hey guys im working a 1995 12v with a wierd problem. At idle cylinder number 1 hits harder than the rest. only happens at idle, and if just crack the line at the injection pump approx a quarter turn on the #1 line it runs just as smooth as silk. iv already adjusted the valves twice to .10 intake, and .20 exhaust. and i just took the injector to the local diesel shop, the pressure should be 260 bar they said since it was aftermarket injectors, 150hp, they would need a known good injector to verify correct pressure. so i removed the first 3 and took them they were stamped 260 bar, #1 was 250, 2 was 250, and 3 was 240. the spray pattern was correct and the could see nothing wrong with the injectors, they said the variance in pressure would not make an audible difference in engine running, they believe something is wrong with pump. im going to swap 1 to position 3 to see if the hard hit moves. but in the mean time any other ideas or suggestions?

 

maybe #one dilivery valve inside the P-7100 is a different one

weird

 

they are supposed to be 191s the guy im doin this for just bought and has had some issues with the truck it has potential but previous owner is one of those guys who dont want putting batteries in your truck much less injectors so there is no telling what is goin onwith it ima swap injectors around and see how it runs if that dont do it then ima try and swap dv i dont have a socket so ima try and find one or maybe channellocks but not so hip on that idea

 

don't use channellocks, youll tear the holders all up.

What sound is #1 making? were all the injector washers the same thickness?

 

not really a sound the engine at idle sounds kinda like a skip but instead of the cylinder being weak it hits hard like its getting to much fuel. if it was weak i could crack the line and it would run worse or no change if its a dead skip. but this thing hits hard until i crack the line about a quarterturn and i get a dribble of fuel out of line connection, then it smooths out and runs like a champ. as soon as i tighten it back up it starts hitting hard again. so i know its a prob with number 1. i wouldnt think there would be a diff delivery valve in 1 but theres no telling. the shims looked the same but didnt pay that close of attention, then again i wouldnt think that being further in or out a few thousandths would make an audible difference, maybe more heat or smoke but i dont know i will definately check it out though. im kinda wondering if maybe they left a shim out of the delivery valve when they were supposedly replaced but unsure how missing shim would effect running on that cylinder whether it would be weaker or stronger. are they all goin to have shims in delivery valves, or only sometimes?

 

ok so i swapped the injector that is on the cylinder that hits hard and moved it to the cylinder that wasnt (#1 hits hard to #3 which didnt hit hard) now the #1 cylinder still hits hard and #3 still is the same. so i checked the line nothing wrong. so im back to the injection pump. it is suppose to have 191 delivery valves installed. if the installer lost a shim from the delivery valve setup, the stroke would be the same but the compression area would be smaller, so would that make it have more fuel to force out or less fuel? because with it running i can take and loosen the line until fuel is spurting out and the engine smooths out like there is more fuel being forced out to that one line. any ideas would be great, and does anybody know where i can get a delivery valve socket?

 

did he lose the shims for the DV spring? or was he talking about the copper seal on the bottom of the DV?

if he lost that shim pack you will prob have to send it to a shop to balance it.

 

i dont know if the installer lost them or what because all of these mods were done when he bought the truck but they were all thrown together. and with all the things that were modded that i had to go back and fix adjust and just plainout redo, i wouldnt put it past the installer losing parts and just throwing it back together. so i think ima go call up the local diesel shop and just see what kinda cost we are looking at to get it balanced and if it can be done on the truck or am i gonna have to pull the pump. thanks for the info and ill give more info when i can

 

For a delivery valve socket:

P7100 Injection Pump Delivery Valve Socket

 

loosen the two nuts that hold the barrell into pump and turn it a little you can tune each cylinder that way