How do you do a compression test? Search brought up no answers....
10-29-2008, 04:23 PM
#1
4th Gear Member
Thread Starter
Join Date: Aug 2007
Location: Florida
Posts: 1,721
How do you do a compression test? Search brought up no answers....
Can someone please tell me how to do a compression test? I rented the tool from autozone and it didn't come with directions. Btw, I did do a search, and came up with no answers.
Also what's my compressions supposed to be in an 03 GT?
Also what's my compressions supposed to be in an 03 GT?
10-29-2008, 06:35 PM
#3
Banned
Join Date: Sep 2008
Location: tn
Posts: 0
Install the tester in the sparkplug hole, disconnect all plugs and injectors, hold TB wide open, crank engine for 3 seconds. It should read 140-170psi. Whatever the highest cyl is the others should be atleast 70% of that number.
10-29-2008, 06:47 PM
#4
4th Gear Member
Thread Starter
Join Date: Aug 2007
Location: Florida
Posts: 1,721
When you say disconnect all plugs, are you saying to simply disconnect the harness from the coil (03's have coil ons not plug wires), or are you saying to completely remove all spark plugs from the engine?
How do I disconnect the injectors? Would pulling the fuel pump fuse in the back of the car suffice?
How do I disconnect the injectors? Would pulling the fuel pump fuse in the back of the car suffice?
10-29-2008, 09:25 PM
#5
2nd Gear Member
Join Date: Aug 2007
Location: Canada
Posts: 175
Yes, pull the fuse rather than pulling injectors. Either way, you must restrict the fuel or you'll be pumping fuel into your Compression Tester. Not good.
I would just hit the inertia switch. An easier way would be to pull the fuel pump fuse as you said.
I would just hit the inertia switch. An easier way would be to pull the fuel pump fuse as you said.
10-29-2008, 11:14 PM
#6
4th Gear Member
Thread Starter
Join Date: Aug 2007
Location: Florida
Posts: 1,721
What about the plugs, do I pull all of them, or am I supposed to only pull one? I've got conflicting stories from all the internet searches I've done. If I'm not supposed to pull all the plugs, am I supposed to disconnect the harness from the coil packs?
10-30-2008, 06:58 AM
#8
Banned
Join Date: Sep 2008
Location: tn
Posts: 0
Pulling all the plugs will save time so go ahead and do it or just disconnect the harness from all of the COP. You can pull the fuel pump fuse under the hood instead of unplugging the injectors. Don't be ghetto and beat on your inertia switch.
10-30-2008, 09:35 AM
#9
2nd Gear Member
Join Date: Feb 2008
Location:
Posts: 301
it makes sense to pull all of the plugs at once since you're going to be testing all of the cylinders. also, to kill the fuel, pull the fuel pump fuse. this is the easiest way to do it. if you get the compression tester that they rent at autozone, it comes with instructions.
10-30-2008, 01:21 PM
#10
4th Gear Member
Thread Starter
Join Date: Aug 2007
Location: Florida
Posts: 1,721
it makes sense to pull all of the plugs at once since you're going to be testing all of the cylinders. also, to kill the fuel, pull the fuel pump fuse. this is the easiest way to do it. if you get the compression tester that they rent at autozone, it comes with instructions.
Thanks guys.
I'll just disconnect the coil ons and do one at a time then. I don't see how pulling all the plugs would give the same reading. if you pull all the plugs at once there would be less compression since the engine wouldn't be sealed......right?
