Getting stuck in a gear???

[FMOS]

This could be a tuning issue, but I have reflashed the ECM twice now and now change. Also cleared the taps once and no change. Also, I have ran two tunes that never did this before, but now both of them do it.

Basically, in 2nd to 4th gear, at more than 75% throttle the truck will rev up to about 3000-3100 and then all of a sudden cut out and drop about 200-300 rpm and then bang back up to 3100 again. It does it quite fast like its hitting the rev limiter.

It won't shift if I hold into the throttle. If I let off then it will shift.

Any ideas? Is it possible that the valve body is buggered, maybe something sticking?

I'm going to try and reflash my tune in tomorrow and clear the taps again. I might even try reflashing the TCM tune, even though its stock.

By the way, its a suncoast 3 kit with precision converter.

 

[sweetdiesel]

Any codes?

 

[draftee]

Fuel filter????

 

[Dozerboy]

Doesn't sound like at filter. Try both T/H on and off, maybe try the stock tune too.

 

[maxxflip]

Fuel filter????

x2

 

[FMOS]

Maybe the fuel filter. I had thought about that already but it didn't seem too likely. It was changed last oil change... or the oil change before that. So either 3000 or 7000km ago. I am almost positive that I changed it the weekend of the Blackout drags, so August 15th, about 3000km ago.

Yes it does the same in both tow haul mode and normal.

I'm not sure if my truck even remembers how to run on the stock tune... or if it even will. It will require some modifications to it anyhow to account for the missing egr and aftermarket turbo.

Any other ideas on what I could do? I will change oil, filter and fuel filter this coming weekend. I will retune the ECM and reset the TAPS.

 

[Turbo Buick 6]

I don't know if a fuel filter could cause that, but mileage means nothing. I've had a filter plug up in under 500 miles because of crap in the fuel, and I've also gone over 15,000 miles on one without problems.

 

[yellowracer2]

same thing was haping to me try making sure the big harrness on the back of the tranny is in securley if not it will cause it to limp in to a given gear mine seemed to be third good luck man

 

[jerseymike68]

Nice information

 

[x MadMAX DIESEL]

ive got kinda the same problem, mine if its either t/h or o/d when i give it trottle and let off the trottle totally the converter stays locked for a moment but seems to be forever then finally unlocks... its done this forever and always bugged me

 

[Jetmech]

To me sounds like it could be a valve body issue. just my 2 cents from talking to some tranny guys. did you bore out the "E" valve (I beleive that is the name of it).

 

[othrgrl]

This could be a tuning issue, but I have reflashed the ECM twice now and now change. Also cleared the taps once and no change. Also, I have ran two tunes that never did this before, but now both of them do it.

Basically, in 2nd to 4th gear, at more than 75% throttle the truck will rev up to about 3000-3100 and then all of a sudden cut out and drop about 200-300 rpm and then bang back up to 3100 again. It does it quite fast like its hitting the rev limiter.

It won't shift if I hold into the throttle. If I let off then it will shift.

Any ideas? Is it possible that the valve body is buggered, maybe something sticking?

I'm going to try and reflash my tune in tomorrow and clear the taps again. I might even try reflashing the TCM tune, even though its stock.

By the way, its a suncoast 3 kit with precision converter.

Could be a few things but I would lean towards C3s are going. With the power you are pushing you need more than a standard SC Stage 3. I would try changing the spin on filter first though.

ive got kinda the same problem, mine if its either t/h or o/d when i give it trottle and let off the trottle totally the converter stays locked for a moment but seems to be forever then finally unlocks... its done this forever and always bugged me

Yours sound more like a TCC issue either in the tuning or mechanical - but if it was mechanical it would likely throw a code when it did it.

 

[FMOS]

Well today I was going down a hill and when I came out of the bottom of the hill its like a fuel limp was going on, couldn't pull over about 2000rpm, more like 1800 was tops. So I just coasted for a bit and then it was back to normal.

So it seems to me that maybe my fuel filter is buggered. I'll put a new one on tomorrow and reset the taps and see if its better.

I wouldn't doubt it if the trans needs a refresh, its been 100,000 hard km since it was built. It was done by Mike L, I'm not sure if he did anything special besides the standard SC3. Its been a stellar unit up till now, so no complaints. Hopefully this fuel filter fixes it.

 

[Mike L.]

Well today I was going down a hill and when I came out of the bottom of the hill its like a fuel limp was going on, couldn't pull over about 2000rpm, more like 1800 was tops. So I just coasted for a bit and then it was back to normal.

So it seems to me that maybe my fuel filter is buggered. I'll put a new one on tomorrow and reset the taps and see if its better.

I wouldn't doubt it if the trans needs a refresh, its been 100,000 hard km since it was built. It was done by Mike L, I'm not sure if he did anything special besides the standard SC3. Its been a stellar unit up till now, so no complaints. Hopefully this fuel filter fixes it.

I have never done a build out of a box. Always do special things on any trans I build.
Pull your tune out and see what happens. Try another brand of tune to see ig things change.

 

[FMOS]

Ok, thanks Mike.

I will do this fuel filter as well, that limp mode was weird. I'll check for codes tomorrow, but I may have all that fuel limp mode stuff turned off... and my FPRV is shimmed so much it probably can't open, so I'm not sure whats up but i got a few things to try.

 

[othrgrl]

I had that limp mode feeling on a customer's truck when I was breaking in his trans. Turns out he should have told me that his fuel gauge, among others, doesn't work and that his truck was about out of fuel when he brought it to us. Change the filter and see if you have any moer problems - especially on a full tank.

 

[FMOS]

I changed the filter and reflashed the ECM and all is well.

Only thing is its starting to get stupid again... I wonder if I got a really bad batch of fuel and its still working its way through the system?

I'm going to change oil this week, clean the air filter and pick up a couple fuel filters to have on hand. just incase it gets worse.

Thanks for your helps guys.