Hard Starting 12v???

[DieselDog]

For some reason my nice 12v is getting real hard to start!! This started about 2 weeks ago, mostly in the morning, but can happen on restart too!! I'm also starting to see some white smoke on occasion, even when the engine is warmed up.

I know you guys are the best so I thought I'd put it out there.

Any one have some ideas to check ???

Thanks in advance.

 

[Jeff H]

I once had a cracked fuel line. This would cause a loss of prime. I would have to manually prime it so it would start sooner. Check for any fuel leaks. Leaks also let air into the system. Which may be causing white smoke.

But white smoke usually indicates bad timing.

 

[swamp rat]

DieselDog,



Sounds a little bit like what I am working on right now. I've pulled my overflow valve, and stretched the checkvalve spring as far as I dare.



I've torn down the prescreen filterbowl and replaced the prescreen, O-ring, and metal lock nut. I still have to go back in and remove the upper O-ring to the fuel heater now that someone showed me what I was overlooking.



After I finish that, I need to drop my tank to clean out the crud that is growing there unless it takes me hostage first.



Total out of pocket expense besides the extra fuel filter I had to buy, $8. 76 for the prescreen kit and upper O-ring from Cummins. Labor/sweat equity, about 4. 5 hours, and thats because I learning the hard way. I figure I'm probably $300 ahead of what DC would charge.



If none of the above work, you might have a bad return line as did I before I got fed up with the extortion I had to face. 2 lines, $400, and it still didn't fix the main problems, (hard starting, white smoke, rough/nonexistant idle) but it did stop the fuel leak.



After stretching the oveflow valve spring the first time, it was still hard to crank, but restarted easier, and ran a lot smoother most of the time. I pulled it out and stretched it to a full 0. 5" instead of the 0. 25" before hand.



After viewing the prescreen, I was amazed it ran at all, but the beast had been sitting in storage for a while.



Thanks to the fine folks on this board, I ain't gonna make those mistakes again.

 

[Joe G.]

DieselDog,



The most likely cause of the problem is leaking fuel hoses. Sometimes these hoses aren't actually wet, but they seep out of the ends. There are two of them, supply and return. While you are at it change both of them. It's a lot easier to do if you remove the starter. Make sure the hose you buy is ok for diesel.



The next most likely is the overflow valve. It's located on the side of the injection pump toward the engine and even with the forward delivery valve. It's part of the banjo fitting on the side of the pump. Cram a rag in the gap between the engine and the pump to catch any washer you might drop. Hard to find if it gets away. You can stretch the spring in the valve to see if that helps. That is a temporary fix because the spring will give it up again. If that's the problem you will probably have to eventually replace the valve.



If none of this fixes it then check the prefilter screen. To do this you need a 17mm socket or wrench. The bottom of the lift pump has a place that this wrench will fit. Be careful here because if you remove it from the bottom diesel will flow out and you may get a bath. If you are careful the o-ring will still be usuable. If there is a mess here you may have to take more of it apart to clean it. If it's full of snot you have an algae infection. Ask Swamp rat about that!!



Lots of labor here but not that much expense.

 

[Howard Durand]

DieselDog.

I had basically the same problem with my 94. It became harder to start each morning and if it was left for several days, it took a lot of cranking to get it going.

I changed out both of the fuel hoses and the problem disappeared.

I changed out the supply hose first, working from both above and from under the truck.

When I realized I also had to change out the return hose, I discovered I could do it all from underneath if I removed the starter and disconnected the front drive line. That gives enough room to get your shoulder up far enough so you can remove the clamps and get ahold of the hoses.

Save the old clamps if you can, they are better than most of the clamps you can buy at the auto supply stores.



Off subject, but I am considering having my whole truck covered with bed liner.

I am getting tired of having my paint pop off.

Three times now, I have had to have work done under warranty to repair paint blisters.

Now it is doing it again.

 

[swamp rat]

You pegged me Joe. Last time I had algae that bad was the last year I had a swimming pool and it turned upside down on my in mere hours. Went from crystal clear one day to murky green a 2 days later. Took over a week to get my chemical balance squared away. Thats the reason I have a hottub now instead of a pool. Much less maintenance.



Anyway, Diesel Dog if you do have to follow my path, it really isn't such a horror unless of course you happen to be my size, and then it's just more tedious than strenuous. If you do need to tear into the prescreen filter, I would double check the short supply line that runs from the prescreen/heater to the lift pump. Mine seems awfully soft and crunchy. I would rather replace a $. 15 hose while I am in there than have it spring another leak at a bad time. (not to be confused with the other supply and return line mentioned above) This one is only a few inches long and clamped to the pump and heater housing. If you tear into the heater there is also a $. 56 O-ring in between the heater and heater housing above the prescreen filter bowl that might should oughta be checked. Thats on my agenda later today when I find out what size allen wrench I need to loosen her up.



If I can help walk you through any of it just shoot me an email, I'm getting a hard learned hands on education these last few days.