Low Power...

[tmiron]

Hey Guys,

I have super low power in my van. I'm thinking I need to check compression. Before I buy a gauge I want to see if I can even fix it if I do detect low compression. I'm guessing that new rings would need a rebuild, but how hard is it to replace a cylinder valve if that is the cause of low compression?

Anything else it could be?

[Burntboot]

Valve replacement doesn't require pulling the engine, just the head, but you really need to diagnose your issue properly, before jumping to conclusions.

Low compression can cause a loss of power, but so can about 1000+ other things.
I have seen lots of cars that have "low compression" that run just fine.

Start with checking for codes and go from there.

BB

[tmiron]

Valve replacement doesn't require pulling the engine, just the head, but you really need to diagnose your issue properly, before jumping to conclusions.

Low compression can cause a loss of power, but so can about 1000+ other things.
I have seen lots of cars that have "low compression" that run just fine.

Start with checking for codes and go from there.

BB

Thanks Man, Here is where I'm at:

no code, o2 sensor is good, New Cat and exhaust, new air filter.
I was burning a bit of oil (about a quart every 2 tanks) but hen I used some additives and switched to Valvoline High Mileage Oil and Now I'm burning a quart every 5 to 6 tanks. So I assume the rings are bad, but I don't want to spend a fortune on that. I'm looking for cheaper things I can o to get some more power and keep the van running for a bit longer

[IronViking]

A compression tester runs 20 bucks to buy or rent from autozone. Its good just to have one in your tool box so Id suggest just buying it.
http://www.amazon.com/INNOVA-3612-Compression-Tester-Piece/dp/B000EVU89I/ref=sr_1_2?ie=UTF8&qid=1443632488&sr=8-2&keywords=compression+tester

[Burntboot]

IV - Couldn't agree more.
It's a handy tool, but just like all tools, one needs to understand how to use it and how to interpret the results.
It WILL tell you the ability of the cylinder to build pressure, however if the numbers are low, it won't tell you why.

Did his oil consumption go down because the rings are working better from the additives or maybe it just swelled the valve stem seals?
If he knew before and after compression readings it may shed some light, but that isn't the case.

He hasn't told us if his ignition timing is correct or if he is getting proper advance or even how old the spark plugs are?
Is static timing steady?
We have no idea what the engine temperature is (if low, maybe he is constantly over-fueling and washing out the oil in the cylinders, thereby reducing compression)
Is the fuel system compromised and unable to supply sufficient fuel under load?

My van suffered from lack of power under load.
While I had no chain noise the timing mark tended to dance around, so I replaced the chain and gears.
Lots of problems disappeared, especially the lack of power.

So, too many variables and not enough info.
This just brings us back to the need for a proper, methodical diagnosis.
BB