What's new
By:
TurboTransAm.com

Register today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

I have a new knock problem now

E

echostatic

Turbooo
I'm at 600 miles on my break in exactly. Since I was told not to boost it past 10lbs of boost for 1000 miles, I was going easy on the throttle. I tried adjusting the wastegate arm to turn the boost down, but since the nut was frozen to the rod, it would not adjust. For some reason, though, I now only get 6lbs of boost. I don't know what changed exactly, but for now that suits my needs very well.

The problem is, now that I can floor it, I discovered it knocks a bit around 6lbs. Scanmaster shows somewhere in the area of 1.7 KR. If I use my boost controller to up the boost to 9lbs, though, I get a lot more KR showing up. The last WOT run I made at 9lbs gave me 4.9 on the Scanmaster. Such low boost should obviously not cause any problems using 93 octane, any suggestion on where to start looking?
 
I would look at fuel at WOT first. Then, you may will need to make adjustments to your chip(fuel curve). You have Eric's chip right?
 
I have a TT chip for alcohol injection, but I haven't put my alcohol pump back in yet and I'm not boosting enough to need it so I have been using the old Red Armstrong 92 octane chip that was in the car when i bought it for the time being. I ran that chip for well over a year making stock boost with no problem, though. The Scanmaster recorded o2's in the low 800s during the run that hit 4.9 KR at 9lbs boost.
 
I'd put some race gas in and see if it goes away. Not a can of octane booster either. Straight 110 Leaded
 
It seems strange but I would look at your MAF readings at WOT. I'm guessing that your KR numbers happen on the run up to WOT and not WOT. The fueling may get skewed because of such low boost in relation to the MAF numbers. Kind of like "soft peddling" produces knock retard.

And i would get yourself a new wastegate controller,one that adjusts without forcing it....I would also run that mother up to 18 PSI of boost. But, it's not my engine, but I think 600 miles is plenty of break-in.
 
I ran it WOT looking at the MAF numbers on the scanmaster, they were 200-230. I'm not sure what that means or if its good or not.

I turned the boost up to 9lbs and got almost 5 deg. KR again, it happed while at WOT.

What is the stock boost level by the way? Before I started using the boost controller I would get 16lbs I think in first gear, then 11 for the rest.
 
echostatic said:
I ran it WOT looking at the MAF numbers on the scanmaster, they were 200-230. I'm not sure what that means or if its good or not.

I turned the boost up to 9lbs and got almost 5 deg. KR again, it happed while at WOT.

What is the stock boost level by the way? Before I started using the boost controller I would get 16lbs I think in first gear, then 11 for the rest.
Click to expand...

255 on the MAF counts (stock Maf)

The only reason I said use the race gas is to see if it's a false knock. Knock should clear if there was an octane problem.. still knocks with the race gas it's prolly false.. I would check the valvetrain.

16.5 is the stock boost setting.
 
WS6 said:
It seems strange but I would look at your MAF readings at WOT. I'm guessing that your KR numbers happen on the run up to WOT and not WOT. The fueling may get skewed because of such low boost in relation to the MAF numbers. Kind of like "soft peddling" produces knock retard.
Click to expand...

Yep... this happened to me too. Couldn't figure it out so I posted on the boards and received the same response. Good looking WS6.:cheers:
 
Well then I may just jack the boost back up in about 400 miles and see what happens. It just seems odd that I would see less than 2 deg. KR at 6lbs of boost and almost 5 deg. KR at 9lbs if it were false, since knock would increase along with boost.
 
I spent Saturday night driving, getting the break in miles over with. After driving over 200 miles, I turned the boost up to around 13lbs. I went WOT and theScanmaster showed almost 10 degrees of knock retard. It was loud enough to hear quite clearly. I decided not to try again.
 
Last edited:
So, when the engine was built, was it bored over? I'm thinking if it was your static compression is now higher.
 
It was not bored over. I talked to the rebuilder about it, he said it should not be knocking (obviously). I should be able to run 10-12lbs of boost with my setup on 93 no problem. He said to check the timing on the cam sensor.
 
Like JP112_89 said, put enough octane to 16.5 psi (like 100+) and it shouldn't knock at all. Then if it does, something else to look for.
 
I filled up with 101 octane to see how it does. I must have a leaky wastegate, because I can't get it to boost past 10lbs. However, since running that much on 93 caused almost 5 deg. KR, I should still have been able to get some answers.

In short, it helped a lot. I made a 0-90 pass on the freeway onramp, and all I got was one quick blip of .5 KR that quickly went away.

I may be having problems with my alcohol system, though. I can push the test button and hear it spray, and the activation light will come on. It will stumble the engine if idling as well. When I make a WOT pass, though, the activation light never comes on. I don't know if the control module isn't reading boost or what.
 
If you're not making but only 10 lbs of boost then probably the PAC controller isn't spinning the pump at full speed.

If the controller is untouched it should be spraying RED by around 5-7PSI and go GREEN by 10-12PSI and be all in after that.
 
The alcohol flows, it stumbles the car. I filled the downpipe with alcohol after getting it reisntalled, it took a lot of cranking clear it out. It does flow.
 
are you using the same TT chip that you used before or did you get a new one for the new motor? Sounds like you might have an old chip because TT chips should lock your MAF to 255 if you're WOT.

Check your TPS it should be 4.5-4.9V for WOT.

Check the compression, I believe the TTA should be around 155psi if I remember right.
 
WS6 said:
If you're not making but only 10 lbs of boost then probably the PAC controller isn't spinning the pump at full speed.

If the controller is untouched it should be spraying RED by around 5-7PSI and go GREEN by 10-12PSI and be all in after that.
Click to expand...

I get no light up to 10lbs.

It's been years since I put the kit in so I don't know if this would make a difference, but the stock boost gauge doesn't read anything at all now.
 
You must log in or register to reply here.
Back
Top