Grid heater not activating

[guyhaz]

On several occasions this summer while up north in Arizona my grid heater will not activate. I pull our toy hauler up the mountain and make camp and the truck sits for several days, usually when I go to start it in the morning to leave the temps are typically under 64 degrees. The truck stumbles on start up and spits out a bunch of white smoke before returning to a normal idle after several minutes. Can a faulty IAT or MAP sensor cause this condition. Sticking FCA? The truck starts just fine down in the valley (Mesa,Arizona).

Also, I recently replaced a faulty grid heater relay and the fuseable link this winter and it worked fine after replacement. Grid heater came on a cycled like it normally would.

Thoughts or things to test/clean?

 

[petersonj]

It is possible that even though outside temperature may be below 60 degrees, because it is now in the heat of summer, the engine block may still be above 60 degrees. The stumbling on startup with a bit of white smoke is probably from the combination of using summer blend diesel fuel, lower engine compression due to higher altitude, and the grid heater not energizing. My guess is that everything is working fine and you will need a much cooler morning to activate the grid heaters.

- John

 

[AH64ID]

The intake manifold temp for grid heater activation is 66°, and it may not cool off that much in the intake manifold even if it hasn't ran. I am often surprised how much heat the block will retain.

Unless it's been sub-zero those starting symptoms point to faulty injectors instead of a faulty grid heater.

Many folks remove their grid heaters all together. On my 05 I often ran with it removed in the winter and it would start the same as with the grid heater down to about 0°F. I started it numerous times at 25°, sometime colder, and above 6,000 feet. Never so much as a stumble at those temps/altitude. When my grid heater was installed I re-programmed it and it didn't even turn on until 30°F and then only for a couple seconds. I didn't really engage it until 15-20°. Cummins states that the ISB starts normally down to 10°F without any external aids, which the grid heater is. Above 20-30° the grid heater is for emissions purposes, not starting purposes.

I see you have a CTS2, you can use that to look at intake temps and see where they are at. It can also show you ambient air temp (sensor in the intake pre-turbo, not the one for the overhead), and coolant temp. After the truck has sat overnight the 3 temps should be similar. That would help pinpoint a faulty sensor, which yes could have grid heater effects...but it still doesn't sound like a grid heater.

 

[guyhaz]

Thanks for the replies guys. I will be up north this weekend and I will check those temps and report back. I was hoping this post would not lead me to faulty injectors..big money and all for injectors. I guess the best thing to do is to take it to a shop and have them tested? Any recommendations on shops in the east valley?

 

[AH64ID]

You can look at the temps at home too and see how close they are to each other.

You should also be able to see the IAT rise as the voltmeter drops when the grids are firing.

 

[sfpcservice]

Only time I had a hard time cold staring was when I had a cracked ring...

 

[guyhaz]

I checked the IAT temps and ECT temps on the CTS yesterday afternoon and this morning on startup. They both are reading the same.

The truck runs and starts fine when at home, what is it about the higher elevation that brings out the issue. Could it be the fact that I am pulling steep grades with a load?

Anyone have a recommendation on a shop near me to take it into and have the injectors tested?

 

[DavidC]

Never had any work done here but we did have a little TDR meeting there quite a few years ago. The owner seemed quite knowledgeable and fair.
https://a2zdiesel.com/

 

[AH64ID]

I checked the IAT temps and ECT temps on the CTS yesterday afternoon and this morning on startup. They both are reading the same.

The truck runs and starts fine when at home, what is it about the higher elevation that brings out the issue. Could it be the fact that I am pulling steep grades with a load?

Anyone have a recommendation on a shop near me to take it into and have the injectors tested?

If anything the towing will help things by cleaning out the cylinders/pistons.

It could be the temp difference in the valley, or it could have been a fluke at elevation.

 

[PBJ2500CTD]

I am inclined to believe that altitude is playing a big part. A couple years ago we spent a week in Woodland Park, Co at an altitude around 8,600 feet. My 02 Ram would stumble on initial start after sitting all night in the cold. May have gotten into the high 30's or low 40's during the night. I noticed the Grid Heat light would come on for a second or two then go out (bulb check only). I remember a similar event occurring several years before while at a campsite at extreme altitude and cool weather. Thought is was just an anomaly at the time. Never occurred at lower altitudes. I couldn't "readily" find anything in the FSM or schematics that would relate these events to altitude. But three times now with temps around 45 degrees and below at altitudes above 8,000 feet I have experienced this issue.

 

[sag2]

As was mentioned, an engine in good condition should not have white smoke even with no grid heaters at those temps. They start and run fine down below freezing without preheat. Injectors or low compression would be more likely.

 

[Ozymandias]

Higher altitude means less oxygen in the ambient air and so the truck suffers from that like we humans do.
Cummins states a 10'000ft full power, but that is under load with the Turbo full speed.
Go to 15'000ft and the air density is so bad that the Ram blows out clouds of smoke all the time that everyone thinks a head gasket is blown.

As long as your truck behaves normal below 3000ft your fine and no need to think about it, its normal behavior.

 

[guyhaz]

Truck did the same this weekend. Readings from CTS2 where...IAT was at 73 and 78 for ECT. Didn't expect the grid heater to activate at those temps. Elevation is about 7200 ft. I did hookup my battery jumper prior to starting the truck in the morning, just to see if it made any difference. Truck acted the same, stumbles and puffs a lot of white smoke. Started it up this morning to go to work, starts just fine with no smoke or stumble. I guess I will be making an appointment at a local shop to see if they can diagnose the issue.

 

[AH64ID]

Certainly doesn’t sound like the grids.

It’s likely the injectors starting to wear, but it may not be enough to do anything about yet.

 

[guyhaz]

Truck at the shop now....see what he turns up tomorrow.

 

[guyhaz]

Here is the aftermarket filter setup I had installed. Could it possibly be air getting into the fuel line feeding the injector pump? Air possibly getting through one of the connections going in and out of the filter base? If so any way to test those connections?


http://m.dieselfuelfilterkits.com/?...mmins_fuel_filter_kit.html&utm_referrer=#2848

 

[Ozymandias]

As you have a pressurized fuel system in its entire length, no there will likely no air going into.

 

[guyhaz]

Talked with shop and apparently it's throwing a code for the IAT. Also he mentioned when the return line was disconnected to test the fuel return rate, fuel was being pushed back up the return fuel line that was disconnected..not end coming from the injector side, the end going back to the tank. He mentioned a possible bad check valve in the intank fuel pump. I should know more tomorrow on both issues.

 

[guyhaz]

Anybody have any experience with a bad check valve on the fuel pump?

 

[guyhaz]

Got the truck back last week. Shop was unable to find any issues. Flow rate and fuel pressure test where good, so I think the injectors are ok along with fuel pump.