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The mkiv Supra Owners Club

Supra N/A misfire, any ideas?


Guest caldoofy

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Guest caldoofy

Hi all, I recently developed a heavy misfire on my na supe it is audible on tick over and really does become apparent from 1200 to 2600 rpm kangarooing and sounding like its runnin on 3 cylinders! After the 2600 rpm point it seems to completely disappear and the car takes off! wondering if anyone had any ideas as to cause ive changed the plugs, leads, dissy cap and rotor arm cleaned all the plugs i could find with wd40 but nothin seems to work is there something im missing? Any help greatly appreciated.

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Guest caldoofy

No i havent cleaned it but ive cleaned the gulley where the plugs sit anyway cause there was looked like sand in there!! so it isnt the water by the plug problem.

 

would the o2 sensor cause this sort of fault?

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This one have copyrights! It supposed to be asked by JustGav :p

 

Didn't realise, sorry:) just remember an american supra site where loads of people where complaining of misfires after washing their engine bays but they were all N/A's and the TT guys where taking the pi55 out of them, was funny! i believe the most common description was that the engine sounded like a subaru instead of a smooth 6 cylinder.

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Guest caldoofy

yeah doin my head in this problem, what was it on the injection side dazzi? HT leads rotor and cap have al been changed for new ones s could prob eliminate that. One suggestion was the advance and retard is not getting a good signal from the crank and cam sensors? after the magic 2600 this system is redundant hence the car taking off after that speed? make sense to anyone? cheers for the help so far :-)

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What does the car idle at once warm? Have you checked all cylinders are firing? Also what spark plugs have you installed and have you inspected them for rich/lean mixture and also if oil is present on the tip?

 

Edit, just to add what is your crank set at? TDC? 10d BTDC etc? have you tried a timing light to see?

Edited by Dazzi (see edit history)
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Guest caldoofy

car idles bout 800 rpm when its warm the idle hasnt really been affected you can hear the misfire when its idling but only slightly, havent checked the timing as yet, plugs are platinum ngks when i took them out there was no oil on any of them all were dark grey in colour electrode was white. Its as though one cylinder is down but keeps comin back to life so thats why i thought connections initially but now everything on that part of it from dissy to plugs is new!!? So am at a loss! Comin off the road for winter anyways but would be nice to get this sorted before it does.

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  • 2 months later...
Guest caldoofy

right just gone back to the car after my winter break and the problem still exsists i have changed the coil aswell but no luck. any other ideas on this people? cheers for your help in advance and a happy new year to everyone.

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Guest caldoofy

i have changed the plugs, leads, dissy cap and rotor arm as well as fitting a new coil pack, how would you check for a sticky injector? cheers for the help so far.

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