Best Injectors

[AndrewKing]

HI All,



I have a 1989 D250 with Cummins (auto trans and 3. 07 rear end... approx 250 K Miles)..... I started having problems with the injectors... . I was wondering what the best injectors were for this engine in terms of getting good fuel mileage & reliability..... The truck is bone stock (except for an after market trans cooler).

I use the truck to haul a total of approx 3600 lbs on a tandem trailer (lawn care). I don't need big power but ironically I have heard that some of the more performance oriented injectors can give better mileage too... I primarily want an injector that will give me the best MPG's possible without having to worry about EGT's (helpers drive the truck). Also where is the best (cheapest and best service) place to buy the injectors from?



NOTE: I am going by what the shop thinks I need and truthfully have no way of actually knowing that the existing injectors are in fact bad... The symptoms

included rough running and smoke at idle... . I did replace the fuel filter and air filter but that didn't help... . In a previous post I did mention that diesel fuel was found in the oil and the mechanic suspected a leaking injector... (I did ask them about the lift pump too and the gasket at the front of the injector pump leaking possibly.



Thanks

Andrew

 

[sdstriper]

That truck already has large injectors, the Non intercooled engines had larger injectors than the Intercooled trucks that followed. More timing as well. How much do you trust the shop your taking it too? I would maybe get a second opinion. For your application I would stick with OEM injectors, have them gone thru.



It could be the Injection Pump main shaft seal leaking fuel into the crankcase. The gasket would leak oil out of the front gearcase or oil/fuel if the shaft seal is leaking...

 

[dpuckett]

I agree with sdstriper- it may or may not be the injectors. And, I have noticed that just because someone knows the N14s inside and out, doesnt mean they know beans about the B-series. They are made by Cummins, inline 6 cylinders, most of them turbocharged, but the similarities become scarcer from that point. No wet sleeves, jerk pump (one line per cylinder, going to the injector), injectors are TOTALLY different style.



A bad injector pump will exhibit the same signs and cause the same problems as a bad injector(s). Your dynamic timing could also be off if the injectors arent up to snuff.



When was the last time the valves were adjusted? When they get out real bad, they can cause similar symptoms.



Daniel

 

[WJune]

I pulled the injectors from both 90 trucks an had them Pop tested an cleaned? today. Black trk had power but smoked at idle an sometimes cold start 160K hard miles.

Gray trk 250K hard miles, no smoke ever, pulls like a carbed gasser on hills. I was prepared to at least get rebuilt or new injs for gray, an have black trk injs adjusted. $$$ I was shocked an disapointed that all but one tested good !

I wanted that Big smilie you guys post after new injs.

I had the injs externaly clean when handed to top notch diesel shop. At least a 5 man shop, that would err on the side of repair or replace. They charged me $8. 50 ea for the test. They are also a Cummins parts supplier.

 

[dpuckett]

Gray trk 250K hard miles, no smoke ever, pulls like a carbed gasser on hills.

By pulling like a carbed gasser, I assume that is good?



It has been my experience that the ones that have worked, and had decent to good maintenance, will have better fuel systems than cream puffs. The fuel stays warmed up longer, and there is less carboning in the injectors, or varnishing elsewhere. My 91 had 250K showing on the odometer when I replaced the head gasket. Got the inejctors tested, and 5 of them were like new.



DP

 

[WJune]

By pulling like a carbed gasser, I assume that is good?



Not Good. In recent years my carbed gassers can't make it up a steep hill pulling 3K - 10K at speed limit. ( think its the crap gas we have now days ) Yesterday my 300 6 cyl stepvan, couldn't pull itself up a good hill. Thats why I drive CTD.

 

[dpuckett]

Gotta have all the pump internals working in harmony to make power, too.



DP

 

[AndrewKing]

HI,

Thanks for the replies thus far... . As far as valve adjustment... I have no I dea when they were last done... . I bought the truck used and the previous owner had no Idea either... . I suppose it is probably time for an adjustment... . As an aside... . Why is it that the Cummins doesn't use a hydraulic lifter like a gasser so as to avoid the hassle of having to do adjustments?... . seems like one less possible problem that could be avoided..... Anyways... The shop still has not picked up the truck yet... . I guess they are very busy... . I think the pump may have been changed out at some point because my pump is tan in color where as all the other dodge trucks I have seen (first gen) were black... . I am hoping the shop won't hit me too hard $$ wise... anybody know of a good diesel shop close to Charlottesville VA?... . I hate to have to tow the truck but may have to because of my fuel in the oil problem.

Andrew

 

[WJune]

I mention this as it relates to your valve adjustment. At 240K I was sure my valves had not been adjusted lately, maybe never. Hoped it would cure my problem. No such luck, valves were in speck ! If you have to pay some shop to do your repairs OUCH ! My sympathies are with you.

 

[dpuckett]

I think Cummins uses the adjusted valves to prevent stuff from going wrong. What is simpler than a solid lifter, going to a solid pushrod? Sure you have to adjust them every now and then, but it beats having a hydraulic lifter fail. Keep It Simple.



DP

 

[sdstriper]

Why is it that the Cummins doesn't use a hydraulic lifter like a gasser so as to avoid the hassle of having to do adjustments

My guess is with that tight a tolerance there's no room for hyd. lifter failure or float so-to-speak. You'd have bent valves etc. Or worse. Risk of interference is my best guess.