Another cold start thread.......

[yellaheep]

Ok, after searching, I've found that most threads about cold starts are during deep winter conditions and glow plug issues. My situation is different.

Just purchased an '89 F350 16' U-haul box van with the 7.3 IDI and C6.

I purchased the truck at 8pm in 10 degree winter weather last week. It was frosted over, owner said he hadn't driven/started it at all that day. It fired right up after the "wait to start" light went out, and idled a little rough for about 30 seconds then was fine.

The past two days have been 45 - 55 degrees out, late morning. Each time I've tried to start it, it cranks and acts like it wants to fire, but won't until I hold the throttle wide open. Then, it'll start and run, but barely - very rough idle, mis-fire sound at the exhaust and BIG amounts of black/gray smoke until it clears out about 2 minutes later and only if I revv it up a few times to "blow it out".

Glow plug issue? Leaking injector(s)?

I have about 20 minutes of seat time in this van (driving home after buying it) so I don't know if this has been a problem in the past, but sure is frustrating that it has this problem now and not when I looked at it before buying it.

Thanks in advance guys!

 

[Diesel JD]

Its probably an air fuel leak on the return side. The most common issue is the return o-rings, caps or lines getting brittle or losing their seal and letting air in. It can also be other areas of air leakage which can be much much harder to track down. I wish you the best of luck with it. Are your injector returns leaking any at all?

 

[Andylad13]

99% chance that this is an easy fix. do what JD said and also bleed the fuel filter periodically. this is definatly an air problem.

 

[yellaheep]

On the '93 IDI you guys helped me with, the return lines and o-rings were definitely bad, but they were leaking fuel, not air.

This '89 doesn't appear to be leaking fuel from those areas (no fuel dripping/puddling like the '93 did) but I haven't pulled the dog house yet to get a better look at the injectors. No fuel smell either.

Apparently it doesn't need to be all that cold out either. It was about 55 degrees today and the van sat facing the sun most of the morning/afternoon. Went to start it and it still wouldn't fire unless I pressed the gas pedal to the floor and held it until it fired. Then, I have to keep the RPM's up to clear out the cylinders for a minute or two, then it'll rough idle until warm.

Still thinking it's fuel return lines and/or o-rings?

 

[Diesel JD]

Not sure its the orings and caps...but its definitely(well almost definitely) air leaks. This kind can be trickier to find.

 

[Michael Fowler]

You might want to install (even temporarily--for diagnostic purposes only) an electric fuel pump. You could even put a manual switch on it.
Then, for your next cold start, turn on the electric fuel pump, then raise the hood, and depress the center stem on the schrader valve on the side of the filter head and see if you get a steady stream of fuel, or is there air present.
If you see air, then you know there are leaks. Even if you see no air, but ir starts right up using the electric pump, you would know there are leaks.

 

[fuzzy1626]

Return lines and seals can let air in before they get bad enough to let fuel out. Are the glow plugs still working? After it has been run and shut down for a couple of hours does it start right up?

 

[yellaheep]

Return lines and seals can let air in before they get bad enough to let fuel out. Are the glow plugs still working? After it has been run and shut down for a couple of hours does it start right up?

Yeah, once it's been fired up and warmed for about 5 minutes, it fires up and idles just fine. It's just the initial start after sitting over night or longer.

It's an old U-haul van and I have the maintenance records for it. It received new injectors and glow plugs in late '05. Dunno how quickly glow plugs go bad, but the mileage on the van then was 130K and it now has 174K. How often should glow plugs be changed?

 

[Agnem]

They generally last a really long time in a properly functioning glow plug control system. They shouldn't be bad.

 

[cleithau]

From the sounds of it, you are deffinately getting air in. That what mine did when I had a leak, started horrible first thing but started fine after that, till it sat for a while. I eliminated the line that went from the return line caps to the fuel filter and replaced all the hoses/caps and o-rings and now it starts great, and added an electric fuel pump. Got rid of the mechanical one entirely.

 

[6.9guy]

My 85 does act almost the same. But it will start up and run for a few seconds then die. When i try and restart it, it justs cranks and cranks. Sometimes it takes a while to restart other times not so long, but it seems I always have to give it some throttle.Could this be an air leak as well?

 

[Andylad13]

oh absolutely 6.9 guy!!!! air is the fastest way for a diesel to shut off. what happends is you get the initial fuel supply goin to help fire, then the air comes in and some cylinders are gettin it, some arnt. and before you know it its off. now when you crank, you are mechanically bleeding all the air out so you can run, often 4-5 times of 10 second cranking. check the injector caps and o rings, and lines. if there is fuel comming out on some caps the o rings need to be replaced. if your lines are the braided factory ones, they will need to be replaced more likely then not.
when i first got my truck i addressed the problem, and my o rings were shot, and my lines were cracked, like when you bent them they would split.
i also replaced that one way valve from the filter head to the return lines.

good luck.

 

[fuzzy1626]

No more than 20 sec. cranking, then a 2 min. cool down for the starter is recomended.