drivers side plugs solid black.. passanger perfect! Ideas?

forum155pl

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#1

• Apr 11, 2007

• #1

Just as the title says.. all 4 of my drivers side plugs are all black.. they look like carbon build up not oil... the passanger plugs are all perfect looking.. they are motorcraft plugs that i put in about 4 months ago..

all were gapped at .40 (i have the PI swap)

any ideas? i'm thinking o2 sensor but i didnt want to go off and buy one till i talked to you guys..

thanks..

 

Mike97gt

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Apr 11, 2007

#2

• Apr 11, 2007

• #2

most likely cause of one bank running rich is a bad 02 sensor, but I would also check your injector pulse for both banks and see if one is much longer than the other.

A exhaust leak can also cause this...

 

forum155pl

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how do i check the pulse?

i put on longtubes when i did those plugs and the ones i took out were exactly the same, i thought it was an exhaust leak then, but now i know there isnt any leaks..

 

Superhereaux

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#4

• Apr 12, 2007

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not too familiar with pre-99 4.6's but aren't there 2 coil packs, 1 for each bank?


might be something to look into maybe

 

CobraRed_96_GT

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#5

• Apr 12, 2007

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Superhereaux said:

not too familiar with pre-99 4.6's but aren't there 2 coil packs, 1 for each bank?


might be something to look into maybe

Click to expand...

yeah, there is two coil packs, but 2 plug wires from each coil pack track to the other side's spark plugs. If one pack when out you'd have 1,3,5,6 go out or somthing

 

forum155pl

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• Apr 13, 2007

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ive changed the packs to f150 packs.. new wires, and new plugs.. and i still got it.. it bucked like crazy on my way home from work just now.. i'm just going to replace the 2 front o2's they are the stockers anyways...

 

Superhereaux

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#7

• Apr 13, 2007

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CobraRed_96_GT said:

yeah, there is two coil packs, but 2 plug wires from each coil pack track to the other side's spark plugs. If one pack when out you'd have 1,3,5,6 go out or somthing

Click to expand...

cool, i learned something today

well that eliminates spark, guess fuel trim it is. if the o2's are stock (10yrs old) then yeah might want to try that

no check engine light? exhaust tick in the morning?

 

forum155pl

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no lights or codes.. i have a tick all the time.. but its not an exhaust tick.. i have no idea on what that is..

 

Mike97gt

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#9

• Apr 13, 2007

• #9

So it' misfiring too? BTW checking the injector pulse width requires a scan tool that is live data capable


Are you burning any oil? any coolant? it's possible that a bad head gasket can cause low compression on that bank, cause the fouled plugs and misfires too.

Another thing to look at is a possible cam timing issue on that bank.. Check the cam sprocket on the bank with the black plugs, we have seen some sprockets crack causing cam timing issues on one bank.

 

forum155pl

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#10

• Apr 14, 2007

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i'll check into that cam timing... i have a leaky timing cover gasket anyways... a buddy of mine has a MAC scantool, i'll get him to scan it for me... thanks guys!