Any Dodge 12valve owners have starting issue with pre-heater/filter bypassed?
March 26, 2011 - 11:40pm
I recall getting advice from folks here that I should bypass the pre-heater and filter screen on the Cummins engine. I wonder if anyone who has done this has had this issue or could perhaps shed some light for me.
I have been having startup problems and have had 3 different mechanics try to figure out the cause. It will start right up, but stalls out after 15 - 20 seconds. It then sends out some whitish greyish smoke. Then, I wait 20 or so seconds and crank and crank and crank and I'm lucky if if it finally turns over with clouds and clouds of black smoke. It then runs just fine, with the exception of needing the idle speed adjusted, as it stalls out randomly when turning corners, etc. You can imagine how much my wife likes it when that happens.
Some more oddities: There is quite a vacuum present in the diesel fuel tank. When I remove the fuel cap, there is a huge whoosh of air entering the tank. Figured this might be the problem, so removed cap before shutting off engine, left it off, next morning, same problem starting.
I just noticed that the bracket on the fuel selector valve has broken at the 90 degree bend. All the fuel lines are good and tight.
I should also say that I've not been running any grease for the last year. This is all on the diesel side.
Here is what has been done to alleviate the problem: New fuel lines all around. New Fuel Pump. New Starter. New gaskets, seals, o-rings. The Cummins shop had it for 3 days. Another local commercial garage has it this time. An excellent local mechanic had it at his house for a week and a half. No one can figure out what the issue is. The mechanic who has it now is convinced that it's the fact that the pre-heater is bypassed. Says the fuel is being heated by the injector heaters at startup, but after that is burned through, the cold diesel is coming in causing the stall. What do you think? My heater is completely shot, or we'd just plumb it all back in. The only one we could find is at the dealership and will cost me $750 to replace, and I don't even know if that will solve the problem.
If anyone has any insight, I would be most appreciative.
March 27, 2011 - 8:55am
#2
Hi MIller:
How you doin?
I'm protecting the city today.
March 27, 2011 - 8:58am
#3
I have a first gen 12-valve with a manual lift pump. I have not experienced any of these problems, sorry.
The only thing I would suggest is for you to install an additional breather tube on your stock tank
March 27, 2011 - 10:49am
#4
I had similiar issues that you are describing and it turned out to be an air leak on top of the diesel filter. I tightened down one of the fittings and it went away. If my truck sits for a few days when the temperature is down around 0 the diesel will gel up and the engine will want to stall a few seconds after startup but after giving it a little gas it will usually work through it. But that could happen with the fuel heater in place. You might consider replacing the seals on the fuel connections on top of the diesel filter if you haven't already done so. Mine were in pretty bad shape when I pulled them off to do my install.
Unless you live in a super cold environment I wouldn't think bypassing the heater/prefilter would give you any problems. I agree with Brian, it sounds like an air problem.
Have you had this problem since you did the install or was it fine and all of a sudden you started having issues?
March 27, 2011 - 11:06am
#5
It was fine for a long time, then it started out of the blue.
March 27, 2011 - 11:10am
#6
I should have also mentioned: If parked on a hill, front of truck facing downhill, it starts a bit better. If front of truck is uphill, it's nearly impossible. ?!?!?!?!?
March 27, 2011 - 11:14am
#7
I am sure one of the mechanics did a fuel pressure test. That should determine where the problem is coming from. Did they check the overflow valve? I would think they would. I remember someone had a diesel filter that wouldn't seal airtight and had to replace the whole unit.
So replacing the lift pump didn't help? If it's not an air leak it's a lack of fuel pressure from something else. That could come from the lift pump, overflow valve, or the worst case the injection pump.
March 29, 2011 - 9:48pm
#8
Ok, another strange thing: When I got back from a 50 mile drive today, I opened the fuel cap before shutting the engine down. Again, big vacuum in the stock tank. So, I left it off, then shut the engine down. Left the cap off for about 30 seconds or so and put it back on. Went out two hours later just to look at the cap, and again, a significant vacuum had built up in the tank - WITHOUT THE ENGINE RUNNING!! How is that possible?
March 29, 2011 - 11:02pm
#9
Maybe you have a huge bacteria colony inside your tank. Their reproduction requires oxygen which pulls a vacuum in your tank.
March 30, 2011 - 5:02pm
#10
Check the electric plug on the preheater if it is wet and smells like diesel your heater is bad and your loosing your prime you can just bypass it. I live in Jersey and haven't had a problem since I bypassed it. Good luck!!!
January 28, 2012 - 2:33am
#11
hey there mr.guitargerber how did you solve this problem? how much did it cost you to fix it? i just would like to know because i am having some similar symptoms on my dodge. this is becoming stressful. good thing there are sites like this given by my friend for Dodge truck parts
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I don't know alot about dodge. but for a diesel engine that sounds like an air problem to me.
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