tyssniffen

Hey,

so, it's not really that cold here in N. CA, but I seem to be getting a 'cold morning' problem. When I start up and let her sit to warm up, she starts idling up and down, and keeps doing that for quite a while... say the first 4 or 5 minutes or so.

Now, I do have a waste veg fuel system, but I purge my system before shutting down -- probably a good five minutes up uphill 4wd before shut off -- so it shouldn't be gelling wvo anywhere.

I'm not by my record book right now, but it can't be more than 4000 miles on my latest fuel filter...

is this cycling, the rrrr RRRRR rrrr RRRRRR for 3 to 5 minutes at warm up regular?
Tys

stillsmokin

How much rev are we talking about here? It might be a dripping injector. I have seen 2 with fan clutches the engage/disengage at idle changing the rpm and making plenty of noise. It might be worse.

wgingg

probably just the heat grid kicking on and off. there used to be a sticky in the 2nd gen thread about this. common

wgingg

https://www.dieseltruckresource.com/...d.php?t=120532

does this sound like the prob?

wannadiesel

I'm gonna put in another vote for the grid heaters.

signature600

You don't have the defrost on do you?? That would engage the A/C compressor clutch and pull the engine down a bit!

Chris

Ilikebikes

I'm also in northern cal, so it doesn't get too cold here. Coldest nights have been high 20s. Anyway, I think the problem you are hearing is the grid heater cycling. It should sound like the engine is under a small load. Look at the voltage in the dash and you should see when the grid heaters are on; the meter will go down to like 10, the engine will sound like its under a load, then the meter will go up and the engine will sound like normal. If this is your problem, its normal.

wheelo90

I was thinking the Grid heaters also, BUT, Shouldn't they stop cycling after about 90 seconds? Wich is only 1 min. 30 sec. Not 4-5 minutes, mine always stop cylcing after 1 min. or so, but never have they stayed on longer than 3 min. not even in -10 * weather.
Would a bad grid heater sensor cause them to stay on longer?

Wheelo

woodrat

what exactly is the grid heater? where is it located and what does it do? I sometimes have the "loping idle" as well, but I was never too concerned about it.

Ilikebikes

The grid heaters are located on the intake manifold, right under the intake horn (if that makes sense?). You'll see a few wires bolted on the outside of it. They are supposed to heat the incoming air charge to aid in cold starting/running until the engine is warm.

wannadiesel

Mine run for about 5 minutes.

stillsmokin

I'll back wanna up on that one. Those grids run for a real long time at temps below zero!

tyssniffen

Guys,
thanks for all the thought and replies, sorry to take so long to check back here (I was getting fat during the holidays)

1. my cycling definitely lasts longer than 90 seconds. I will time it tomorrow.

2. this cycling doesn't seem like a small voltage change, it seems bigger than that. of course, I don't know much. if I had a 4 year old curious kid, I could convince them that I had 'truck gnomes' that sit in the truck while it warms up and they slightly push on the 'skinny pedal' over and over.

I hope it is the heater thing, and a normal situation.

dozerdawg2

Hey Ya'll, I do agree on the grid heater. I live here in Fairbanks Alaska and believe me when I say it gets cold here. I have a '92 Ram 350 and is is it a sweet truck.