Grid heater

[BIGNASTY]

Is the grid heater controlled partly by the temp gauge in the over head. It runs longer when colder naturally but where dose it get it temp reading to control the heater

 

[B.G. Smith]

From the IAT sensor (intake air temp) which is mounted in the intake. bg

 

[Wingate]

From the IAT sensor (intake air temp) which is mounted in the intake. bg

yep... and it may also look at the coolant temperature and make a decision based on the two readings... IAT and Coolant temp...

 

[BIGNASTY]

yep... and it may also look at the coolant temperature and make a decision based on the two readings... IAT and Coolant temp...

That coolant temp mite explain why it was on so long. I turned of the Espar and forgot to turn it back on. The wife went to start it and said it took for EVER TO get the Grid Heater to go off. Is it on a timer ? I think she got nervous and turn the key off and back on to start cycle again and thought is was one long cycle. .

 

[CKelley1]

you do not need to wait to start. the wait to start light comes on even if ait is not calling for heaters to train you to wait to start every time. the heater is not needed and is for emissions and is not even on off road 5. 9's most of us remove the heater. the next time you get into the truck just turn the key on and start.

 

[AH64ID]

Grid heater operation is driven off of intake manifold temp. If the intake manifold is 66° F or lower then the grids will tell you "Wait to Start", the duration is based on the ambient temp from the engines ambient air temp sensor (in the intake pre-turbo).

The grids will also cycle without a WTS if the ambient/coolant temps are low enough.

 

[Prairie Dog]

I always just get in and hit the starter without waiting. Never a problem.

 

[HHhuntitall]

... on any of the 24v a short wait is good. It gives the lift pump time to prime the fuel system. I don't really care about the WTS light... . I don't even have heaters on my '03 or one of my '97s... . unless it's well below freezing. So the ECM takes a signal from the water temp sensor regarding grid heater cycle? Good to know.

 

[BIGNASTY]

I have allways done what the book told me and thats wait for the light to go out

 

[rbattelle]

So the ECM takes a signal from the water temp sensor regarding grid heater cycle? Good to know.

In my opinion, no. Pre/Post heat are dictated by ambient temperature only.

-Ryan

 

[AH64ID]

In my opinion, no. Pre/Post heat are dictated by ambient temperature only.

-Ryan

Intake air temp dictates pre heat, and I beleive ambient dictates post cycle frequency (on-off-on-off) but the main thing that dictates post is time or speed, 2 minutes or 18 mph.

 

[AWeiman]

I have allways done what the book told me and thats wait for the light to go out

i agree and do the same. the light does not come on at all in the 06 when the truck is warm or when it is warm outside.

 

[Wingate]

That coolant temp mite explain why it was on so long. I turned of the Espar and forgot to turn it back on. The wife went to start it and said it took for EVER TO get the Grid Heater to go off. Is it on a timer ? I think she got nervous and turn the key off and back on to start cycle again and thought is was one long cycle. .

to be entirely honest, I do not know for sure exactly how the little Cummins logic is written... but on the little Cats of similar size that have grid heaters, when the ECM is powered up, (keyswitch in run position) it immediately looks at the coolant temperature and inlet air temperature, adds the two together and IF they are below a certain range, it engages the grids for say 20 seconds. If when it adds the two together, the sum is is higher than that, but still low enough to require a grid cycle, then it energizes the grids for say 10 seconds. . (note time is for example only)

IF when it adds the two numbers together it is above a certain degrees, it will decide that no grid heat is required and will not energize the heaters.

So basically, it adds the two readings and decides how much time to energize based on the software logic. .

I would not be surprised if the logic on the Cummins is very similar... .

 

[rbattelle]

I would not be surprised if the logic on the Cummins is very similar... .

It isn't. It's ambient temperature and time or speed (as AH64 points out). ECT is not included.



-Ryan