Odd thing with Ford 6.9

rrlund · Feb 22, 2010

I took a load of cattle to the stock yard this morning with my 85 Ford 6.9 diesel. About 40 miles one way. The roads were misserable,snow,slush,wet. Ran about 40-45 miles an hour going over. When I started home,I took the state hightway. It was mostly just wet,so I got up to about 55. The darned thing started sounding like it was missing. Sounded just like a gas engine would with a wet wire or fouled plug. Went about 20 miles that way and it started smoothing out. Got home,floored it and it sounds fine. I figured it was a valve or injector,but I don't know why it would have smoothed out like it did? Doesn't make sense.

JDemaris · Feb 22, 2010

Could be one of those old pintle-injectors got stuck open for a bit. If so, it will happen again if they've got real high miles on them. My 1985 6.9 and some of my GM 6.2s have done it. Sometimes when skipping, the cylinder will also knock a little when the nozzle sticks open.
New injector nozzles are only around $8 each, so usually just put a new set in when a few start acting up.

Could of been some water sloshing around in your water-trap also. Have you drained the bottom of your fuel filter lately? It will hold water only up to a certain level and then start giving problems if you don't drain it.

Have you ever had to pull the DB2 pump apart on your truck? 1985 is the year that the plastic ring inside the pump was eliminated (same as used in Deere, Ford, IH, AC, and Oliver farm tractors).
Since the change was model year 1985, some 1985 trucks came with the new upgrade and some did not.

Odd thing with Ford 6.9

rrlund

Well-known Member

JDemaris

Well-known Member

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