Confirm my diagnosis

[ThreeFitty]

All winter I've had a suspicion I'm due for glow plugs. Right before it got cold I put a GP relay in the truck to try and cure it's no start problems when it gets coldish. The truck won't start up under 45 without some serious coaxing, it started this morning at 44 degrees on the 4th try. Now if I plug it in for a few hours, lights off instantly, no smoke, no bull, no nothing. When I don't it it in and crank it I get a very strong smell of fuel and white smoke out the exhaust so I know it's getting fuel.

So with all that being said, I think it needs glow plugs. Checked power to and out of relay and it was good as well as ohmed the plugs through the harness, they all checked out. Previous owner did under valve harnesses 19 months ago, have a reciept from dealer for that.


So what do you guys think?

 

[rentstdi]

What's the condition of your batteries? Does it crank slow? How's the starter.......

 

[ja_cain]

Yeah, check those batteries. If the voltage is dropping into the 9's or below the relay may not be energizing. My batteries are bad and you would know right away if this was happening as it would have a longer crank time on days in the low 20's and high teens. Then it would smoke some for a few minutes once it caught. Damn oil viscosity must jump significantly at those temps

 

[ThreeFitty]

Batteries were brand new in December as I thought it was my issue, it cranks very fast. Faster than it did with my old batteries during the summer. One thing I will say is that when in the cab and I turn the key on I really don't see a drop on the voltage gauge. Like my buddies truck you notice the drop, not mine

 

[rentstdi]

You could ohm out the glow plugs or the wiring to verify no issues before replacing things

 

[ThreeFitty]

I ohmed out the plugs through the harness. All 8 checked out fine

 

[ghohouston]

If gp system works fine, it could be the injectors are worn.

 

[Magnum PD]

How long does the wait to start light stay on? When it's cold?

 

[ThreeFitty]

Usually over 10 seconds

 

[ThreeFitty]

Is it true that ohming it out through the harness jut checks to make sure the connections are fine with the UVH and the GP's? On the reciept it makes no mention of glow plugs being replaced

 

[Magnum PD]

That's how I check them.
As long as the current is getting to the glowplugs.

 

[ThreeFitty]

Might be injectors then? It smokes a touch of blue on occasion but nothing to cry about.

 

[mandkole]

had a similar issue with the neighbors 99 and we changed the plugs. The issue was fixed. I can't always rely on ohm'ing thru the harness.

 

[DEEZUZ]

Injectors are worn

 

[ThreeFitty]

I'll start with plugs and see where it goes from there I guess

 

[mandkole]

good move-- you've already said it lights good with some heat, so be certain its getting heat.

 

[ThreeFitty]

good move-- you've already said it lights good with some heat, so be certain its getting heat.

Exactly, I also want to verify the harness's look good under there. The good thing ism it's getting warmer so my electric bill can come back down. Sucks having a toaster oven going outside all night!

 

[OBS-Addiction97]

Exactly, I also want to verify the harness's look good under there. The good thing ism it's getting warmer so my electric bill can come back down. Sucks having a toaster oven going outside all night!

You can get a timer for it so it runs about 3 hours before you drive it.

 

[ThreeFitty]

You can get a timer for it so it runs about 3 hours before you drive it.

Yeah I thought about it but with plowing and needing it at different times I just plug it in and go. Would be too complicated to have it set for this and then the next morning I need it earlier or later and then it's cold. I just need to fix the issue. Plenty of buddies with 7.3's that don't plug in till we get down to the teens without issue