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Thread Title:

n14 performance

Created On Wednesday September 30, 2009 19:00

nels

Posts: 8
Joined: Sep 2009

Wednesday September 30, 2009 19:00

I have a recon cummins engine.The recon replaced a 1994 n14 engine. Under warranty i had two sets of injectors put in it,two sets of heads,at different times and because of excess oil use,new liners and rings. The engine will rarely idle decent,kind of erratic. The power comes and goes. Sometimes it will run really good,then it will be a dog. Lately, the bottom gears seem to have power but when i get to 5,6,7,8, its like its starving for fuel,sometimes the whole engine and truck shutter and shake. Sometimes at 15 to 1700rpms it loses power, then it comes out of it. I have had two cummins shops look at it and no one can figure it out. Any help would be appreciated,Mark.

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silo04

Posts: 32
Joined: Feb 2009

Wednesday September 30, 2009 19:35
Have u ever had fuel tanks cleaned?

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nels

Posts: 8
Joined: Sep 2009

Wednesday September 30, 2009 19:41
I only use one tank,the other is shut off. the tank is about a year old,replaced it after a deer hit. It looks clean inside.

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westcoast

Posts: 982
Joined: Dec 2008

Friday October 02, 2009 06:05

Whats your cpl number ? Do you have top stop injectors or stc ? Was this problem associated with your old engine as well as the new one or just this engine ? Erratic idle is usually air in the system - fuel pump coupling ( plastic coupling broken )- or the fuel pump itself - Check the fuel return for air bubbles and get somebody to check your fuel crack off pressure . Depending what you find determines where you go from there - Check from the pick up pipe through to the pump for a restriction in a fitting or hose ( rubber flap or debris ) Regards David

-------------------------
detroit

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nels

Posts: 8
Joined: Sep 2009

Friday October 02, 2009 08:42

The cpl no. is 1844. My pre recon engine was also cpl 1844. The reason I put in a recon was my old engine was acting alot like the recon is now. I do not know about the injectors. They were put in by a Cummins distributor,so I assume they are right.I could call them and find out.My first engine started having issues after my factory injectors needed to be replaced and only recon injectors were available.The engine at that time had about 850,000 miles on it.I got fed up with old engine and put this one in.This one acts alittle like my old engine,but its different.Basically,erratic ,sometimes it runs good,sometimes not.Lately,its been better,but still acts like its starving for fuel in 6,7,8, gears.The other day I took hose off from filter to pump. It had black slime in it. I cleaned and blew it out.Also on output fuel fitting ,it has a depressing pin. I pushed in on that with truck running and held a plastic cup in front of it. I got some small pieces of black crap coming out with fuel into cup.Even after this it still runs erratic.Maybe I need to have pump cleaned. Also check for air in return fuel,restrictions, and check fuel crack off pressure that you suggested.Hopefully,this added history will give you more insight into this engine problem. Any more ideas into solving this would be appreciated. Thankyou,Nels

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westcoast

Posts: 982
Joined: Dec 2008

Friday October 02, 2009 15:09
Celect engine - Still check for air in fuel and fuel pressure - sounds like you,ve either got a gutful of algea or a rubber fuel hose coming apart inside , as I said check from the tank through to the pump , make sure your not sucking air around fuel filter Regards David ------------------------- detroit

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marc7242

Posts: 254
Joined: Sep 2008

Saturday October 03, 2009 16:01
I agree, at this point change all of the lines and fittings, everything, even the standpipe if you can. Check the ECM cooling plate and drain-back valve, these are commonly missed items, you can try bypassing the cooling plate temporarily. Have you tried a fuel pressure and restriction gauge? marc

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marc7242

Posts: 254
Joined: Sep 2008

Saturday October 03, 2009 16:02
also, if there are any OEM filters/housings, try bypassing that

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nels

Posts: 8
Joined: Sep 2009

Saturday October 03, 2009 19:45

The drainback valve had a piece of metal sliver in it,just past valve in four hole part of valve. I cleaned that out,did not seem to help.I did put new fuel hoses on it before I put in the recon engine. I guess its possible to have a new hose come apart or debris or maybe a floater.I think checking for air and fuel pressure suggested earlier is a good idea. I had a cummins service man suggest that this cpl 1844 engine with new low nox emission software,could be causing an issue. What do you think? He tried to convince factory guy to try old original software. He would not do it. What were you saying about ecm cooling plate being a problem? In a previous reply I told about slime in fuel hose from filter to pump and getting crap out of fuel high pressure tap fitting on pump.

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marc7242

Posts: 254
Joined: Sep 2008

Tuesday October 06, 2009 16:06

The aluminum plate behind the ECM has fuel in it, and there is a check valve in one of the fittings. The passages in the cooling plate can become restricted and the valve will sometimes stick. You can check for air in the fuel by looking for air in the return fuel, but this test can be very deceptive to interpert. One thing you can do is remove the lines at the tank and pump end. Plug one end and pressurize the other end and see if you can find a leak that way. The sludge you found could possibly be plugging that cooling plate. Do you have quick connect fittings on the pressure and suction side of the fuel system? If so, you can get pressure and restriction gauges at a hydraulic supply store and plumb them in with long enough lines so you can see them when driving. Cummins should have done this but you never know. Did they do anything to it or did they say they couldn't get it to do anything. Remember if there is chance of warrantee, the dealer will avoid it if possible
marc

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nels

Posts: 8
Joined: Sep 2009

Wednesday October 07, 2009 06:25

It would not act up when they had it. I do have fittings on fuel pump. I will make up my own gauges and run into cab so I can monitor the pressures. I did blow out the passage behind the cooling plate. I replaced both fuel lines from filter to pump and to block. I had harness plastic wrap on these old fuel lines. These were original hoses,the only two i have not changed. I found a wet spot on one from block to filter when i took plastic protector off. Maybe it was sucking a little air there. I have not pulled a load since. I am hoping changing these hoses takes care of it. I will let you know how it goes. Thanks,Nels.

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marc7242

Posts: 254
Joined: Sep 2008

Thursday October 08, 2009 15:29

The gauges will tell you the truth whether its restriction or pressure. If restriction is high, you just need to find it. If pressure is low but restriction is good you could have a pump issue or being sucking air. If restriction is too low, it could mean you're sucking air, like a hole in a straw. The results could be difficult to interpret, but if one of the gauges starts acting up when the problem happens, it'll be your clue.
marc

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nels

Posts: 8
Joined: Sep 2009

Sunday November 01, 2009 20:54

I checked for air in fuel. I had some . Changing the filter head took care of that.I ran gauges on suction and output side of pump. The pressures seemed good. Like I said in an earlier post in 6,7,8, gear,especially 6th gear going full throttle, the engine would stutter and shake.My mechanical boost gauge seems to show good boost. A friend of mine had a diagnostic device he hooked up. at 1600rpm to 1800rpm My electronic boost would fall off completely then come back about 1800rpm. My mechanical boost on my truck gauge seemed fine.I put a new boost sensor on. It did not help. I wonder if I could have an injector thats not putting out to full fuel,or a crack on an injector o ring? My oil level seems to go up about a half a gallon and stay there. I ran an oil sample and everthing came back normal.My antifreeze level is ok. there is no snot under the oil fill cap on the top of engine. Any ideas would be appreciated. Thanks,Nels.

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