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Plugs coked and car runs really bad, whats wrong!?


Sean1933

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This is on my friends evo3, not my Supra...but i figured the same principles applied.

 

A week or so ago my friend started his car in the morning and it was running like a sack of poop, sounded like it was missfiring or even not running on all cylinders.

 

We pulled the plugs and they were coked as anything, atleast one of them stunk of fuel, cant remember if it was one or numerous. They were cleaned, gaps checked, and refitted. She started like a dream, we test drove and it ran great.

 

The next morning the car was the same as before, running like poop. So the plugs were pulled again, again they were coked albeit not so bad (but car hadnt been run that long). On closer inspection the cylinders were also coked badly. So plugs were cleaned and full engine flush (in oil) and oil change was done. Again the car ran great.

 

Next day it ran crap again...whats going on! AFRs are fine, in a little rich but nothing extreme. Im wondering if an injector is leaking or something, but im guessing.

 

Also can anyone confirm if a fuel regulator should show pressure when engine turned off...because it doesnt.

 

ANY ideas please!

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Yep there black and sooty. The lambder sensor is the standard one so i guess its in the downpipe. The probe for the WB sensor is in the decat pipe, prob 3/4ish ft from the tubby.

 

My guess was a leaking injector, but why would it run ok after cleaning plugs but not the following morning?

 

Should the pressure regulator hold pressure too?

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Yep there black and sooty. The lambder sensor is the standard one so i guess its in the downpipe. The probe for the WB sensor is in the decat pipe, prob 3/4ish ft from the tubby.

 

My guess was a leaking injector, but why would it run ok after cleaning plugs but not the following morning?

 

If the injector/s are leaking once the engine is turned off and if they continue to leak as the engine cools down then the already sooted up pistons/head and plugs Will be soaked in petrol when it comes to be started again, so compounding the problem,

it will also do the engine no favors as it will effectively be bore wash, and will accelerate wear:( tell your mate to check out the injectors pronto!

 

Should the pressure regulator hold pressure too?

 

The regulator will be loosing ots pressure due to the leaking injector.

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