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twistedjack

surging and other problems

13 posts in this topic

Okay guys I will try to explain this the best I can. Under load as I add fuel the boost and pyro will come up together like normal but then will rapidlly fall off and if I don't lift my foot will almost die and then notice blue smoke as the motor stumbles. If I lift the throttle it recovers and then the boost will come back up. It was "surging" really bad back when I was on the road and spent a lot of time on the phone with Muddy trying to figure if I had a boost leak or not which I don't think I have. It stumbled and died on me, I had to re-prime the system so I am not getting enough fuel to it. I replaced the fuel filter and cleaned the screen which didn't look bad. I think it is the lift pump but I don't have a gauge that reads high enough to test it. Do you guys have any suggestions? I dont want to run out and buy a pump if it is somethng else.

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Sure sounds to me like you are having fuel issues.

What was your EGT's while this was happening? If it is a boost leak then the engine usually still fuels without enough air, usually resulting in high EGT's and rolling coal out the tail pipe. If you run out of fuel, then boost drops as well.

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Have you checked for fuel leaks or maybe gummed up lines? Sounds like a fuel problem to me too but I'm still a dume :D with this stuff

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The fuel lines are new all the way from the straw in the tank to the pump. The egt's were only high went the boost comes back quickly not much some out the pipe at all.

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If your EGT's were dropping, then I would say you were running out of fuel. Time for a fuel pressure gauge.

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Definetly sounds like you need to check your fuel pressure. Terry at Moonlight had a gauge made up that you would thread into the top of your fuel filter housing and set on your cowl so you could drive around and monitor the fuel pressure under different driving conditions.

Justin

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check all the fitting's on your fuel line, especially at the back of the pump. Even a slight leak will cause stumbling. If it seems to run fine at lower rpms, with light fueling, and gets worse as more fuel is applied then i would definatly check for leaks. It doesnt take much air to get into the system for it to lose its prime.

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Well a little update it is definately the lift pump. Today I hooked up a holley"blue" pump that I had laying around. I hooked it up to the fuel line along the frame ahead of the stock lift pump. When I took it for a drive it stumbed so I turned the pump on and it instantly started running right. Turn pump off started running like crap again. So Monday I will order up a new pump.

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I picked up the pump yesterday at Cummins in boise for $90 with all the gaskets and seals. Not a bad price since the dealer wants $160 and the parts stores want $200 It was the same price as the cheapest I found on the internet with shipping.

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Glad to here you are getting it fixed and that it did not cost you an arm and a leg

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I picked up the pump yesterday at Cummins in boise for $90 with all the gaskets and seals. Not a bad price since the dealer wants $160 and the parts stores want $200 It was the same price as the cheapest I found on the internet with shipping.

It is funny how much cheaper Cummins is than Dodge on some stuff. I bought a vac pump seal kit from Dodge that was opened, so I could read the Cummins part # that was under the Dodge #. Called Cummins to price check and was speechless. Dodge cost with discount was $80, same exact thing through Cummins was $8.50...... Needless to say, I returned the set right away to the dealer.:thumbup:

Now that she's running better, time to start the 4wd conversion!

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Yeah Dodge is highway robbery on Cummins parts. Doesn't make sense to have that kind of mark up!

Would be interesting to see what the actual cost is on the all the other parts that are outsourced.

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