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Inconsistent running

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Old May 9, 2024 | 01:06 PM
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Inconsistent running

So I searched this forum, but the search feature just gives me unrelated junk.
I recently tried a new cetane booster at the recommendation of a local diesel shop. For a week the truck ran amazing. Then 3 days of rough noisy gutless with a couple good starts in between. Yesterday it just ran like crap after running amazing in the morning.
Has anyone had this problem and solved it? Is there a common fix?

I should add that last week it would not start 2 mornings in a row until I cranked it awhile and gave it a little pedal. Then it surged and fell back to the normal idle. White puff of smoke both times. Normally just a little black puff.
 
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Old May 9, 2024 | 02:59 PM
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when cold, remove the fuel filter and see if it is full, or half empty.
i am thinking the cetane booster may have loosened up the return line cap o rings just a bit and you are now starting to get a touch of air intrusion.
 
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Old May 9, 2024 | 06:42 PM
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Thanks, I have the kit but have not installed them.
 
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Old May 11, 2024 | 09:44 AM
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Any, I mean Any air in system will manifest itself in so many ways, that its best to be sure everything spanking new and tight in the return system. Also tiny bits of debris in injection or return system will cause many problems.
It's just all got to be clean and tight before you go into any troubleshooting.
Some of the return line kits are garbage. I got one once...caps were such a poor fit I opted to use 34yo Navistar ones instead with Viton orings. Snap on really nice and zero leaks for 3 years so far.
Others may chime in here and tell us which are the good and bad quality.kits.
 
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Old Jul 16, 2024 | 11:35 AM
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Thought I would follow up on this post, I left the van at a diesel place for the 2 weeks I was in Maine and had them install the return line kit and tune the TPS in. Very different machine! So now I have projects to complete like new cooling system, transmission service, and rear differential service. Looking ahead, I am mulling over a turbo.....maybe....Is this worthwhile? Is it affordable? Depends how deep my pockets are right?
 
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Old Jul 16, 2024 | 11:38 AM
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I also asked them to evaluate the mileage on the engine. They seemed to believe the low miles based on how clean it is and original parts.
 
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Old Jul 16, 2024 | 12:41 PM
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turbo kits for vans are harder to come by than pickup kits are. and a lot more expensive too.
 
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Old Jul 16, 2024 | 12:50 PM
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I just read where you said you would not trade your Banks for any price on your 6.9......it is that dramatic of a difference?
 
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Old Jul 16, 2024 | 02:04 PM
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when boost comes on, it is ON. pulling heavy loads i saw boost at 12-1300 rpm. and pulled HARD
also when shifting it stays in boost, unlike a wastegate blowoff valve that dumps boost once the load is off during a shift and you have to build boost again.
 
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Old Jul 18, 2024 | 03:22 PM
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So this morning it would not start until the 4th try.....just keeps befuddling me. Ran great all day. I believe it is easier to make it smoke now, just put the foot in it a little. Having done some searching and reading about CAI's and flow both intake and exhaust, I realized this is like a gas engine. You cant get it in if you can't get it out. And you can't get it in and out thru a straw and air temp matters. So I hooked up a thermistor I have with a portable monitoring device and put it in the intake on top of the radiator. At speed, temps are the same as ambient, that surprised me. Slow down or stop and the temp starts climbing like a rocket. Getting the intake away from the top of that metal radiator would be good thing. Then I need to get the breather off and see if it has the restricted plate in the bottom, I know it does not have the bowl. Last but not least I should go to a 3 or 3.5 inch exhaust....Not sure it will gain much but anything will help, short of a turbo. Any other advice out there?
 
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Old Jul 18, 2024 | 04:17 PM
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you already have a cold air intake, all the aftermarket units are scams to take your hard earned money. but they dont do anything.
anything larger than 3 inch exhaust is a waste.
 
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Old Jul 18, 2024 | 08:43 PM
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I figured as much and there is no place to put anything that takes air from outside the engine compartment in a van. Just seems stupid to lay it on top of a hot radiator. 3 inch is what it will be eventually then. Still has a nice tight exhaust from the factory.
 
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Old Jul 24, 2024 | 08:16 PM
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Now it won't start after setting for any time. Something with those new return lines I am betting. Usually starts after an overnight but did not this morning. Was having to leave it for the weekend to not start. ANy suggestions other then take it back to the guys that did it?
 
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Old Jul 25, 2024 | 07:45 AM
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Do your glow plugs work? Try hooking up the block heater for a couple of hours and see if it's still hard to start
 
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Old Jul 25, 2024 | 12:45 PM
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It is over 80 here every morning. The plugs have worked perfect since I bought it, the light stays on for several seconds even on the warm mornings. It only started this after having the return like kit installed. Usually turns over maybe once and runs.
 
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