12 Valve 2nd Gen Dodge Cummins 94-98 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with P7100 Injection Pumps

fuel problems

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  #1  
Old 01-11-2010, 05:01 AM
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ok guys bear with me as i am not a dodge guy but i am triing to figure out what the problems are with the fatherinlaws truck are. i beleave its a 90s model (grill stays attached to the hood when you open it if that helps)he had a problem with it not running right so wee changed the fuel filter then it would only stay running for a short period of til but still wasnt running right then found out then found that it was just running the fuel out of the filter and shutting off so we replaced the mech. pump on the block but it is still just only running the fuel out of the filter but not keeping fuel in the filter. th anks for any help anyone can give its a 94 with a straight 6 cummings
 

Last edited by stonedmason666; 01-11-2010 at 06:09 PM.
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Old 01-11-2010, 09:08 AM
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sounds like either the fuel sock in the tank is stopped up or you have a crack in the pick up tube either way it sounds like its in the tank
 
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Old 01-11-2010, 04:10 PM
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I'm going to move this to the 2nd gen section seeing as how I think that is the truck you are working on.

Good luck!
 
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Old 01-11-2010, 06:16 PM
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well i cleaned out the fuel heater/prefilter hoping that was it. it was really dirty but now i cant even hand pump the fuel into the filter guess there no way around dropping the tank and as my luck would have it he just filled the tank up
 
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Old 01-12-2010, 06:52 AM
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Before you drop the tank put some fuel in a bucket and run the suction line from the LP to the bucket and see if it will pull the fuel from the bucket and run. If so take the plastic line from the tank to the frame and put some rubber line to the steel line on the frame and see if it pulls the fuel from there and runs. If not them replace the steel lines with diesel rated rubber. They are notorious for leaking and sucking air but not leaking fuel. There could be something in the tank yet but it's easier to check out the lines vs. dropping the tank. I would also just replace the lines that run from the engine to the frame rail. 3/8" supply and 5/16" return FYI. Also.....it's CUMMINS.... there is no "G" in it.
 
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Old 01-12-2010, 06:59 AM
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Originally Posted by Dusterb318
Before you drop the tank put some fuel in a bucket and run the suction line from the LP to the bucket and see if it will pull the fuel from the bucket and run. If so take the plastic line from the tank to the frame and put some rubber line to the steel line on the frame and see if it pulls the fuel from there and runs. If not them replace the steel lines with diesel rated rubber. They are notorious for leaking and sucking air but not leaking fuel. There could be something in the tank yet but it's easier to check out the lines vs. dropping the tank. I would also just replace the lines that run from the engine to the frame rail. 3/8" supply and 5/16" return FYI. Also.....it's CUMMINS.... there is no "G" in it.
thanks for the info and dam i make one little spelling mistake and your ready to jump down my throat said iwasnt a dodge guy
 
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Old 01-12-2010, 07:20 AM
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It's just a pet peeve of Cummins guys. The stock fuel lines are notorious for sucking air on these trucks. Most guys I know just end up replacing ALL the fuel lines with diesel rated rubber line.
 
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Old 01-12-2010, 05:30 PM
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check fuelline between the tankand the frame.. thats were i found me seaping. the werent leaking but seaping enough to cause me issues.
 
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Old 01-12-2010, 11:13 PM
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Sometimes its easyer to pull the bed up about a foot in the front rather than drop the tank in the end by yourself it takes the same amount of time in my opinion.
 
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Old 01-13-2010, 07:00 AM
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Originally Posted by joey
Sometimes its easyer to pull the bed up about a foot in the front rather than drop the tank in the end by yourself it takes the same amount of time in my opinion.
i would rather lift the bed i think its alot easyer sence the bolts are easier to get to even with the ball hitch plat in the bed.but it all depends if fatherinlaw lets me do it that way

---AutoMerged DoublePost---

[QUOTE=Dusterb318;469490]Before you drop the tank put some fuel in a bucket and run the suction line from the LP to the bucket and see if it will pull the fuel from the bucket and run. If so take the plastic line from the tank to the frame and put some rubber line to the steel line on the frame and see if it pulls the fuel from there and runs. If not them replace the steel lines with diesel rated rubber. They are notorious for leaking and sucking air but not leaking fuel. There could be something in the tank yet but it's easier to check out the lines vs. dropping the tank. I would also just replace the lines that run from the engine to the frame rail. 3/8" supply and 5/16" return FYI. Also.....it's CUMMINS.... there is no "G" in it.[/QUOTE

after i did the the hose to a fuel can direct to the lp it ran fine until ihooked the fuel heater back up and noticed aleak CUMMIN from it so to make sure i was just the heater i ran a temp line from supply line to the inlet on the pump and it runs fine now so i hope i dont have to mess with tank but now i need to find a fuel heater anyone know where i can find one pretty cheap
 

Last edited by stonedmason666; 01-13-2010 at 07:00 AM. Reason: Automerged Doublepost


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