Compression test / results and Seafoam ?

redsnake · **Joined:** Fri Nov 26, 2010 9:51 pm **Posts:** 41

OK... so I've been chasing some problems on my '03 KJ for a while now. It's a 3.7, Auto, Limited 4x4 w/ 124K miles.

I believe I've finally fixed the oil leak by replacing the Pass Side Valve cover gasket. That taken care of now I'm still trying to find my P0306 code and fix that. Swapped all Spark Plugs w/ NGK plugs. Replaced the Coil on Plug 6... code came back. Swapped Coil pack 5 and 6... code P0306 came back. KJ has been running fine, but the Check Engine light is bugging.

Today I ran a compression test (Engine at Op Temp. Pulled all plugs, Coil Packs and Fuel Pump Relay). Compression is highest on Cyl 6 @ 183 psi. Avg across the board is ~ 175 psi. Lowest being Cyl #1 at 172 psi. No Zero's or Super highs. I would say it looks good.

So after getting everything back together I ran about 1/2 a can of Seafoam thru the Intake via the Brake Booster Vacuum line. Turned off the KJ and let it sit for about 15 minutes. Fired it up and drove it around the block, down the street and got it up to about 65mph... of course it SMOKED like crazy at first but that burned off and she ran just fine.

Got back home and pulled the OBDII codes. Still had the P0306 but also now have P0113. I checked to make sure all sensors were plugged in good. No exposed or broken wires that I can tell. Is there a way to check the Intake Air Temp Sensor (P0113) voltage or could the Seafoam have damaged that one? Is that sensor located on the drivers side about 1/2 way on the plastic air intake? Anyone have a pic of where it is and how you can remove it?

I put the other 1/2 of the Seafoam bottle in the gas tank to run thru and help clean the fuel injectors. Hopefully that will help as well.

My other thought is perhaps one of the O2 Sensors could be going bad (never changed in 124K miles) but the OBDII Codes don't show that.

Thanks for reading this... any suggestions would be appreciated.

JeepinJarhead03 · **Posted:** Fri Dec 17, 2010 7:02 pm

02's will show codes if it's 02's

after seafoaming you'll need new plugs again

170psi-225psi is the psi range for the 3.7 no more than 25% difference across so that's in spec

doesn't answer all of your questions but hopefully clears a few items up for ya

redsnake · **Joined:** Fri Nov 26, 2010 9:51 pm **Posts:** 41

JeepinJarhead03 wrote:

after seafoaming you'll need new plugs again

Thanks for the info. Why would I need new plugs after running the Seafoam? I have not heard this before... but doesn't mean I don't need new ones again.

JeepinJarhead03 · **Posted:** Fri Dec 17, 2010 7:32 pm

the carbon broken loose can, and often does, reattach itself to the plugs

poor plugs = less burn = more carbon

it's just been the general rule of thumb, seafoam then plugs

Compression test / results and Seafoam ?

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