Cold Starting Question

[mgFray]

I searched and didn't see this anywhere, but I may have used the wrong terms.

I don't think this is the typical "fix your glow plugs, EESS box, neutrals" thread, but something slightly different.

When I start my HMMWV when it's "very" cold out, -10F to 30F range.. I need to sit in the vehicle and push on the accelerator pedal while I crank or it will fire and immediately die. I have to push "more" at -10F then at 30F [and for longer]. A light push for 10 seconds or so at 30F, a medium push for 30 seconds at -10F.. and then the vehicle starts to idle well and will warm itself up (no further intervention needed.). (To be clear glow plugs are new, engine starts, even at -10F within seconds -- which is why I'm confident glow plugs, eess, and neutrals are fine.)

Being new to mechanically operated diesel engines, is this 'normal' for this type of vehicle (the housemate who was in the Army in the mid to late 90s said it was) or is there something wrong/sticking at cold idle that should be doing this automatically on cranking?

Thoughts?

 

[TOBASH]

There is an engine temp sensor that might have gone bad. I forget the exam name or location but others here like retiredwarhorses and 86humvee will know

 

[Action]

It is fuel injected
The cold advance switch is on the RH rear of block. 2 wires and accessed thru doghouse.

 

[mgFray]

It is fuel injected
The cold advance switch is on the RH rear of block. 2 wires and accessed thru doghouse.

Thanks this gives me a place to start diagnosing. I thought there was a sensor, but I wasn't finding the name of it so I could search the diagnostic manuals.

EDIT: Looks like I need to disconnect 569B at the switch, then check if there is power at the switch (not wire). If engine is cold, and no power -- switch is bad. Seems easy enough.

 

[Hummer Guy]

I searched and didn't see this anywhere, but I may have used the wrong terms.

I don't think this is the typical "fix your glow plugs, EESS box, neutrals" thread, but something slightly different.

When I start my HMMWV when it's "very" cold out, -10F to 30F range.. I need to sit in the vehicle and push on the accelerator pedal while I crank or it will fire and immediately die. I have to push "more" at -10F then at 30F [and for longer]. A light push for 10 seconds or so at 30F, a medium push for 30 seconds at -10F.. and then the vehicle starts to idle well and will warm itself up (no further intervention needed.). (To be clear glow plugs are new, engine starts, even at -10F within seconds -- which is why I'm confident glow plugs, eess, and neutrals are fine.)

Being new to mechanically operated diesel engines, is this 'normal' for this type of vehicle (the housemate who was in the Army in the mid to late 90s said it was) or is there something wrong/sticking at cold idle that should be doing this automatically on cranking?

Thoughts?

My M35a2 always need to be idled a bit higher in colder weather, I just pull the throttle cable out around 1,000 RPM until it warms up, I would think the same would need to be done on the 6.2 humvees

 

[TOBASH]

My M35a2 always need to be idled a bit higher in colder weather, I just pull the throttle cable out around 1,000 RPM until it warms up, I would think the same would need to be done on the 6.2 humvees

My 6.2 N/A does just fine without my foot goosing the throttle. I think the OP has a sensor failure IMHO (or I’m just lucky).