Compression Test and Injector Test

[99red7.3]

Alright guys need some info,

My truck is a 99 7.3 with around 240,000 miles on it and since I’ve owned it I’ve put two new batteries glow plugs and a relay in and still have starting issues. Will only start with block heater plugged even if its 80-90 degrees outside but problem is defiantly getting worse so I’ve come to the conclusion that my problem is either injectors or low compressions. So I need some help on 1 testing the compression on the truck the procedures for that would defiantly be great and also testing injectors. They passed the buzz test the first time but need other options should I pull them and have them flow tested?

Any input or advice would be great. Help me get this thing running right.

Thanks for your time,

Evan

[nathan]

To compression check you need to pull the valve covers and remove the glow plugs. Take all of the glow plugs out it helps save the starter and batteries. Get an adaptor that will screw into the glow plug hole then adapt to a compression gauge. The gauge should be for diesels because a gas compression gauge will not go high enough. I am pretty sure the min reading should be around 450-475. If they are all above this then also make sure the lowest is within 75% of the highest. I don't know of anyone that can check these injectors. The intensifer plunger is generaly what causes low injection pressure and you have to complety disassemble the injector then with a microscope inspect the plunger and barrel.

[99red7.3]

What are my other options on testing the mechanical aspects of the injectors if they are un able to be flow tested? Also can someone point me in the right direction on what a cylinder contribution test is and how it's performed ?

[ToMang07]

Originally Posted by 99red7.3

What are my other options on testing the mechanical aspects of the injectors if they are un able to be flow tested? Also can someone point me in the right direction on what a cylinder contribution test is and how it's performed ?

A CCT is done with a good scanner, Like Auto Enginuity, or what Ford has.


These guys have a great rep and can test your injectors:

Rosewood Diesel Shop

[99red7.3]

Had a buddy of mine run a CCT test today came back with 4-5-6 were bad if i remember right. Going to pull all the injectors and have them flow tested to be sure then hopefully order some new ones.