how to do a 2H compression test

[coldtaco]

How do you do a compression test on a 2H? FSM doesn't say anything about cutting fuel. When I don't do anything with the fuel I get a lot o fuel mist coming out of the glow plug holes. The gauge I have does not appear to work right, first it does not hold the "hits" of pressure, then it only show's just shy of 200psi from what I can see as the needle bounces up and down, also behaves odd sometimes. I will take the gauge back. Is there any video's specifically doing a compression test on a 2H? Thanks.

 

[tlaporte]

Not Toyota or 2h-specific, but I found the following YouTube video to be very instructive when I was researching compression testing last year.

 

[coldtaco]

Yeah I watched that too. I'm guessing my new gauge is bad. Did you do anything with the fuel?

 

[tlaporte]

I haven't gotten to the point where I've done the test yet.

 

[vwluv10338]

Disconnect your EDIC and wire the arm forward into fuel cut. My EDIC had been removed on my truck and replaced with a cable to cut fuel and turn off the engine so all I had to do was pull on that cable and crank the engine.

 

[roscoFJ73]

So, I have had a lot of white/gray smoke on start up after sitting for over 6hrs

Does it pump out in time with a cylinder or is it a constant stream of smoke. I assume it goes away when warm?

 

[coldtaco]

Does it pump out in time with a cylinder or is it a constant stream of smoke. I assume it goes away when warm?

In the past it would clear up in 30 seconds or so. Now it seems to take twice as long.

 

[vwluv10338]

Check your glow plugs too

 

[coldtaco]

Check your glow plugs too

Glow plugs are good, got power and continuity.

 

[roscoFJ73]

In the past it would clear up in 30 seconds or so. Now it seems to take twice as long.

They tend to do that as the compression drops off. Brace yourself

 

[tlaporte]

I originally tried a compression test but didn’t remove the other glow plugs. I thought that that might have been the source of my issue (see below)



I thought my problem was my compression tester (I had bought it used off of eBay). I bought a new one and got a very similar result. Then I realized that maybe I should be removing all of the glow plugs. I did that, but as you can see it’s pretty much the same result.



So, what all should I be disconnecting before I test the compression in my 2H?

1. All six glow plugs?
2. Injectors?
3. EDIC wiring?

Also, on a side note, why doesn’t my gauge’s needle hold at a peak value? It just bounces back to zero. This has been the case with two different compression testers. I’m using a Lang glow plug adapter for the port.

 

[duncanrm]

If the injector is still installed in that cylinder in the video then you've either got zero compression in the cylinder (unlikely if the engine was previously running) or you've had two faulty EBay gauges in a row. I have had absolutely no success with cheap diesel compression gauges from EBay - one broke after 4 cylinders, and the other was DOA. Do all cylinders show the same on that gauge? If so, just more evidence the gauge is broken.

You only need to remove the glow plug for the cylinder under test and disable fuel by tying the fuel control lever all the way forward.

If the engine was previously running OK.. just close her back up and go on a trip somewhere. Or spend around the $500 mark for a good compression tester.

 

[Freewheel]

Here some notes I took when I successfully measured compression with a relatively inexpensive compression tester. (My 2H is turboed so skip turbo pipe notes yours is naturally aspirated)



Here’s the procedure.

Remove Turbo pipes on top of Valve cover. (air cleaner to Turbo & turbo to intake manifold.

Remove glow power rail, and protect power rail end at glow#6 from grounding.

Take out Glow plugs

Loosen nuts on fuel supply pipes.

Connect compression tester to glow plug adapter on cylinder

Open throttle wide

Turn engine over for 8 seconds.

Check numbers

Release pressure on gauge

Repeat.