Well here's the deal, I just got tuned by Doc nearly 2 weeks ago for my mods listed in sig. He flashed my car with his tune and we test it down the road and immediately I notice the improvements all around. Just was a bit too lean at 12.3 so he made some adjustments and got it to a good solid 12 flat which is where I wanted it. Again we tested down the road like 3 times and the car performed just as I wanted. Also, I asked him about the knock and he said I only get slight knock during shifts which is normal(burst knock).

Nearly a week later though, it's like a completely different car. My interceptor gauge reads upwards of 5 degrees of knock. My wideband is back down into the 10s as it was before the tune plus I've noticed the last 2 days at random times if I downshift and go WOT, it'll feel like it hits a rev limiter at between 4-5k then clears out. I totally don't know what the hell is going on and I'm open to any all suggestions...

I've thought it could be a clogged cat or some exhaust rattle or something along those lines but IDK. I've also thought where I have my interceptor gauge power source(sunroof), I could be getting some of the electrical bus noise I've heard about...

 

definately need to scan it again....I am not understanding whats going on without seeing it.

 

which plugs are you running..?
NGK BKR7E

 

BCP tuning FTW!! J/K Doc. Good luck with fixing the problem guys, i hope everyting works out for you. Bump for ya.

 

It's our cars wonderful learning computer.. ****** things never keep to the tune. After 100 miles or so your VE tables change and it adjusts itself to run in the factory range. Which is why I flash my car every friday night when I take it out. guarantee you do a read on the car and quite a few things have changed.

oh and not to mention that it "decides" after a while what amount of timing it likes.. only way to completely override this is to make both high and low octane tables identical, which really isn't the safest thing to do.

 

Zex plugs

 

u need plugs . I had same proablem it was the plugs

 

you need MASE to tune it or you need to buy his tune either one

 

thats no good

 

unfortunately these cars hate elevation and climate changes.... so it kinda helps to be tuned by your area.... which is why for the cars I tune over the internet (people that already have hpt) I send a safe rich tune... let them log for me, and I adjust accordingly. so far, so good

 

Where I was tuned had the same elevation as my home area. I thought about that before I went and looked it up. Anyways I was thinking...what all can cause false knock? I strongly beleive I'm getting alot of false knock. Let me get this straight, if a car is reading knock whether false or real, I know it pulls timing BUT does it also dump more fuel? If thats the case then that would explain my sudden richness. I believe I have some exhaust vibration and a clogged cat. I will buy a zzp downpipe soon and get the exhaust checked and retightened and see if it improves. This whole situation is baffling considering I'm just running a 2.9" pulley...

Something else making me beleive the knock is false is I can be cruising 35 MPH and just give it a little gas(maybe press the pedal down no more than half an inch) and will get a knock reading of 0.3-0.7

 

no freaking clue what happened there...you beat the **** outta it though. I could tell that...you had oil everywhere...inside injectors, inside spark plugs.
the cars pull timing when knock is sensed, or it gets too hot....it dumps fuel for the same reason. Why either is happening has me scratching my head.

 

bump for more exposure....does anyone think where you get your power source could affect interceptor readings?

 

bump again! Got some more info about the knock. When I go WOT, it'll be zero for a bit maybe till 2.5k rpm then instantly rise to 5 degrees and gradually work its way down and when it hits 1 degree it immediately jumps to 5 again. Does this repeatedly. It's like it's pulsating or something. I'm thinking when I had my bung for the wideband sensor welded in, he got some debris in the downpipe and it killed the cat. That plus my exhaust could be loose also.

 

nope that's just too much timing. Or did you not change your plugs yet?
I've seen my car do that when I tried pushing my limits of the amount of timing the car can take. It's how the car works, it pulls timing (KR) and once the knock goes away, it tries it again hence the spike.. ramp down.. spike... ramp down

 

I didn't add any timing....I added fuel but no timing.

 

my car is kind of doing the same thing! it stops pulling at around 5000 rpms at full boost too, I replaced my plugs last night and its still doing it Im running a 2.6 though.

and its running rich as hell too. I have a lil knock too but not much

 

Yeah i was gonna ask you but I remember saying you can add timing or fuel and you added fuel on mine.

 

right but stock timing on a 2.6 on pump gas can = knock. I know people that had to pull there timing down to 12-14 degrees total to avoid knock, hell I'm only running 15 degrees timing on my car since my meth kit crapped out (Maf-t failed) but with the meth 2.55 pulley I run btw 23-25 degrees total.

 

I'm running a 2.9"...

 

oh.... oh really.... that's def odd

 

bout time Paul....

 

I didn't see all the info... my bad man... lol. I'd like to see a log to see what's happening

 

I noticed two areas with knock at or above 5000 rpm so I reduced the timing in those cells and didn't get a repeat. I have the log it just won't allow me to upload it on here. Chit...

 

I've totally sure it's an exhaust rattle now. There's a really bad vibration noise when the engine is under load and it's so bad I can even feel it. I'm going to get the downpipe and was wondering if sometime in the future would the header also be good or would the gains be minuscule? I think the cat is shot also but I'm unsure as the symptoms of a clogged cat. Clogged or not, that thing is coming out along with tightening the entire exhaust again.

Doc, how much timing should I be seeing at the most during WOT?