When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I'm trying to test compression on my 7.3 but it seems the adapters I have just aren't working. I have both a snap-on adapter (the long one) and a harbor freight adapter (the short one).
I've tried 3 different cylinder (2, 4 and 6) and they're all the same. Nothing shows up on the gauge. I also tried a different gauge, still nothing. Very rarely it shoots up to 200psi on the first compression stroke and then nothing. I had the intake rocker off at first but now I'm testing with it on.
I tried to screw just the adapter in with no gauge or schrader valve and see if it blows out. It did on the little adapter, but I can't get a hose on it when it's in place. The long adapter does nothing. I tried changing out the o-ring too.
I have seen the compression test procedure in the 7.3 tech folder. Should I just get that little pipe thread to 10mm adapter and a grease hose, and make the adapter myself?
Found the issue, the hydraulic lifter was pumped up and not allowing the intake valve to close all the way. I let the engine warm up and I finally got it to work (with the setup from the DIY)
