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Surging? Missing? Not Sure!

d00dz

By d00dz,
in Engines & Forced Induction

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d00dz Grand Master

d00dz

Posted
Posted

Hi all..

Well... Not sure if you know, but car atm is running 7-10PSI, turbo back w/ hi flow cat, FMIC, stock ECU.

Ok setting scene.. Around 11PM, driving on M7, cold nite.

Car running 10PSI as a max on 39% duty cycle. Ive seen it only goto 0.69bar @ 6814 rpm once, in like 2nd or 3rd. (according to AVCR)

1st gear no problems, switch, backfire, 2nd gear no problems. So far so good.

2nd ->3rd, no problems.

1,2,3 all seem to goto 5.5-6.5krpm no problems.

At 4th it gets funny. When I floor it in 4th, around 4.5krpm or abit above, it starts to surge? or miss?. Feels like there is lack or power or not enough fuel or cylinders not igniting. However if I dont floor it it will happily goto 5 or 6 but slowly.

So question is, is this a fuel cut or the engine missing?.

Using NGK Irridum Sparkies ~30k done on em. Stock fuel pump. Stock coils.

This only recently happened when I put the AVCR in, ie. increase the boost.

Some say its the sparks, some say its the coils, some say its fuel cut.

What do you guys think?

Cheers!

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ranicx Veteran

ranicx

Posted
Posted

my car surges when its cold and ya try and floor it.. but that im assuming is normal

i dont think it would be fuel cut unless you trying to get past 180ks. as for spark plugs.. could be a miss, but if its a miss, that cyl would cause a backfire every time, mine did that when i got a drop of water on one of the coils once and it would arc out and not fire the sparkie on boost.

check your sparks, make sure there gaped to the right amount.. think its 0.7 cant remember.

but thats all i can think of off the top of my head, i havent had any dealings with AVCR's

Craved Grand Master

Craved

Posted
Posted (edited)

excess airflow protection is a violent backfiring nasty thing, so i doubt it is that.

gap the plugs to 0.8

check with other coils that aren't doing it.

my cars doing a similar thing and i know that is the coils, im running 0.6 gap to try and stop it, but it aint working anymore

try dropping the gap lower til it goes away, til you can get new coils.

Edited by Craved
Swiper the Fox Grand Master

Swiper the Fox

Posted
Posted
Hi all..

Well... Not sure if you know, but car atm is running 7-10PSI, turbo back w/ hi flow cat, FMIC, stock ECU.

Ok setting scene.. Around 11PM, driving on M7, cold nite.

Car running 10PSI as a max on 39% duty cycle. Ive seen it only goto 0.69bar @ 6814 rpm once, in like 2nd or 3rd. (according to AVCR)

1st gear no problems, switch, backfire, 2nd gear no problems. So far so good.

2nd ->3rd, no problems.

1,2,3 all seem to goto 5.5-6.5krpm no problems.

At 4th it gets funny. When I floor it in 4th, around 4.5krpm or abit above, it starts to surge? or miss?. Feels like there is lack or power or not enough fuel or cylinders not igniting. However if I dont floor it it will happily goto 5 or 6 but slowly.

So question is, is this a fuel cut or the engine missing?.

Using NGK Irridum Sparkies ~30k done on em. Stock fuel pump. Stock coils.

This only recently happened when I put the AVCR in, ie. increase the boost.

Some say its the sparks, some say its the coils, some say its fuel cut.

What do you guys think?

Cheers!

Sounds like the duty of the AVC-R is set incorrectly

d00dz Grand Master

d00dz

Posted
  • Author
Posted

Thanks siksII, does look like a missing issue.

And Yea Craved, might have to check at regapping the current sparks.

Car isnt a daily driver now so its ok, though I would like to give it a bit over the w/e ie. missing would annoy me :/

Sounds like the duty of the AVC-R is set incorrectly

Hmm... Maybe, ill play around with it abit... Though its set at 35% duty less than 3000RPM, then each 500RPM up it goes up 1%, untill 40% duty.

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