Hitting Rev Limiter

**sreve** · 10-07-2007, 11:33 AM

i've got it dialed in with tunercats firm shifts under heavy throttle only, no torque management. i like it. there is one problem on the 1-2 and the
2-3 shifts. at WOT only it will bounce off the rev limiter 2 or 3 times takes a second or less then i feel it shift. it does not do it every time. it is most likely to do it on the 1-2 shift from a hole shot and then shift to 3rd just fine. it is more likely to do it on the 2-3 after downshifting to 2nd at 60-65mph. if its mechanical i have not completly broken it yet. this does not seem to be a slip issue but more like a delayed shift.
something leaking off? or it gets confused? tuning issue?

**performabuilt** · 10-07-2007, 05:12 PM

Try dropping the MPH and RPM tables for the shift a little you may not be allowing quite enough time for the shift to take place.

**sreve** · 10-08-2007, 04:15 PM

i do not belive thats the problem as all the shift points are stock. i do keep tweaking the tune though which is like a fuel trim reset. does that put the adaptive strategy back to square one? i have not changed any shift times, as i understand it is part of the adaptive strategy to compensate for worn parts.
what i have changed is torque management delete, bumped up shift pressure vs torque, pulse width mod. on the converter clutch delete, its either off or on i picked up one mpg on my city\highway tank of gas on that.
the car shifts @6000, rev limiter @6200 these are oem numbers. i could bump
the rpm limit to 6500 and let it learn after several runs as i have not really done this after tweaking the tune. but thats kind of a moot point as i want
to go to the track and dial in PE at WOT and i really do not need the tranny
throwing hissy fits trying to get the fuel right.
uh-oh i have been comparing files as i write this and yes the shift time tables
are not oem. very possibibly the root cause. OOPS!!!!
oh well i have been one finger typing too long not too post this.
i will post back if its the cure or not. thank you for the reponse any and all ideas or feed back is wecome. i'm going to go eat my crow now.

**performabuilt** · 10-08-2007, 05:30 PM

Just remember everythin affects the trans even changes that affect the way the engine runs fuel. air. torque managment etc.

**eautocad** · 10-13-2007, 10:22 AM

I have the same problem. I've tried changing the RPM redline and shift points, but still nothing. The only way it shifts is if I let off the gas, slightly.

When I bought the car, the speedo was slow 7 mph, I wonder if that isn't the reason why. It never missed the shift when it was like that! I think when you program to be off slightly, you get more shift pressure... I don't know its just a guess

As far as what to do,I dont know. I'd love help as well.

**performabuilt** · 10-13-2007, 10:49 AM

Try this though it may sound odd. Lower the line presure a little at a time not so much the shift become sloppy but just a little and see whats the effect is. Releasing the throttle just a little has the effect of doing this also.

Originally Posted by eautocad

I have the same problem. I've tried changing the RPM redline and shift points, but still nothing. The only way it shifts is if I let off the gas, slightly.

When I bought the car, the speedo was slow 7 mph, I wonder if that isn't the reason why. It never missed the shift when it was like that! I think when you program to be off slightly, you get more shift pressure... I don't know its just a guess

As far as what to do,I dont know. I'd love help as well.

**eautocad** · 10-13-2007, 11:14 AM

great tip! Thank you! I'll see if it works.

**performabuilt** · 10-13-2007, 02:19 PM

Let me know what happens. I have seen where the line presure is a little high and will cause the solenoids to flood, If they cany vent the fluid fast enough the shift valve wont move and no upshift.

**eautocad** · 10-13-2007, 05:05 PM

I think you were right. I put it at 50% and lowered the shift levels and rpm red lines back to stock. It didn't do it after that. Thank you!

**performabuilt** · 10-13-2007, 05:31 PM

Now you want as much presure to be as high as it can and still shift but not nessesarily more than stock , But glad it works now I would tweak it up a little at a time,

**eautocad** · 10-16-2007, 02:48 PM

OK well I thought it was fixed. Is it normal for this vehicle to hit redline at WOT? I thought the tranny should shift before the motor redlines. I'm not letting off the gas at all, just WOT.

I just noticed the redline for this motor is 6200, according to the post above. I guess I'm not redlining, its just skipping. Maybe its my spark plugs?

**oneBADDz** · 10-16-2007, 02:55 PM

Take your MPH down several mph, many people set it at 0 and just let it shift off of rpm.

**eautocad** · 10-16-2007, 02:58 PM

it was set at 0, then +1, and -6.. all the same

I'm leaning towards spark plug issues.. The car at times runs funny at idle, and the plug wires are MSD (Red) and they look like they haven't been messed with in a while b/c they're dirty w/o finger prints.. Do you think it could be a spark plug issue?

PS thanks for the quick reply, that was FAST

**oneBADDz** · 10-16-2007, 02:59 PM

maybe the tranny is just going out, that's what many of them do when they get hot too much

**performabuilt** · 10-16-2007, 03:51 PM

Well you could be missing I guess but one question just how close do you have the shift point comanded to the rev limter. It can take anywhere depending on the condition of the trans from 200 to as much as 600 PRM to make the shift. So for instance if your shift point is set at 5800 and your rev limter at 6200 you still might not have allowed enough time, Hydraulics are not instantaniuos like the PCM .

Originally Posted by eautocad

it was set at 0, then +1, and -6.. all the same

I'm leaning towards spark plug issues.. The car at times runs funny at idle, and the plug wires are MSD (Red) and they look like they haven't been messed with in a while b/c they're dirty w/o finger prints.. Do you think it could be a spark plug issue?

PS thanks for the quick reply, that was FAST

**oneBADDz** · 10-16-2007, 03:58 PM

Originally Posted by performabuilt

Well you could be missing I guess but one question just how close do you have the shift point comanded to the rev limter. It can take anywhere depending on the condition of the trans from 200 to as much as 600 PRM to make the shift. So for instance if your shift point is set at 5800 and your rev limter at 6200 you still might not have allowed enough time, Hydraulics are not instantaniuos like the PCM .

if it takes 600 rpm you're just putting a bandaid on a tranny that won't be in service much longer though right? If that's the case, the tranny is something that's better to have built while it's in this condition before something actually breaks, it's a $$$$ saver

**performabuilt** · 10-16-2007, 04:06 PM

Originally Posted by oneBADDz

if it takes 600 rpm you're just putting a bandaid on a tranny that won't be in service much longer though right? If that's the case, the tranny is something that's better to have built while it's in this condition before something actually breaks, it's a $$$$ saver

Yes 600 rpm for the shift for most cars would indicate the trans has alot of clutch clearance or wear. Now there are exceptions with really high powered cars and cars on NOS because the amount of time it take the trans to make a shift at WOT is a fixed number and anything you do that makes the RPM rise more quickly such as the things I listed would increase the number of RPM for the shift to occur. And Of course a stock trans takes longer to complete the shift than a built one or one with a shift kit.
As for saving money not sure if you order a built unit would make no difference and actually since a increased shift time would seem to be and indication of clutch clearance and these are normally replaced in any build not sure that would make much difference either , If its dying its dying.

**eautocad** · 10-16-2007, 04:13 PM

I wouldn't be surprised if its the tranny. It's already been rebuilt once, and the mechanic said that my 2nd gear was about to go out. I have an automatic fyi.

I bought more plugs, I'm going to have him do that tomorrow as well. I don't know if it will fix it, but it can't hurt.

I have the rev limiter set at 5500, maybe thats my issue. IDK wtf td, I guess just tell my mechanic tomorrow my story and see where he goes with it. I was looking at transmissions on EBAY, and there is one that they say is really good, its got an orange case, and a bunch of updated parts. I'm not really looking forward to replacing the whole tranny, but hopefully the mechanic can catch it early.

The program i use only lets me change shift points by MPH not rpms-- FYI dont' get a hypertech max energy.

Thanks everyone

**eautocad** · 10-16-2007, 04:37 PM

okay i switched the computers redline from 5500 to 6200, the car went smothly to 6200-- Its not the plugs. I think its something to do with the transmission.

Sorry for thread-jacking.. I didn't want to create another thread b/c its pretty much the same issue