car falling on its face under boost

[KevinBuckham]

I have some "remote diagnostic" ideas for you:

- Is your MAF connector in good shape? Since this is intermittent, I'd think electrical, and since you've been through the knock sensor side of things, air flow metering would also cause you the issue. 

- Is it going into limp mode?  (On my car the only way I knew was it would basically stall once I gave it throttle.)  A failing electrical connection to an important sensor will throw the ECU into limp mode. (At least I assume 1Gs behave similarly.)

- A failing FPR could give similar symptoms.  Generally you will go very lean as your manifold pressure rise above atmospheric, but feels basically the same as being aggressively rich.  Also the wideband does odd things if the timing gets retarded enough at the same time. 

[Joliesa Lepp]

Not a boost leak as it only does it intermittently. Strange. Was retarded to drive yesterday and now its fine. Just made it over the coke and i boosted more than a few times and nothing.  I run a gm maf and it could be a loose wire grounding out since it doesn't do it all the time. Other options are a bad tps, but its so weird it'll be interesting to see what actually is causing this.

[GlenMartin]

Not a boost leak as it only does it intermittently. Strange. Was retarded to drive yesterday and now its fine. Just made it over the coke and i boosted more than a few times and nothing.  I run a gm maf and it could be a loose wire grounding out since it doesn't do it all the time. Other options are a bad tps, but its so weird it'll be interesting to see what actually is causing this.

mine started doing this, while i had a gm maf in their too. try adjusting your wot, and mid dials either up or down one click. bet you that's part of it. something while being down in vancouver changed the way your car was running and threw your fuel loops out of wack, the gm maf is set to within a certain range, so your ecu fuel loop signal was out of those ranges and your car was bucking because of it. kind of hard to explain, but i hope that helps.

[Joliesa Lepp]

No worries, it makes sense, and I did adjust them and it didn't make any difference, so I just put them back to the same settings. Thanks Glen.

[GlenMartin]

No worries, it makes sense, and I did adjust them and it didn't make any difference, so I just put them back to the same settings. Thanks Glen.

you figure this out yet? cause another idea i have is plug wires, or coils. i never fully fixed mine or was totaly able to test it as i just removed the maf....it did indeed fix it, but when it was doing it only happend after the car had been running for awhile and was so random that it was only a guess. as far as electrical signals go it makes sense in my mind. when electrical components heat up they dont work as well. so a coil could be on its way out or a wire could be faulting.

[Brett Haviland]

phantom knock or actual noise from the engine thats setting off the knock sensor...

unthread the knock sensor and ground it out...  see if the hesitation goes away.

[Bryan Hoytema]

unthread the knock sensor and ground it out...  see if the hesitation goes away.

 how do you ground the knock sensor ?just unplug it ? newb question I know lol

[Brett Haviland]

some people solder a wire to the knock sensor outter metal housing and then ground the wire out.  I imagine you could also take a hose clamp, wrap a wire around it, and then tighten the hose clamp around the metal knock sensor body to squish the wire against it.  Then ground that wire out to the firewall.

[KevinBuckham]

I run a gm maf ...

I'll bet you're running a MAF Translator and not something like ECMLink direct support for a GM MAF.

[Joliesa Lepp]

Yes yes I am. Ryan was right. Was a maft wire grounding out against the firewall amongst my mess of wiring.  :-)

[John Hartman]

so it wasn't so much the engine under load, but when the engine was under load it torqued and the movement caused the bare wire to ground out the firewall?

[Ryan Coft]

Bwahaha I win!

[Joliesa Lepp]

John. Pretty much. Bahahaha at Ryan.