Holy smoke from under the hood Batman!

[J57ltr]

So if you've been following along my 05' GTP has had some issues with going into boost, losing power when trying to accelerate at a higher rate of speed. Under normal driving conditions I was pulling 15* Kr just moving to 30 mph and under 10"Hg. Then around 3-6* just maintaining speed. Then it magically stops and I might .1*-.3*. Then nothing sometimes I can ease on the throttle and get to 5psi then it will drop to .1psi (the ECU seems to open the bypass) I haven't checked Comanded TP verses actual to see if the throttle is being limited as well. Timing will go to -15*. I watched the O2 go dead lean once and let off.

things I've done.

removed the gauge from my fuel pressure gauge and added an oil pressure sender in order to moniter fuel pressure from inside the cabin slightly more safely. Pressure holds at a constant 65psi all day everyday.

monitered those above items plus MAF cfm and have as high as 1,990 cfm at about 8psi (sometimes it will run decent for a second)

plugs and wires Autolite 606 coppers gapped to .050"

no misfires

went from 3.4 that came on the car to 3.6 and changing to 3.8 tonight (Thanks Casper00693)

Cleaned MaF and TB.

tonight I was on the way home and got on it while watching timing, didn't go full throttle but about 3/4 accelerating from a 20mph roll then engine layed over and timing went to -15*, the engine was not in boost 0 on the gauge and .3psi on T app. Then everything went south traction control went off reduced engine power popped up on the DIC, I went pulled into a parking lot barely, the engine was running real rough and looking at the O2 it was dead lean and timing was fixed at -15*. I started pulling codes in this mode before I shut it off and restarted. Well in the few minutes
It took to do this I noticed smoke starting to pour from the right side of the engine under the hood. I shut it down and did get a P0068. I popped the hood and the smoke was coming from the rear of the engine. When I looked it seemed it was the exhaust overheating -15*+dead rich makes for some very high EGT's. So after sitting for a few minutes I fired it up again and drove of as if nothing happened. Hope I didn't cook the Cat.

my theory is bad knock sensor for one (be nice to know which) don't know if the ECU will freak if I disconnect one or both.

as far as the P0068 I am wondering if the 3.6 is causing more airflow than expected. The output seems proportional cruise is about 230cfm idle is about 50-65cfm.

I'm stumped what do you guys think is going on.

Thanks,

Jeff

[WolvesSoulZ]

Uh, did the car come with any mods other than a 3.4" pulley? 'Cause with that low of a pulley and that much KR on an otherwise stock engine could indicate the engine is toast already.

[BillBoost37]

If you have a bad knock sensor, that'll do it. So will a bare knock wire

[Booba5185]

^ that's what I've been saying too.

[CrazyGuy03]

So did the rear knock sensor come out of the block ? That would through coolant everywbere

[J57ltr]

Uh, did the car come with any mods other than a 3.4" pulley? 'Cause with that low of a pulley and that much KR on an otherwise stock engine could indicate the engine is toast already.

The car is an 05’ and has had the exhaust replaced from the manifold to the Y there is no U bend, and has 2.5” flomasters on each end. (2.5” from the flange to the cat, to a resonator then to the stock Y) the car only had the 3.4 for about 1 week before I put a 3.6” due to not being able to get a 3.8” and unwilling to remove the modular system to press on one from another M90. The airbox and ECU were loose in the airbox when I removed them for an intake and filter so I am not sure if the computer has been fooled with. The engine is not toast it runs just fine. More below.

If you have a bad knock sensor, that'll do it. So will a bare knock wire

When you say bare knock sensor wire you are meaning chaffed and grounding out causing it to show lean correct? Or are you referring to bare as in disconnected, just to be clear. I will look into that.

Booba, I remember you stating that in one thread, I just don’t know how to figure which one is acting up.

Crazy, no, the knock sensor did not come out, the smoke was from the exhaust being smoking hot as far as I can tell I will put the car up and check tonight if I get a chance.

So now for the rest of the story…

My 3.8” pulley arrived yesterday (thanks Casper) and later last night I went to Advance to pick up a belt. I told them and when I got the belt I didn’t look at the number and the idiot gave me the accessory drive belt. Well instead of removing the pulley and reinstalling the old belt I just decided to run without it. I have done this in the past when I shredded a belt on my SC so I figured it wouldn’t hurt. I ran back to the parts store and they were closed. On the way I noticed the engine ran well and though I had about 1.4” Hg (at WOT) it didn’t lay over like it did before. I ended up driving it into work this morning and it ran ok other than being underpowered and no supercharger whine. I did have the timing go to -15* again along the way and watched the O2 and I think that looks ok, it is spiky and isn’t as smooth switching as my Wife’s Montego, but that is a different operating system. I did see about 2-15* of retard again with no blower so now how do I check to see which one is doing it? I am thinking that this car is smart enough to tell if it’s got a knock sensor disconnected, and I don’t see a value for separate knock sensors.

Thanks,

Jeff

[Booba5185]

First I'd jack it up and check the continuity of the wires with their pins on the PCM (I'll look them up if you want). If they both check out I'd pray it's the front one and try it first, since the back one is such a ***** in the car (from what I hear\read). Be prepared for a coolant bath when you pull it out.


Oh and I was trying to imply you ignored me or anything, it's just nice to have one of the veterans (so much a veteran he went German) come to the same conclusion I did, lol.

[J57ltr]

Booba,

If you could get me a quality schematic on this car. Man I will buy you a beer, or steak dinner if I get in your neck of the woods, and that's kinda often.

Thanks,

Jeff

[Booba5185]

Lol. Lemme look it up.

PM me with your e-mail. Alldata has 13 diagrams for it. I also have a pinout for the 2005 PCM here:
http://www.grandprixforums.net/threa...=1#post1344598

[J57ltr]

Thanks for the info Booba! That helps a lot.

So I went to pick up some fasteners for work today because I needed to replace one of the button head screws I mangled. Well I told the guy I also needed about a dozen of those 6X1.0X10mm button head screws and he ended up just giving me them for free. Score.

i think I may put this knock sensor issue off until next weekend I'm going to clean and organize my tools, I can't find anything. But I may multitask. I've got the prints so I'll ohm them out and trace them as far as possible.

Jeff