What is involved in testing the comression on a NA 7.3L by using the glow plug holes. What equipment do I need? Ive seen compression testers at Autozone but I dont think they have the right adapters or go up high enough.

The truck has 230,000 miles, new injectors, newer ip, return lines, glowplugs and relay, and still starts like ****. I just thought if it had bad compression it would burn alot of oil but its only a quart low every 3000 miles and thats mostly from normal leaks around the oil cooler and front main.

 

Dieseldan,

Have you done the batteries, starter cables and starter?

Depending on how much starting you do, starters start to get tired around 150k to 200k. As the starter looses its pull the engine will become more and more difficult to start. Note, a tired starter may not be all that noticable just from listening to it turn.

Old batteries won't deliver the amps needed.

Old cables or bad connections also tend to reduce the amps.


Just a thought....


Seb...

 

My engine cranks over plenty fast and starter was replaced 30 or 40K ago. I just want to know how to test compression.

 

There is an adapter that screws into the glow plug hole.
The compression tester needs to go to at least 800 PSI to be safe, 1000 would be better.
The last one I tested was a 6.9 with about 165,000 miles on it and it was carrying in the 450 PSI range.