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

[Hoss 350]

Just so you know, it is almost certainly not the exhaust doing this. You said "I normally don't run it up there, but was testing the exhaust", so I am guessing it was/would have done this before if you had driven it similarly, but you probably hadn't done so, and therefore had never felt the skip.

If you are in one of the two lower modes of your SCMT (60 or 80 HP, IIRC) then I'll bet a can of peach flavored chewing tobacco pouches (it's a long story, sorry. ) that it is your rev limiter. If you are in the high setting (110 HP, IIRC) then the rev limiter has been removed, and I am at a loss as to what is causing your skip.

My advice the same as your doctor would probably give you, when the patient said "Doc, it hurts when I do this!" and the doctor says "Well, then don't do it!"

I will continue to think about it, but I am pretty sure that it is the rev limiter unless you have it in 110 HP mode...

 

[PSD PAC]

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....

Might also be running out of high pressure oil - I know that mine had trouble like this when I had a leaking HPOP, it would run up to a point where it would just fall flat on its face, and did it in each gear (probably around 3400 rpm).

Even if you don't have a leak, the programmer might be calling for more HPO than you're able to put out.

 

[smokyred]

Hey, it's Hoss.....

......I'll bet a can of peach flavored chewing tobacco pouches (it's a long story, sorry. ).....

HEHEHE, now whatever do you mean Mr. lumberjack, err, I mean Hoss??

Could it be that his trans is trying to shift but slipping or not getting enough pressure to engage? I'm no tranny expert, but my truck will run up around there and stay, and then I let off because if I don't, the trans either slams or slides into the next gear.

Dave

 

[dzl_x_4x4]

Yes I tested in 110 and 80 HP modes and it did it in both. It reminds me of when I had a CPS or injection harness issue (both replaced) IT will run fine before during and after, it just misses a beat and continues. doesn't feel like the tranny because I hear no additional reving and it doesn't bang back into the same gear or slide bak into the same gear, when it does shift it feels strong and X quick (so-so). I will test it in stock this weekend and update with anything new.
Will a HP crossover fix the pressure issue if that is what it is? Or a new HPOP? What about fuel?

Thanks!

 

[jvencius]

...I'll bet a can of peach flavored chewing tobacco pouches (it's a long story, sorry. )...

Need I remind you about Hoss 350's off-duty persuasion?

 

[powerboatr]

Need I remind you about Hoss 350's off-duty persuasion?

Stop my sides cant take it anymore
I even watched Monty Python last night

hhmmmm need a few bars of a particular song

 

[Hoss 350]

Yes I tested in 110 and 80 HP modes and it did it in both....
...Will a HP crossover fix the pressure issue if that is what it is? Or a new HPOP? What about fuel?

Thanks!

Then I am . Sorry, man...

An HP crossover will most likely not have any effect on running out of oil. A new HPOP is an expensive thing to buy if it is not the problem. You can have it diagnosed to see if it is coming up short, but I would not buy a new one without first testing your old one.

Fuel is where I would be curious. Have you changed fuel filter (I see you have, never mind)...

How aout the screens inside the fuel bowl? Sometimes, gunk collects on the goes-outta screens of the fuel bowl, so even if you change the filter, you still have clogged feeds.

Also, it may be a fuel pump issue, not keeping up with the demand. Or a clogged pickup in the tank...

Here is what I would do. Stick a fuel pressure guage on it, which you can monitor from the cab, and watch that puppy when it does it. If the pressure doesn't go down whent he trouble occurs, then fuel is not your problem. Take it in to have it diagnosed for a low HPOPressure issue. If those don't do it, then maybe it is a code of some sort defueling for some reason, or it is your SCMT doing something goofy.

Have your tried it in stock mode?

Oh, BTW, since it still does it with the rev limiter removed, it looks like I owe you a can of peach-flavored chewing tobacco pouches.... where would you like that sent?

 

[Hoss 350]

Need I remind you about Hoss 350's off-duty persuasion?

To everybody that does not know the joke, that is NOT me in those pictures. THese guys are just picking on me...

Oh, if I were to get into a little spandex body suit like that, it would be a scary thing. I am 6'4" and 295 pounds. Not exactly the type that would look great in a pair of those...

 

[PSD PAC]

Will a HP crossover fix the pressure issue if that is what it is? Or a new HPOP? What about fuel?

Thanks!

Hard to say without a little more info. I know when I had my leaking HPOP the two biggest symptoms were (a) falling flat with my foot in the floor (typically when next to a duramax), and (b) running a little louder with lower mileage - but this was subtle.

There are people who've rigged gauges on their HPO lines to get a feel for what they're doing. You don't want one of these in the cab though, in case it pops - high pressure fluids do bad things, even in small volumes. I'm pretty sure there's a P code that is set by inadequate HPO, but someone who knows for sure will probably chime in - but you'll need a scanner.

If this becomes consistent, there's only a couple of fixes I know - change your programmer (I really like my Jody Tipton program), clean/replace your IPR ($30-200), or change out your HPOP ($bank). An HX hose might be helpful, but I think the most important part is to find out what your pressures are doing before chasing an elusive fix. If pressures consistently run low on the top end of your RPMs, I think you're looking at an HPOP. I know I want one!

I'm trying to figure on why the addition of the exhaust would bring on this problem, only thing I can think of is that lower backpressure on the exhaust is showing a weakness in the engine.

In any case, I'm interested in what you come up with, so I'll definitely watch your progress.

 

[powerboatr]

psd pac
do you have leakage now at eh HPOP line orings at the cyl head connection?
thes orings are very famous for letting go, some at low pressures some at high.
mine leaked like a prison ***** @@@ at idle and very little at higher rpm
This was probaly mentioned but i didnt see it.
The HPOP resivior, have you suctioned out the bowl and checked for build up of grime etc.
most folks never drain this resivior during oil changes and it gets very ugly inside there. if you have never doen it the acces is on top through a torx nut.

and engine oil level to i hate to say it, but even great ones overlook it
just thinking outloud
and hoss
picture the Incredibles