s14 sr bucking at 4,500 rpms, knocking on first rev and running rich, any ideas?

[clovers525e]

i've been scratching my head about this for the past few days now and i cant seem to come up with a good answer. the problem is that at 4500 rpms under wot or close the car will jerk violently and blowing clouds of black smoke out of the exhause and wont climb over it, i changed spark plugs the other day and it seemed to help a little but after a day or so the plroblem was back. when it is above 4500 it pulls ok, it doesn;t buck but the power band dips down at 5500 and pulls again at 6000. i plan to check for a vacume/boost leak to see if that could be the culprit since its running about .4 to .5 bar until 5500 and then .6 there on up. its running really rich too so i plan on getting a new o2 come pay day, installing my emanage and switching to a z32 maf. which brings me to my next few questions, whats a generally good setting to use on the z32 maf with the emanage, do i need to lower the maf signal or raise it?and what o2 should i use for a s14 sr since the one in the part interchange section is only a two wire plug. and last but not least, when i first rev the car when it is cold it will knock for a moment, and then be fine until it sits for a little while, i'm pretty sure the lifters just need to be bleed but is there an easy way of doing this or do i need to take them out, soak them in oil and all that jazz?

[IanS]

what mods do you have, and what is your setup, what spark plugs are you running and what are they gapped to.

[clovers525e]

just a stock s14 sr, front mount, walbro 255, z32 fuel filter, three ply silicon hose couplers, t-bolt clamps, s13 ka24e (sohc) maf and these plugshttp://www.frsport.com/NGK_Iri....htmlin heat range seven

[HPR]

check your TPS and see if it has a dead spot on it? errr... possibly knock sensor is bad? let us know how it goes

[exode]

Bro - Have you done anything to your ECU =)? Those SOHC MAFs are mezzo mezzo... How close is your MAFS to the Turbo Inlet?

Bad ECU, Bad TPS, Craptastic MAFS, Bad O2 sensor shouldn't affect it that much. Check your timing too, hell, it could be a combination of all the above.

Give us more details and we'll slowly isolate this.

[clovers525e]

i checked the tps the other day and adjusted it. i'm going to work on it today, maby go get z32 maf and put on the emanage. does anyone know the cross reference for the s14 sr o2 sensor?

[clovers525e]

i leaned it out the other day and ran test runs at the drag strip, at the end of the night i wound up with -25% all the way through and didnt have any problems with it bucking. i got a z32 maf today and got it wired up but with -25% set on the emanage hardware and minus fifty though the software of the emanage its still running at like 2.5v at idle, way way way rich, so i guess i'm going to continue tuning the s13 maf until i get that right and see if anyone has anything to say about using the z32 maf with an emanage. i think i might get a drop in resistor to bring it down to 2V where i can detune it down to the right voltage with my emanage. still dont know what o2 sensor to get, guess i could always just start testing voltage to see which one works best. i know the dohc ka's have the same clip and three wire config. thnks everyone for the help. one day it shall be tuned right. p.s. it only ran a ten flat in the 1/8th, kinda dissappointing, but i started off with an eleven five so progress is getting made. that and every time i launched, the car was half sideways for the first few feet. still beat a riced out civic and a stock s14 and drove a wrx sti and a s2ooo so it was a fun night.