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The mkiv Supra Owners Club

Basic Engine experts please!


RobSheffield
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ok, Rover V8, sounds a bit rough

 

new plugs, leads and points before first start up a couple of weeks ago.

 

using the old 'remove the plug leads and whichever doesnt make a difference must be the cause' method, we isolated plug on number 8 as a problem, removed plug, started engine with plug on block, VERY weak spark (confused me as plugs normally work or dont).

 

so new plug in and it worked great, on a 5 mile warmup run (only 30 miles from rebuild) it felt nice, dad didnt push it too hard though, newly rebuilt car and all. got home, sounded a bit rough, so removed plug 8 again, and it made no differnce, removed plug 2, no difference, all 6 other leads made a difference when removed. we didnt change anything else, so as not to cloud or confuse the issue, and worked systematically through it

 

has me a little baffled to be honest.

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plugs are getting fouled up due to bad mixture? just a thought...

 

inside 5 miles?

 

it was a brand new plug that went in, we can confirm it IS sparking so appears the lead is ok, and if the plug is ok, then its a bloody mystery...

 

cant see how removing 2 leads can still allow it to run, albeit as rough as if they are on, its a bit 'splashy' hunting and sounds irregular in its V8 beat.

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thanks Mate, im thinkin Michael may have it with the lead swap, will try that at least....for both pot 2 and 8 to be off, must be a solution that applies to both...

 

they are silicone kevlar leads, and i cant help thinking one or two of them may be a little bit 'intermittent'

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plugs are getting fouled up due to bad mixture? just a thought...

 

 

I agree, have you had the carb apart? check the jets! Even the EFI have a carb type set up being SPI.

 

I had a friend with a jag V8 had a similar problem, turned out to be the EFI - the main jet was slightly bent, so the wrong mixture was being mixed. You can easily tell the jet is bent if you roll it on some card.

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Thankyou very much Mark

 

was fantastic top speak to John, and as a result my dad is going to order new coil and distributor cap/rotor arrm.

 

i shall update in due course :)

 

 

no probs mate, anytime you have a problem re the motor just drop a pm and i will send you my number again,

 

let me know how you get on, as if not that then possible something else, john woudl be happy to come to you aswell, he is not a well man but woudl keep him busy

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