Code P0351 Follow-up
02-19-2011, 09:38 AM
#1
2nd Gear Member
Thread Starter
Join Date: Jul 2008
Location: Alabama
Posts: 174
Code P0351 Follow-up
Well good news and bad news (depends). Good news is I found why coil number one is not firing. The reason why its good news is because I spent two weeks trying to find out what the problem is and now Im not totally clueless nomore. The bad news is that the connector to the plug and the wires have been melted (on just the #1 coil) wow...... SO! How do I go about fixing this , who fixes this? Am I going to have to save up for a year for such a repair? Thanks guys
02-20-2011, 03:10 AM
#7
TECH SAVANT
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
When the COP boots go bad, plug gap opens up, and/or other situations occur in which the COP is dumping its "full load" (entire charge) repeatedly the COP will get VERY hot, very fast.
I built a COP Tester a while back, and though there was a lot of interest generated I never pushed it further because I found that if mis-used it was a very effective COP-Destroyer.
Forcing a COP (any COP) to dump it's full charge¹ more than 12-15 times in rapid succession will kill it, and make it so hot that you can smell it burning up--I measured an Accel COP I killed at 350°F+--the limit of the infrared thermometer I had immediately at hand. As the terminals have direct electrical, and therefore thermal, connection to the coil there could easily be enough heat transferred to melt the connector and wiring.
When the boots go bad the COP can fire the plug so there's no misfire, AND dump the rest of its charge into the head through the bad boot--this will not trigger a DTC because as far as the PCM is concerned² there was no problem.
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¹ - With the COP-Destroyer I did this by opening the spark gap up to the maximum the COP could fire across.
² - The misfire monitor does not monitor ignition, AFR, or anything else; but instead "watches" the crankshaft rotational velocity and acceleration to detect misfiring. This is important to understand as a common misconception is that misfire DTCs (P0300 through P0310) automatically mean an ignition problem. This is not so, anything that creates less than expected velocity/acceleration of the crank will trigger a misfire code.
================================================== ===============
I actually made up a packaged COP-Destroyer for my own use--not practical for the mass market though:
I built a COP Tester a while back, and though there was a lot of interest generated I never pushed it further because I found that if mis-used it was a very effective COP-Destroyer.
Forcing a COP (any COP) to dump it's full charge¹ more than 12-15 times in rapid succession will kill it, and make it so hot that you can smell it burning up--I measured an Accel COP I killed at 350°F+--the limit of the infrared thermometer I had immediately at hand. As the terminals have direct electrical, and therefore thermal, connection to the coil there could easily be enough heat transferred to melt the connector and wiring.
When the boots go bad the COP can fire the plug so there's no misfire, AND dump the rest of its charge into the head through the bad boot--this will not trigger a DTC because as far as the PCM is concerned² there was no problem.
---------------------------------------------------
¹ - With the COP-Destroyer I did this by opening the spark gap up to the maximum the COP could fire across.
² - The misfire monitor does not monitor ignition, AFR, or anything else; but instead "watches" the crankshaft rotational velocity and acceleration to detect misfiring. This is important to understand as a common misconception is that misfire DTCs (P0300 through P0310) automatically mean an ignition problem. This is not so, anything that creates less than expected velocity/acceleration of the crank will trigger a misfire code.
================================================== ===============
I actually made up a packaged COP-Destroyer for my own use--not practical for the mass market though:
Last edited by cliffyk; 02-20-2011 at 03:13 AM.
02-20-2011, 09:17 AM
#9
TECH SAVANT
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
There are two types of misfire monitoring cycles, one with a 200 engine revolution window and one with a 1000 revolution window. The first will cause the MIL to blink during the misfire event(s) and store a DTC (MIL stays off), the second will turn on the MIL and store a code.
02-21-2011, 11:09 PM
#10
2nd Gear Member
Thread Starter
Join Date: Jul 2008
Location: Alabama
Posts: 174
Well to my surprise it wasnt the melted wire. Its actually the first coil plug on the passenger side. When I unplug all the rest of them the engine dies down alittle, when I unplug coil #1 the engine stays the same. Question Is why would jjust one coil not fire if it was the ecu? Wouldn't a broken ecu not make any of the coils fire?
Last edited by boothay; 02-22-2011 at 05:35 AM.