m20 acceleration problems

[abit]

reposted:
Hey, my car is having some management (I think so) problems and I can't stand it anymore.
engine is m20b28 with m50 management and chip.
Sometimes when slowly accelerating, till 1.5k revs it goes smooth, and then it starts to like loose power, poorly increases revs and then when it reaches 2.5k rpm's starts to rumble again :grin: and in that 1.5k - 2.5k revs range it sometimes just starts to twitch car so hard like to back and front that you just have no other choice than release clutch and stop that shit :grin:
also sometimes idle is very rough and rpm's drop low about 500.
and somethimes when driving I release gas pedal, car bangs exhaust like mad turbo car running veeery rich? why?

Diagnostic doesn't show anything, AFM looks like working, Lambda sensor ok, tps seems like wokring too, etc., only I dont have cam sensor.

fuel pump is fine pierburg 3.8 bar, fpr 3.5bar, green top m50 injectors, bosch platinum sparks (with ngk's it was all the same problems).
maybe some coil problems? or injectors? (before installing I checked them and they were fine about 3 months ago)

please help, and sorry for my bad language :giggle:

[Regnar75]

only posting since i noticed no one has yet, i wish i could help you but i know nothing of m20b28 builds. curious though but your using m50 management and chip and yet have an AFM?

[squidmaster]

Moving to M50 ECU you should also switch to the MAF

[abit]

my bad, of course Im using m50 MAF.

but looks like problem is solved now, after changing lambda sensor it goes ok. don't know, maybe sensor has been hit earlier and now sometimes had and sometimes had no connection or something like that.

[Dirty325ix]

Sorry I'm clueless but what's going on with you plugs? How much of the m50 harness do you swap and what does it do?

I love how clean it looks

[Cabriolet]

try another crank position sensor. also Never run platinum plugs in an m20, this is a big no no.
if it's not the KPS, then check and make sure your injector harness is secure at the plug. if it's not that then you have bigger issues.

[abit]

try another crank position sensor. also Never run platinum plugs in an m20, this is a big no no.
if it's not the KPS, then check and make sure your injector harness is secure at the plug. if it's not that then you have bigger issues.

crank sensor was first thing what I changed :D

why not to use platinum plugs? Im using them for 3 years now (buying new every year, like changing after ~ 11k km's), and no issues, It goes like mad and fuel consumption seems ok

and now with m50 management it was all ok too

edit: actually I'n now back on ngk zgra's and maybe Its just me or what, but it actually feels like lil bit down on power, because with platinums it was like ''boosting'' rews afer 3k rps, but now it goes just smoothly up in rew's hmmm...

[squidmaster]

Could just be a difference in gap (did you gap the plugs at all?)

Platinum are okay, but if you can grab copper. Just personal preference though, but copper has better conductivity than platinum or iridium and runs a little cooler. I mean, copper conducts electricity a LOT better than platinum.

Overall though you shouldn't notice much of a difference at all between plugs to be honest.

[abit]

spark plugs gap is set like oem @ 0.7mm, should I set different gap?

[Mr. Tasty]

Sorry I'm clueless but what's going on with you plugs? How much of the m50 harness do you swap and what does it do?

I love how clean it looks

I am assuming he is running the m50 harness for the COP's (coil on plugs)

[squidmaster]

spark plugs gap is set like oem @ 0.7mm, should I set different gap?

You should gap to whatever the plug manufacturer recommends. Each plug conducts differently and has different cathode systems.