old combo. The difference is the old combo had water/meth and 8-9 degrees more timing, but a lot less boost (35-38 vs 50-55). And again, the old combo lost a piston after 15000 miles on that tune.

This is not to bag on the twins, just that I do not have it sorted out enough to equal or beat my stock single combo. Plus, there are still some minor defuels going on and on this last datalog my mm3 dropped to 85 for a while, which it has never done before. And to top it off, I heard a pfttttttt sound at 85 mph or so and aborted the run. Now if the boost hits 48 psi or so the sound comes back and stays until the boost drops. Sounds like a split boot or possibly intercooler, but a quick look didn't show anything. Won't make any noise at 45 psi though, seems like a split anything would do it under just about any boost. I hope it's not a head gasket...................... The good news, the last datalog went 11.74 0-100 mph with me pulling my foot out of the throttle for a full half second, when I thought I heard the noise. So once I figure out the noise, figure out why the mm3 dropped for a second or so, and can make a full run I should be close.

EDIT: It appears after looking at the logs closer that either my trans is slipping or the converter is not staying locked and slipping. My speedo settings are the same from a year ago with my old combination logs, but the rpms vs mph do not line up. At the top of each gear they're the same, but after the shift the rpms are 300 or so higher now than they used to be. It would drop down to just over 2500 rpms after an upshift at wot, no it's over 2800 rpms after an upshift, yet the rpms just before the shift and the mph at the shift line up still. That's too big of a difference, either the converter is not locking or the trans has an issue. So never mkind about the power, because if it's that close with the converter not locking/slipping trans then it's making big power now.

I still would like to be able to shut the pilot off and control the timing, so hopefully Ross can figure that out.

Jody