At boost hesitation

[Evan]

this just started yesterday. it drove fine all through the hottest day of the year so far, then at the end of the day i unplugged the battery for a bit.

now that i plugged it back in there is a small/medium hesitation right at the transition from vacuum to boost. i believe its also only making 12psi.

i unplugged the battery again and checked for any split boost hoses and saw that the line to the bov was a little loose, so i zip tied it and reconnected the battery. it ran fine the rest of the night but now its doing it again today.

any ideas? it definitely seems like a sensor/electronics related thing to me. theres a utec in there but the map is in stock mode and its still doing it.

 

[4WRXter]

You know a whole hell of a lot more about cars than me, Evan but could it be oxygen sensor? About what RPM do you go to boost? Mine was acting up around 3k. Just tryin' to help out. Sometimes we (at least I) look right past the obvious.

And also that sig is just disturbing!!!!!!!!

 

[Evan]

i notice it most in 2nd gear at part throttle, so the changeover to boost is about 2500rpm.

the rpms raise smoothly, but you can feel the car hold back, then let go all the sudden and accelerate as it should. sometimes it does it 2 or 3 times before it accelerates normally into boost.

 

[4WRXter]

I'm N/A but that sounds like what mine did. When I ran codes I had misfires on all 4. I don't remember the exact code number. How many miles? Have you ever changed your o2 sensor??

 

[patsti]

evan we can data log the utec on my laptop and see whats up. swing by on sunday whenever and Ill hook it up. 829-8084

 

[Evan]

thanks pat.

no, i haven't replaced the o2, and i dont know if it ever has. it does have a bunch of miles on it. wouldnt that throw a code though? (even with utec?)

i just drove it down the street again. it seems to start bogging at 0psi, and accelerates normal once it hits 4psi and goes above.

 

[junkyardgabe]

i'd check anything that has to do with vacuum leaks loose clamps cracked hoses and so on

 

[Evan]

yeah i looked at the vacuum lines, but i haven't had a chance to check the intake pipe or y-pipe.

 

[junkyardgabe]

ya i would check the intake pipe i've heard of them splitting

 

[Evan]

hrmm maybe because it was so hot it split, and now its acting up when the temperature is right for the split to open up and let air in/out.

 

[patsti]

I didnt see the car today which means your "really nice" inlet pipe mod must have worked right, or atleast till the tape burns off? Ill drop the socket off on my way to work tomorrow i just didnt see your car there today and figured you had gone to work.

 

[dyzfr6]

where in cumberland are you. i grew up there and live in yarmouth now. just curious.

donny

evan we can data log the utec on my laptop and see whats up. swing by on sunday whenever and Ill hook it up. 829-8084

 

[Evan]

main street. what year did you graduate? i remember a donny from HS.

so i sealed the inlet pipe and its still doing the same thing. its just a slight hesitation/bucking from 0-4psi, anywhere from roughly 2300 to 3000rpms.

 

[patsti]

plugs>?

 

[Evan]

i'm thinking that its something computer-related because it only happens at that one boost range and rpm range. i will probably pull the plugs this weekend anyway and see what they look like. they could probably stand to be replaced anyway. pat are you gonna be around friday afternoon to datalog the utec?

 

[patsti]

yeah just call me I should be out of work by 1 2 or 3. Iam pretty used to doing the plugs so lmk if you need a hand with one side to make things go a lil faster.