Hi. I'm having trouble getting my 84 Superduty 6.9 Diesel 4x4 to start in the morning now that's cold here in Michigan.
If I plug the block heater in, it will fire up instantly and run like a champ no matter how cold it is outside. If I don't, it seems to go through the proper motions to start (GP system cycles for the 10 -12 seconds its supposed to then the Wait to Start light turns off) but when I turn the key, it turns over fine and sounds like it wants to start, it just doesn't. Actually, it sounds like it wants to start the first time I cycle the key but if I have to pull the key out (to give the starter a break), when I reengage the starter the motor sounds somewhat different, almost like a gasoline engine with the spark plugs disabled (ie. when it turns over fine but has no spark).
I have done a search on this and I read about the cold idle solenoid and such. Is it possible that when the engine temp is still cold (like it would be by NOT being plugged in) that one of these solenoids would interrupt or somehow cause fuel to not be pumped into the engine? Like maybe a temp sensor is telling these solenoids to do something they shouldn't?
Also, as an FYI, my "engine temp" light likes to flicker on and off (but usually quite dimly) even when the engine is running great. Also, my temp gauge never seems to get into the normal range (just stays to the left of the COLD line).
Anyway any help would be appreciated. I don't use the truck as a daily driver so it's not life or death but it would be nice to be able to start it without plugging it in. Once it's running it runs great and summer time poses no problems, but winter seems to be a bit of a challenge.
More background on the truck: I replaced the glow plugs last year (all 8 with new Berus), put in a new starter last summer, and just had 2 new Diehard batteries put in. The truck was originally from Texas so the engine bay is very clean (no corrosion) and this is only it's 3rd winter here.

 

Does the cold idle solenoid and timing advance solenoid work when ignition is on and engine is cold. Do you press your foot to the floor or at least 1/2 way when starting.

 

I'm not sure how to tell if the Cold Idle or Timing Advance solenoids are working properly or not. Would that be a visual check?

As for starting procedure when it's cold out I press the accelerator all the way down and then turn the key to start (I release the pedal after I release the key from the start position or when the thing starts....). Basically the gas pedal stays on the floorboard during cranking.

 

It could be the fuel. Try a fuel additive or use a premium fuel. I've started my 93 not plugged in in the recent 15 degree weather with no problem. Since you've about eliminated everything else.

Another thought... Look at the fuel return lines between the injectors. If painted gray they are original rubber lines. Replace.... they are leaking air into the fuel system letting the fuel drain back to the fuel tank. They won't leak fuel out just air in.

 

Mine grumbles about starting when cold too, at the teens it starts, but is difficult kind of. My glow plugs work fine, at least as fine as an 86 operates them... It is the nature of diesels to be temperamental in the cold, especially under 20 degrees.

 

1995sho,
Welcome to FTE and the IDI diesel forum.
I would test the glow plugs first.

The old style system will look like it is operating just fine with several burnt out.

 

1995sho, I have an 84 as well...I don't see the cold temps you do but we just had a recent cold snap, so I can relate. Here are some of things that have been succesful for me and might worth trying...
-I use a diesel additive with every fill
-I blocked off the return fuel line from the filter head to the #1 injector
-I crank the engine over for about 5 seconds to get the oil flowing
-I use a manual push button to operate the glow plugs for 8 to 10 seconds and really cold weather, I do it twice

I had an 86 that had no problems with the controler or relay and didn't need a manual push button and let it cycle twice in really cold weather

I hope this helps....you might have other issues such as the o ring seals on the injectors thats letting air in or the fuel return line, lol.

 

Hey, 1995sho, sorry to get off topic - but your screen name intrigues me.

Do you own a 1995 Taurus SHO?

 

bc6.9
"-I blocked off the return fuel line from the filter head to the #1 injector"

So you completely removed the line & closed the ports?? I'm interested, does this have any ill effect? Could you explain this to me please. I replaced all my return lines & o-rings with a kit, it's been doing great but last night I forgot to plug it in & this morning it wouldn't start, but it acts like there's air in there again, I got out & hit the valve & nothing but air. Funny thing is it started right up, stalled, than wouldn't start again. Would removing that line help?

 

There is a check valve in the fitting at the fiter head that likes to fail, and then it allows fuel to drain back into the tank, and syphons some out of the filter, leaving you with a short tart time, then it essentially runs out of fuel. Then quite a bit of cranking to get the air purged out.

 

So the cure is to remove the line from filter head to injector? Or are we talking about 2 different things here, I'm sorry, you'll have to excuse my ignorance, this is my first diesel so I kind of need step x step.

 

Yes, that is the fix, cap off the fitting at the filter head, and the first injector, and life is happy again.

 

WOW! Thanks man, that very well could be my problem, (fingers crossed) I really thought I had it fixed with th return lines. I did them at t-giving & all has been good till this morning.

 

I ran mine dry on a hillside when it started giving me trouble. I had fuel in the tank, but the grade was too much, so it was not at the sump. After that, it would fire for a few seconds, die, then take a lot of cranking to get it back. It would only do that after sitting for more than a few minutes.

 

Does anyone have a diagram of this? On my 91' I noticed on the bottom of my fuel filter is a small fitting that runs into a small hose that appears to go down underneath the engine. At some point this line came disconnected a few months ago and leaked onto the valve cover. I reconnected it but there was no clamp or anything present. No noticeable help with starting but is that the line you are talking about? I'll try and get a pic of it tonight.