Finally caught it on a scan... Major Knock.

[shenanigans]

Alright guys here is an off and on problem my car has always had. I have heard others have it as well.

Makes no sense. Car was fully warmed up, I am running 93 octane, fully not mixed.


Like I said the car has done this in the past, if tou let off the gas, push the clutch int and start over the car will run fine still this has bothered me before.

so any clue as to what it is?

http://amoxsoft.com/mike/new2/view.p...MustangEater82


I have a "tune" loaded but it should no way affect it, since its just fans, speedo recal, speed limiter removal and 1st gear spark limiter.

I ran the car numerous scans and no problems whatsoever this problem just pops up like maybe 4-5 times a month. I just "drove" through it to see what it would do on a scan.

[Tyler]

holy **** 13.1 degrees of knock retard. what the hell are you doing to your car?!?! lol im only play'n.

[shenanigans]

Originally posted by Tyler:
holy **** 13.1 degrees of knock retard. what the hell are you doing to your car?!?! lol im only play'n.

hehe I know, Its been driving me fecking nuts for years... I think its done this as long as I have owned the car. Just one day in 1st gear get bad knock, for awhile I thougt maybe it was the drivebywire goofing up and not opening. But tested everything on that and it came out.

Its pretty random actually doesn't happen as frequently as it used to but as you can see its VERY noticeable.

and for the most part the car is stock except for homemade intake and a cutout.

[HBHRacing]

could very well be a contaiminated knock sensor (or 2)... could be exhaust hitting, could be a coil breaking down. could be a lot of things. I would first do the easy things and make sure that nothing is hitting the motor or exhaust. I have seen this happen from contaminated knock sensors before, especialy on LS1's due to the location but considering the 3.8's location a lot of moisture and road debris can get to it.

[shenanigans]

Originally posted by HBHRacing:
could very well be a contaiminated knock sensor (or 2)... could be exhaust hitting, could be a coil breaking down. could be a lot of things. I would first do the easy things and make sure that nothing is hitting the motor or exhaust. I have seen this happen from contaminated knock sensors before, especialy on LS1's due to the location but considering the 3.8's location a lot of moisture and road debris can get to it.

no rattles clangs or anything on the exaust/motor.

cutout was open but has done this in the past with it capped and even when it was full stock exhaust.

[HBHRacing]

I would eally look into these things first...

Lower your engine temp (160* thermo and manual fan switch)
run a fuel pressure test
change your fuel filter
Check your Ign systems (faulty coil breaking down can do this)
Have a good shop do a "top engine clean"(it's possible that you have a chunk of carbon biult up in the cumbustion chambers that is getting super heated and pre igniting the fuel mixture)


If all that fails replace the knock sensors.

[Seppo Kaitainen]

Just looks like to me the sudden lug in the engine...

2265 to 1484 rpm in 1/2 a second when the KR starts. Then maybe engine noise until it decides to recover.

[black98V6]

honestly I think the random of it suggests you are reading false knock and it's electronic or "ghost knock" if you will, car reads it and backs the timing way off. I am doubting it's a coil because in my experience when one of those goes it's not a halfway thing, when it goes it's like somebody has flipped a switch and your car runs like **** until you replace the coil, done this 2 times already. anyway all this is IMO

[shenanigans]

Originally posted by black98V6:
honestly I think the random of it suggests you are reading false knock and it's electronic or "ghost knock" if you will, car reads it and backs the timing way off. I am doubting it's a coil because in my experience when one of those goes it's not a halfway thing, when it goes it's like somebody has flipped a switch and your car runs like **** until you replace the coil, done this 2 times already. anyway all this is IMO

Not only that if it was a coil wouldn't hptuners pick up a misfire?

[HBHRacing]

bad coils don't always present themselves as a missfire.

[shenanigans]

Thing is though I have had this off and on for like 2 years.

in that time I have pulled new bests and run times like consistant 14.5s...

if I had a bad coil I doubt it would show up as a problem.

[Turbo V6 Camaro]

Originally posted by HBHRacing:
bad coils don't always present themselves as a missfire.

my coil whent out an oly affect the idle and i had a bit of knock from the "coil lag" or "leaking" the coil ohms where down so it was not taking as long to charge and the spark would come to soon and on the other post it was shorted so the spark was week.....

look at your coils ohm them all out its cheap and don't vary long

[HBHRacing]

When my friend picked up his 01 V6 he had a bad miss under load at 3-3500 RPM. You could feel it in the whole car. On the scanner when it hit the knock retard would jump from 9-14 degrees. one of 2 things fixed it. The top engine clean that I did or the swapping coils. there were zero missfires in the history and it never picked it up as a missfire.

[Turbo V6 Camaro]

Originally posted by HBHRacing:
When my friend picked up his 01 V6 he had a bad miss under load at 3-3500 RPM. You could feel it in the whole car. On the scanner when it hit the knock retard would jump from 9-14 degrees. one of 2 things fixed it. The top engine clean that I did or the swapping coils. there were zero missfires in the history and it never picked it up as a missfire.

i remeber that took about 3 weeks to figure out what it was

[HBHRacing]

more like 3 months to tell you the truth. With him living an hour away it wasn't easy to find time to meet up so that i could take a look at it. The car was still under warrenty but the dealers he went to were morons. They replaced the PCM twice and then said they didn't know what to do next. I instead tested EVERYTHING. Finaly I did a top engine clean and swaped the coils out for 3 spares. After that the miss went totaly away. I wish I knew which took care of the issue. Thats when he went from a mid 16 car to a mid 15 car. That miss was horrible.