Hope this is the appropriate location for posting on the subject.
Brief history.


2006 Pontiac G6 aluminum head motor, 3900 V6 with 6-speed trans in an 86 body, managed with the 730 ECM using 89-90 Turbo Grand Prix code mask, 8F.

First install ran very strong with a rough tune twin turbocharged (T3s).
Stock 9.8:1 compression (rated for 87 octane from the factory). The engine showed detonation resistance even at 212 deg inlet temps and a few lean spots on 89 octane at 7 psi sustained with no detonation/knock counts.

Built a forged stroked version, 4.2L, 11.5:1 compression, premium fuel. Upgraded to a single T67 turbo. Made some absent minded mistakes and one terrible one and damaged the engine; burnt valve or burnt rings in cylinder #5.

Both motors ran as high as 8 psi without a detonation problem, the second with alcohol injection.

A problem with detonation developed where sometimes the engine would detonate giving the characteristic bucking sensation and occasional pop from the exhaust sometimes when trying to launch hard from a stop but more consistently at about 4 psi and above at speed which seems to be a consistent trigger point. It also continues to pepper lower cells with retard eventhough I've let off the throttle during these times.

Thought the motor had gotten worse causing oil contamination and put the first motor back in.

Same thing, except this motor compression tested at 238 psi on all 6 cylinders and is still low mileage <10K.

Recall it ran fine with 212 deg inlet temps, 89 octane (without alky injection) and a rough tune. Now it detonates under the same circumstances even with 93 octane fuel and the lower 175 deg inlet temps the T67 produces at 7 psi.

Spark plug change didn't help.
Premium fuel in the reinstalled stock motor didn't help.
Water injection with premium fuel in the reinstalled stock motor didn't help.
The turbo is not blowing oil from the compressor.
AFR under boost is in the mid to low ~11:1 range.

I suspect:
ECM
Ignition module
Coil pack
Glitch in the code mask during an edit

Will be changing back to Code59 which didn't exhibit this problem and the 3 bar map along with a different 730 ECM which should clear two items from the list if the problem persists. Initially 8F ran fine.

I can't think of anything else to consider. Remember the same setups ran boost without a problem initially so things like fuel and engine specifics should be irrelevant. Yes the motor is VVT with the cam parked advanced for the moment but that was not a problem previously.

I included screen shots of the problem under the same tune except the worst example was at engine coolant temps 25 degrees (180) cooler than the less intense example ~208. There is also a zip file of the log that the worst example occured in.

TunerproRT5

 

Here is the appropriate XDF file. For those who are curious and would like to look at the run.

 

u need to bring those inlet temps down, id suggest an intercooler to start.
what plug gap are u running, and what heat range. spark being blown out gives a bucking sensation that ur are describing as well.

when u pulled the plugs was there any pepering on the porcelin?

edit i just saw were the new motor is 11.5-1 cr, ur not going to run that on pump gas reliably

my destroked motor also a 60* v6 runs just shy of 11.5-1 cr even on 93 oct pump gas with alky injection would detonate, i had to run the motor on e85


btw any pictures of the build, also check out the v6 section lots of guys there that are very vamiliar with the 60* engine family

 

You may be on to something with the plug gap. I actually changed it from .030 to the stock .040, I just don't recall if it was before or after the problem started.

The air temps are on the high side briefly and only at 7 psi, however that shouldn't be an issue as the motor initially saw 212 degree inlet temps without a hint of detonation when it was twin charged.

The 11.5:1 motor was damaged by a mistake I made in the tune where either the rings or valve at piston #5 was burnt. Before that it was a brute and did well on pump gas although it wasn't severly under cammed which limited top end performance.

It's the stock motor I'm working with now with 9.8:1 compression.

I just switched in a 749 ecm and back to code59 to rule out two possible causes. I'll address the plugs tomorrow and see what happens.

 

gap the plugs at .025-.028 i can almost bet that is the issue, let me find the video of a friend v6 i helped build a turbo system for, at .035 plug gap it sounded like alot of missing and detonation at only 4psi, u can see if ur car sounds like his in the video

 

Will do, so much happened within a very short window it's difficult to know for sure if something I did good or bad caused the problem. The day prior to the problem I had been running it naturally aspirated because the turbo had been sent out for a suspected problem which turned out to be elevated crank case pressure.

I had turned checksum off in the code and was using a bin with other modifications/overrides and various other patches during that time and when the turbo was put back on the car using a Holley Black fuel pump as an oil scavenge pump to isolate it from smoke causing back pressure, I routed an extra drain line from the oil pan to the air filter for more crank case ventilation.

On the first hard acelleration attempt after reinstall, oil got in that hose and was blown up to the filter and ingested into the engine, seemed like half a quart causing a quick stutter and some oil burning and the problem was present from that point on.

But that doesn't mean other changes made were not the actual cause as that was also the first time they had been subjected to boost. The new colder plugs were also set at stock gap so what you're saying makes a lot of sense. I know the spark intensity will be greater with the tighter gap.

 

u can hear it a tiny bit in this video at 11 seconds in, listen when he shifts into 3rd gear
http://www.youtube.com/watch?v=ePqjCncFM68

and in this video once he goes into 4th gear at like 23 seconds
http://www.youtube.com/watch?v=TnHaB3bSbOE

in his case he had extreme spark blowout once we closed the plug gap up it went away and ran perfect. his car also had the stock hei style ignition system, so ur dis system will be able to handle a lil more before the spark blows out

and this is my car @9 psi with a 61mm u can just hear it break up right before the 1-2 shift @ about 8,200 rpms
http://www.youtube.com/watch?v=k9klW...eature=related

 

The second video at 23s sounds very similar to what I'm talking about although my experience seemed to be a bit more intense but that's probably dependent upon the boost level.

I like the sound of the turbo spooling up, I can't do that with mine as openning up the exhaust enough would upset some people.

 

i was tunning his car as we shot those videos, we didnt relize what it was at first so we were taking it very easy, i had him shifting at 3,500 rpms and using just enough throttle to make a little boost cause at first i thought i had the base tune way rich the way it was acting. if he got on it any harder it was even more noticable.

get the gap down on them plugs im almost 100% sure ur having the same issue and this should fix it

 

I gapped the plugs to .030 and will test it tomorrow. I've also added alcohol to the water in the injection system. Hopefully this remedies the problem. If not, the only thing left to consider would be the coils, wires and ignition module.

I was stumped by the high idle 1250 rpm until a search reminded me that there is a specific idle setting for when ALDL is linked.

 

With the plugs gapped to .030, alcohol mixed in with the water in the injection tank and a little timing pulled, 167 deg coolant temp and air temps only hitting 110 deg at 4 psi, I still got about 1.5 deg of timing retard in the exact same area suggesting I need to look at the knock sensor which I know is slightly distorted.

I can't imagine that kind of consistency in the problem being an issue in the engine considering it has run flawlessly at 7 psi on midgrade fuel, no alky injection and much, much hotter intake temps as well as warmer coolant temps.

I will have to push it towards 8 psi to be sure the bucking under a boosted load has been resolved. Otherwise, there is no reason it should be pulling 1.5 degrees of timing in the same location after all of the antidetonation changes that were made.

 

Switched ECMs, MAP sensor and closed the gap on the plugs, added alcohol to the water in the injection kit, boost cells are showing AFRs as low as high as 9s in some cells and I'm still getting timing retard in as little as 2-3 psi of boost intermittently.

I never had this problem before even with 212 deg intake temps at 7psi. I'm going to change the knock sensor next and after that the ignition module and coil packs. After that I'm not sure what I'll do.

 

The problem turned out to be the knock sensor, disturbing the plug at the sensor while reaching for something else caused a code 43 to set. Relacing the sensor has so far cleaned up the seemingly senseless timing retard.

 

Does that BIN include the wb02 patch?

I'm looking for a good 'starter bin' for running this on a V8 with Dizzy.

Also, what did the pinout on the '730 end up being?

Thanks!

-- Joe

 

Yes, but you'll need to switch the patch for the type WB you're using on. F14 is the pin. If you're planning on boost you'd be better off with code59 in my opinion since it already has the proper limits for a distributor and a spark table more typical for an engine with iron heads.

The bin posted above did not have the proper injector constants plugged in for battery offset and bpw at the time and that creates problems for closedloop operation as well as VE table responsivenes at idle when it seems nothing you do raises the AFR in the range it should be in.

I'm reworking it now as a result.

 

Interesting to know.

Other than the DIS vs DIZZY, what is your general feeling towards $8F over $59? I've heard some folks say it's as good as $8D, and others say it's just a bloated version of $58.

Which wideband patch was that? I'm using the LC1.

Right now I'm running $58 in a '730, but I'm exploring other options. $58 is a little quirky and funky with large injectors.

-- Joe

 

I like them both, however, 59 gives you more control over important parameters. The problem is table definition. It's important to know exactly what does what, when and how and that's the missing link in all of the hacking. We have all of these tables but don't know how they work or, when and that's crucial for working out the bugs both 59 and 8F have.

I started with 59 but went back to 8F for simplicity, I just want the motor to run correctly consistently and I found it is extremely important to dial in all the important tables managing the injector PW, not just "set the BPC and go".

Right now I have a problem with intermittent wideopen performance, sometimes it flies, sometimes it goes flat for some reason low in the rpm range which I suspect maybe spark insuficiency since the motor doesn't pop like it use to but does send out a lot of **** although it doesn't show pig rich in the log at that point. I'm working on it though.

Scroll through the wideband patches and check the one for LC1, I use Zeitronix.