How to keep converter locked at 0% throttle

[thunder550]

Every time I let off the gas when I'm driving the converter clutch releases. The problem that I'm having is that when DFCO activates, the engine slows down enough to hit the DFCO RPM disable point because the converter unlocks. This disables DFCO at anything under about 40mph or so, which makes it essentially useless around town unless I'm getting off the freeway. I'd like to keep the converter locked at 0% throttle in 4th gear any time I'm over something like 20-25mph or something close to that. Any way to do this?

[Lextech]

Have you tried to reduce D1006?

Jeff

[thunder550]

I'll try it, but offhand I don't think it will change anything. My 4th gear release speed it set to 42 mph at 0% throttle, but the TCC releases at 0% throttle even if I'm running at 80-90 mph :(

[joecar]

I think it's either in an unpublished/undiscovered table or in the OS.

[thunder550]

So I guess it's common then? I didn't remember my truck doing this from the factory but I never really paid close attention either.

[joecar]

Yes, it is common...

F-body, Y-body follow D1005/D1006, while others (mostly trucks) just unlock at zero throttle regardless of D1005/D1006.

[dc_justin]

Yes, it is common...

F-body, Y-body follow D1005/D1006, while others (mostly trucks) just unlock at zero throttle regardless of D1005/D1006.

It's mostly the 4L80e tunes that do this inconsolable unlocking. Quite annoying.

[thunder550]

Well I'm running a 4L80E so that's probably what it is.

[ScarabEpic22]

Do truck 4L60Es do this 0% unlock regardless of D1005/D1006? I cant test this for another 3 weeks, then Ill do a bunch of testing all summer.

[cmitchell17]

My 95 truck did this also.

Because the TC unlocks, is this the reason DFCO disables so early?

[thunder550]

My 95 truck did this also.

Because the TC unlocks, is this the reason DFCO disables so early?

That's what happens to me....converter unlocks, DFCO enables and pulls engine RPM down to below the DFCO disable RPM.

[cmitchell17]

Yeah now that you said that thats exactly what happens when the TC unlocks the engine can idle down when it does that it hits the disable rpm.

Looks like theres almost no way around that unless you just made the TC unlock right before the 4-3 shift which I guess is right around 30mph?

[Ira]

If I was guessing, I'd assume GM added that feature because it improves gas mileage. The lower the reverse load on the vehicle, the further it coasts and the less gas you use.

It's possible it seems so clearly correct to them that that rule is not in a table anywhere.

Ira

[cmitchell17]

Wait I thought the point was to cut the fuel off to save fuel and it helps braking to?