BAD shudder when towing???
 

Coming home from the lake yesterday i started getting a shudder when i would start to pull a hill.. or put a load on the truck, so i started watching everything, seemed to start around 26psi and go all the way up, i switched tunes on the adr. and nothing changed, so i loaded up the factory tune and still had it, the smarty is on the fuel saver and the adr. on 0 with the factory tune and it still did it, fuel psi is good, egts were fine, is this something with the adrenaline? It only does it when i'm towing, today i was honkin on it and no shudder?? Oh i did notice that if i downshifted to 4th and ran the rpm's up it seemed to go away? I've towed this same stuff all summer on the same settings and never a problem unless i had the adr. on...?? Any Ideas?? Thanks

Capn

Sounds like a clutch issue to me, but you shouldn't be at the limits of that OFE yet. Stupid question, but any codes?

Not a clutch.. definately a engine shudder.. just like if i have the adr. up to hi when towing i'll get a shudder,, if this was a gasser i'd call it a miss.. and no havent checked for codes yet.. maybe tonight..

I'm having the exact same problem. I figure it's an injector (I hope) or the Injector pump going out. I'm ordering new injectors first, mine are factory and I'm going to RV275's. Seems I can buy the RV275's for about the same as it would cost to pop test the old ones. I also cleaned my ground connections a few days ago, have not towed since so I don't know if it helped. I also had a little miss at idle that cleaning the grounds seems to have eliminated.

Sure would like to hear from someone who has fixed this problem.

Ken

Try turning the timing down.

Agreed!

The fuel saving mode on the Smarty is not suppose to be used while towing. It will cause your engine/tranny to shudder due to increase of timing.

However, reading your sig and your post again. I am starting to lean towards you may have ended your clutch's life. Do you have an aftermarket clutch? Reason if you downshift to 4th it goes away is because you are putting less strain on the engine and transmission.

OP states that it does it even set to FACTORY tune. I think that eliminates a timing issue. As far as the clutch is concerned, mine does the same thing and the clutch is new (valair).

I still think it's an injector. I'l know next week when my RV275's arrive.

Ken

Same issue here when towing w/the XZT+, 3k tune. New VP and injectors are fine.

I'm going to try an APPS reset. After reading through some old threads, it seems some folks reported it being a cure for "bucking" in 5 and 6 speed trucks.

Worth a shot anyway!

Ken

do you have a link for that thread

Under "24 valve engine and drivetrain", see the sticky for "24 valve tech articles/FAQ", and click "APPS reset procedure". Don't know how to make a link.

In the list of things it's been known to cure, it lists "bucking" in 5 and 6 speed trucks. I have found a few references in old threads (as in several years old) where some claimed it had worked. Not sure I could find them again since I have searched for this problem with every keyword I can think of.

Ken

No, the OP said that the ADR is set to the factory tune. He indicates the Smarty is set to fuel saver.

The fuel saver timing is excessive for any kind of heavier than empty load.

Switch your Smarty timing to #2 for towing-- watch the problem go away!

JH

Ok sorry its been so long to get back.. workin 16hr days...grr.. so i checked for codes and have a 602.. calibration error? Any ideas with this? Also i thought the fuel saver on the smarty was no timing? it list all the levels that have timing and it doesnt show that one as having timing? and isnt that the #2 on the smarty? thought it was 1/2 power then fuel saver.. i'll look after work today.. i just towed the trailer without the boat yesterday and no problems with any kind of shudder?? i was running #2 on the smarty and the adr. at 0..so i'm still stumped here?? i'll try the apps reset tonight..its been awhile.. thanks

Capn

As for my clutch, its a southbend OFE, i've know several ppl that have dyno'd 575, as i did with out any slippage, this really felt like the adr. shudder when they first came out..in the engine..??

Actually, #1 (Fuel Saver) has more timing than any of the timing levels. The extra timing was said to help with mileage, but there are warnings not to tow with it.

#0 is the 1/2 power mode, #2 is fueling only, #3 is fueling and timing (but just a basic curve, not the CaTCHER curve.

Here is the rundown on all levels from the MADS website:

SW# 0 : Half power .
SW# 1 : Fuel Saver
SW# 2 : Only more fuel and Boost fooling
SW# 3 : Like # 2 + added timing
SW# 4 : “Soft” CaTCHER no added timing
SW# 5 : Like # 4 + added Timing
SW# 6 : Mild CaTCHER no added timing
SW# 7 : Like # 6 + added Timing
SW# 8 : CaTCHER no added timing
SW # 9 : CaTCHER with Timing

Software number Zero,
About half the power of a stock software. Use it whenever reduced power is desired or when you have to make sure that NO SMOKE is produced .

Software number One,
The Fuel Saver software. Mpg gains vary, in most cases a + 2Mpg has been reported.
Please notice that the timing in this software is rather aggressive.
HEAVY TOWING is not recommended with this software.

Software number Two,
This software increases the fuel delivered by the ECM and does the boost fooling.

Software number :Three
Same as software # 2 but timing has been added.

CaTCHER softwares from number : Four to number Nine
The even numbered softwares are identical to the odd numbered ones, except for the timing. The softwares without added timing are intended for use with timing adding boxes.