Compression test

[scott2093]

Your compression tester is showing such high pressures that I question it's accuracy.

hmmm..It was a pretty new looking oem tools...was actually going to keep it because I had a $20 reward towards it but decided to get a set of plugs instead. Not sure about the threading. It did look like that weird overseas metal...almost like an anodized aluminum brass look instead of brass. It would thread perfect in most plug holes but would bind in a couple and with the hose grip, I really couldn't overcome that. But all the spark plugs went in with no issue....weird....does have some unfavorable reviews

OEMTOOLS 14mm and 18mm Compression Tester Gauge Set

Shop for OEMTOOLS 14mm and 18mm Compression Tester Gauge Set with confidence at AutoZone.com. Parts are just part of what we do. Get yours online today and pick up in store.

www.autozone.com

Any opinion on those little sandblasting bags for cleaning spark plugs?

Higher battery voltage allows higher cranking speed...which leads to higher compression pressure. So--maybe--your best reading being your first reading is related to battery voltage

I did have a full charged battery and had it jumped to another fully charged battery while doing the test....and all the spark plugs were pulled...and all I did was floor the accelerator pedal..I couldn't find something to block the throttle bores open. Is that ok?



dang...I knew as soon as I took the tool back and put plugs in, I'd regret that decision....
Guess I'll be revisiting this soon...
Just going through some things to say I did but I'm spinning my wheels it appears.
Did do an exhaust back pressure test yesterday and it looked good afaik...
Putting some new plug wires and cap on as well...
Getting ready to do a quick test of the icm and coils from the manual...I think I recall you're not a fan of those tests?...just go/no go or something?
will see...

 

[Schurkey]

OEMTOOLS 14mm and 18mm Compression Tester Gauge Set

Shop for OEMTOOLS 14mm and 18mm Compression Tester Gauge Set with confidence at AutoZone.com. Parts are just part of what we do. Get yours online today and pick up in store.

www.autozone.com

Any opinion on those little sandblasting bags for cleaning spark plugs?

I've used 'em. Given appropriate media, and enough air pressure, they work just fine.

I use an actual glassbeading cabinet, and about one second has 'em looking like new in terms of removing deposits.

Most spark plug manufacturers frown on the procedure. Too much abrasive can erode the porcelain, changing the heat range. They get concerned about media getting "stuck" inside the plug, and coming loose as the engine runs. And particularly on old-style plugs with thick center electrodes, worn electrodes that don't have sharp edges require higher voltage to fire--a downside of used plugs. The center and side electrodes can be filed, but often not enough to make them "as new".

I did have a full charged battery and had it jumped to another fully charged battery while doing the test....and all the spark plugs were pulled...and all I did was floor the accelerator pedal..I couldn't find something to block the throttle bores open. Is that ok?

That's fine. You had enough voltage to that starter to complete the compression test.

am I supposed to read the inner ring on gauge? maybe that makes more sense?

Inner ring seems to be calibrated in bar, rather than PSI.

Important for Europeans, meaningless in the USA.

For the record, "bar" is equivalent to "barometric pressure", not quite 15 psi at sea level. So for example, "2 bar" is just shy of 30 psi.

Did do an exhaust back pressure test yesterday and it looked good afaik...

OK.

Putting some new plug wires and cap on as well...

OK.

Getting ready to do a quick test of the icm and coils from the manual...I think I recall you're not a fan of those tests?

There's no problem with those tests...if they're complete.

Internet doofuses--and even the service manual--think that an ohmmeter can prove a coil is "good", which is not possible. They can prove a coil is bad, though. A device that in normal operation produces tens of thousands of volts, can't be thoroughly tested with a meter that provides some minimal single-digit voltage.

Much the same with testing ignition modules. They're so complex that it's near-impossible to test every function. It's easy to test the below-400-RPM "does it make a spark" function. Verifying the computer-controlled timing advance is WAY harder.