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! 

 

First off don't bother pulling the IAT sensor. Just hook up a live data tool and watch the data. Nothing is ever gained from the old myth of cleaning the IAT sensor. I quit doing that years ago and just watch the sensor data.

 

Colder the IAT the more advanced the timing will be come. Optimal IAT is when it lands in the green zone.

 

 

Any codes? Mine didn't have any codes and I experienced similar problem like you but on higher rpm, closet to 1800. Been chasing this problem for few years now, at first things pointed to injectors, helped but didn't cure it, then ac noise from alternator rebuild it and much better, then it did it again this time I had a code for low voltage to map sensor, I think I traced it down to oil pressure sender, it shears same 5 volts with map. Haven't driven it much but code didn't come back ether. This whole time could of been a 15 dollar oil sender. Maybe not, but it is a learning thing for sure.

Is this something new? The reason I ask is if I shower down on mine in 5th or 6th at 1400 rpm, it is not going anywhere quick until the turbo spools near 17 or 1800 rpm. Then it's off to the races. It is not as noticeable in the lower gears since they spin up much easier but it has always been present in mine. Possibly just turbo lag.

Edited May 14, 20168 yr by dripley

I guess I should have read that a little better. This only happens in cold weather and not hot weather?

Is there anything else done to the truck?  What exhaust and intake?  Any other history which may help?

Sorry for such a late response to this thread. I just realized that you guys responded. 

Just for the record. Cold weather is back and what I call my "timing advance stutter" has returned. 

I pulled camper all over va, nc, and sc over the summer and not a bit of hesitation anywhere. 

Pulled the camper home in the high 30's last weekend and it hiccup'd a few times when pulling grades. 

It will not happen if temp is about about  45-50 degrees. I guess I'm advancing the timing just enough in cold weather for it to run rough. Never had the problem until I put RV275's in with the EZ on. It's still noticeable with level 2 and maybe even level 1 but I have have not run truck in the winter without EV to see if it goes away. 

Below are my specs on my truck.

 

2002 CTD,4x4,QCSB,4" DP -5"exhaust, NV-5600 6 speed,
3.55 gears, Anti-Spin Rear Diff, Fass DDRP 02,
VP44, isspro gauges, Edge EZ, RV275's, 
tires size: 265 Michelin MS/2's, 
16100 lbs gross-28ft 5th wheel

 

I wonder the high idle/MPG fooler would take care of this cold weather problem?

Edited November 11, 20168 yr by woodtrucker

Time to break out a live data tool and see what your IAT and ECT temperatures are actually doing when this occurs. Most likely the foooler won't resolve it but I'm curious if there a data problem being fed to the ECM creating this issue. 

 

Just with winter fronts and running 65 in 40-50*F weather...

When cold the ecm does command a TON of timing.  

 

A cold truck will idle at 23*

while warmup above 20* is not uncommond even at low revs.

 

 

The ez will just make that worse as it adds timing on top of ecm timing.  

 

In tuning the quadzilla I actually ended up pulling ALL extra timing until coolant temps are up, otherwise timing was just sticking at 25* , aka max, 

I would probably start with the easy stuff. Maybe try pulling the EZ completly off the truck. If the problem goes away, that would be a start. What kind of fuel pressure are you seeing? That may also point to a possible issue depending on what that looks like.

Another interesting thing I see is this problem started AFTER putting in the new injectors. Maybe its an injector issue?

I would be curious to know if switching the EZ to a lower setting or disconnecting it helps.  After re-reading your last post, I will say that I've had similar lite burps in the power when accelerating from a lower RPM range in the upper gears.  And, yes only in the cold winter weather, and yes only after the 275's.  But also pointing out, this is only under mild throttle.  Never felt anything while being more aggressive on the throttle.  Kinda chalked it up as temperamental fueling.....

How do you hook up a live data tool and where would somebody access one? I've asked around with no luck so far locally. 

KATOOM,I've noticed it on all levels but it's not as noticeable on level 1 as it is on level 3. 

It didn't start until after injectors and it COMPLETELY non-existent issue when outside temps are about about 40-45 degrees. 

The heavier the load you are hauling the more noticeable as well just. ie-went camping a month or so back and we left out of the campground at 8 am and it was 33 degrees out. I got out on the interstate it when it happened it would jerk the camper around a little each time it cut out/stumble. I've pulled that camper all over the blue ridge mountains in the summer and it runs like a top. strangest thing.

Have you consider calling Edge and seeing if there is updated flash for your module?

I agree.  This sounds like an issue with the Edge.

Sounds Like too much timing at those temps, probably an Edge issue.

Thanks guys! I called Edge right after I put the module on about the issue and they assured me that it wasn't an issue. I'm not convinced but it does seem to work pretty good otherwise.

Here's all the live data I got! Haha.

This was back in august on a super hot day pulling my rig up a steep grade. I topped the 3-4 mile grade running about 60 with these levels and truck doesn't hesitate one bit. Pull that steep grade tonite and after coolant gets up to temp and it would still hiccup and hesitate on the low end of rpm band and as the boost builds. 

Edited December 8, 20168 yr by woodtrucker

Wonder what your IAT is reading.

Edited December 8, 20168 yr by KATOOM

 Don't mean to nit pic......but isn't your fuel pressure too low ? Thats VP damage level there. Have to stay above 14 Scott.

Edited December 8, 20168 yr by JAG1

That's the hardest pull I ever made and never goes below 13 psi. The Fass DDRP-02 usually runs 13-14psi on the bottom. 

I know it's not a 150 pump but it seems to keep up pretty consistently at 13-14psi. 

 

KATOOM, I wonder if I could find a cheap thermocouple temp gauge to temporarily rig up near the IATsensor to monitor the temps when this is happening. It's funny that once it starts getting cool in the fall 40-50's it runs better than when it's really hot out (diesels like the cold air) but as that IAT drops when ambient gets colder below 40 it's starts running like crap. It's certainly a timing issue. I might try to call Edge again and talk to them about this. 

Pull the IAT on a cold day and check resistance.

And just to point out, all engines prefer "cool" air but diesels do not like COLD air.  Cool air offers a denser combustion chamber charge, but when the intake temperatures get too cold in a diesel then the combustion temperature becomes too low for complete fuel burn and power is lost.  This is why its not advised to run a direct cold air intake in the cold climates.  You'll only cause more problems and lower your fuel mileage.  What intake do you have?

Edited December 8, 20168 yr by KATOOM

stock box unmodified. thanks for the info!