Sturmcrow

I did my first ever compression test last night. The results ranged from 140 to 150PSI. It seemed like they got higher as the engine cooled (#4 was 135 at first), but it could also be that it took me a bit to figure out how to get a good seal on the tool. I wasn't using a wrench to tighten slightly into the spark plug hole at first.

2 - 145 1 - 140
4 - 150 3 - 150
6 - 142 5 - 150

I know that 140 is on the low end of the specifications, however, do you think that combining that with the fact that my fuel economy is in a pretty good place (just below 18 mpg with mixed driving) are good signs that the engine is pretty healthy? Its got 180k on the odometer. There is a pretty loud valve tapping/ticking coming from the left bank, either #4 or #6, but these decent compression numbers are telling me that it will actually be worth the trouble of adjusting the valves to try taking care of the sound.

FWIW, I too found that changing out the steering column firewall gasket was a very effective way of quieting the ticking sound!

Also, I do not know if this would affect the pressure, but I did not remember to disconnect the EFI fuse. I did ground the ignition coil to the block. Hmm, would unburnt fuel in the cylinders eventually cause a slight increase in pressure the way that oil does?

Sturmcrow

I know it's only been a few hours, but with 50 views and no replies is it safe for me to assume that my numbers are pretty standard for a 20-year old engine?

I didn't want to make a separate thread, but I've been thinking recently about how silly it is that folks dog on the "3.slow." Mine is bone stock and seems to be just fine with getting onto the highway or passing when needed. I assume that these engines were designed something like 26 years ago. That's approximately 1/4 the time that cars have existed at all! Sure they aren't as fuel efficient or powerful as modern engines, but there sure are a lot of them still out on the road, 20+ years later.

TNRabbit

Not bad numbers for an older engine. S/B 172 psi optimum. Did you check with all spark plugs removed, engine warm, VAFM & igniter disconnected with Wide Open Throttle?

The ticking is probably either the Fuel Pressure Regulator:



...or an exhaust leak.

rattlewagon

Those are respectable numbers for a engine with that type of mileage.

And I agree with you, the 3.0 isnt a bad engine. Its certainly more powerful than a 22re. The headgaskets just scare people away, and most who hate the power it produces, have one with an auto tranny behind it. Ill take a 3.0 over a 22re any day.

Sturmcrow

I did not electrically disconnect the VAFM, though I also did not reconnect the air intake tube after removing the spark plugs. Don't worry, I was really careful that nothing was nearby to get sucked into the throttle body. My air intake tube is falling apart and held together with electrical tape, so I keep the installs to a minimum. Luckily, I saw that they have it for $30 on Rockauto, so it'll be replaced next time I make an order.

There is no way on earth I am going to recheck the right bank cylinders. That was about the most frustrating exercise of my life. I'm feeling pretty proud that I have a number for #5 up there, because I was this close to chucking that pressure gauge hose off a bridge! However, I might consider redoing the left bank ones... and actually read the FSM beforehand.