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Discussion Starter #1
Well im going to do a compression check on my truck, what is the compression in each cylinder suppose to be on a 5cyl...
 

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I've been told it's 215psi. :shrug:

As long as we're on the subject I've been wanting to do this as well. You should just have to pull the fuse for the fuel pump to keep it from starting, correct? Or is there something else that would work better?
 

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just turn the pulley on the crank.. shouldn't it be just like doing a V-8..
 

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I've always been told to turn it over with the starter, because you can't turn it over fast enough by hand to get an accurate reading. I could easily be wrong though, because unfortunately I don't know everything. :D

I'd imagine Turbizzy will be able to give us the best method for our trucks tonight when he gets on, I'm sure he's done it plenty of times.
 

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i work on planes.. and we use to just turn the engine over by hand with a gaint braker bar for leverage.. ur basically trying to see if u have blow-by pass any seals.. i think if u do it with the starter its gonna be hard to see an accurate reading do to how fast it may turn the engine over..

but i'm just like u BRAKENIT just someone who might know how to do it.. not really sure
 

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The compression gauge holds the highest reading though, if thats what you mean be "see an accurate reading", I dunno. I know it's worked fine for me in the past doing it that way, and given me #'s that were correct to the vehicle I was testing but I've never tried turning it over by hand either so maybe it works just as well. :shrug:

Hopefully we'll get an answer from someone that knows for sure, I've been meaning to test my truck for a while. I even bought a new compression tester just for it like 6 months ago. :lol:
 

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after losing power and getting crappy mileage I decided to do one of these.

You want to crank the truck over 3 times with the guage attached and the fuel pump fuse pulled. If the pressure builds quickly to 210 psi (I think spec is 210) you're good. If it buils slowly and doesn't make it to 210, like mine, which built slow and only made it to 175 on the 3rd turn-over, you likely have piston ring damage. If it builds quickly and levels off quickly it's likely your valves aren't sealing.

Another note, I starting to notice a pattern. People who have ran 120+ mph and then started getting crappy mileage. I'm starting to think the heat generated form a long high-speed pull pushed the already weak valve train components over the edge.
 

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My mileage has been getting better, 23mpg if I take it easy and 19-21 if I'm not. I still don't have an explanation to why my trap speed has never improved at the track, but I think it's related to my tune.
 

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Pull the fuel pump fuse, remove all the spark plugs, hold the gas pedal at wide open throttle and crank engine a few times while watching the compression gauge. Once it stops climbing and just goes up like 1-2 psi per crank stop there and compare all cylinders.
 

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o nice.. so u do crank it.. ok thats alot easier than doing it the other way i know of.. thanx turbizzy
 

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Pull the fuel pump fuse, remove all the spark plugs, hold the gas pedal at wide open throttle and crank engine a few times while watching the compression gauge. Once it stops climbing and just goes up like 1-2 psi per crank stop there and compare all cylinders.

It specifically says in the instructions to only crank a specific number of times (3 or 4 I can't remember but I think its 3).
 

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It specifically says in the instructions to only crank a specific number of times (3 or 4 I can't remember but I think its 3).
Yea well... :jerkit:

Whatever you want. I usually go about 5 compression cycles (when you head the engine slow down then speed up with all the plugs pulled.
 

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Discussion Starter #13
the compression check is done...:lmaowtf:
cylinders and the compression in each
1=180
2=172
3=150.....
4=175
5=190
i dont know what the f**k is going on... this isnt good though...
 

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That doesn't look too too shabby. Is there a problem with your truck?

You can always drop a lil oil in the cylinders and reperform the compression test. This is called a wet compression check. This will seal the little bit of air blowby through the rings and give you a better reading.

The ultimate test is a cylinder leakdown test but you need a leakdown tester and a good air compressor for that. Best to let a shop do that.
 

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Discussion Starter #15
yea it burns oil, i think it only burns oil when im getting on it and over 4300rpms( royal purple) other than that no smoke or nuthing
 

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How much oil does it burn? Have you actually measured and in how many miles? Because all cars burn oil, it just depends on how much is acceptable.
 
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