no start, then later start with high rpm?

[SPR1NK]

so my truck has done this periodically in the past and it did it again this morning, went out to start it, cycled the GPs for about 10 seconds then try to start, cranks over just fine but will not fire, tried several more times and it still will not fire. so i drive the ol lincoln to work, then come back to look at truck 8 hours later, cycle GPs and it fires right up, but as soon as it starts it revs to almost 2000 RPM right away for a second then comes back down to normal idle
seems like everytime this happens it does this once and then is fine for a month or two then does it again. i would lean towards it being a GP issue but the high rev thing makes me wonder if something else is messed up
an help would be greatly appreciated, thanks in advance guys

 

[Clb]

High idle solenoid?
Air intrusion?
No start condition Sounds like the fuel solenoid aint comming on?
Next time it happens hit the ip with a test light see if its hot.

 

[SPR1NK]

Can the high idle solenoid do anything If I don't touch the throttle pedal?
I could see how air intrusion could cause a hard start, but could it cause the massive sudden jump in rpm on start?
Would the fuel solenoid be an intermittent issue if its going out?
Or is that one of those parts that just up and dies?

 

[SPR1NK]

Oh, forgot to mention, it blows plenty of white smoke out the tailpipe when trying to start

 

[Shadetreemechanic]

Air in the system. It speeds the burn and has the effect of advancing the timing causing it to rev. Does the same thing just before you run out of fuel.
You need to find where your air intrusion is.

 

[SPR1NK]

I think I have a couple of return caps that might be leaking, but they only look like they aren't collecting dust like the others, there isn't fuel pooling around them, think those would be where the problem is?
Sorry for so many questions, I struggle with this fuel system alot

 

[bbjordan]

The white smoke indicates it is getting fuel. I leaning more towards the glow plug system.
When it does go, it is burning all the fuel in the cylinder. That is why it revs up for a bit.

 

[SPR1NK]

A friend of mine told me to check my glow plugs with a test light that's hooked to positive terminal of the battery and if they all light then they are good, so I did that and every plug lights up, so I figured they were good, is this an accurate way to check them?

 

[79jasper]

Not the best way, but should work good enough.

Sent from my SAMSUNG-SM-G890A using Tapatalk

 

[bbjordan]

Check connections

Yes, it looks like your glow plugs are good, but are they getting power to them? I assume you are using the 7.3 type controller? Check the ground connection from the controller. Also, check the power feeds from the battery to the controller at the connector on the passenger side fender. They are notorious for having problems.

You can rig up a temporary controller bypass by running a line with a momentary switch between the negative terminal on the battery and the Relay Ground on the glow plug relay. You should hear a click when you press the momentary switch. This should give you voltage at the glow plugs. Watch the volt meter when the plugs are glowed. The voltage should drop noticeably to about 9 -10 volts.

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[Black dawg]

Oh, forgot to mention, it blows plenty of white smoke out the tailpipe when trying to start

So it is fueling plenty. When it finally does start (depending on how much you have cranked on it) there is a build up of fuel in the cylinder that causes the engine to rev up.

 

[SPR1NK]

Yes I'm using the 7.3 controller, but the controller box is unhooked and I have the relay manually controlled, when I push the button for my glow plugs I hear the relay click, WTS light comes on, and it is putting power to the glow plug wires

 

[SPR1NK]

Ok, that makes sense as to why it revs up then, but would that fuel not blow out the exhaust as I'm cranking it?

 

[Black dawg]

Some does go out the exhaust, but it does start to build up, and it doesnt take much. You should wire up the wait to start light to the glow plug side of the relay so that you know when they are actually getting power.

The light has key on power to it, and the controller sends the ground, so you do have to switch the wires around a little.

 

[SPR1NK]

I checked on the glow plug side of the relay with my test light and it is putting power through