3vz, why do i feel down on power? any ideas?

[RandomHero]

like the title says. i have a 3vz swapped 91. first off, ive seen dyno graphs and what not, but why do i feel severely down on power? any ideas on what to look for/check for? the other day i rode in my buddies stock 2000 honda civic si (b16 power) and it felt like he would rape my mr2.

i cant even get it to break loose in corners in first gear unless i rev up. and there is a weird power spike at about 5200. i know its not something that can be diagnosed over the internet but maybe you guys can tell me something that i should look for/service. or something liek that.

ideas would be great?

[RandomHero]

anyone?

[Mark_Dorman]

A little more info might help. What size wheels are you using, what size tires, how heavy are they, what transmission are you using, what does your dyno sheet say, have you done your afm mod, what is your timing set at???

[RandomHero]

Originally Posted by Mark_Dorman

A little more info might help. What size wheels are you using, what size tires, how heavy are they, what transmission are you using, what does your dyno sheet say, have you done your afm mod, what is your timing set at???

its all stock, so whatever the stock timing is. and im using the n/a tranny, and ive got ap1 (s2000) wheels im not sure of the size but ill find out. i havent been on the dyno yet.

im just asking is there something i can do? i checked the top 3 plugs and they are all spec'd and not fouled out. so that leads me to believe the othe 3 under the intake mani are good.

i dunno maybe its the weight of the car, but like i said it feels like my buddies 1.6 DOHC VTEC would rape me.


what is this AFM mod?

[RandomHero]

i heard i can lean the iming out a few degrees. can i do that while the motor is in the car? and how exactly do i do it? ive never done it, and my dads done it on older models mustangs, so i dunno if he can on this motor.

[Mark_Dorman]

On the 3vz you can twist the afm 3-4 clicks forward and advance the timing to around 17 degree's and it bumps you up to 200 hp. Your car should feel fast with a NA tranny. The gearing on that should make for killer acceleration. What did your compression look like before you put the motor in?

I'll find you a link for the afm mod.

[Mark_Dorman]

Here's a link to my thread. There is a link at the bottom of the thread to the actual mod page...

3VZ-FE output???

[RandomHero]

i dunno about the compression. i bought the car with the swap, and for kind of a cheap price, maybe this is why. but it also has been wrecked and repaired and its kind of bare. so its not "too cheap" i should get a comp test done.

theres no real werid things with the motor other than how it feels down on power, and the weird spike at 5200. it sounds fine, runs rich and bogs underload during warmup (which i hear is normal but fixable) and it doesnt leak either. i been thinking about seafoaming it too.

[Mark_Dorman]

There's a lot of things you could check. Could be build up in the intake from PCV blow by, could be a compression issue, could be timing being off, the TPS may be bad, you could have an exhaust leak, or a bad AFM.

Does it feel the same at WOT?

[RandomHero]

yea, anytime i run WOT it feels like i have 3 or 4 passengers in the car.

[Mark_Dorman]

Sounds like an AFM (air flow meter) or TPS (throttle position sensor) issue...

[Mark_Dorman]

Just out of curiosity have you checked out your ignition system?

[RandomHero]

Originally Posted by Mark_Dorman

Just out of curiosity have you checked out your ignition system?

not really yet. i pulled the top 3 plugs and they were good. i plan on pulling the distributor later on sometime and checking it out/ cleaning it and what not.

[Mark_Dorman]

Should probably check the coil, cap, rotor, etc. Get a Digital Mulit-Meter and test the AFM and TPS

[RandomHero]

Originally Posted by Mark_Dorman

Should probably check the coil, cap, rotor, etc. Get a Digital Mulit-Meter and test the AFM and TPS

i would test to see if they are getting enough power? ive never used a multi meter. i know they are cheap though, so thats no problem.

[RandomHero]

sorry if im asking really no0bish questions. im thr type of guy that can do oil changes and change brakes and swap rotors and do spark plugs and stuff in my sleep.

but ive never taken a motor out nor have i ever been "inside" one, and i have the electrical capabilities of a 2nd grader.

[Mark_Dorman]

Sounds like me a couple years ago...

Find out what the specs for them are (look up the 3vz manual) and do a continuity test. Where do you live. I'll see if I can find the manual online.

[RandomHero]

i live in san antonio tx

[U-235]

I'm sorry I can't provide an addition items for you to check up on but it really does sound like a bad AFM to me... Every car I've ever driven with a shot AFM will feel solid like it has "balls in reserve" if you creep up the accelerator but when you floor it, it revs up fine but you get absolutely no power.

Does that about sum up what you're experiencing?

[RandomHero]

Originally Posted by U-235

I'm sorry I can't provide an addition items for you to check up on but it really does sound like a bad AFM to me... Every car I've ever driven with a shot AFM will feel solid like it has "balls in reserve" if you creep up the accelerator but when you floor it, it revs up fine but you get absolutely no power.

Does that about sum up what you're experiencing?

actually, yea. so is it easy to replace the entire unit? can i possibly pull one from the junkyard?