After the engine rebuild I'm having this problem. Grid heaters turn on with key in our weather right now, this part is fine. Start truck, starts fine. BUT:
When the grid heater cycles on and off, at the moment the solonoid opens and closes, the engine stumbles noticeably. but momentarily.

I disconnected the grid heater and the problem has ceased. BUT, I'm going to need the heater right away and would like to find the issue.

Anyone seen this issue before? Anyone know the nominal resistance for the heater? Is there a way for the heater to short/cause issues?

Alternator issue? Battery Issue or Heater issue?

Thanks.

 

First thing I would do is check the condition of the batteries. And the output of the alternator.

MikeyB

 

Perhaps the engine was not properly grounded during installation? How much resistance is there between the block and frame and batt neg post?

 

During my warm-up cycle(while grid heater is doing its job) my truck has the "stumble" also. It does it maybe 2-3 times during the cycle then its fine.

I had posted on here about the issue in the past and the consensus was that it was normal...others chimed in and said that their trucks did it too.

 

I believe it is perfectly normal and nothing to worry about.

 

It's not normal. My truck had never done it before this year, obviously something changed.

I replaced both batteries yesterday, should be cold enough tomorrow to test it out. I'll post results. Thanks for the help so far.

 

Maybe your grid heater never really worked before the rebuild. Just a thought.

 

It certainly did, 100%. It wouldn't be starting in -50 if it wasn't!! Hopefully the batteries were the issue, find out tomorrow!

 

Let us know how you make out....

 

normal!

 

2 new batteries. I could only make it happen once when I started it yesterday. It may be better, it may not. We should get cooler weather and snow tonight, I'll keep an eye out.

 

Normal. Especially the first start of the day.

 

Mine stumbles, it doesn't bother me b/c I know it's working, but what I really hate is the click heard inside the cab when the solenoid cycles. Do you all hear the clicking too?

 

I have the same thing, first start of the day (when its cold seems to be the only time) start, then the stumble usually with the first 30-45 seconds then its fine. It didn't do it right away from new but a month or so latter which prompted a dealer trip. They supposedly could duplicate it, which is rather amusing seeing as it always does it to some extent without fail when its cold and it was cold the day they tried, makes you wonder how much they pay attention to what they're doing. Sorry for the wordiness, glad to know it seems to be normal - or at least I'm not alone.

 

Would a higher amperage alternator help? Is there an aftermarket alternator available to stop this?