My Misfire P1399 Po301-Po304
09-11-2010, 01:03 PM
#1
Thread Starter
My Misfire P1399 Po301-Po304
So... where to start. This has been one of the most aggravating problems i have dealt with in awhile so I want to add my problems and possible solutions and what actually fixed the problem.
My car and the conditions:
2004 with 50k miles
always use Chevron 91
weekend car that is not abused and driven lightly with occasional vtec
CEL comes on only at low rpm between 800-2000 and usually at cold starts but started getting worse and started to come on after clearing code with the engine warm then became worse and cel started blinking for 1-5 seconds at low rpm(idle mostly or coasting to a stop).
Problems started when my cel came on at about 45k miles and didn't think much of it because it went away the very next time i started the car after the cel came on. stayed off for a few thousand miles and then started to have cel stay on. checked out the code with my obdII reader and it was the dreaded misfire p1399 along with all cylinders 300-304. DTC codes were always random and would read different DTC's. sometimes cyl 1 came up first then others followed and sometimes other cylinders came up first but everytime the rest followed. it finally came conistent and started reading #4 first then the rest followed.
Read through all the misfire threads and it all pointed to injectors. Others reported solving the problem 65% injectors, 10% map sensor, 10% coil pack(s) 10% valve adjustment, and 5% with other problems that were not related to this issue because of over rev or engines that had more major problems that were not specific to my conditions.
After reading through owners repair manual it points towards fuel system and not electrical like sensors and ignition components.
My possible fixes started off with:
1. map sensor switch with same year s2k
2. coil swap with same year s2k
3. new oem plugs
After all this nothing really changed and we decided to do the compression check.
results were:
1=220
2=210
3=210
4=150
After this, i felt that it needed a complete teardown pretty much figuring it was a bent valve/burnt valve because the plugs seemed normal so no cylinder damage to #4 i figured so we moved on to do a valve job. exhaust valve on #4 was tight by 1 full turn of the adjustment screw and couldn't even get the gapping tool in. It raised the compression to 180 in #4 after adjustment. I was pretty relieved that it went up that high so we just went with it and put everything back together hoping that compression might go back to normal after running for a few miles and reseals itself better after being adjusted. All other valves were within specs. Intake is suppose to be .21-.25 and exhaust is .25-.29.
Afterwards i did the idle learn procedure(turn car on with all extra accessories off and let the fan turn on for 2 cycles about ~5min. This is for 00-05 models. 06+ is different and i didn't bother reading about that because it didn't pertain to me so you 06+ guys are gonna have to look this one up but i believe the HDS(honda diagnostic scanner) is needed to do this.
Ran the car for about 40 miles and no more codes and proceeded to let the sensors go through the complete cycle until it fully registered in the ECU. Went to go get smog and passed with almost no emissions at all.
The solution:
Valve adjustment
Things I learned:
Do compression check first if you have similar problems and get a OBDII reader and read through manual so you know how to use it. It takes 40 cold start cycles to turn off pending codes and 80 cold start cycles for DTC non pending codes. Takes about ~50 miles to for all the sensors to register as a complete cycle with the evap sensor taking the longest to register. Street driving is better for the cycles to complete and no highway driving is needed for sensors to complete the cycle and be in the READY ecu status.
I hope this helps out other people with similar problems. There's thousands of posts with similar problems but most incomplete. Random 1 and Billman(s2k members) had the best advice and seemed the most knowledgeable about this subject and reading through their threads helped a lot.
My car and the conditions:
2004 with 50k miles
always use Chevron 91
weekend car that is not abused and driven lightly with occasional vtec
CEL comes on only at low rpm between 800-2000 and usually at cold starts but started getting worse and started to come on after clearing code with the engine warm then became worse and cel started blinking for 1-5 seconds at low rpm(idle mostly or coasting to a stop).
Problems started when my cel came on at about 45k miles and didn't think much of it because it went away the very next time i started the car after the cel came on. stayed off for a few thousand miles and then started to have cel stay on. checked out the code with my obdII reader and it was the dreaded misfire p1399 along with all cylinders 300-304. DTC codes were always random and would read different DTC's. sometimes cyl 1 came up first then others followed and sometimes other cylinders came up first but everytime the rest followed. it finally came conistent and started reading #4 first then the rest followed.
Read through all the misfire threads and it all pointed to injectors. Others reported solving the problem 65% injectors, 10% map sensor, 10% coil pack(s) 10% valve adjustment, and 5% with other problems that were not related to this issue because of over rev or engines that had more major problems that were not specific to my conditions.
After reading through owners repair manual it points towards fuel system and not electrical like sensors and ignition components.
My possible fixes started off with:
1. map sensor switch with same year s2k
2. coil swap with same year s2k
3. new oem plugs
After all this nothing really changed and we decided to do the compression check.
results were:
1=220
2=210
3=210
4=150
After this, i felt that it needed a complete teardown pretty much figuring it was a bent valve/burnt valve because the plugs seemed normal so no cylinder damage to #4 i figured so we moved on to do a valve job. exhaust valve on #4 was tight by 1 full turn of the adjustment screw and couldn't even get the gapping tool in. It raised the compression to 180 in #4 after adjustment. I was pretty relieved that it went up that high so we just went with it and put everything back together hoping that compression might go back to normal after running for a few miles and reseals itself better after being adjusted. All other valves were within specs. Intake is suppose to be .21-.25 and exhaust is .25-.29.
Afterwards i did the idle learn procedure(turn car on with all extra accessories off and let the fan turn on for 2 cycles about ~5min. This is for 00-05 models. 06+ is different and i didn't bother reading about that because it didn't pertain to me so you 06+ guys are gonna have to look this one up but i believe the HDS(honda diagnostic scanner) is needed to do this.
Ran the car for about 40 miles and no more codes and proceeded to let the sensors go through the complete cycle until it fully registered in the ECU. Went to go get smog and passed with almost no emissions at all.
The solution:
Valve adjustment
Things I learned:
Do compression check first if you have similar problems and get a OBDII reader and read through manual so you know how to use it. It takes 40 cold start cycles to turn off pending codes and 80 cold start cycles for DTC non pending codes. Takes about ~50 miles to for all the sensors to register as a complete cycle with the evap sensor taking the longest to register. Street driving is better for the cycles to complete and no highway driving is needed for sensors to complete the cycle and be in the READY ecu status.
I hope this helps out other people with similar problems. There's thousands of posts with similar problems but most incomplete. Random 1 and Billman(s2k members) had the best advice and seemed the most knowledgeable about this subject and reading through their threads helped a lot.
09-17-2010, 02:42 PM
#4
Moderator
That is strange. the tightest exhaust valve I've ever found was .009. one full turn is enormous. Were the valve adjusted by a former owner? dealer?
09-20-2010, 09:38 PM
#6
Thread Starter
Originally Posted by Billman250,Sep 17 2010, 02:42 PM
That is strange. the tightest exhaust valve I've ever found was .009. one full turn is enormous. Were the valve adjusted by a former owner? dealer?
now that the s2k is running fresh i've already purchased some wheels/strut bar/lugs for being such a sexy beast
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