I read the thread on IAT relating to MPG performance during winter weather. I have possibly a similar issue and was wondering if anyone else has experience or if anyone might know what is causing it. Just a piece of mind thing more than anything. 

Set Up:

02 cummins, 6speed,  102k miles, with Edge EZ and RV275's

 

Symptoms: 

I have confirmed that during cold weather usually below 50-55 degrees I have a noticeable hesitation around 1400-1600 rpms when I get down on it. My version of a romp does not involve spinning up a $1000 set of michelins so just know that I don't hammer on my stock clutch like that. It usually happens in 5 and 6 gear. Especially in 6th if I'm low on the rpm band when I give the beans. It's usually even more noticeable if I do that at the bottom of a fairly steep hill and about mid ways up the pull as I increase throttle heavier, I can feel it cut out a couple times. Feels like two or three quick bumps. I have not noticed this at all since we've had warmer weather. 

 

Causes:

Could this be a air/fuel ratio issue? I am going to pull my IAT and see how nasty it is as a first cause. Anything else that I could check to help figure out the cause would be very helpful! 

 

I would love to learn how that stuff works. I would take a class if such class existed. I'm always very interested in stuff like that. 

One question yall can answer I'm sure. If you say timing advance, is that the angle before TDC that the injection of fuel happens? So I don't know where it would happen on a stock engine. say 30 degrees. Then a timing advance would be moving the injection event to 25 degrees from TDC (ie-closer to TDC)? I assume the duration is the same and the fuel rate is not at play here when talking timing advance. 

All these gauges and feedback on that scan tool has got me thinking! haha. 

The one thing other thing I can't get my head around is if the truck is leaning due to timing advance, wouldn't the fuel pressure drop way down if it was leaned out to the point of an engine miss or stumble? That makes the overfueling issue in lugging range more plausible. Regardless, I'm gonna pay attention and try to shift to start 5th and 6th only when the RPM's are 1700-1800 pulling grades and see if the conditions improve when cold outside. 

our trucks typically idle at between 11* and 13* then at WOT high revs the ecm will ask for ~25-26* of timing.  if the engine is rotating faster you need to inject fuel sooner to give it enough time before TDC to get full combustion.

 

Fuel pressure to the injection pump won't change in a perfect world.   the injection pressure is purely related to the vp44 vane pump. 

Edited January 13, 20178 yr by Me78569

Also there is no such thing as rich / lean conditions. VP44 is capable of shutting down fuel completely during deceleration or coasting. There is fine line with timing that will make or break MPG numbers. Like right now I'm working on my tune because I'm advancing too much and killing my MPG number.

Does the EZ mess with fuel since it does not tap the pump?

23 minutes ago, dripley said:

Does the EZ mess with fuel since it does not tap the pump?

 

Yes. Edge EZ can modify fuel and timing both on the CANBus level only. This is the limit of the 60-65 HP of the CANBus. To fuel more you need to tap the pump wire. 

Another thing I notice on the symptoms is that level 1 (lowest ez setting) it's barely noticeable but you can tell it stumbles in relatively the same spots rpm wise. Accordingly, each level (1-3) which alters fuel and timing more and more, progressively worsens stumble effect. So it makes me wonder if the timing is set up the same on every setting and as fuel changes the symptom worsens. I probably just need to live with it and stop obsessing. Lol. Again, it's just interesting to me and I like figuring out why things like this happen. I'm just too uneducated on engine theory to figure it out! 

 

we are in the 50's for the next week at least so looks like I won't get to do anything but enjoy the heck outta driving it around awhile. 

Like I'm learning quite a bit about timing and it effects to performance and MPG's. My last update to the Quadzilla they changed the timing software around and the way its handled. I ended up being more advanced in timing. When you crank up the timing more the torque curve moves up in RPM's. So if your advancing to far the low end tends to suffer for launching. Like i'm working on tweaking the Quadzilla now to give so retarding back at low RPM's which now I did tonight and improve the launching and low RPM range. 

 

If I weren't neck deep in a paint job, I'd jump on one of those quadzilla's. Will be spending the next $1000 on paint. Thank God I got a great body man at my work that's helping me. I do the grunt work and he does all instruction, stud gun work, and the spraying. Hood and top now in primer! 

 

Edited January 14, 20178 yr by woodtrucker

On 5/12/2016 at 8:43 AM, woodtrucker said:

I read the thread on IAT relating to MPG performance during winter weather. I have possibly a similar issue and was wondering if anyone else has experience or if anyone might know what is causing it. Just a piece of mind thing more than anything. 

Set Up:

02 cummins, 6speed,  102k miles, with Edge EZ and RV275's

 

Symptoms: 

I have confirmed that during cold weather usually below 50-55 degrees I have a noticeable hesitation around 1400-1600 rpms when I get down on it. My version of a romp does not involve spinning up a $1000 set of michelins so just know that I don't hammer on my stock clutch like that. It usually happens in 5 and 6 gear. Especially in 6th if I'm low on the rpm band when I give the beans. It's usually even more noticeable if I do that at the bottom of a fairly steep hill and about mid ways up the pull as I increase throttle heavier, I can feel it cut out a couple times. Feels like two or three quick bumps. I have not noticed this at all since we've had warmer weather. 

 

Causes:

Could this be a air/fuel ratio issue? I am going to pull my IAT and see how nasty it is as a first cause. Anything else that I could check to help figure out the cause would be very helpful! 

 

This problem happens to me too. Started 4 months after i install rv275 injectors. Only happen like 4 times but its always cold and im always on the gas going up a hill.

99 ctd,nv4500, banks power pack tlc, rv 275, bhaf , new south bend clutch , mopar man high idle switch, fuel pressure gauge, etg gauge, boost gauge, oil temp gauge. Fass fuel ti 95.

Edited February 3, 20178 yr by tbo1450

reporting back after a winter grill and bhaf install and I'm happy to say that 30 outside degree temps do not seem to affect performance anymore. I'm sure I will drop down below a threshold at some point where the truck will run rough again but it's much farther down the ambient temperature curve making a significant improvement with wintertime driving! Thanks for all the feedback! 40-50 degree temps are a real sweet spot for optimum throttle response on my ride. now back to the new paint job...

28 minutes ago, woodtrucker said:

40-50 degree temps are a real sweet spot for optimum throttle response on my ride.

 

I'm going to bet you broke above 80*F on the IAT when that happens. 

Yep. I think it was running around high 80's 90 ish. 

It seems like I'm good now down to about 25 degrees then it will start to bronc and buck! lol.

Also, someone mentioned not lugging and I've upped my shift points a little so that my rpms stay about 1500-1600 on the shift and that seems to help too since the turbo is spooled a little higher at beginning of acceleration. The bhaf helps to b/c it seems like the turbo spins a little more freely. could be in my head but seems to. 

 

Edited February 7, 20178 yr by woodtrucker

I recently made & installed a IAT fooler. Set it to 122 *f

Made 1 trip, 23.3 mpg highway steady driving.

Jag, Very interested in this long term. This had crossed my mind. Did you attach a temperature controller or something? I'm sure this would solve the problem of cold weather operation. Just bump it up in winter and back in summer. Awesome! 

Again this follows my IAT optimal range. 100-140*F is the optimal temperature for the 24V engine.