falcorider

Two weeks ago I bought my 2002 S2000 with a scant 7600 miles on the odo. The engine runs great, so I have no reason to suspect that anything is wrong with it, but I'd like to do a compression test to get some baseline numbers for future reference. I've done compression tests before, and I've looked up previous threads on this topic but I have a few questions:

1. Where is the fuse located that disconnects the fuel injection?

2. How should I disconnect the electronic ignition so that the plugs are not getting any juice? Or is it even necessary to do this? On previous cars, I disconnected the wire from the distributor to the coil.

I already know about doing the test with WOT and a warm engine, but I'd appreciate any other info.

TommyV

Not sure about 1. if I get a chance I'll look it up in my service manual for you. I am pretty sure, if unplug each harness on the injectors, it should prevent them from spraying fuel.

2. S2000 has four individual coils - one for each spark plug, pretty sweet stuff huh? If you just disconnect all four of the connectors, you won't have to worry about the spark plugs firing.

I'd suggest you have a friend help you do the test, it's kind of a PITA because you can't really position the meter to a point where you can watch it while you crank the engine.

Good luck, and please post your numbers!!! I'm curious to know the results.

xviper

You can pull the one labelled "fuel pump, SRS" to disable the fuel pump and/or the one labelled "starter signal" to disable the injectors but this will also disable the ECM. After you pull the fuse, crank it over for a few seconds to bleed off the fuel pressure.

falcorider

Hey, thank you much for the help! This should be enough to get me through the task. You're right about having someone else helping me; I have a remote starter but I don't think it'll be worth the effort to try to hook that up correctly.

I'll definitely post the results when I finish, probably sometime this weekend. I'm curious to see how they compare with others that I have seen on this board and with those from my other car, a '90 Mustang GT. I'm pretty sure the Honda's will be much higher

falcorider

Ok folks, I was finally able to check the compression values this afternoon. My results from front to rear:

1. 245
2. 250
3. 255
4. 250

The measurements were taken with a Sears Craftsman gauge with the engine warmed up for about 5 minutes and with the gas pedal held to the floor. I took out all the plugs and coils and then disconnected fuses number 12 and 10, the fuel pump and the coil. I found that by using the flexible tube attached to the gauge, I could rest the gauge on a towel layed on the left side of the engine so that it faced towards the drivers seat. I could then watch it while I was cranking the engine. The numbers are close to those I've seen in other posts, so I'm happy with the results.

xviper

Thanks for these numbers on a "fresh" engine. They will be helpful for others down the road.

RazorV3

thats a healthy motor...i guess you got a problem when you have a 15% compression value difference b/w the cylinders right?

fireball

can i ask what is a leak down test ?
and those numbers put up.... what units is that ? or is that a univeral number ?
is there anything else to do when checking a 2nd hand engine?

schismS2K

Altho, a very late response.

Just finished a compression check myself. The Sears (Craftsman?) compression tester tool was used.

MY01 34,xxx Miles.

Bone Stock USDM F20C1 block/head. Engine fully warmed, Wide Open Throttle (WOT), Cranked over roughly 7 times (a second for each crank, would peg and hardly move with anymore cranks).

Cylinder #1: 260
Cylinder #2: 260
Cylinder #3: 260
Cylinder #4: 260

Hope that helps any.

yogi

260?? Using a cheaper Kragen tester, I got ~220's across the cylinders. I didn't disconnect the fuel, but added a little bit of oil to help seal. The service manual says the stock compression is 235....how come you guys are getting such high numbers??

Edit: it was ~210's not 230's