You said you checked the operation of the VICS, what about VTCS, maybe it is sticky and pops into place, or the actuator diaphragm is making a popping sound somehow?
I'm not sure how exactly the EGR functions, but bear with me.
The tube that comes out of my EGR is crimped and welded shut. I wasn't sure if it was possible for my EGR to be open while I was in boost, and somehow that tube fills up with air pressure. Then, when I turn it to the "on" position, the EGR valve opens and creates the "pop" noise?
I'm not sure how exactly the EGR functions, but bear with me.
The tube that comes out of my EGR is crimped and welded shut. I wasn't sure if it was possible for my EGR to be open while I was in boost, and somehow that tube fills up with air pressure. Then, when I turn it to the "on" position, the EGR valve opens and creates the "pop" noise?
EGR only recircs under light throttle/cruising conditions. Instead of having it crimped up, why don't you cut a block off plate for it? If for no other reason it would make for a prettier install.
It's not the MPI...I pulled that, and it made no difference.
Also, while the MPI was plugged in, it was reporting a CONSTANT A:F ratio from the primary O2 sensor. It didn't do it's little sin wave thing like it normally does. It just drew a flat line.
Also, when I unplugged the primary O2, it ran about the same.
I checked the wiring in my FM clamp...seemed ok.
I pulled the plugs...they looked fine...a little browned.
Ok, the "pop" happened again and I got to see it again (while my friend turned the car to the "on" position). On the driver's side of the engine bay lies my intake and my joePMBC.
Both of them "jumped" when the pop sound was made. This confused me. Then I heard a "fizz" come from the passenger side of the engine bay.
My friend came up with this theory:
-my extra fuel rail in the intake mani may have a slightl slow leak. Maybe the rings aren't 100%, or mayble the injectors or bad. Something along those lines.
-When you turn the key to the "ON" position, the MPI tuner sends SOME KIND of signal to the ignition coils. Whether or not it fires the plug we don't know. But assuming it does...
-it would then ignite the few drips of fuel and send the pressure through whatever opened valves there may be, through the intake and exhaust manifolds.
That would explain the "pop" noise. Although it doesn't totally explain why the car would run funny afterwards if I tried to start it without it sitting. Maybe the pressure would create a bubble in the fuel line somewhere through the less-than-perfectly sealed injector?
So anyway, to test this theory, before I start the car each time for the next week, I will...
1-unplug the two wires that plug into the ignition coils.
2-Turn the key to the "on" position
3-plug the wires onto the ignition coils one at a time.
If the "pop" happens while I do #3, then my friend just may be correct. Thoughts?
that seems like a pretty rational explanation. I'd say try that then take it back to the drawing board if it doesn't work..I'll think about it for a little bit.
hmm...I wonder why the o2 wasn't oscillating at your 750 idle? Still get that pop though? I wish we could have heard it that day. I keep imagining a pop like blowing the top off of a pringles can or something, but after reading your friends theory I am imagining a pop like a backfire or similar.
I wish we could have heard it that day. I keep imagining a pop like blowing the top off of a pringles can or something, but after reading your friends theory I am imagining a pop like a backfire or similar.
I had a issue like this,it was cuased by my MBC,not sure how,but I could disconect it,and reset the ECU,and everything was fine.
however,if I put the boost controler back in,"POP",and it ran like ass.
I had a issue like this,it was cuased by my MBC,not sure how,but I could disconect it,and reset the ECU,and everything was fine.
however,if I put the boost controler back in,"POP",and it ran like ass.
I had a issue like this,it was cuased by my MBC,not sure how,but I could disconect it,and reset the ECU,and everything was fine.
however,if I put the boost controler back in,"POP",and it ran like ass.
It was a definatly a noticable "POP",and instantly I had drivability problems.at first it was itermitant,but not for long,after about a month it did it every time I tried to put the boost controller in.I was useing a turbo XS,the reg. one,but switched to the highperformance one,and it still happened.
the odd thing is I was still reading full boost,and NONE of my sensors seemed out of range when I put it on a scan tool.
so,try removing your boost controler,and reset the ECU.see if it helps
