lack of power while in boost

[Dark DSM]

ok guys bare with me, im doing this from my phone. have 420a boosted normal 20psi, working fine all summer until recently. now i boost up to ten psi and runs like crap, wideband says rich, however "acts" like it running lean. using PF with stage 5 cal. two step colder plugs. like i said never did this before, its not the plugs, gas, coil, map sensor, missing link, or vacumn leak. so im kinda stumped. any ideas?

 

[allrice4g63]

im having the same exact problem. i boosted a n.a. galant with the 2.4 i put a dohc head on it and the only code that comes up that would make sense is the map sensor.

 

[LD25Delta9]

Do a BLT and check your injector seals.

 

[Dark DSM]

ok ive come to find that the, map, cam, and fuel pressure are ok. found out that when i turn OFF the PF it will idle ok, but will run like crap, lean, and feels like ignition is stumbling. have not checked crank sensor. wondering if knock sensor has an effect on it??? any input on this??

 

[LD25Delta9]

I know for a fact that a knock sensor going out can cause phantom knock. Or you could actually have knock...It's odd though because normally the ecu will throw a code. I do not know what the resistance readings should be, but I'll bet you can find out here.

 

[96TurboGS]

There isn't a resistance you're looking for as the sensor is a crystal. The only way to truly test it (if the wiring too and from it is in good shape) would be a hard tap to the sensor with a volt meter on AC or better yet a oscilloscope set around 5ms/DIV. Not to say that the sensor won't fail, but they will last a long time. I've never trusted the stock ECU with our knock sensor with boost (in any case), but I do like the sensor.

Do you know what advance your running when this is happening? Do you have detcans?

 

[Natedsmeclipse]

ok guys bare with me, im doing this from my phone. have 420a boosted normal 20psi, working fine all summer until recently. now i boost up to ten psi and runs like crap, wideband says rich, however "acts" like it running lean. using PF with stage 5 cal. two step colder plugs. like i said never did this before, its not the plugs, gas, coil, map sensor, missing link, or vacumn leak. so im kinda stumped. any ideas?

did you pull the pugs to see if they look as if the motor is running lean or rich? i know what the wide band is saying but the pugs will tell you for sure.

 

[Dark DSM]

yes ive pulld the plugs and they look blackend like i would expect then to be. i just have afeeling that something in the ignition is breaking down, wondering if tach adpt is screwing up. but when i turn off PF it cant get out of its own way but will idle just fine.

 

[Boosted_talon98]

yes ive pulld the plugs and they look blackend like i would expect then to be. i just have afeeling that something in the ignition is breaking down, wondering if tach adpt is screwing up. but when i turn off PF it cant get out of its own way but will idle just fine.

Did you try a few pulls with you PF off.. what was your wideband reading with it off? Did you change anything major or just all of a sudden started running bad.. because if its not a sensor it sounds like plugs... It doesn't take much to foul 7s and if you said two steps colder I am thinking you are running 8s then right ?

 

[Dark DSM]

ok read a lil further back and ull see what ive already done, with pf off it idles ok, but anything else is immediate lean and runs shitty, no power. im sstarting to think the ecu took a shit, or limp mode

 

[Boosted_talon98]

ok read a lil further back and ull see what ive already done, with pf off it idles ok, but anything else is immediate lean and runs shitty, no power. im sstarting to think the ecu took a shit, or limp mode

can a 420a ecu go into limp mode ... I know my hatch idles at 200rpms when it is in limp

 

[Dark DSM]

well, ive replaced jus about every major sensor witha working one,. and yet still no change, including the ecu. basically it still runs lean, and has no power (with PF off), and when u turn PF on it hesitates till PF kicks in then boosts up to 10psi then ignition cuts out, so im not sure where to go from here. Anyone have any more ideas, im already thinking a wire or two (like a ground or signal wire) has corroded or broke down internally.....

 

[Dark DSM]

ok screw the sensor issue...... its come down to this, i truly believe theres an f-ing short! ive checked almost every ground, and even set up a grounding system... Has anyone had a short causing drivability problems, and extreme lean conditions?

 

[Dark DSM]

Yeh, figures it would take me this long after not touching the car for a few months now, i drove it on one of our warm days, and of course figured it out. Turns out i had a short in the OE harness for the entire car, and when the system did short it screwed with my AFC Neo and settings got changed. Basically i was running way to rich for its own good. So i fixed all my wiring, and revamped all my settings and runs absolutly great now. Just waiting for my new front bumper to show up

 

[LD25Delta9]

I'm glad you figured this out. I was following this thread for a little while with no advice to give.