Engine/Transmission (1998.5 - 2002) Disconnected the Grid Heaters

[Gary - K7GLD]

I tried Vaughn's trick on my '02, and promptly got a "check engine" light - wonder if later trucks do this by design, or coincidence struck my truck, and something else actually generated the light? Everythings seems to operating OK, except for the grid heaters...

 

[Loren]

The grid heaters have two purposes. The first one is to warm the intake air so the engine will start when it's cold. My experience with both a 1995 and a 2000 model is that if it's above freezing, you needn't wait for the "Wait to Start" light to extinguish. Below freezing, starting gets questionable without using the grid heaters.



The second purpose is to prevent excessive exhaust smoke with a cold engine. This is why they cycle after the engine has started. If you don't like the dim-bright-dim-bright cycling on your lights, or the intermittant 200 amp draw on the batteries, you can disable them. The worst that should happen is a little smoke.



Loren

 

[illflem]

Can't you just drive? On my 12 valves the grids go off after you reach 18 mph.

 

[WeirCummin]

Gary, I had a feeling about this. I think the California/CARB trucks are going to bring on the MIL=check engine light. I think that the Cal. ECMs are set up differently than the 49 state ones. When Nowel was down here, his MIL had come on after he pulled the GH relays out. It's hard to tell when scanning his truck. To many codes and a different ECM, but the thought did cross my mind.



Dean

 

[JHansen]

I've got the Practical Solutions Intake System Saver on my truck (2 thermistors that screw into the water jacket in the head and disable the grid heaters when the engine is above a certain temperature). It has never turned on the Check Engine light, but it does set fault codes for #1 and #2 air heater grid failure. How does it know? Either it senses there is no relay coil resistance or it looks for a large system voltage drop when it trips the heater circuits in... ... I guess anyways . Have you seen these codes with your setup Dean? Just curious..... I don't think they affect anything other than leaving a trail in the ECM.



Jason

 

[Gary - K7GLD]

I suppose I could measure the coil resistance of the GH relays, and then install a suitable resistor across the disconnected leads - not sure that it's worth the bother - I have a few other non-related issues to work on right now, like replacing axles on my 5th wheel...

 

[Cummins Cowboy]

one thing i do when i am in a hurry and don't wanna glow the heaters is just pump the pedal a couple times while starting, however this will not work when i gets really cold. I like the heaters on my first gen better, when they where needed they would make a loud audibal pop when they came on and then do it again when they went off didn't even have to look for a light also the light was off to the side so as to be seen easier with my new truck the steering wheel is sometimes turned and i have to look around it to see the light on the dash. also the wait to start tends to blend in with all the other lights doing their self check. sometimes i wish i would have kept that old truck especially when i have to make the payments on the new one LOL

 

[krs]

So, if the grid heaters were deactivated couldn't the truck be started and run with one battery of about 800 cca?

 

[HVAC]

Yup

Yup.

 

[15w40]

Originally posted by JHansen

It has never turned on the Check Engine light, but it does set fault codes for #1 and #2 air heater grid failure. How does it know? Either it senses there is no relay coil resistance or it looks for a large system voltage drop when it trips the heater circuits in... ... I guess anyways . Have you seen these codes with your setup Dean? Just curious..... I don't think they affect anything other than leaving a trail in the ECM.



Jason

It actually uses the IAT sensor to monitor the rate of change of the intake air. In early ISBs like mine, no MIL was set as JHansen said, but it would not suprise me if the EPA is tightening the noose of later trucks.

 

[jburnes]

Grid heaters

I live in So Cal and seldom see temps below 40 degrees. I thought taking the grids out would be OK. I'm sure they create some undesired turbulance. Any Ideas?



96 2500 4X4 Banks bombed 4"RipRook T-T exaust TrannyDone

 

[Texas Diesel]

Originally posted by Vaughn MacKenzie

Yes this is a common complaint, TPLasek. I thought about the IAT sensor but figured it would be a waste of $$.



I heard someone smoked their alternator 'cause they got into a situtation where they were stuck in traffic or something and the darned grid heaters kicked in so long it finally fried it.



This morning was a good test to see how it would start without them since it was quite a bit colder than it's been lately. It got down to 25F or so, but it's usually been in the 30s & 40s overnight in this part of Washington.



Vaughn

Perhaps this is a good reason to change the OEM design, emission only related improvements NEVER help the MPG or longevity of the design.



It was 22F here recently, let the wait light go out and it started pefectly with no smoke, no dimming lights or overloaded alternator. Thanks Dean for helping get the grid heaters to function correctly.

 

[Big_Daddy_T]

I ran my truck for almost an entire winter with one battery. It was a mild winter. It didnt get below -10 all year. It had 775 cca 124 min res and was a deep cycle. I still have this battery and use it daily. I did add a second but mostly for gp. I do run it every day like I do and drive 1000 miles a week min. it doesnt seem to bother it any. The alternator is pretty beefy. As long as your not pulling major amps it should completely recharge in about 1 hour. Just a guess.