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What temp is too cold?

4K views 20 replies 10 participants last post by  hevyevie 
#1 ·
Hey guys, I'm new to this forum but from reading through many threads already I can tell everyone is very helpful. Looking forward to owning my 1994 2500 2wd that I picked up last week. I had been pulling my ski boat with the wife's toyota suv and it virtually destroyed the transmission. Decided it was time to get a real truck made for towing.

Anyways, I am in Minnesota and it gets damn cold here. I know that the block heater is the recommended method for best starts in the cold, but I work 9 hours during the day where there are no outdoor outlets. What I am wondering is, how long should I expect the truck to be able to sit in 0 degree (farenheit) weather and still expect it to start?

The other day it was 25 and it sat for 6.5 hours unplugged and when I went out to start it, it didn't want to stay running. Gave it some throttle and it started eventually, but it fogged out the parking lot with smoke. Any thoughts to why so much smoke and tough starting? The PO did mention it was time to change the fuel filter... but it idles and runs great once it is started. If the engine is warm, starts with hardly a turn of the key.

Thanks
 
#2 ·
they will start no matter how long they sit, all the white is just diesel fuel not burning

just give it a slight throttle until it smooths out, nothing over like 1300 rpm

also in case you dont know, take it very easy on your truck until its up to operating temperature......if its cold and you mash the throttle you risk blowin the head gasket
 
#3 ·
25 shouldn't be that much of a challenge to get it started, even not plugged in. Is the grid heater working? Is it cranking over fairly fast at that temp? It's normal for cold thick oil to slow the cranking speed down some, but it shouldn't be turning over a whole lot slower than it does in warmer temps. If it's cranking at a fairly normal speed and is still that hard to start, I'd wonder if perhaps the timing had slipped a bit.
 
#4 ·
I figured that was the case (always start in the cold), but it really doesn't want to start. It cranks fast, fires almost immediately and then dies instantly. After a few tries, and some throttle it will eventually start up, tons of smoke (like, look at me, my car is struggling in the cold, amount of smoke), lots of shaking, and some more smoke. I am going to debug the grid heaters to make sure they are functioning. I'm pretty handy with electronics and with a wrench.

I do find it odd that I have only seen the wait to start light stay on longer than 2 seconds just once. Would the block heater increase the intake temp high enough to bypass the need for grid heaters? It was out for 4 hours one night in 0 degree temps, unplugged, and when I headed out to start, the wait to start light was on for about 10 seconds. According to the charts I've seen here, I would think it should be 30 seconds, but I suppose the intake temps will stay warm for some while after running.

I will also look around here for timing adjustment instructions and make sure that mine is set correctly. Thanks for the thoughts so far. Just would like to stop worrying that when I head out to start my truck after work that it's going to take some effort to start and when it does, anyone in a 30yd radius is going to get smoked out with diesel fumes.
 
#5 ·
Ok, that's a little different. You said it starts almost instantly, then dies. That to me says that the basic problem isn't the cold. If it were, why would it be able to start almost instantly? I'm wondering if you have an air leak in the fuel system-one or more hoses leaking air in and losing prime. Meaning, there's a leak, and the fuel starts running down toward the tank. You go to start it after it sat for a while and the little bit of fuel in the injection pump and injector lines immediately lets it start, then that bit of fuel is gone, and you must crank it for a while to purge the air out. You recently bought this truck? It may have been doing this for some time now, or perhaps it just started, but I'd look at the rubber hoses in the supply side of the system first. Then I'd see if the fuel heater on the side of the engine is leaking air in. They've been known to do that where the wires enter the unit, and everybody that has their fuel heater leak seems to just eliminate the heater with no ill effects. Apparently, if it's cold enough for fuel to gel, it'll gel at other places in the system than were that little heater is.
 
#6 ·
I forgot to address your grid heater questions-I can't recall mine ever staying on more than about 10 seconds. The coldest I've ever started my truck is probably in the high teens. This would have been not plugged in.
 
#7 ·
Well, if it had a leak, would it start instantly, with no added throttle, after 12 hours of sitting if it's been on the block heater? That is the case. Last night it was -8 here and I had it plugged in... went out at 7am, fired right up. Appears to only occur when the engine is in fact cold.
 
#8 ·
I've seen them fire right up, for just a second, with a leak. It may depend on where the leak is. So far as only doing it when cold, the only thing I can come up with is that maybe the hose hardens up and starts leaking only when it's really cold.

Or, I may just be completely wrong about the whole leakage thing. The thing that made me wonder about it not being simply an engine-too-cold-to-start-easily issue is the fact that you say it'll bust right off and run for a second. Hell, it might be some other different issue that neither one of us has thought of.
 
#9 ·
I am in Oakdale MN. It is cold -10 F last 2 morning and 20" of snow the other day. My truck will start at any temp. It starts better when plug in. If I do not plug it in it will start but sometimes will start and die once. I cycle the grid heater twice and that seems to help (you will know if your grid heater it working big draw on the batterys). Still smokes a little when cold but I let it warm up for about 10-15 min. before I go any where. A good tune up (oil change, fuel filter, clean screen) is a good idea. I run 15/40 oil. It is like jelly at cold temp.
 
#11 ·
i have to agree on the too cold part. i drove up and stayed up north last winter for a few weeks. i think the temps were like 5 or so. but anyways. i didnt have it plugged in a few nights and went to start it in the morning it would fire right up and die unless i gave it throttle. not too much throttle tho. like 1200-1300 rpm. after i plugged it in the last few nights i was up there i never had that problem anymore.


also on your grid heater wait to start light thing. as of right now its about 40 degress here in texas and my grid heater stays on for atleast 10-15 secs before i hear it click off and start it. so i would think that if its colder it should take longer. maybe your grid heater is not working correctly. or its cutting off too soon. cause with it plugged in like u did the last time, it sounded like it started right up. so i would think its working,but just cutting off too soon.

but i dont know, never touched my grid heater before. i just know it says on longer then 2secs =)
 
#13 ·
Thanks so much guys for the feedback. I'm fairly convinced at this point that something is amiss. Here is what I know now after some "debugging" last night.

I think that the relays for the heater grid need replaced. I had them off and bench tested them. Was getting 0L on the DMM, but could here a clicking sound. After jostling and a few more tries, I was starting to get a proper reading. Must have knocked off some internal corrosion. Anyways, I am going to order the replacement parts and put them in. I recall reading somewhere some cheaper relays that would work rather than the $70 ones?

I then tested the heater grid resistance and they seem fine. Also checked the readings from the air temp sensor and although the readings jumped around a bit, they were in range.

So, I left the truck off the plug last night and it was down to 6* F. I went out this morning and turned the key to ON about 3 separate times to cycle the heaters. This time I verified the clicking sound and had the lights on and could tell that current was being drawn. One weird thing though was that the light was still only on for 10 seconds. I would expect based on readings here and seeing a chart that at 6*, it should stay on for at least 20 seconds. At any rate, I turned over the engine with about 1/4 throttle and she fired up, very rough, lots of smoke and after about 10 seconds at 1k RPM (kept my foot on the throttle), I let off and it stayed running. I could tell the grid was still cycling because every 20 seconds or so, the lights would dim and the engine would bog a little.

So, it starts, but I think the roughness and smoke is abnormal. I am going to shoot a video clip so that you experts can view and see if you agree with me?

Thanks again. BTW, I am going to take the advice and change out the fuel filter and clean the screen to see if that helps.
 
#20 ·
You should see mine now. Who knew 5x18's and 24* timing was not ideal for my winter climate?

I have started it recently as cold as -20 without plugging it in, but it wasn't an easy start. Still, if I can get this fired up at -20, a stock truck should start at -20 but it will probably take a little warming up to get to the point where it is drivable.
 
#15 · (Edited)
Hi
My truck starts unplugged with no problems, the last week it was -5.8 to -9,8F. In this low temperatures it smokes a lot, thats normal. Wait to start is on for 10 to 15 sec. I think you have to check your timing.
 
#16 ·
well its starting thats a plus. and yes the smoke and starting out rough is normal for really cold temps. my starts to do that if its around 30 degrees F and gets worse as its colder. during warming climate it does not do it. show us the video so we can look at it and see if its more then usual.

but these engines hate the cold. so they do need some loven to start up =) nothing wrong with that. means you have a real engine lol

if it wasnt starting still then that would be a problem. and the manual says the truck might need 1/4 throttle on start ups.
 
#17 ·
Alright, so I took the video and

Still haven't done the fuel filter yet... waiting for the pre-filter to arrive in the mail so I can do them both at once. Picked up new relays for the intake heaters, hoping to get those in today. Please take a look at the video and let me know what you think. After I let off the throttle and the smoke cleared, it idled just fine.
 
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#18 ·
I live in Vermont. I haven't plugged mine in yet this year, and we've seen temps near zero a few nights. It starts in 1/2 second (first crank) after a single "wait to start". A touch of throttle to keep it at about 850, then I let it idle back down to 600 or so and it works its way back to 850 in the next 20-30 seconds.

I've started it after 8 hrs unplugged in -teens. It's ugly (smoke and noise) but it fires right up.
 
#21 ·
That seems normal to me. Maybe a little rough on the engine part but the smoke is normal. Mine does the same thing when that cold also. I try to keep it plugged in whenever possible and that has proven to make a world of difference! I'd surely change the filter and screen and then would look towards the pump timing. The smoke seems normal, the roughness maybe not so much. I hate to be the first one to make this comment, but if you would fill out your signature describing your truck a little it would give others the information to make more educated guesses.
 
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