Engine/Transmission (1998.5 - 2002) 65hp on EZ with rv275's and slight stumble on hard acceleration

[woodtrucker]

I let my savvy mechanic buddies ride in truck after my upgrades to see if they thought I was slippng clutch. They didn't think that was the problem. They thought it was something else going on.

After EZ install, I could run level3 no problem. No hesitation
Under load in 6th gear near full boost.

After RV275 install/level3 on Ez:
Did same acceleration and it bucks twice/stumbles twice pretty much Always around 1800-1900 rpms.

No fuel leaks, no real noticeable bucking on level 2 on EZ.

Is it a fuel delivery issue w lift pump?

 

[NIsaacs]

Do you have at least 2-3 psi fuel pressure when this happens? Do you have any codes?

Nick

 

[woodtrucker]

My fuel pressures ALWAYS stays between 18psi and 14psi even when I feel it cut it. It's like a split second sometimes twice. It cuts out and comes back before I could even respond to the stumble.
No codes.

 

[woodtrucker]

Also, I run only a 89GPH pump. Its a FASS DDRP02

 

[NIsaacs]

That pump should be fine, that's what mine is, however my max psi is 15 measured at the injection pump. I would run in for a while and if it don't get better or gets worse I would call Edge, they might have an idea. My first EZ only lasted about a month when it started stumbling like yours. They sent me a new one and it was still working fine 12 years later when I sold it.

Nick

 

[woodtrucker]

Hmm. Thats interesting. I never thought that the ez could possibly be the issue. I didn't dog it on the way home and it was pretty smooth. I'm gonna keep it there for awhile and see what happens.

 

[woodtrucker]

Thanks for the feedback!

 

[woodtrucker]

I contacted Edge. They said a problem with box would present itself in every level. Not just one level. Mine is still stumbling under high load and 1600-1900 rpms hard fueling level 3. It's seems to be just enough to cause the transmission to bounce a little. I can feel it in the stick but it doesn't cut completely out. all the gauges look good. It's really weird.

 

[NIsaacs]

Did you disturb/remove the inner injector hold down bolt at all, the one with the shoulder? If you did, did you reinstall tight on the shoulder before installing the hold down clamp and remaining bolt? The special bolt insures the hold down clamp is square/flat on the injector, that way there is no possible way it can deform the injector and allow it to become sticky. Clamp bolt torque set at 89 in lbs? I assume the injectors were new not rebuilt?

Nick

 

[woodtrucker]

Injectors were new from Diesel Auto Power. I did notice that one of them didn't have a plastic cover tip on it but it looked just like the rest of them and even bagged exactly the same.
I tried my best not to disturb those inner bolts although it would have been hard to say way back on cylinder 6.
I was very careful. I did have to use pry bar to install 5 and 6 since they weren't where I could tap them in. I couldn't push any of them in by hand.
Nothing really seemed out of the ordinary when reinstalling the hold downs. crossover tubes went back in good and I actually fixed a leak I had before the injector install that was happening on the #6 line nut at the head. I torqued clamp bolts down to 89 in-lbs.

 

[NIsaacs]

Sounds like the install was well done. Is it possible that it is not a miss at all and is just the torsional vibration in the transmission/drivetrain that can occur, with low rpm and high torque? Your combo will produce huge torque now, the result is strange noises, especially in fifth gear.

Nick

 

[woodtrucker]

That's a little bit of what I was thinking Nick. I'm very in tune on noises vibe's and the like. I'm a mechanical guy in general (mechanical designer at Virginia Tech's Aerospace Department) and those kinda things bug me but I also think I have a good pulse on when I think it's something more severe of a problem. I do feel like it could be general drivetrain movement. I was wondering what axle wrap symptoms would be but from what I've read that kind of stuff occurs on boosted launches??? Not sure on that but I just know when I get into it hard, it will go. No clutch slipping and 5th and 6th gear are laying down the power and torque that is for sure. Performance wise, I've been very satisfied with the upgrade with the exception of more timing noise out of the engine. I actually can hear the timing uptick once truck reaches 150 degrees and EZ kicks in. Timing noise is definitely more pronounced. Funny thing is I didn't really have the timing noise as much with just the tuner but when I added the injectors it made the timing rattle much louder. I've been driving it for weeks and symptoms seem to be consistent and not getting better or worse. Don't feel it much when laying on it in 5th but I do feel it in 6th. ohh well. I'm not touching anything until I have a real problem like smelling fuel, low fuel psi, or stumbling to the point of loss of power. Towing the camper will be the true test! Can't wait for that!

 

[woodtrucker]

I'm going back to the idea that maybe the clutch isn't fully slipping but causing a little bucking action. I dialed it back to level 2 to be safe and don't seem to notice it as much.

 

[radyvolk]

I have the same problem with my truck. Pulling the 5th wheel uphill in any gear there is a jerking feeling. I have set the edge in setting 2 & 3 with the same results. My truck has the original VP & injectors. I'll keep an eye on this thread to see if anyone has solved this problem.

 

[NIsaacs]

I have the same problem with my truck. Pulling the 5th wheel uphill in any gear there is a jerking feeling. I have set the edge in setting 2 & 3 with the same results. My truck has the original VP & injectors. I'll keep an eye on this thread to see if anyone has solved this problem.

Do you have a fuel pressure gauge? What happens with stock or #1 setting? Does it help to have a full tank of cool fuel v/s a hot low tank?

Nick

 

[woodtrucker]

I had a discovery in my issues over the last week.
One. I ran across a post discussing an Edge EZ and bigger injectors causing rough fueling during really cold weather. I might have saved post on my computer so I'll try to post here.
Two. I made a run last nite with a diesel friend to see if he could help me troubleshoot.
It was a bit warmer and not every time I burned thru the gears did I get the problem in 6th as usual.
I am recalling that it seems most of my troubles seem to be on the coldest days.
Made several runs up to 6th last nite in the 40 degree temps and I saw no problems. Especially towards end of run when truck was hottest. Interesting find and I'll pay attention to fuel levels too.
Good thing is, we are looking at possibly 60's the next few days so I'll try again and see if the problem dissappears further.

 

[NIsaacs]

Do you have less fuel pressure when it is cold, then normal as it warms up? If so, have you changed fuel filter lately, it might need one?

Nick

 

[SnoKing]

Not sure we are talking about the same thing, however 2nd gens (mostly with power increases) are noted to get a pulsing vib under heavy pulling situations. I noticed it from time to time while towing the 5th wheel on a grade. It was thought to be the rear springs wrapping up under the power pulses of the engine. SNOKING

 

[NIsaacs]

Not sure we are talking about the same thing, however 2nd gens (mostly with power increases) are noted to get a pulsing vib under heavy pulling situations. I noticed it from time to time while towing the 5th wheel on a grade. It was thought to be the rear springs wrapping up under the power pulses of the engine. SNOKING

I don't think it is spring wrap in this instance so much as a different drive shaft angle with a load and or using different bearing locations on the u-joints. Actual spring wrap only occurs in the low gears on launch mostly. But yes, more power can sure as heck make your truck sound/act different than stock and sometimes it is not the engine at all giving the weird feel.

Nick

 

[JR]

Are you sure the engine is stumbling or could it be vibrations at that specific RPM you are feeling? Have a good look at your damper to make sure its not coming apart. The OEM damper is designed to dampen a specified frequency at a given horsepower. A substantial increase in horsepower will result in increased torsional vibration and frequency. This is further amplified with high mileage dampers or dampers that are in their early stages of failure. I know of late I can feel a very slight increase in engine vibration when I'm under a good load and under 2000 RPM. My damper passes the visual inspection but it is also 18 years old so I will be replacing it in the near future.

Just something else to keep an eye on, especially as you add horsepower.