Compression test on 2K maxima
08-01-2004, 01:54 PM
#1
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Compression test on 2K maxima
Decided to pull the coils & plugs and do a compression test this afternoon. Not too bad but I think those readings are a little high (?)-
I am assuming the cylinders go in order with cyl#1 being on the rear bank, far passenger side, and cyl#2 being the front bank, far passenger side going in a zig-zag order with cyl#6 being the front bank, far driver side.
Cyl#1: 225psi
Cyl#2: 220psi
Cyl#3: 220psi
Cyl#4: 225psi
Cyl#5: 220psi
Cyl#6: 230psi
Isn't that a tad high? (and should I run some kind of engine cleaner like SeaFoam through it?) or is that perfect?
Although I recall one thing... I forgot to floor the accelerator while cranking the engine. But I did let it crank through about 9 revolutions for each cylinder. The engine was warm too; I pulled the plugs ~15-30 minutes after I shut it off.
As for the plugs... I changed them last winter with 6 copper plugs from DAVEB. As it turns out, one of the plugs shipped was a platinum, so I decided to put that one into cyl#1. So I actually have 1 platinum and 5 coppers in there.
Here's the condition (and type) of the plugs:
Cyl#1: PFR5G-11 ... mostly clean-looking, just white soot all over the ground/center from wear I guess.
Cyl#2: BKR5E-11 ... Similar white soot to cyl#1, except the ceramic insulator is yellow-colored on the outer side (facing away from the ground strap), or kinda a gradient of brown/green/yellow/orange.
Cyl#3-6: BKR5E-11, pretty much the same story as cyl#2 (brown/yellow/orange color on the side of the center electrode facing away from the ground strap). Cyl#6 also has some very tiny brown spots (they weren't shiny like aluminum, I'm pretty sure they were brown.)
Didn't look like any oil control issues either.
One thing I'm not sure about is the spark plugs--I noticed all my old OEM platinum plugs were PFR5G-11, while these coppers are BKR5E-11. The 'G' in the PFR5G vs. the 'E' in BKR5E... do I have the wrong heat range for the coppers, or are those the correct STOCK heat range for the copper plugs?
Any other comments/suggestions appreciated
P.S.: After doing the compression check I did have the SES light come on. I checked it with my Palm-based OBD-II scantool and it had code P1340 (I think... didn't write it down) in Pending state ("ghost code"), which is an Ignition system code. I cleared it with the scantool. I assume that code was due to the fact that all 6 ignition coils were disconnected (since, to perform the compression test, I had to run the starter with the coils removed with the compression gauge in 1 cylinder at a time)
I am assuming the cylinders go in order with cyl#1 being on the rear bank, far passenger side, and cyl#2 being the front bank, far passenger side going in a zig-zag order with cyl#6 being the front bank, far driver side.
Cyl#1: 225psi
Cyl#2: 220psi
Cyl#3: 220psi
Cyl#4: 225psi
Cyl#5: 220psi
Cyl#6: 230psi
Isn't that a tad high? (and should I run some kind of engine cleaner like SeaFoam through it?) or is that perfect?
Although I recall one thing... I forgot to floor the accelerator while cranking the engine. But I did let it crank through about 9 revolutions for each cylinder. The engine was warm too; I pulled the plugs ~15-30 minutes after I shut it off.
As for the plugs... I changed them last winter with 6 copper plugs from DAVEB. As it turns out, one of the plugs shipped was a platinum, so I decided to put that one into cyl#1. So I actually have 1 platinum and 5 coppers in there.
Here's the condition (and type) of the plugs:
Cyl#1: PFR5G-11 ... mostly clean-looking, just white soot all over the ground/center from wear I guess.
Cyl#2: BKR5E-11 ... Similar white soot to cyl#1, except the ceramic insulator is yellow-colored on the outer side (facing away from the ground strap), or kinda a gradient of brown/green/yellow/orange.
Cyl#3-6: BKR5E-11, pretty much the same story as cyl#2 (brown/yellow/orange color on the side of the center electrode facing away from the ground strap). Cyl#6 also has some very tiny brown spots (they weren't shiny like aluminum, I'm pretty sure they were brown.)
Didn't look like any oil control issues either.
One thing I'm not sure about is the spark plugs--I noticed all my old OEM platinum plugs were PFR5G-11, while these coppers are BKR5E-11. The 'G' in the PFR5G vs. the 'E' in BKR5E... do I have the wrong heat range for the coppers, or are those the correct STOCK heat range for the copper plugs?
Any other comments/suggestions appreciated
P.S.: After doing the compression check I did have the SES light come on. I checked it with my Palm-based OBD-II scantool and it had code P1340 (I think... didn't write it down) in Pending state ("ghost code"), which is an Ignition system code. I cleared it with the scantool. I assume that code was due to the fact that all 6 ignition coils were disconnected (since, to perform the compression test, I had to run the starter with the coils removed with the compression gauge in 1 cylinder at a time)
08-01-2004, 03:08 PM
#3
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Yep, just found out that the local Advance Auto carries SeaFoam. About ~$5/pint. Directions say 1/3rd pint through the carburetor/intake (brake booster hose), 1 pint in the fuel tank (1 pint treats 8-25 gallons of fuel, avg. 1oz per gal), and 1 pint per 10 quarts of oil if you use it in the crankcase. I use Mobil 1 so I doubt I need it in the oil, but I'm gonna go drive out to a remote backcountry parking lot near this area and put this stuff in the brake booster hose. Then go joyriding through B.F.E. with massive amounts of smoke spewing from my exhaust. ("Be sure exhaust is well ventilated. Fumes will be extreme for a short time." 
)
)
08-01-2004, 04:49 PM
#4
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oooh... SeaFoam = Welcome back low-end, mid-range and top-end!
I did the treatment twice... 1/3rd pt. for one treatment, drove around for 15 minutes, then did the treatment a 2nd time, so I have ~1/4-1/3rd of the first bottle left. I noticed the difference after the first try, once the smoke stopped pluming out the tailpipes. Best way to describe it is "stronger throttle response".
I bought Advance Auto's last bottle afterwards and put it in my fuel tank just now. I'm going to reset the ECU and take it for a spin.
While waiting 5 minutes with the engine off during the 2nd treatment, I plugged my OBD-II scantool in just to check on things. It showed the Catalyst and O2 sensors as "I" (not sure what that means, but normally all Emissions-related components show "C" next to them, for "Checked" I guess). I'd imagine the ECU noticed some funky O2 sensor behavior after the treatment, so we'll see if it clears up after the ECU reset.
I did the treatment twice... 1/3rd pt. for one treatment, drove around for 15 minutes, then did the treatment a 2nd time, so I have ~1/4-1/3rd of the first bottle left. I noticed the difference after the first try, once the smoke stopped pluming out the tailpipes. Best way to describe it is "stronger throttle response".
I bought Advance Auto's last bottle afterwards and put it in my fuel tank just now. I'm going to reset the ECU and take it for a spin.
While waiting 5 minutes with the engine off during the 2nd treatment, I plugged my OBD-II scantool in just to check on things. It showed the Catalyst and O2 sensors as "I" (not sure what that means, but normally all Emissions-related components show "C" next to them, for "Checked" I guess). I'd imagine the ECU noticed some funky O2 sensor behavior after the treatment, so we'll see if it clears up after the ECU reset.
08-01-2004, 05:13 PM
#5
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did you disconnect all six coil or you do it one at the time?
cylinder arrangement - odd numbers face the firewall and evens face the radiator.
[fire wall]
1 3 5
2 4 6
[radiator]
your comp. # are good to me.
if you see some white dots on your plugs, that means you are running a little bit lean. What does the center insulation look like? If the shape and texture looks like that of the new plugs, you are fine.
It is weird that your plugs look different for each cylinder, 'cause mine look all the same.
cylinder arrangement - odd numbers face the firewall and evens face the radiator.
[fire wall]
1 3 5
2 4 6
[radiator]
your comp. # are good to me.
if you see some white dots on your plugs, that means you are running a little bit lean. What does the center insulation look like? If the shape and texture looks like that of the new plugs, you are fine.
It is weird that your plugs look different for each cylinder, 'cause mine look all the same.
08-01-2004, 05:55 PM
#6
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I disconnected all 6. I did the test with the fuel pressure relieved, all 6 coils removed, all 6 plugs removed, compression gauge inserted into whichever cylinder I am testing. Luckily this SES light isn't a problem for me since I own an OBD-II scantool (it can clear the code and reset the SES light).
My plugs do look the same for almost all cylinders (exception being cylinder #1, which is a platinum plug, not a copper one). Cylinder #6 does have a few extra spots on it, which is slightly different than the rest, but not by much. My first post reflects this.
The compression readings don't look bad, as in I seriously doubt I have a hole in any pistons or cracked rings or whatever, but they're too high. The manual specifies normal pressure to be 1275 kPa (~184psi), with a minimum of 981 kPa (~142psi). 220-230 is a tad high.
On a side note, I'd love to see the compression readings now that I've used SeaFoam in the engine's intake. Unfortunately I'm too tired and lazy at the moment to go through the trouble of pulling the coils/plugs again.
My plugs do look the same for almost all cylinders (exception being cylinder #1, which is a platinum plug, not a copper one). Cylinder #6 does have a few extra spots on it, which is slightly different than the rest, but not by much. My first post reflects this.
The compression readings don't look bad, as in I seriously doubt I have a hole in any pistons or cracked rings or whatever, but they're too high. The manual specifies normal pressure to be 1275 kPa (~184psi), with a minimum of 981 kPa (~142psi). 220-230 is a tad high.
On a side note, I'd love to see the compression readings now that I've used SeaFoam in the engine's intake. Unfortunately I'm too tired and lazy at the moment to go through the trouble of pulling the coils/plugs again.
08-01-2004, 05:57 PM
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P.S., the "running a little lean" part might be consistent with carbon-buildup in the cylinders.
Carbon buildup can soak up gasoline like a sponge, thus making the engine run lean and probably coercing the ECU into higher Long Term Fuel Trim values so it runs richer to compensate. It also produces abnormally high compression, since the carbon seals the cylinder a little better. It's also harder on the piston rings, and that combined with the aforementioned "fuel soak" phenomenon makes it worth getting the carbon out of there, despite the relative "compression loss" that results.
Carbon buildup can soak up gasoline like a sponge, thus making the engine run lean and probably coercing the ECU into higher Long Term Fuel Trim values so it runs richer to compensate. It also produces abnormally high compression, since the carbon seals the cylinder a little better. It's also harder on the piston rings, and that combined with the aforementioned "fuel soak" phenomenon makes it worth getting the carbon out of there, despite the relative "compression loss" that results.
08-01-2004, 06:01 PM
#8
I- means that the readiness tests have not completed on that emissions equippment. The ECU tests out EVAP, missfire monitor, O2 sensors, CAT, EGR etc... it needs a specific drive cycle for it to pass or FAIL ( you will get a check engine light for fail for the specific system of the EFI). It takes about a week worth of driving or so to change the cat from I to C- meaning complete. As far as high compression readings- we had problems on some 96 SE-Rs with this.. it ended up being the camshafts where ground improperly causing the compression readings to go up, and power to go down. There was even a Slow 96 club on the SE-R list at one point.
08-01-2004, 06:14 PM
#10
Have you dynoed ? stock ? the "Slow 96s" where about 10WHP and 10lbs of TQ down from the normal 95s and 97s on our SE-R list. No matter what you did the TQ was always low... It could put out like 142WHP with CAI, pulley, header and exhaust, and like 117lbs of TQ. My 93 SE-R was at 146WHP with just a CAI, HS header and Greddy catback with 134lbs of TQ. I need to investigate if the cams are same on all VQ30s.
08-01-2004, 07:48 PM
#11
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Never dyno'ed. Not sure if I'm worried about this "cam problem", but I should do another compression check soon to verify that it's not something chronic like you're talking about...
08-01-2004, 08:24 PM
#12
Originally Posted by spirilis
P.S., the "running a little lean" part might be consistent with carbon-buildup in the cylinders.
Carbon buildup can soak up gasoline like a sponge, thus making the engine run lean and probably coercing the ECU into higher Long Term Fuel Trim values so it runs richer to compensate. It also produces abnormally high compression, since the carbon seals the cylinder a little better. It's also harder on the piston rings, and that combined with the aforementioned "fuel soak" phenomenon makes it worth getting the carbon out of there, despite the relative "compression loss" that results.
Carbon buildup can soak up gasoline like a sponge, thus making the engine run lean and probably coercing the ECU into higher Long Term Fuel Trim values so it runs richer to compensate. It also produces abnormally high compression, since the carbon seals the cylinder a little better. It's also harder on the piston rings, and that combined with the aforementioned "fuel soak" phenomenon makes it worth getting the carbon out of there, despite the relative "compression loss" that results.
really? because that I was what my plugs look like when I was running 14-15:1 AFR with my supercharger. (ideally I should run around 11-12:1 AFR) but I was running lean and couldnt tell on the plugs. Finally someone told me that the white dots on the electrode are the signs of leaness.
so if you disconnect all six plugs, do you have to disconnect the crank sensor? Did you have someone read the gauge for you?
thx
08-01-2004, 08:47 PM
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Originally Posted by [maxi-overdose]
really? because that I was what my plugs look like when I was running 14-15:1 AFR with my supercharger. (ideally I should run around 11-12:1 AFR) but I was running lean and couldnt tell on the plugs. Finally someone told me that the white dots on the electrode are the signs of leaness.
so if you disconnect all six plugs, do you have to disconnect the crank sensor? Did you have someone read the gauge for you?
thx
so if you disconnect all six plugs, do you have to disconnect the crank sensor? Did you have someone read the gauge for you?
thx
I did this alone, because my compression gauge (like probably all others) has a 1-way valve in it that allows it to hold pressure. So the reading you get when you see the gauge is the highest reading. There's a bleeder button to release the pressure inside the gauge.
So I basically twist the gauge's hose into the spark plug hole (it has a screw-fitting the size of a 5/8" spark plug hole) until its rubber O-ring starts to seal (you can tell 'cause it becomes harder to screw in), then put the gauge on the other end, let it sit, get in the car, operate the starter for ~9 cycles (you can tell the cycles by the sound of the engine as it spins), get out of the car, look at the gauge, write down its value, hit the bleeder button, unscrew the hose from that hole and go to the next one. Rinse, repeat.
I have some pictures on my camera, maybe I should get them off there and upload them
08-03-2004, 09:02 AM
#14
nevermind, I was thinking about doing each cylinder one by one without removing all the coils and plugs. but again, I could disconnect the coil first and leave the coils in the engine. stupid me....
thx for the instruction and please upload some pics for us
thx for the instruction and please upload some pics for us
Originally Posted by spirilis
No... why would you have to disconnect the crank sensor? Just run the starter with the coils disconnected and the coil connectors hanging around dangling. The only side effect is the SES light when you're done, which isn't an issue for me since I have the tool to clear the code
I did this alone, because my compression gauge (like probably all others) has a 1-way valve in it that allows it to hold pressure. So the reading you get when you see the gauge is the highest reading. There's a bleeder button to release the pressure inside the gauge.
So I basically twist the gauge's hose into the spark plug hole (it has a screw-fitting the size of a 5/8" spark plug hole) until its rubber O-ring starts to seal (you can tell 'cause it becomes harder to screw in), then put the gauge on the other end, let it sit, get in the car, operate the starter for ~9 cycles (you can tell the cycles by the sound of the engine as it spins), get out of the car, look at the gauge, write down its value, hit the bleeder button, unscrew the hose from that hole and go to the next one. Rinse, repeat.
I have some pictures on my camera, maybe I should get them off there and upload them
I did this alone, because my compression gauge (like probably all others) has a 1-way valve in it that allows it to hold pressure. So the reading you get when you see the gauge is the highest reading. There's a bleeder button to release the pressure inside the gauge.
So I basically twist the gauge's hose into the spark plug hole (it has a screw-fitting the size of a 5/8" spark plug hole) until its rubber O-ring starts to seal (you can tell 'cause it becomes harder to screw in), then put the gauge on the other end, let it sit, get in the car, operate the starter for ~9 cycles (you can tell the cycles by the sound of the engine as it spins), get out of the car, look at the gauge, write down its value, hit the bleeder button, unscrew the hose from that hole and go to the next one. Rinse, repeat.
I have some pictures on my camera, maybe I should get them off there and upload them
08-03-2004, 06:47 PM
#15
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PS, I expended the last 1/4 bottle of SeaFoam I had today.
Dumped it in through the brake booster hose a little faster than previous runs, promptly shut it off and let it sit for 10 minutes (instead of 5 minutes). Started it up... it took a lot of effort to keep it running, however it eventually caught on and I was able to maintain ~2-3K RPM with white smoke billowing out the tailpipe.
Driving around a little, shortly after I pulled out of the parking lot the white smoke turned to a translucent BLUE smoke. It kept on like this for another ~2 miles, blowing blue (oil) smoke every time I gave it a decent amount of throttle. Afterwards it stopped...
I filled up the tank, started the engine w/ tranny in neutral and parking brake applied, reached my right foot in and revved it. Didn't see any smoke come out. Score.
Runs pretty well now. This'll be my first tank after using seafoam, since I had 1 bottle of seafoam in the last tank. I should check the LTFT parameters with my OBD-II scantool soon to see if they've changed.
Sometime soon I'm going to buy 6 new copper spark plugs, pull 'em, do a followup compression check and install the new plugs at the same time.
Dumped it in through the brake booster hose a little faster than previous runs, promptly shut it off and let it sit for 10 minutes (instead of 5 minutes). Started it up... it took a lot of effort to keep it running, however it eventually caught on and I was able to maintain ~2-3K RPM with white smoke billowing out the tailpipe.
Driving around a little, shortly after I pulled out of the parking lot the white smoke turned to a translucent BLUE smoke. It kept on like this for another ~2 miles, blowing blue (oil) smoke every time I gave it a decent amount of throttle. Afterwards it stopped...
I filled up the tank, started the engine w/ tranny in neutral and parking brake applied, reached my right foot in and revved it. Didn't see any smoke come out. Score.
Runs pretty well now. This'll be my first tank after using seafoam, since I had 1 bottle of seafoam in the last tank. I should check the LTFT parameters with my OBD-II scantool soon to see if they've changed.
Sometime soon I'm going to buy 6 new copper spark plugs, pull 'em, do a followup compression check and install the new plugs at the same time.
08-05-2004, 05:48 PM
#16
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Pics 
http://spirilis.net/gallery/comprtest-08012004
SeaFoam anyone?
Yeah, compression was a little high...
http://spirilis.net/gallery/comprtest-08012004
SeaFoam anyone?
Yeah, compression was a little high...
08-05-2004, 10:27 PM
#17
Originally Posted by spirilis
Pics
http://spirilis.net/gallery/comprtest-08012004
SeaFoam anyone?
Yeah, compression was a little high...
http://spirilis.net/gallery/comprtest-08012004
SeaFoam anyone?
Yeah, compression was a little high...
thank you
08-06-2004, 08:29 AM
#18
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I swear, my car feels so darn "effortless" on the highway after doing this. I definitely feel a consistent improvement in the butt dyno.
I'm trying to get a setup arranged where I can have my Palm mounted with a windshield mount (ordered one off ebay), and a custom OBD-II cable setup that allows me to keep the OBD-II scantool hooked up all the time without it interfering with my left leg. After that I'm gonna give the Auterra OBD-II Dyno-Scan's 1/4 mile and dyno features a run (pun intended
) and maybe get some rough numbers.
I'm trying to get a setup arranged where I can have my Palm mounted with a windshield mount (ordered one off ebay), and a custom OBD-II cable setup that allows me to keep the OBD-II scantool hooked up all the time without it interfering with my left leg. After that I'm gonna give the Auterra OBD-II Dyno-Scan's 1/4 mile and dyno features a run (pun intended
) and maybe get some rough numbers.
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