Hard starting in cold weather

[Tom Welsch]

Im sure this has been beat like a dead horse but im stumped here. As soon as the temperature hit 0 Celsius (thats 32 Fahrenheit for you south of the border fellas) my 2002 2500 does not want to start. Above zero it starts without missing a beat. Has a newer fass drp 02 with fuel pressure gauge, check valve on fuel line, winter fuel with conditioner and water drained regularly. Any help appreciated. Truck has 235,000 km (146,000 miles)

 

[RBeard]

I live in central Texas and I block heater under 45F to make it easy start and cabin heat sooner. I assume your grid heaters are working at that temp. right.

 

[Tom Welsch]

yes grid heater works and even after leaving it plugged in for a hour or two its hesitant to start.

 

[BigPapa]

Are you SURE the grid heater's working? Even if its' not working, your truck should start easily at 32*. Has anything else been done to the truck lately? Any kind of programmer or other mods?

 

[Tom Welsch]

I changed the intake horn a month ago and burned my finger testing the grid heater lol. So yes it works

 

[GCroyle]

I learned something last week that makes for an easy test for a DC circuit that I didn’t know existed.

A clamp on DC ammeter on a fluke.

Slap that puppy around the grid heater cable and test away.

Testing is a good thing.

 

[Tractorat]

A couple of years ago I was having a similar problem. And, I thought the grid heaters were working. The wait to start came on fine. But it turned out I had at least one relay that was bad.

 

[BDaugherty]

Something is not right. Both of the VP44 trucks I owned started immediately in 15-20 degree temps. I suggest going to blue chip diesel and following their troubleshooting guide.

 

[KATOOM]

Things to look for are:
1) Condition of both batteries (test them correctly too)
2) Condition of battery cables (corrosion/tightness)
3) Grid heater function
4) Starter performance

If the batteries are weak or have a dead cell then cranking speed will suffer.
If cables are corroded or loose then voltage drop will affect cranking speed.
If the grid heater isnt working right then intake temperature during cranking will be too low. (typically a code will generate if this is the problem)
If the starter is weak or dragging then cranking speed will be too slow.

Cranking speed is everything because diesels ONLY generate combustion heat by piston speed and compression. If cranking speed is reduced by a mere 20 RPM then it can affect starting in colder weather.

FYI - dont replace the OEM starter with an over the counter lifetime warranty unit from the parts stores. They're garbage and will not last very long. The OEM starters are very stout and generally only need a contact replacement everything 100k miles or so. If the starter was ever replaced with one of those parts store ones then thats what I'd look at first as the culprit...

 

[fest3er]

Cranking speed is everything because diesels ONLY generate combustion heat by piston speed and compression. If cranking speed is reduced by a mere 20 RPM then it can affect starting in colder weather.

Quoted for emphasis. If either crank RPM or temperature is, or both are, low enough, the piston/block/head will absorb enough of the heat of compression to prevent ignition.

 

[Tom Welsch]

Its lookin like its a fuel issue.If I bump the ignition and get the lift pump to run it will fire right up then

 

[Bmosely]

I heard of the heaters sticking or not working years ago. I wanted to know exactly when they were on so I added the 2 red led’s in the picture. One to each heater. No question anymore.

 

[gtwitch]

Sounds like you are getting air into the primary fuel system (somewhere from the tank to the VP 44) could be at the tank pickup or at the lift pump connections or at the fuel filter! I had this issue twice and found the air was getting in on engine cooldown (parked in the lot) after a pull up the hill worked the truck a little and this was happening every time I made this pull with the trailer on behind. The fuel filter was leaking air in and displacing the fuel, thus making a hard start condition. I found this by soapy water test when the lift pump was in its cycle prior to cranking and I got air bubbles at the filter so I loosened the filter top and re-tightened and stopped the air being sucked into the filter on engine cooldown. I hope this helps. I only stumbled on this by chance but was looking for fuel leaks and obviously I was not leaking fuel out, only "AIR" in! and back out under fuel pump pre start pressure up.
gtwitch in wyoming

 

[Tractorat]

I dont know how old your fass is, but theyve changed the installl procedure from when mine was installed a few years ago. It had to do with the hose connection to the tank. I believe the shop replaced the old hose (it looked like it was cracking but not necessarily what caused the problem) and made the connection with the new procedure. I dont remember if the old way was to use putty tape or if that was the new way. But it cleared up the problem.

 

[Bill Lins]

FYI - dont replace the OEM starter with an over the counter lifetime warranty unit from the parts stores. They're garbage and will not last very long.

I hate to tell you this, but my OEM starter lasted 5 years & the NAPA lifetime warranty unit lasted 9 years. The free replacement has lasted 8 years as of now & is still working well.

 

[KATOOM]

I hate to tell you this, but my OEM starter lasted 5 years & the NAPA lifetime warranty unit lasted 9 years. The free replacement has lasted 8 years as of now & is still working well.

Don't hate to tell... You're simply the exception to the rule.