injection pump

[jeeppuller]

Friday afternoon on my way home I noticed the truck hunting for idle. It seems like the governor is cutting fuel until the idle drops then it comes right back up,this just goes on and on. I think I've got an internal leak but not sure what would cause this high/low surging. I realize this is probably a Bosch-only servible part but I'm curious if there is anyway to check for an internal leak.

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93 W250 5spd Getrag, 16cm2 housing, Bank exhaust, K&N air filter, pyro and boost gauges and moderate pump adjustments. Daily driver.

 

[ScottB]

I had what sounds like the same thing happen to my truck. I used standayne fuel treatment seamed to help a little but it kept getting worse. I got my pump into an injection shop. They said my pump was ok but govenor was tired. But they were already into the pump so it was rebuilt.

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93 W350 5spd White 3. 54 gears 4" stack Powerwagon Injectors. Headache rack with lights. Cummins Mudflaps. 2" lift on seat. Goosneck ball Beefed up reciever. Fog lamps, Back up lights. CB 98 Factory sound system

 

[DJP]

Do you have a tachometer? It sounds like your idle speed is set too low. Try turning your idle screw in a little to kick up your idle speed. I have found that setting the idle speed a little higher will not only eliminate the surging, but will also help the turbo spool quicker on acceleration.

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89 D-250 LE 5 speed 3. 55 Limited slip, Banks Intercooler, 'Ol Blue Specials, K&N, Full Boar Muffler, 3" exhaust, Diesel Dynamics Stage 1 kit, Boost/Pyro. & 16cm2 215K miles.

 

[jeeppuller]

My tach reads normal, about 850 when the idle drops but thens revs to 1500 and back again. If I rev it up to 1500 then lift, it will calm down long enough to shut it down. I don't think it's an idle adjustment because I haven't touched the pump in about a year and it hasn't changed before.

 

[unclebilly]

This is the first sign of wear from not running lubricant in your fuel - to replace the sulpher. I suggest you start running some now. Hopefully, the pump is not completely phuct and the additive will return it to somewhat normal operation.

One boat that I ran had a CAV pump and the hunting started to happen, adding a litre or 2 of outboard motor oil every 100 gallons of fuel seemed to rectify the situation - although I did get a spare pump and keep it handy.

Scott.

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91. 5 CTD 4X4, 5" Stacks, Tweaked Pump, 33" Boots (in the summer), Unlimited Slip,
<P><B><A Big, Bad Dodge

 

[jeeppuller]

Thanks unclebilly, any recommendations on what to run for lube? I've never run any additives but I guess I may have to now, hopefully it's not too late. I'm sure I'll be sending the pump out soon, the truck has 120,000 miles on it.

 

[unclebilly]

Go to a truck stop and buy Diesel injector lube. I'm running Bardahl in my Cummins. We run outboard motor oil in the fishboats because it is readilly available. Even Walmart carries injector lube - get as big of a container as possible so you get the economy of scale.

About 5 years ago, the refineries quit putting lubricant in fuel and kept quiet about it (I'm guessing this was to reduce emisions). I remember how many fellow fishermen replaced injector pumps that summer, luckily I caught mine in time. I remember trolling along (or dragging) and the engine would surge to 1300RPM and then drop back to 800RPM. It was really puzzling until word got out what the problem was... Adding the lubricant definately solved the problem. A freind of mine was running a new 6BT in his troller at the time and replace his pump with less than 1500 hours on it.

Good luck!

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91. 5 CTD 4X4, 5" Stacks, Tweaked Pump, 33" Boots (in the summer), Unlimited Slip,
<P><B><A Big, Bad Dodge

 

[Power Wagon]

It's possible the pump has a problem... I wouild check carefully for air in the fuel... as in a leak on the vacuum side of the fuel pump, or at the fuel pump itself.

That could cause some odd running/surging like you describe.


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ICQ 3807791 Power Wagon
www.my2kcity.com/powerwagon
Mark Koskenmaki, General Diesel Moderator

 

[jeeppuller]

Thanks again guys for the info, I was going to check all my fuel pressures but haven't found the time in last few days. The power in midrange and top end are normal so my guess was the pressures would be OK but logic like that usually gets in trouble so I'll be breaking out the gauges today. In the meantime I'll be shopping for some fuel lube to try that.

 

[Jim Curry]

On the advice of a diesel Mechanic i put one QT of transmission fluid in every tank of diesel. Lubes the fuel system and is not as expensive as the fuel additives. It is also available at any gas station. Fuel additives may have other benifits but the transmission fluid works just fine. I have almost 163,000 miles on my 93 D-250 and have had no problems with engine,fuel pump or transmission for that matter. So in a pinch give the transmission fluid a try . It has worked for me.
Hope this helps with another alternative to try.

JIm Curry

 

[jeeppuller]

Well, I thought I'd try some Husky 2 stroke oil this morning. It's the only lube I had that I figured would burn without smoking too badly. I drove 15 miles to work and now the truck idles normally. I have about 30 miles on it since adding the oil and it is idling great. I guess I'll be running fuel lube regularly now. I talked to the Bosch guys we send our pumps to at work and they're curious to get in the pump and check it out. Now maybe I'll have the Bosch guys crank it up and a set of injectors. Thanks guys.

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93 W250 5spd Getrag, 16cm2 housing, Bank exhaust, K&N air filter, pyro and boost gauges and moderate pump adjustments. Daily driver.

 

[Matt S]

DO NOT PUT TRANSMISSION FLUID IN THE FUEL TANK!

It is an abrasive. There are friction modifiers in it. Unless you think you need an abrasive to clean out your gummed up system. Otherwise your causing undue wear on your expensive fuel system parts.

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90 W250, 5-speed, isspro gauges, 16 cm2, K&N, Borgeson shaft, JRE 3" exhaust, Banks Intercooler, Lucas injectors