I bought a 94 5 speed Cummins 4x4 for $800 the other day. The bed is hammered to the point of being unuseable. Grinds going into 3rd. Interior ratty. I swapped the middle two injectors for the front two and the miss stayed with the front two (exhaust manifold cold on those two cylinders while running). I've got a piec of crap Snap On compression tester that doesn't work so I'm in the process of doing the compression test. Oil pressure is 38 psi at idle according to the factory gage. No loud noises. No smoke. Is there any chance the IP could go bad on the front two cylinders? Fuel is getting to them but I don't know if the pressure is sufficient.

 

Possible specially since you swapped two known good ones and got the same results... But def gonna have to do a compression test. Is it making oil? (fuel getting into the crankcase) Blowby out of the tube dipstick or oil fill?

 

Very minimal blowby cold or warm. Little accumulation of oil on dipstick tube.

 

How many miles? either way you got a hell of a deal

 

snap on makes a adapter for testing compresion for around 60 doll. if you have bad comp pull head before pulling motor, not to bad of a job. Does it have blue smoke?

 

I have that adapter. It doesn't work. The whole Snap On tester is a POS in my opinion. The check valve doesn't work and the hose leaks.

How hard is it to get the back head bolts from underneath the windshield wiper tray?

What internal ip failures could cause only 2 cylinders not to work?

 

Check the lines and connecting tubes for some sort of blockage.

 

Well, if you don't have alot of blowby, and its not pushing oil out of the dip stick, is it puffing white smoke? If so, then you most likely have a cylinder issue. If not, then you most likely have a fuel issue. Honestly, as bad as that truck is hammered I would not at all be surprised to find out the pump it trashed. I seen that thing on CL.

 

Fuel is getting to the injectors, it leaks out when you crack the nuts. But how does one measure the pressure? I might be able to rig up an inline pressure gage, but that would affect timing to that cylinder, right? But I guess it wouldn't hurt anything. But first I gotta finish my compression test. I made my own adapter and have tested a good cylinder without a check valve and can see 300 or so and the engine running on 3. Hard to read with diesel spraying all over the place. My fuel shut off is disabled so I've been running it to check the compression. Then I have to get in the truck and stall it. Not real fun. I guess I should crack open all injectors to prevent it from starting. Duh!

 

Disconnect the power to the shut down solenoid and use a zip tie or something to hold it down if yo need to. That will keep it from running. To get an acurate compression test you need to have the engine warm (plug in the block heater for a hour or 2 prior) and you want to try and get the same number of rotations per cylinder if possible.