Hello everyone!

I've been having an issue with my 6.9L. Namely, the truck will crank with no sign of firing. The other week a passerby gave me a shot of ether to get it home after it wouldn't start and it cranked right up, but I don't want to keep using that stuff.
When I first started noticing a long crank, there was white smoke out of the tailpipe, and it would eventually fire. It ran fine after it started up, but with an excessive amount of white smoke for the first few minutes of idling. Now, I don't have any white smoke at all.
It's got a momentary switch for the glow plugs, but I've already tested the system with a DMM and its working fine.
When I hit the valve on the fuel filter, I get fuel coming out immediately, and if I go to unscrew the filter, I get fuel pouring out of it immediately. But I may need to take it all the way off and see if it's clogged?
Batteries are fully charged but I haven't voltage dropped the cable down to the starter yet(just as something to check), and after viewing the post at the top of the forum I feel like mine may still be cranking slower than it should.

Most of the starting/ignition system isn't even two years old(including the batteries and starter) and I barely drive this truck.

Any opinions, direction, and advice is greatly appreciated!

 

Could just be air intrusion. How do the fuel lines look? Cracked, old, stiff? I would get a return line kit and replace that and the injector O-rings, It's cheap and cures a lot of hard start problems. Have you tested the actual glow plugs them selves? Are they Motorcraft? If they aren't I would get those too.

 

Thanks for replying!

I actually did change the glowplugs myself about a year ago and put Motorcraft in there. I took Autolites out, and it was a scary process doing so. I didn't think I was going to get them out as they had swollen pretty bad.

I also put new return lines,o-rings, and the T fittings on too about the same time because they had a slight leak. Found a nice kit online with everything I needed to do so.

I took the fuel filter off just now and it's feeling pretty heavy, so I'm going to grab a new one of those tomorrow. Turned the key to on with the filter off and plenty of fuel is being pumped out.

I also voltage dropped the cable down to the starter and it's only dropping 300mV while cranking with full source voltage available(only dropping to a little over 10V at the starter), but I can't test current unfortunately.

I'll definitely try again tomorrow after I pick up a filter.

 

Do you hVE this problem when the engine is cold, or hot, or all the time?

 

Only after the engine has cold soaked, but that's even after two hours of sitting in about 70 degree weather. If it's been running and it's still hot/warm it'll crank right up.

 

I hate to say it but it sounds like glow plugs, if you see white smoke while cranking that smoke is unburnt fuel, and that it started with a touch of either just about varifies it. If it was just an air problem it would start fine but quit within seconds.

 

Disconnect the glow plugs, then try a small bit of ether(into the air filter; it should mix it better) and if it fires up, well, you know where your problem is.

 

it sounds like either the glow plugs or the glow plug relay is bad.
since you replaced the plugs last year, i am going to say relay.
check with your volt meter if there is power going to the glow plugs when the button is pushed.
the very first thing i do to diesels is put a real glow plug light int he cab connected to the output of the relay so i know for a fact the plugs are getting power.

 

Sorry for the late response. I've been on vacation.

So! I had a little over 12 volts going to the glow plugs at their connectors, but after realizing checking source voltage at the connector doesn't really mean jack if I don't check what voltage is there with it still plugged in and the circuit operating, I did the next best thing(as my assistant isn't here to hold the button down); I cycled the glow plugs a few times and then immediately pulled one out. It was dead cold. I also noticed some damage towards the end of the glow plug which has me pondering if there's any other issues going on in the engine or if this is normal..





As I said, I barely drive this truck and these plugs are about a year old.

I'm going to properly check the glow plug circuit when I have an extra set of hands available and go from there. I'm thinking relay at this point too..

 

that glow plug looks like it was powered up too long of a time and burned out. look at the tip. those pockmarks are from being lit too long.

 

The best and simplest way to check just the glow plugs is-1. Pull the wire connector off the glow plug. like the picture you posted just the glow plug. 2. Use a 12 volt test light, any type or brand will work just make sure you test it first, put one end on the positive battery terminal and the other end on the negative battery terminal the light must light! next leave one end connected to the positive terminal on the battery and put the other end on the top (spade) of the glow plug only, if it lights up glow plug is good. If you touch the lower part of the glow plug or any other metal part on the engine the should light if your connections are good.
Glow plugs will have all different shapes when used, in rare cases they will swell so much they will not come out without breaking off.
Where the glows plug are located inside the engine they cannot be damaged by any moving parts so that is not a concern