bad miss, need suggestions

[Manshando]

I have a 93 6.5 turbo, and suddenly yesterday out of the blue it started missing, above 2500 rpm its not as noticable, but i'm sure its still there, becuase when i'm in boost, my gauge is flickering back and forth..... any suggestions?

[Robyn]

Does it idle smooth with no issues?

Check the fuel filter and if the issue is still there make sure the lift pump is working
The easiest way is to open the water drain up front and put the hose in a can. With the engine idleing there should be a fair amount of fuel squirting out the hose into the can.

No fuel equals no fule pump operation. The pump can fail as can the Oil pressure switch that runs it.

Check for fuel at the drain and then the filter.

Check these things and then we can go from there.

Robyn

[Manshando]

No, she dosent idle smooth, definately at least one cylinder constantly missfiring. Already drained and checked for water, and the filter was new maybe a 2k miles ago. and i believe the lift pump is working. I had to replace the oil pressure switch a couple months ago. I think i've pretty much moved on to an injector problem now. But i'm left with figuring out which one. I've looked around the forums a little bit, and i couldent seem to find a procedure on how to check my non-computer controlled version... any ideas there?

[Robyn]

Ok
Lets take a quick look at the amount of blowby coming over the top.
Unscrew the oil fill with the engine running and seer if we are getting a "Puffing" out the fill pipe. If the blowby is far more than normal or is definately huffing like an old locomtive then we have an issue.

Now if this turns up no ugly stuff lets check the injector nozzles.
With the engine at idle crack loose the high pressure fiting on each injector one at a time until you find the offending little beast.

Once you narrow it down you can unscrew the one thats not working and replace it.

Hope this helps

Robyn

[Manshando]

How much blow by is considererd normal for 170k?