My problem is: Its now getting to to be around -20 deg C, and I'm experiencing "bucking" from my engine under load, now this is only at hiway speeds. I can stop the rough running by turning off my edge comp. I do have winter front on my grill, but since I have big tires and tall rear-end, I'm able to travel fast on the hiway (lots of heat transfer across my intercooler) at fairly low engine loads.

I have considered removing my fan for the winter, and watching my temp gauge closely.

I believe an intercooler bypass pipe (go directly from my turbo to intake) would solve my problems.

I would run with the comp off, but without it the engine doesn't have much passing power on the hiway. Truck details are in my sig.

Any thoughts or suggestions would be welcome.

 

Don't bypass the intercooler. It's there for a reason. Turbos produce a TON of heat when they compress the air. Not to mention your EGT's will shoot up sky high without it. If your truck is bucking with the comp on then I think you have other problems besides cold air.

 

There is bucking at appox -10 deg c and colder, this is at 80mph and faster only.

 

Sounds like it's either running out of fuel or something else. Maybe injection pump or problem with the comp.

 

I'm almost 100% sure its from too much injection advance. Cold intake air temps will advance injection timing (I think this is true, as gas motors advance timing when intake air is cold, due to the air being less volatile). So the comp sees this advance on injection timing, and adds even more.

The truck runs fine around town, or in 4th or 5th gear on the hiway, but at high speeds the air gets too cold. I've ran it down the road in these cold temps outside, and then pulled over to check under the hood, the compressor on the turbo is luke warm at best, and the aluminium intake on the motor is ice cold! BTW I have me cold air port on my fender blocked off with a sheet off metal. This did help some.

 

True that the comp will sense the colder air and advance the timing, I have a hard time believing that it will advance it far enough to cause a stumble. Not calling you a liar, just my opinion. This is actually the first I've ever heard of a comp causing this kind of problem in the cold.

 

I think my setup is special, in that not many people have 39" tires with 3.55 gears, I don't ever tow, so I amost idle down the road at hiway speeds.

 

I remember with my old comp that if I made a WOT run on anything above 3x3 and then started cruising at real light throttle the truck would surge real bad. You might want to ship it back to edge and see what they say. Like I said, I've never heard of a comp doing that to a truck.

 

Unplug the comp...that should narrow it down to a few possibilities!

Chris

 

I guess I shouln't say I'm getting too much injection timing, after driving today I've realized the intake air just gets too cold, going through the ice cold intercooler. I'm going to try some cardboard behind my winter front.

 

Cold Weather.....diesel......it does get thicker. Might try to heat the fuel a bit....insulate the fuel lines going to the pump......might be worth trying....-10 is COLD...cant say i have ever been in that.......heck 60 is cool here in the winter! haha....

If the intake air drops below 40 degress.....i believe the intake heater will kick on to help heat the air.....that should do very well to reverse the over zellous intercooler. Might want to see if your grid is working correctly.....i would assume that it is working since you are still driving your truck! haha....

I agree...if you have any reason to think that your Comp might cause the stumble, i would disable it. See if the issue still occurs and then go from there. I dont think by-passing the intercooler would be a great idea...but would not hurt the truck if you did. I would not run the comp if you did.....

Why cant your just put card board blocking the IC 100%? Whouldnt that greatly decrease the effecenty? that is my 2........

 

I used my stock floor mats to block off the intercooler today, they actually make a good wall against the cold air, I think this may have my problem fixed.

 

He's talking degrees centigrade. This is 14 degrees F. Yes, still cold though..

The grid heaters shut off after the truck goes over 20mph, and don't come back on until you shut off and restart the truck..

 

The computer uses the IAT (intake air temp sensor) and the ECT (engine coolant temp) to determine whether to cycle the grids or not. If the grids do get cylcled to aid warmup, THEN speed becomes a factor, as the grids will shutoff at a predetermind coolant temp (around 160° I believe), or when the vehice speed exceeds 20-25 MPH (note, the speed at which it cutoff varied. Different year model trucks shut off the cycling at different speeds, but still within 20-25 MPH).

 

How about fuel pressure at that speed????