SL-2 Help! Cylinder 3 Misfire
#11
01-02-2018 | 09:06 PM
Junior Member
Joined: Jan 2018
Posts: 3
Need help plz
Sorry for bringing up old post but need help. I got a 2002 Saturn sl for next to nothing had random misfire code so I changed the plugs wires coils.. now getting p0303 misfire #3 so before putting more money into the car I figured do compression check. This is what I got #1 180psi #2 180psi #3 155psi #4 180psi. So would that cause a misfire code ? The car runs but I can not get inspection with the engine light on. Didn’t know if I should try injectors or EGR And so on. I mean I know #3 is lower then the rest is 25psi make that big of a difference?
#12
01-02-2018 | 11:03 PM
Super Moderator
Joined: Apr 2015
Posts: 2,598
From: Willamette Valley, Oregon
Does it misfire?
So it had a po300 code before the tuneup and now it has a po303?
clear the codes and do a drive cycle to see if all the obd monitors will run.
See what comes back.
let us know.
clear the codes and do a drive cycle to see if all the obd monitors will run.
See what comes back.
let us know.
#13
01-02-2018 | 11:32 PM
Junior Member
Joined: Jan 2018
Posts: 3
Yes
yes it originally had a p0300 random misfire detected so figured just do all the plugs wires coils. Then cleared the code started up not even a mile into the drive cycle monitoring light was back on blinking. P0303. So took fuel pump rely out pulled one plug at a time checked all for spark that was good. So then figured do a compression check before continuing to put money into it. That came back as such cyl #1 180lbs #2 180lbs #3 150 #4 180 from left to right.
#14
01-03-2018 | 09:12 AM
Super Moderator
Joined: Jul 2005
Posts: 11,027
From: Slightly off center
the fact that the blinking ses did not return until half a mile down the road would lead me to believe the plug is either getting oil fouled, fuel fouled or a little of both.
I've driven S cars with much lower compression across the board without misfires.
Pull #3 and I'll bet it is fouled. It fired fine for 1/2 a mile so the compressions is likely not the issue.
Gas or oil fouling more likely. The service limit is supposedly 180 but I've driven them much lower.
You may have a head gasket issue emerging around #3, and coolant may be seeping into the cyl as well. Should just burn w white sweet smoke. Check exhaust for burning coolant smell
SMALL chance you got a bum new coil. swap positions and see if the misfire moves or not.
Also, did you replace the DIS module under the coils that controls the ignition system? It is rare for it to lose a single cyl and you don't want to spend the $$ on a new one unless you are out of options.
I've driven S cars with much lower compression across the board without misfires.
Pull #3 and I'll bet it is fouled. It fired fine for 1/2 a mile so the compressions is likely not the issue.
Gas or oil fouling more likely. The service limit is supposedly 180 but I've driven them much lower.
You may have a head gasket issue emerging around #3, and coolant may be seeping into the cyl as well. Should just burn w white sweet smoke. Check exhaust for burning coolant smell
SMALL chance you got a bum new coil. swap positions and see if the misfire moves or not.
Also, did you replace the DIS module under the coils that controls the ignition system? It is rare for it to lose a single cyl and you don't want to spend the $$ on a new one unless you are out of options.
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