New Issue
 

Ok, this is hard to expalin but here we go. The tranny does like these new tunes. The 1-2 shift rarely feels smooth and almost seems to bind up sometimes. Sometimes under light throttle it almost feels like the engine is bogging down but the RPM's are not altered. It is very wierd. THe other day it did it on the highway so bad I thought I had a flat tire and I had to pull out of traffic. Thats how rough it was. But the RPM's were fine staying around 1800.

I flashed it back to stock and drove 2 tanks through it and no problems. I flashed the 87 perf tune back in and 2 days later it started again. THe tranny issues are always there for some reason, but the engine/tranny stutter is not cool.

No DTC's, safe mode, or any form of error signals.....

At a loss here....

A side note the other am when I was leaving the house 1st thing it backfired up front. Sounded like it came from the intake but I was half awake and could not really tell.


Need some help on this one guys...gonna flash back to my VMP tune until I can get this resolved...

Perf wise my Mods are AFE CAI, SIDO Super 40's, Livewire (VMP-Troyer/Gryphon (PHP) depending on whose tune I am running.

What do you have everything set up at?
What's the torque coverter doing? What's on the display?
What's the shift firmness setting at?

Lars

I have altered nothing from how Bill sent the tune. I will monitor the gear to check for shifting/TC issues. WHat other PID's could I utilize to better diagnose this issue?

The edge/gryphon software/settings is new to me..

Interesting, I was just reading a tech article about TC hard lockup issues and they pointed out that its not always TC/ trans issue
"A simple random misfire
could prevent the PCM from engaging
the converter clutch, and there need not
be a DTC set for this to occur. Yet openloop
scenarios, faulty ECT sensors and
VSS problems are still the familiar reasons
for a loss of TCC. A more sophisticated
TCC apply strategy provides additional
possible causes for its malfunction"

Probably not you case but you may want to PM Cody and see if he has any ideas...

I don't think he's got a diesel, southpaw.

But, it works good for a while and then goes south?

I suspect, sadly, this is another job for the Mad Doctor!

- Jack

THe tranny always does not shift good from 1-2 at any load and sometimes 3-4 under light-moderate load.

The bizarre shudder wtf deal happens every now and then.

I tried PM'ing Bill. We'll see.

Update
 

Ok, so I changed to monitor some different values. I have hte Gear Comm and TC monitoring along with the RPM's and TFT.

When I get the shudder it is usually in 2nd gear with the TQ converter locked and the TC showing a value of 5. Whatever that is??:shrug:

Okay I've used that feature before here is some of the values I remember. Level was at 0 stock.
These are upshfts.

1-2. #0
2-3. #5-7 briefly.
3-4. #0
4. #14 only with cruise on.

Lars

Any idea what those numbers mean, Lars? I've never monitored that particular readout.

SinCity - is it true we're talking about part throttle shifts here, or are you at WOT and hard acceleration? The reason I ask, is because my transmission spends so little time in 1st and 2nd gears under normal acceleration, that it's almost like they don't exist. I've NEVER seen the TC lockup in 1st or 2nd. I've seen it lock at times in 3rd, on the highway in a hill climb situation shortly before shifting back to 4th and that one tends to be a "harsh" shift.

Perhaps you'd benefit from my Custom Options settings:

1-2, 2-1 upshift/downshift: -2
2-3, 3-2 upshift/downshift: -3
3-4, 4-3 upshift/downshift: -5
1-2, 2-1 TC lock/unlock: -3
2-3, 3-2 TC lock/unlock: -5
3-4, 4-3 TC lock/unlock: -10

I may not have the TC values correct here for 1-2, 2-1 and 2-3, 3-2, but I set them at the MAX negative limits.

My reasoning was that I wanted to shift as rapidly as possible into 4th and have the TC lock up as soon as possible to save gas. I don't HAVE to beat everyone to the next light, I just want to flow with them. And, I wanted to delay the downshift/TC unlock for the same reason, in normal driving.

It all seems to work out fine for me. I get very quickly into 4th (at about 40 mph) and the over eagerness to downshift or get TC unlock at part throttle I've talked about in previous posts during mild hill climbs is largely gone. I even have these settings in place when I pull our trailer, and it somehow, feels better.

None of this effects WOT shifting though. The power's still there when I need it.

- Jack

I'm probably not going to be a huge help on this, but I will throw in my $.02.

The backfire you describe can be one of two things.

1. Lean condition. The mixture is lean enough that it's burning slowly and still "on fire" when the intake valve opens again. It's common in a carbureted vehicle to exhibit this same condition when overly rich as well since the extra fuel will pool up (become a liquid again) and cause a lean condition. Since it's hard to get THAT rich with an EFI vehicle unless the ECT sensor is open and giving a reading of -40 degrees...........


2. Exhaust valve not opening. I doubt this is the case since you don't have any other engine related problems.

Your transmission issue really sounds like a shift timing problem, but it's difficult to get the PCM to command 2 gears at once without it knowing about it.