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! 

 

Try being down to -31*F. That's cold. At that temperature the IAT measures out at about +20*F this is getting seriously cold even for a running engine.

 

 

I'd say! I was fooling around and plotted this for my trip to work this morning 4-6 degrees ambient. 

 

The winter front obviously didn't help much on intake air temp and that's what is used to set up timing advance. 

So with that said, I guess if I put a cold air intake in with a winter front, I suppose that would probably raise intake air temps enough to make a difference in the timing advance by taking some engine air along with fender air.Just an idea.

 

I'm beginning to think based on your comment about HO trucks liking more fuel/injectors rather than more timing, that I should get a tuner that taps fuel and try to replicate the hp/tq I'm gettting with EZ/RV275 set up with a system that taps fuel (with no timing added) along with my current RV275s and see if I can keep my clutch from getting trashed and eliminate this running like crap in the winter. 

 

 

 

 

 

I see roughly +10 to 15*F gain in using a winter front on the grill. The BHAF drawing air from under the hood than cold air out of the fender aids slighly being the inter cooler is mostly blocked off. So at -31*F outside I was seeing +20 to +25*F or so IAT temps. The colder it gets the better the winter front works. 

Dang that's way down there! I'm not sure my truck would even run with the timing advance I have and that cold. It ran like crap the last few days of teens.  Well I'm at 50 degrees intake air. I didn't block off intercooler. I stuck the carboard between it and radiator which doesn't really help me at all except keep air hotter around engine. I'll block off the grill and do another test run and see what the IAT ends up being before I spend money on a BHAF. Based on what I've learned with thanks to your advice and your numbers plus what my truck ran at this morning to work, If I can add another 10-15 degrees with a winter front, then that should allow my truck to run without issue down to about 25-30 degrees versus the sputtering it does at 40 or below outside. 

Dang you live in the cold weather. I hate the cold here, so I couldn't imagine the cold there! brrr.

Edited January 9, 20178 yr by woodtrucker

 

Every winter. I'm always seeing temps around the -20*F for at least a week at a shot then flip back. Like right now its +40*F here and mild. Like summer weather. 

can't imagine if that wind speed ends up going up to about 10-15mph. That's like a -50 wind chill. sheesh. I wouldn't even want to go to get outta bed...

 

All I can say is the colder the IAT temp the more and more timing advancement will be given. Excessive amount of timing will produce lower MPG's numbers. Currently I'm playing will timing values and attempting to understand a good point for cold weather operation. 

I have to ask the question about oil pressure coming up too slow. Mine is an 02 without a true pressure sender. While starting in this cold weather I always see my pressure gauge come up almost immediately. by that I mean in less than a second it starts to move. How I understand it is my sensor responds to about 6# of pressure. I am assuming the only reason it goes higher is because the ECM is just reacting to input from said sensor. I guess the only way to really know is to install an oil pressure gauge. Since I dont normally see the temps I am experiencing now it is not on the top of my list.

 I guess I did not ask a question, just trying to be sure I am seeing correctly.

Yep true oil pressure gauge is your only choice.  once your sensor triggers "oil pressure" that's all you know.  

 

I've used a test gauge a few times on my truck and dash readings are typically lower than actual. 

23 minutes ago, Mopar1973Man said:

I've used a test gauge a few times on my truck and dash readings are typically lower than actual. 

Using that as a base line, my dash gauge is up over 40 in less than a couple seconds. Even this am at 15*. I have to temper that with having it plugged in and the water temp reading at 73*. I have also started the truck at 20* without being plugged in with very similar results. A  little harder start but the oil pressure goes up fairly quick.

 

 I have also noticed several folks her say they have to plug in quite early to get the temp up. I plugged in this am and was up to  73* in just over an hour. ECT read 73* and IAT read about 50*.

Just blocked off the grill and took a drive. Best the truck has ever run under 40 degrees running at 36 degrees outside. It seemed to be right at the cusp of giving me the stumble though. I might have felt it just a little on the ramp up from 155 to 195. But seemed to go completely away when truck was up to temp. I think the winter front added 10 degrees at most at these temps. Most importantly the truck ran better. I think I might go ahead and put a BHAF in so it can rob some of the warmer air that builds under the hood. 

Then in summer towing if the egg's run a little warmer than normal, I drop in a heat shield to protect BHAF from sucking in too much hot air. With winter fronts out of course! Can't get data from scan tool for ambient temperature. Need to figure out why that's not working. Ohh well, I seem to finally be getting somewhere. I'm gonna definitely call this issue a timing advance issue and if I just get IAT up a little closer to the good range the truck should run like a champ year round or at least anytime I'm above 30-35 degrees hopefully! Thank for all the advice and direction! I did find an old thread from turbo diesel resource that had HO cummins owners seeing the same issues. No resolution was ever revealed in that particular thread but it was nice to know a few others have experienced this. 

 

Now you know why I've got the tablet with both ECT and IAT temperatures. Then marked my optimal ranges for both with green.

I found this post on another site the other nite after hours of looking for people with similar problems just to see what others have learned. Looks like nobody has complete solution although the winter front was not mentioned so I'm interested to see how the rest of winter plays out with my front in and unloaded travel. 

shudder under acceleration

 

 

I am sorry if this has already been addressed but approx what rpm and gear are you in? To me it sounds like you are lugging the engine and the fueling is trying to compensate but it cannot over come it. I know the extra fuel added is exasperating the situation. I found a similar issue when using a lock up switch on my auto when screwing around in low rpm & locking the converter.

Sound very plausible... I can do similar with my manual attempting to keep traction on ice or slick roads.

2 hours ago, Mopar1973Man said:

Sound very plausible... I can do similar with my manual attempting to keep traction on ice or slick roads.

Was wondering if you had a different tune for slick roads 

If you are running a Quadzilla tuner you can build your fuel map rather weak on the lower boost levels or cut fuel in the lower boost levels giving you better chance at traction. Then you can apply all the throttle you want without the rear breaking loose. 

Very good insight jlbayes. I feel like it's during the build cycle on a hard acceleration. I'm usually unloaded in cold weather months so it's on a hard pull unloaded up a pretty steep grade. As the boost builds, it's certainly more noticeable on the ramp up but never seems to clean up completely. Far worse the closer to lugging range for sure. 

 

Most of my shifts are usually starting me out about 1500-1600 rpms in 6th. That's where I notice it most. Slightly even in 5th but it has to lug a little bit. 

It's tough to replicate at higher speeds than this just b/c I'm already pushing 60-65 in an acceleration before the symptoms. 

Maybe I need to get out on the interstate(uncrowded) and ramp from 65-80 and see if it's just as evident there. If not, then that would definitely be a low rpm over fueling issue. It's most prominent definitely when I'm pouring the fuel to it. 

At 55 degrees last nite, it was fueling so smoothly (just like in summer) that it made me smile. I drive it at 20 degrees outside and it stumbles and carries on like it's starved of fuel but maybe it's just pushing too much fuel to keep up like you guys are saying.  That drive last nite proves to me that my set up is just perfect for me and then cold weather hits and I'm afraid I'm doing damage to my engine...I'm a confused soul on this! Thanks for thinking through this with me fella's. 

Edited January 13, 20178 yr by woodtrucker

Without knowing how the EZ adds fuel and timing there are a lot of things that could be going on.   I would just keep revs up a bit more and see if your issue goes away.