Go on eBay and get a quality used one.

I've seen Matco leak down tester last go for $44 - $50ish

So a quality used compression tester should be obtainable, buy from vendors who offer returns, DO NOT BUY FROM PEOPLE WHO REFUSE TO ACCEPT RETURNS, PERIOD.

I've gotten a lot of used quality tools for cheap.

"It ran better for a day." -It just seemed to run better for the rest of the day after the diesel purge was done. The next day's cold start was back to rough running.

I tested the harborfreight guage with compressed air and it is holding pressure. Narrowed the leak to the injector fitting. Should I be doing this test with or without the heat shields in?

My HF unit works fine. I'd simply take it back and exchange it - they've always been really good about that. If you have the receipt it's dead easy and I've even gotten some stuff replaced w/o receipt by talking with the manager. Of course, they DO know my face when I walk in there.

Dan

Long time ago I got one from JC Whitney. It is still a good tester, uses the same adaptors as Snap-on, (same dimensions, anyway the Snap-ons fit in it) Dont know if they still sell 'em, dont know if they're still around, even, , , Had it for 30+ years.

I gave the HF tester one last chance to redeem itself since the guage seemed to not leak. Wrapped the quick connect fitting threads with teflon tape, used copper sealing washers, and torqued the injector fitting to 70 nm. Still not working. The tester can't be exchanged at the store, so rather than buying another junk set I'll look for a good used one on ebay.

If you believe it is only the Injector adapter that is the issue you can purchase them seperately on places like eBay,

Also the setup uses schrader valves like are like the ones on Tire Valve Stems and they can often be the cause of problems.

You should be able to return or exchange your HF compression gauge. You must have the receipt though.
You have to tead the instructions! It tells you to use the supplied copper washer if you use the inj adapter.
The injector adapter will give you a lower reading than the glow plug adapter due to the extra volume in the inj adapter, provided both are sealing well. Absolute accuracy is less important than relative accuracy in a compression gauge.

I've found that there are too many poor quality fittings in the HF set, each being a potential leak source, that I have modified mine with my own quick fittings and hose, so that it is quick/ easy to use and accurate. I can take a compression reading in less than 2 minutes per cyl via the glow plug holes of a 617 except #5, which takes longer because of tight access.

Turn the switch and see how long the glow cycle last. If you leave the driver's door open watch the light to see when it brightens.

If the cycle is as it should be replace the glow plugs with a new set of Bosch.

I ordered an old Mac tester kit off ebay. In the meantime, I found out why the engine is running rough. I pop tested the injectors and one is "peeing". They are also out of balance, so I'll work on rebuilding them.

Good find! That WILL mess things up.

Dan

Grezzer is set up to refurb injectors for not much money and has already been through the learning curve. Easy and correct vs diditmyself - after effort and almost right. Gotta pick your battles.

Do you have blow by also when the engine is at operating temp?

It very well could be imbalanced injectors that are leaking causing your rough running from a cold start. Fuel leaks can do that as well. Read DieselGiants page on checking glow plugs. Make sure you hit range on the meter till it zeros out so it doesn't jump around everywhere.