Lately, when trying to start the truck in the mornings *this happens in cold and normal weather*, the truck will crank for a LONG time to get started..
In the process it will smoke white and you'll have to give it some pedal to keep it idling once it finally fires, then within about 20 seconds it usually smooths right out and idles fine, although it usually will smoke white for the first mile or so.

If it was loosing prime, wouldn't that mean NO Fuel initially?

The grid heaters are working BTW.

This is getting aggravating... Any ideas?

Thanks in advance.

 

If you haven't changed the fuel lines yet you probably should start there. Yes if its losing prime the fuel will drain back in tank and it will take longer cranking time to get the fuel back up to the pump.

 

Yeah if you haven't changed the fuel lines yet, I would say that is causing your prime to go away.

 

my truck did that and the fuel return was leaking, however It didn't white smoke like your describing, but it alo didn't have the dv, injectors, timing it does now. (same as yours)

 

What're your Fall ambients up there?

White smoke generally indicates too much fuel for the available heat

 

My truck is a different animal but when my truck lost prime my sealing washers was left out by some one who installed my lift pump *whistles* i need to find that guy an give him a kick the butt LOL. if you have any sealing washers on your fuel system you might want to check that out also.

 

You've difinitely got an air leak somewhere. I just traced mine down finally. Definitely a big load off. I'd gotten too used to just manually priming it for the last few months. I finally took the fuel heater (that part with the strainer in it), it didn't seem like it was on there very tight, it was a possible source for the air leak. I also replaced the hose that goes from the fuel heater to the lift pump at the same time (1/2" ID. with a sharp bend). I'm suspecting this hose as the source because I saw some dry rot on the outside. I had already replaced the return and feed lines at the back of the engine and they didn't help any. Good luck tracking yours down, if it comes down to it, it can't hurt to replace all your rubber fuel lines with new. Then you at least know they're good for a while.

 

Did you ever figure yours out Bobcat? I thought I had mine pinned down but it still evades me. Grrrrr......

 

Two areas of concern, here -

A fuel leak is also an air leak - air leak(s) can cause fuel drain-back to the tank, with resultant hard-start but no white smoke, which is fuel starvation.

Very bad for the Inj Pump, hard on the starter.

All these trucks normally blow white smoke at cold startup in cold ambient temps - the cylinder temps are at ambient temps, cold intake air thru the heater will be cooler, and the fuel is cold = lower combustion heat.

You see a little white vapor until the cylinder temps increase - the lower the ambients, the longer it takes.

Some of the white vapor is condensation from the cold exhaust sytem - no worries if the odor is not anti-freeze.

As more fuel is injected - dumped - the greater the clouds of raw fuel vapors out the exhaust = white smoke

Big injectors and hi-flow DV's are installed specifically to dump increased loads of fuel into the cylinders for more power - unfortunately, they also do this at lower rpms, including START rpms, indicated by raw fuel vapors = white smoke.

The Inj Pump has no way of monitoring the actual fuel output at any demand, nor does the intake air heater circuit know that greater fuel flow is available, so it is up to the ECM between the owner\mechanic\driver's ears to compensate.

Longer glow duration, use the block-heater, less throttle input at START - whatever it takes to compensate, once the injection system has been tuned for 'my throttle isn't variable - it's only on or off' type operation.

White smoke is unignited fuel vapors - not enough heat, or too much fuel for the available heat.

Black smoke is unburned fuel vapors - not enough oxygen to combust all the fuel, combustion temperature drops, flame goes out = black, sooty vapors out the exhaust.

Bobcat's truck is a runner, no doubt about that - but with that setup, it will also, unfortunately, be a hard-starter in cooler weather.

Possibly, not even an Inj Pump God would be able to adj the pump to compensate.

Imo, of course...............

 

Id replace the overflow valve too if you havent. If mine sat for a week before i replaced the OF valve it would be a little hard to start, and would miss and sputter till it got warmed up some. It doesent do that anymore with the new overflow valve.

Eric

 

Hey CrimeDog where did you get the heater strainer and hose assembly from I'm in need of both parts,those two items are the last thing that could be causing my lose of prime all else has been changed......

 

I used some of the red all purpose napa hose, 1/2" ID. As far as the strainer I just cleaned it out. I didn't replace anything. You can get it from fleetguard though, it's pretty cheap. Try a search as I don't remember part numbers off hand. If nothing else you could get everything from Cummins, too.

 

Your owner's manual gives a procedure for cold-starting, it's also on your driver's side visor. I have used thie procedure for 5 years and have never once had to crank more than six seconds, and I rarely get too much wite smoke. However it's a little rough running until all six cylinders get firing. Hold your rpm's at around 800 - 1000 for 2-3 minuites in cold weather before you let it idle. However don't liet it idle too long.

If you've changed injectors & timing - I'm sorry but this procedure may not work for you very well.