I have a 99 F-350 with the 7.3. Here’s my problem. First it’s a nightmare to start if it’s not plugged in and it hasn’t even gotten that cold out yet. Sometime when it does start I have to fight with it to keep it running until it warms up. I have to hold the rpm’s around 1000 to keep it running. Also I will get some whiteish blue smoke coming out sometimes to. That’s the first problem. The second problem is once it is warmed up it runs pretty good but some times it will randomly start idling rough. Also it recently started blowing massive amounts of blueish white smoke out of it while driving down the road. It doesn’t always do it but it’s doing it more and more now. It’s seems to only do under certain throttling positions. If I floor it the turbo kicks in and the smoke clears up but it will go right back to doing the same thing.
So far the only thing I have done is changed the fuel filter. I did buy Rottela 5-40 oil and a new oil filter and air filter that I haven’t had a chance to change yet.. I would like to do it today but it’s raining. I may do it anyway. I know it sounds like I have two different problems here but maybe some input would help. This truck is my lively hood and I need it for work.

 

One other thing is that I notice while trying to start the engine and it is cranking it dosn't start until I see the oil pressure come up on the gauge. It seems like once it builds up oil pressure that's when it starts.

 

Are you throwing any codes? How long since last oil change? There is lots of info on this subject just have to do some searching.
I would start with checking your GPR and GP's, do a search on this and you will find details on how to ohem them and your injectors, its a good place to start.

 

It sounds like you HPOP resevior is allowing the oil to leak down and the extended cranking is required to refill the resy. before it starts. Check the level before your next start. Pull the little plug out of the top of the resevoir, hex head plug, and the oil should be within 1" of the top. If that is good, the you could have weak batteries. Check voltage while cranking, anything less that 11 volts can cause starting problems. As stated above, the GPR (glow plug relay) could cause problems as well. Are you getting a WTS light? You can turn the key on, jump across the large post on the GPR for about 1 minute and see if it starts easier, if so, GPR is not energizing. Also mentioned, make sure your oil is full and not too old.
The smoke issue sounds like you may need a new air filter. What are you using for a filter?

 

Ok I changed the oil and I’m almost embarrassed to post this but before I drained the oil I checked the dip stick and found no oil on the dip stick. Soooo It was very low. I changed the oil with 5W40 Rottela and installed a new oil filter and air cleaner. This is REALLY bad but I put almost 4 gallons of oil back in and I dumped the oil pan back into the empty containers and only filled one and a quarter of the containers back up with the used oil. Good god I’m surprised I didn’t burn it up. Well I will take this as a lesson learned and hope this fixes my problem. I do still have a problem with long cranking before it starts. It has done this from day one since I bought it and it doesn’t matter if its cold or warm. Do you think this is because of the HPOP letting the oil Drain back down? Or maybe the batteries are weak? I will look at the oil level tomorrow morning before starting it to see were it’s at. I did look at it once before but it hadn’t been setting for very long after it was running and it was fine. Also I will check to see if my batteries have at least 11volts while cranking. Thank you guys for your help.

 

Wow man that is way low, do you know when the last oil change was? Makes one wonder if some local shop did it and only put in 6 qts not knowing better

 

I bought this truck around March and the guy that I bought it from just had it serviced so I left it at that. I should have looked at things a little closer. It didn't start running like this until it started to get a little cooler out.

 

I guess just watch the oil level as you progress through time. As for hard starting, I am sure that will be figured out here shortly pending the results of the HPOP reservoir level.

 

OK, I will give you the possible bad news. None of the ideas offered so far explain your blue exhaust and loss of oil along with hard starting as it cools off. What may explain it is bad compression. You may have a bad injector oring but that would show signs elsewhere too, like overpressurizing the fuel system or getting into the coolant via a bad cup. Just some things to consider.

Sorry for the problems but you are started in the right direction by looking for the problem. BTW, it is hard to burn up a 7.3 with lack of oil as the engine will quit running without oil because there is no oil to fire the injectors. Good luck.

 

OK, sorry, that last post did not recommend anything. Fire the truck up and pull off the oil fill cap on the valve cover. Look for excessive blowby evidenced by a choo choo type smoke coming out of there. If you have blowby, you have bad compression and problem has been identified.

 

First thing this morning I pulled the plug from the top of the HPOP and I tested it using a wire tie. It's about a half inch from the top of the HPOP body (bottom of the plug thread hole).

Ok I checked the GPR and I have 11.8 volts to the second post after the key is turned to the on postion. I also do get the WTS light.

I checked the batteris while cranking and they drop to just below 11volts. They were both between 10.5 - 10.8 volts.

Also the truck wasn't pluged in last night and I started it and didn't wait for it to warm up (it's not that cold out) and it ran perfect. It started easy and ran smooth. Normaly it would have needed to been plugged in and it would have had to run for 15 minutes or more before I could drive it and this would be fighting to keep it running for 15 min. Anyway I took it for a test drive and it ran smooth, no smoke and idled perfectly.

When I got home I removed the oil fil cap and look for the "Choo Choo" smoke and it was just a steady steam' I'm not so sure it was smoke. It look more like steam and it was steady, not pulseating.

Well the truck is running good again and I will keep an eye on the oil level to see if there is any change. If there is any major change then I will have to figure out were the oil is going. If I had a blown head gasket wouldn't there be a loose of power and the engine would smoke from the tail pipe all the time?

Thank you to everyone, I'm new to diesel engines and if it wasn't for this forum I would have probbaly put it in the shop.

 

10.5 volts is the very minimun for the PCM to work. It sounds like your batteries are weak, cold weather will take it's toll on them. The steam is normal, the puffing Mike spoke of is very noticable and puffs smoke out of the fill tube. You may want to look about replacing your batteries. You are at the very bottom of the scale and anything lower and you will have a hard time cranking. Keep a check on your oil level. That blueish smoke is coming from something. That color usually means oil is being burned.
How bad was your air filter?

 

The air cleaner was really dirty as well. I have driven the truck almost all day today and it starts better then it ever has and there is no more smoke of any kind. I may go ahead and replace both batteries though. The ones that are in there are Interstate but I may go with the Walmart batteries. I have read quite a few people on here that really like them. I have also put them in other cars and trucks as well as my boats and they seem to be pretty good batteries. Ive never had any problams with them.

 

A dirty filter can cause smoke because of lack of air. Usually the smoke is black/gray. Sounds like you have 'er fixed. Get the best WalMart batteries with proper amp rating and you should be good. Be sure and replace the pair, never do just one.