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! 

 

@woodtrucker

 

Noticed your post on TDR, I would be shocked if the Comp didn't use the same timing map as the EZ so I doubt changing to the comp would solve your issue.

 

I agree. I did contact Edge today and they said they'd be happy to take my box and look at it but it's doubtful the box is faulty...he also mentioned that it sounded like a a fueling issue. He said ECM comps and runs way more rich in colder weather and that maybe that's what the problem is. Make me wonder if I block off the grill this winter and let the truck run a little hotter in winter if the problem would simply go away. This experiment is leading me to buy that wifi scan tool to pipe to my iPhone. Then I could check and compare temps and performance with and without blocking grill and see if I see an improvement or elimination of the stumble. 

Again it about having enough IAT temperature to get the fuel to go bang. Being IAT is based on coolant temperature it important to monitor both coolant and IAT temperature. That's why I marked the gauges with normal ranges for optimal performance. 190 to 200 coolant temperature and 100 to 140 for IAT temperature. Again it's about having the warmth to ignite the fuel.

Buying the scan tool now. I will find out what's up on both! And that scan tool will be nice for our other vehicles too! 

Thanks for letting me know about it. 

 

I ran a scan tool for a short while the other day and it looked like everything was working ok regarding c temp and iat but I guess their has got to be an issue with one or the other and the grill block off plates should help get temps where they are supposed to be if they are off. I will monitor a few daysafter getting scan tool and report back! Supposed be cold cold later this week. Thanks. 

This is why people are misled into thinking diesels benefit from true cold air intakes like gasoline engines do.  There's nothing wrong with keeping the intake charge cooler in order to maintain optimal air density, but if those intake temps get so low that it reduces power and mileage then it would seem as a disadvantage.

In defense of that, there are applications and cases where differences apply.

If the Edge comes back fine then it would be interesting to see what your new scan tool reveals is going on in live data.

It will be here on Thursday. I have also read up on some engine specs and noticed the 01-02 HO cummins has a different vp-44 than everybody else. 027 and not a 026 hot rod vp. 

The 01-02 HO cummins has a higher compression ratio (17:1) and a lower rate of fueling (600cc)compared to the SO. May be why HO's have more issues with aggressive timing (my set up) and whether fueling is capable of keeping up with it (hence the stumbles when cold).  I am far from understanding diesel engines but learning more each day. So I wonder if due to the engine specs of the HO that it has much less leeway when timing is advanced for the fuel to keep up. Makes me wonder if all 01-02 HO cummins engines have this problem. somebody please set me straight here if I'm wrong. This is interesting none the less. I'm always one who not only wants to solve the problem but understand the reason for the problem as well. 

Yes, you're correct in that the HO motors use a different VP which has more timing than the SO.  Which is why the HO trucks respond better to injectors than boxes and why SO trucks respond better to boxes than injectors.....to a point.

In either case now the Quadzilla Adrenaline is the best module to customize both fueling and timing for you application. 

On 12/8/2016 at 10:42 AM, Mopar1973Man said:

Just using a OBDLink LX...

http://www.obdlink.com/

 

You can use a smart phone or tablet...

Which one do you have Mike Green red or black, looking to buy one on Amazon right now. Thanks.

I've got the OBDLink LX (Green).

Headed home to get my new OBD link for my iphone and REALLY cold weather so I should get some good info in the next few days out of the scantool if I can figure out how to get those PID modes sending me data!  Thanks for all the help and great information here. I've certainly learned more than I ever dreamed and I'm determined to find out why and understand why my HO cummins with EZ(on level 3) and RV275's runs rough when it's cold out. Still yet it doesn't nearly run as rough as a night in jail so I'm really not too concerned except for the fact that if I'm advanced out too much on timing on level 3.  Just don't wan to blow out any pistons that for sure. lot's of other things on my list for my dec. 17th-jan3rd break from work. 

Vacuum pump rebuild and start sanding and priming for a new paint job this spring!!! WHOO-HOOO!

 

Well I'm not sure if this cold weather issue is causing this or not but I found a fuel leak on the injector line that was hardest to reach to tighten when I put injectors in back in October. Regardless, I'm not sure how I'm gonna tighten it. Can't really reach it with my tools but I gotta get it tightened up for sure. Maybe it fuels ok with leak but when timing advances in cold weather maybe it can't keep up? Just thinking out loud here. lol

If you haven't already, remove the engine lift bracket back there and you should easily be able to reach the line with a torque wrench.  But you'll still need a crows foot adapter.  I think if I remember correctly, its a 3/4".

OMG!!!!! I checked over my intake manifold bolts and I'm missing one!!! AHHHHH! Who knows how long that bolt has been out but I would imagine that would hurt my performance for sure!!!!! I sure hope I didn't mess up anything major guess I would have more problems if that was the case. I was still making 30psi boost even with that bolt out. I'll bet you installing this bolt and torquing the leaky fuel lines will solve my "man made" problems... sheesh. smh. 

I'm down for a few days. Have the hood off for primer and while it's off, I'm gonna fix a leaky vacuum pump seal then double and triple check all my bolts! man...how stupid...

 

 

Not stupid but a man made learning experience.

I keep running into more and more discoveries. Apparantly the PO burned up a VP-44 at 36k (from what he told me when I purchased truck at 83k mi. He sprang for a reman'd pump and I did a search on the Bosch reman'd pump he installed and it's for a SO truck not HO! Apparently that's ok but putting an HO pump on SO cummins is a no-no correct? 

Edited December 18, 20168 yr by woodtrucker

no issue either way

You can install either pump on either engine, but the timing and pressures are different which can affect performance.  That said, the SO is the better of the two.

And check that missing bolt hole.....  Not all of them are all the way through.

You guys are awesome. Thanks for all the feedback! Enjoy this forum emensely and I've learned a lot already! 

First thing I did was slow run a small screwdriver down that hole to see if it went thru and yes it does. It was a location where and injector clamp was located. 

Recent update on the performance issue.

It is very evident that the colder it gets, been in the teens most of the day, the worse the problem is. It's an issue getting fuel to ignite I'm getting more sure of it: i stuffed a pc of cardboard between the radiator and the intercooler to try as a winter front temporarily to see if that might bring up intake air temp to a good operation range to ignite fuel. I'll see if the increase temps under the hood is enough to correct the timing issue back enough for it to run like it does in the summer which like a scalded dog. No problems at all in summer. Make me wish summer was here today cause it's chilly Willy tonite! 8 right now!!!!