Added 4" SS exhaust and now I have a 3,250 RPM skip

[dzl_x_4x4]

Hey everyone, just added a 4"SS from the turbo back and now under WOT I get a engine skip (like it is going to shift) then it goes to 3750 RPM to shift, not where I run my motor usally, but I was testing the exhaust. The motor feels OK all the time. The only time it does it is at WOT + 3250 RPM, 1-2 & 2-3 have the problem. I have yet to test 3-od. The motor feels strong, I don't get any flutter/surge that I can hear. Trans locks quickly, shifts quick and fairly hard, I will be buy a FTVB in the next 1-2 weeks hopefully. I re-programmed it down to the 80HP setting to see if it was SCMT problems, but it still does it. I will set it back to stock next to see.
Does anyone have any ideas or suggestions on what to look at or test?

1 odd thing was when I pulled the DTC codes the first time there were 0 codes, not even the 0603 code.

Thanks for all help.

 

[Hoss 350]

Hey everyone, just added a 4"SS from the turbo back and now under WOT I get a engine skip (like it is going to shift) then it goes to 3750 RPM to shift, not where I run my motor usally, but I was testing the exhaust. The motor feels OK all the time. The only time it does it is at WOT + 3250 RPM, 1-2 & 2-3 have the problem. I have yet to test 3-od. The motor feels strong, I don't get any flutter/surge that I can hear. Trans locks quickly, shifts quick and fairly hard, I will be buy a FTVB in the next 1-2 weeks hopefully. I re-programmed it down to the 80HP setting to see if it was SCMT problems, but it still does it. I will set it back to stock next to see.
Does anyone have any ideas or suggestions on what to look at or test?

1 odd thing was when I pulled the DTC codes the first time there were 0 codes, not even the 0603 code.

Thanks for all help.

What year/engine, etc? Assuming a 7.3, since you are describing a 4-spd auto. If so, then you may be bouncing off the rev limiter. Have you ever run it up there like that before? 3,250 sounds a little soon for your governor to be kicking in, though, but I have had mine kick in when the RPMs are going up really fast at high RPM. I think it is a preventative thing, to stop the rev before it gets enough inertia to carry it way over redline.

BTW, don't try this on a 3-od shift, you'll be going something like 90 MPH. We can assume it does it there, too, and save you from having to try it.

Also, it never hurts to check/change fuel filters...

 

[stroker2]

Sorry to interrupt, new guy here. FTVB???

 

[Glassdude]

Sorry to interrupt, new guy here. FTVB???

Factory Tech Valve Body. It's an aftermarket valvebody that improves shift performance. Link
Welcome to the site. Stand by to absorb lots of info.

Mike

 

[dzl_x_4x4]

What year/engine, etc? Assuming a 7.3, since you are describing a 4-spd auto. If so, then you may be bouncing off the rev limiter. Have you ever run it up there like that before? 3,250 sounds a little soon for your governor to be kicking in, though, but I have had mine kick in when the RPMs are going up really fast at high RPM. I think it is a preventative thing, to stop the rev before it gets enough inertia to carry it way over redline.

BTW, don't try this on a 3-od shift, you'll be going something like 90 MPH. We can assume it does it there, too, and save you from having to try it.

Also, it never hurts to check/change fuel filters...

2000 Excursion Limited
7.3
auto
SCMT 1705
AFE StageII
4" turbo back w/muffler
6" ProComp Lift
35" Xterrains
ProComp Ladder bars & front Multi shock hoops w/ MX-6
and other goodies.

I don't want to run it to 3,750 RPM. But it does what it does.

The FTVB is basically a Modified Valve body it has already been beefed up and some other mods to the valve body. I would have peace of mind for $125 more than the Sonnax Tri kit.

I would like any feedback!

Thanks

Dzl_X_4x4

 

[95_stroker]

Have you tried it at the stock programming yet? Sure sounds like the rev limiter to me and I dont see how this could have come on with the addition of an exhaust system?

 

[dzl_x_4x4]

I was going to try that this weekend. But I may wait until I get the FTVB just to spare my tranny any additional stress. I will let you guys know!

 

[Frankenstien]

I don't think there is a rev limiter wiht the 1705 plugged in.... I can hit about 36-3700 rpms.... the engine doesn't die or skip.... just runs out of go....

 

[95_stroker]

I don't think there is a rev limiter wiht the 1705 plugged in.... I can hit about 36-3700 rpms.... the engine doesn't die or skip.... just runs out of go....

Depends on what program you have selected. My 1705 limits the revs in first two modes, the extreem mode removes the rev limiter IIRC.

 

[Frankenstien]

Depends on what program you have selected. My 1705 limits the revs in first two modes, the extreem mode removes the rev limiter IIRC.

huh... I did not know that.... thanks...