Ive just recently put in an APS blowoff valve and noticed when i shut the hood while the car is on; the car practically stumbles in rpm... anyone have similiar problems with this? This is probably an indication of when in rare occurrences, the car stalls...I am thinking, this is what stalled me today, when stopped at a red light, clutch in to go and person in front of me stopped quickly - clutch out, quickly.

any ideas or theories? All hoses are tight, all clamps are fastened.

 

It is normal for the rpms to stumble, someone explained it here once. As for it stalling I guess if the hood closes fast enough it creates a stronger disturbance.

 

i have hks ssbov and it stumbles all the time.. sometimes idles 1500-2000 rpm in the cold.. eh.. so long as its fast and sounds good

 

ideas / theories as follows..


A: your car is mad at you cuz its what you get when you play with it with out dans help...

B: your imagining all your issues

C: DONT SLAM YOUR HOOD YOU BIG MEANIE!

D: LEARN TO DRIVE STICK

E: you told me 100 - 150 rpm if you meant droped a little below 1k rpm like 700 - maby 600.. seen that a few times..

F: YOUR CAR HATES YOU

G: YOUR CAR WANTS A BETTER DRIVER

H: idk bro just messing with you.... next time ill let you drive n if it dont do it im blameing it on your driveing or a cold car .... and if it does do it ill know.. wich of the above a true n false.

 

the loud bang of the hood closing gets picked up by the ecu as knock for a second and makes
a quick adjustment for it. i have heard of some cars doing it at a light with a loud harley next to
them. i'd also be interested if anyone has had this happen to them when staged next to a open
exhaust car at the track?

 

It's not the knock sensor. It's the disruption of the vortices passing through the MAF. The MAF counts these vortices as they pass through in order to calculate the mass of the air flowing through intake. When you drop the hood, are near a loud noise such as open headers or a loud booming stereo system this can happen.

 

why doesn't it happen on my car with the hood open with gusty wind blowing around then.
no way you can move enough air from another vehicle to effect the maf. it's not the air movement it's the sound.

 

always thought it was the knock sensor.

Since I got my dealer flash, (desensitized the ecu sensitivity) it happens less frequent.

Like when you're at the track next to a loud mustang or something, your rpm stumbles.

 

That happened to me, I was like WTF is wrong with my car... I guess now I know

 

Dear Dan,

Spell check is your f'ing friend. For your information my driving skills have come a long way and even impress me as i smoke 120hp corolla's and vw bugs.

 

^^^ hey man its what a good driver can do when you have a car with 3x the HP of a corollea and vw bugs them suckers hard to beat.

 

speak for yourself. You lost to that fricking beretta.

 

Don't the EVO's have a harmonic balancer which might trigger a drop in rpm's from loud noises such as rediculus V8 idle masters and slammage of hood (why slam it anyway?)?

 

are you referring to me slamming the hood? I dont know if you could consider (if you are) my description a slam. I drop it a few inches above where it catches, so it closes with out me having to push down on it. Not always, but in this case i did.

 

Very good question., simple answer. ECU sensing knock for a sec and pulling timing. Nothing is wrong with your car. I have done a lot of re-search about this topic and some cars have very sensitive ECU's (our EVOS do) they sense knock even when knock is not there. You want to hear something funny. When my car is on and I drop my hood half way through I get engine check light. . The ECU thinks it’s a knock when it’s really just my hood slamming. Now I close my hood when my car is off or I just lay it down and press it.