replaced headgasket and now missfire

[scottypimppin]

So i replaced my HeadGasket and now im getting a missfire (CEL flashing) i have replace everything that i can think of and i checked checked and rechecked everything so I don't know now.

codes are p0300, p0301, p0302, p0303, p0304

also its a 98 eclipse 420a auto trans

 

[VelocitàPaola]

And you've checked all the more common causes of the P030x codes?

OBD-II Trouble Code: P0300 Random/Multiple Cylinder Misfire Detected

 

[scottypimppin]

yes done all of those

 

[bullettdsm]

Misfiring all over......hmm. Let's see if we can identify if its mechanical vs electronic. How does it idle? How does it run? Spark plugs gapped properl.....wait let's start with the first two questions before we go further.

MB

 

[evileagleawd]

sounds like t belt is off check timing!

 

[scottypimppin]

idles at like 800 to 1000, spark plugs are all gaped right, and it runs great

also the timing good

 

[bk120]

when you took the cover off did you hit any sensors?

 

[bullettdsm]

idles at like 800 to 1000, spark plugs are all gaped right, and it runs great

also the timing good

So its just throwing the codes but not afffecting the way the engine performs? If that's the case then it tells us that its a very quick short blip of information to the ECU. I think I would start with un-plugging and looking at connectors (to see if there is any wires etc. cracked or broken). Look at any wires that would generate misfires throughout the 4 cylinders (say the connector for the injector harness. Or the connector for the coil). There is also the common "egr tube" wires that house the harness for the coil etc. Be sure that you don't have any of those wires damaged (even damged before you did the HG and the movement made them worse).

Let's see........what kind of plugs are you running? Hopefully not some special irridium, fusion, plutonium, hexagonal tipped, gold plated plugs. Standard NGK's work best for our cars. How about plug wires? Bad wires can show misfires as they arc out on each other, but it doesn't necesarily affect the engine. Um....fuel? Any chance that you have a bad load of gas in there? This usually affects engine performance, but its possible.

A little to work with.

MB

 

[scottypimppin]

ok so i just did a tune up, ngk wires and ngk plugs copper, but when i was doing the tune up i did a compression test and it came up 210/200/180/180 and the cel is still flashing?

 

[scottypimppin]

anyone?

 

[starfish]

this might not help but about a year ago I all of a sudden started getting all those same codes(multipal missfiring).I canged all my plugs,wires sensors.even bought a new ECU.I went to go get gas in my jeep and when I got to the station it was all closed off with yellow tape and they were digging up the tanks.I went into their office and they told my that the tank was cracked and it filled up with water during the storm.I rushed back home and pulled out my FP and took out a glass full of gas.It was nothing but water in my tank.their inssurance comp. sent me a check for $984,the cost of all my receipts.(I should of dropped in a new motor).Any how is it possible that you got moisture or water in or on your motor while you were working?Did you try erasing your codes ?Alot of times I would work on my motor and afterwards the same codes would come up(300,301).Once I erase them everything would be OK!

 

[BoostedPhoenix]

If this is right after a head gasket i would say the timing is off a tooth either from being correct or from how it was before. If the engine is running fine and the computer just thinks its misfiring its because of an unexpected variance between the cam and crank sensors. After a new timing belt the DRBIII can be used to reset the corrolation between the cam and crank sensors to avoid erroneous codes like this. Since the ECU learns over time the difference in values between the two it will take several drive cycles to relearn without doing it manually, but this is not a normal occurance and most likely caused by the belt timing being off significantly.

 

[VelocitàPaola]

anyone?

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