2 Cylinders not Firing

[Kevkeller]

I had to take my FIP out to unfreeze a few of the plungers. I put the pump back in according to directions (timing wise).  I’ve been able to run the engine but it seems like number 3 and 4 cylinders are not firing.
1. I pull the spark plug wires and don’t notice any drop.
2. I loosen the fuel injector lines and both have fuel coming out.
3. I replaced both injectors with brand new injectors. 
4. I’ve checked compression, both 160#’s. 
5. When I have removed the spark plugs they are wet.
6. The plugs have a strong spark.
7. I’ve used a glass spark plug to watch the actual combustion. I see the spark but not sure if it’s igniting the mixture. A good cylinder shows a lot more light from the combustion than #3 and 4.

I used an aluminum drift to loosen up the frozen plungers so I don’t think I damaged the plungers.  It didn’t take too much persuading to get them to move. I’m quite sure the plug wires are in the correct position.
Any ideas?

[Benz Dr.]

Go back and check plug wires to make sure they're timed right. Small possibility you have a vacuum leak.

[A Dalton]

  1 5 3 6 2 4   CW

#1 is @ front of engine.

[Shvegel]

Any dirt between the delivery valves and the top of the barrel (Cylinder) in the injection pump can cause an internal leak in the pump that will reduce the amount of fuel delivered to the cylinders. you might be getting fuel against no back pressure but with the line tight it has to make 200PSI to open the injector. 

[Kevkeller]

I’ll try to check those things in the morning. Thanks for the comments.

[Kevkeller]

Pat,
Are you talking about the check valves on the discharge side of the FIP?

BTW I haven’t forgotten about the package I’m sending you.  I’ll hopefully get it out soon. 

Thank you.
Kevin

Any dirt between the delivery valves and the top of the barrel (Cylinder)

[ja17]

Make sure the fittings on the IP are torqued to specs 18ft. lbs, or 21 ft lbs on a 280

[Shvegel]

Yes. The discharge valves of the pump.  The nylon washer only keeps the fuel from leaking out of the pump above the delivery valve.

[Kevkeller]

Joe,
I’m curious why you said that. Is it for leaks or would that effect the output of the pump itself?  I did torque the check valves  to 21 initially but they leaked so I upped it to about 25# and it stopped. Maybe my torque wrench isn’t that accurate.

Kevin

Make sure the fittings on the IP are torqued to specs 18ft. lbs, or 21 ft lbs on a 280