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Terrible Start Up Idle Rocking

ClutchBurndout-:(
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ClutchBurndout-:( Grand Master

ClutchBurndout-:(

Posted
Posted

Morning.

r33 gtst series 1

splitfire coils

stock injectors

7's gapped at 1 or .9

This morning when i turned my car on i had terrible idle, i currently have a very mild miss on warm idle and always have, but this morning, and only this morning (so far) it just decided to idle shit, the motor was rocking and you could feel it through the car, i wouldn't say it was a crippling rocking, but enough to shake the motor and car.

The rocking was a perfectly sequential fast paced rock, as apposed to an occasional light miss from the motor. it felt like it was missing every revolution and about 6-8 times a second on startup idle (1200-1500rpm) it almost felt as if you had washed the engine and a bit of water went into the valley, and you get that miss that it does.

I should note that the idle was starting to smooth out as the car was on, but turned it off before it was fully gone.

My guess is an injector is blocked? or a spark plug fault? but its weird that this didnt happen yesterday when i used the car. Could this be in relation to my usual very mild occasional miss that i get normally?

Ive tried to give as much info as possible, if i've missed anything let me know.

Cheers guise

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ClutchBurndout-:( Grand Master

ClutchBurndout-:(

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Posted (edited)

check your plugs first man... i'm guessing that they are gone.

did you drive it at all? and if so did the problem rectify itself after a while?

I just reversed the car across the road, and i think the idle was starting to smooth out after about 30 secs to a minute, but didnt want to leave it running, since i thought it might be leaning out on a cylinder or something.

I will check the plugs.

i went out just now and the idle was fine, but id still like to know what happened, as i assume this can happen again.

Edited by ClutchBurndout-:(
SargeRX8 Grand Master

SargeRX8

Posted
Posted

Those misses you say you get when warm are not misses, they are lean pops. They don't happen on idle due to the richness that the car runs to warm the engine up. If you drive your car when its in its cold state and switch it off soon after, the unburnt fuel can quickly foul old plugs. Ive had mornings where my car will start and misfire its face off. Change the plugs and bam its back to normal. My car was running rich all over the place so after I fixed that it didn't happen.

ClutchBurndout-:( Grand Master

ClutchBurndout-:(

Posted
  • Author
Posted

Those misses you say you get when warm are not misses, they are lean pops. They don't happen on idle due to the richness that the car runs to warm the engine up. If you drive your car when its in its cold state and switch it off soon after, the unburnt fuel can quickly foul old plugs. Ive had mornings where my car will start and misfire its face off. Change the plugs and bam its back to normal. My car was running rich all over the place so after I fixed that it didn't happen.

lean pops you say? not on idle? this ONLY happens on idle, how do i fix the lean pops on idle? checking for fouled plugs? what plugs will solve this?

i was very low on fuel yesterday, but filled up yesterday and drove another 30mins home on new fuel, that wouldnt affect it this morning?

so which plugs to use, some are saying BCPR7ES and some are saying BKR6ES?

  • 4 months later...
Black_CSR Rising Star

Black_CSR

Posted
Posted

7's are too cold for your application. Go down a heat range of 6. If the plugs can't get warm enough to it's operating temperature it can't burn off the excess carbon on the plug to clean itself and foul. Assuming your still running stock injectors your not putting out big power and 7's are too cold.

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