Plug gap question - misfire on boost
#1
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Plug gap question - misfire on boost
Tonight on my way home from work my Cosworth developed a misfire over 1.2 bar in 5th gear Boosts up to 1.2 bar perfectly but once it gets there is starts to misfire and hold back so I backed off
When I got home I took the plugs out and they look good but the gaps are slightly all over the place & I don't know what they should be gapped at and can't get hold of anyone at MSD at the moment. The gaps are currently between .60 and .75mm and the car is a stage 3 on one of Stu's chips.
Anyone know roughly what the gaps could be or what else might be causing it?
Thanks
When I got home I took the plugs out and they look good but the gaps are slightly all over the place & I don't know what they should be gapped at and can't get hold of anyone at MSD at the moment. The gaps are currently between .60 and .75mm and the car is a stage 3 on one of Stu's chips.
Anyone know roughly what the gaps could be or what else might be causing it?
Thanks
#3
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Thanks Phil I thought .75 was a bit wide, if that doesn't fix it I'll get some new plugs, it hasn't done hardly any miles but the plugs have been in there 3 years That's about 2,500 miles use at a guess What plugs do you recommend?
#7
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I just took the plugs down to mate who is a mapper and he agrees that the engine is (was ) running well and it's just a little bit rich. The plugs in there were NGK 9's but they are worn out and he's advised me to get new plugs so I'll get some off Mike and gap them to .6mm and try that
Thanks for your help
Thanks for your help
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#12
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Thanks for explaining I'm just trying to see where I can get some the quickest at the moment, I want the car back on the road by the weekend.
#15
I have about 600 in stock and you should gap them to 0.65mm
However, you would do far better with a set of denso iridium IK27's.
With regards your friend reading the plug colour and advising engine mixture conditions, did he ask you for a detailed explanation of engine run time and load and then ensure that you cut the engine dead under load and coasted to a halt before removing them from teh engine? If not, with all due respect, ignore any mixture advice he gave you.
However, you would do far better with a set of denso iridium IK27's.
With regards your friend reading the plug colour and advising engine mixture conditions, did he ask you for a detailed explanation of engine run time and load and then ensure that you cut the engine dead under load and coasted to a halt before removing them from teh engine? If not, with all due respect, ignore any mixture advice he gave you.
#17
#24
PassionFord Post Whore!!
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I have about 600 in stock and you should gap them to 0.65mm
However, you would do far better with a set of denso iridium IK27's.
With regards your friend reading the plug colour and advising engine mixture conditions, did he ask you for a detailed explanation of engine run time and load and then ensure that you cut the engine dead under load and coasted to a halt before removing them from teh engine? If not, with all due respect, ignore any mixture advice he gave you.
However, you would do far better with a set of denso iridium IK27's.
With regards your friend reading the plug colour and advising engine mixture conditions, did he ask you for a detailed explanation of engine run time and load and then ensure that you cut the engine dead under load and coasted to a halt before removing them from teh engine? If not, with all due respect, ignore any mixture advice he gave you.
My friend did advise me that was the only real way of diagnosing plugs, he said that's how they used to do it tuning bikes. It was just an indication I was after
New plugs ordered today from Matt Lewis after a quick call to see when he could deliver them.
#27
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Now i am going to be honest here, the denso plugs are NOT meant to be regapped from out of the box, you do sometimes hear of these tips dropping off and destroying engines, maybe you can get away with it once???...they are very weak in tip terms.
Not trying to annoy anyone its just what i have been told and shown when a tip falls off!
Not trying to annoy anyone its just what i have been told and shown when a tip falls off!
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