I recently did a compression test on my V6 and the numbers were all about the same most of them at 190PSI. Now the Haynes manual says something about 150 max. And the original factory manual doesn't say anything at all. Is this a common number? "Compression low" is found everywhere but I don't know what a high compression number means on a stock engine. Does anybody have any ideas? Thanks.

 

I did a test a few months ago, 120's-150 on my 2.8 175k

 

You have excessive carbon buildup in the combustion chamber- this will increase your compression readings.

 

Yep; does your engine "ping" much? That'll happen with carbon buildup/increase of compression. You can decarbon the walls by removing the air intake tube to the throttle body. Fill an old (and washed out!!) windex bottle with water. Start the motor (might take two tries if you have 85-89 2.8 with MAF), and while it's running, "mist" the water spray in front of the throttle body. This will run into your combustion chambers, convert to steam, and should break the carbon up.

Note that if you poured water into the engine, you'd hydrolock it (water doesn't compress like air) and bend some connecting rods. That's why a windex bottle "misting" water in front of (not into) the throttle body is the way to follow.

My compression numbers a few years were 5 cylinders between 140 and 160, and my #1 cylinder ******* it at 125 psi.

 

Whow, I never heard of that. Something to try on my dodge that pings alot.

 

A little water goes a long way... just like steam cleaning your engine!

I always change my plugs afterward, tho... no real reason why, I just do

 

Don't they make cleaners to do something like that Tom? The idea of water in an engine is a scary though, even if it is only small amounts at a time...

I'd give it a good amount of time between sprays also to make sure the water doesnt remove any oil from the combustion chamber walls so the pistons scratch them up.

 

Well you have to think of it this way, hydrolock occurs when there is too much water. But with only a mist, once inside the combustion chamber, most would turn to vapor after it combusted; in turn not hurting your engine, but if you let in a few onzes of water in at once it would start bending engine componets.

There probabaly is a cleaner out there. But often times the best solution is the simplest.

 

GM top engine cleaner- buy a can, read the directions

 

to dales reply, dodge magnum engines have always had a problem w/ pinging and spark knock. the magnum engines are known for that. in the late 90's trucks, if you look in the owners manuals, it actually says some spark knock is normal, hahahaha. now its 2003 and they still cant get rid of it. its just got something to do w/ the magnum design i guess. all of them do it, the 3.9, 4.7, 5.2, 5.9. just letting you know about that.

 

Hm, found three sets of instructions on the web. Which one's right?

1: http://www.sytyarchives.com/howto/vi...php&dir=engine

2: http://www.gnttype.org/techarea/main...e/cleaner.html

3: http://www.fbody.com/members/stevenm...ne_cleaner.htm

The end of the third set talks about the 1st set's method... hm...

 

This one.