Knock Question

[fast]

1986 GN Hotwire kit, Fuel Pump, Adjustable Wastegate (1 turn tighter than factory), gutted cat, adjustable fuel regulator (44psi) open element K&N, stock injectors, turbo and a new 93 chip.

I put my new street chip in from turbotweak. After warming up I took some readings.

At Idle
o2 770....falls to 550 or so after idling for a while
Af 05
L8 35
Bat 13.6
Int 128
BL 126
Clt 167
Ats 127
rpm 750
Tps .48 when running... .46 when off
IAC 23
cc jumps from 20 to 250 on an incremental rise

After the car was warm I did a couple of full throttle runs.

The O2 stays consitent in the 770-800 range

My boost gauge read 15 pounds (1 turn tighter than factory length wastegate rod...no boost controller) I also tried the boost at a couple of different settings (Lower) and it acted about the same as far as the readings go.

Ok.....so heres my question. The most knock retard I saw was .05 on the scanmaster....however my caspers Knock gauge went into the red a couple of times. Actually the scanmaster reads 0 95% of the time.
I would like to hope the scanmaster is right.....I just kind of really scared myself though.

Before installing the new chip I read KR's of 4.4 on the gauge and it didn't even hardly light the other gauge up...?

Anybody seen this before? Shouldn't the gauges read about the same....could I have messed this up somehow? Any guesses?

I did notice that if I start off part throttle and go to full throttle the knock gauge will light and then go back to green.

Thanks for everyones help....I guess all may be fine....I just want to be extra cautious and see what you guys had to say.

 

[ES1]

The SM will not pickup real time knock as it is after the computer.
So I would trust the knock guage more.
I would set the TPS to .42 engine off and the push the pedal all the way to the floor and make sure it hits 4.6.

You could try to up the fuel pressure to see if that would take some knock away.

 

[rangerjimbo]

David,
Already doing some stuff to the car huh? One question, and I am pretty sure you probably did this because the instalation directions for the chip probably told you to do it, but did you disconnect the computer before you installed the new chip? This will be an issue if you didn't. Part of the fun of having the car is working out issues like this. I hope you are enjoying the car.

Jim

 

[fast]

Hey Jim,

Yeah, I unhooked the wire. I just don't understand why the knock gauge is going crazy while the scanmaster is showing nothing....and it did before the new chip. I have everything set really conservative as I don't won't to tear anything up. I am never going to drive the car hard...I just like to have everything just right. I probably just need to drive it. lol

Did you ever notice the light coming on much when you had the hypertech chip in Jim? I noticed in your post it had a lot of knock showing on the scanmaster.

Thanks,

David

 

[rangerjimbo]

There was a lot of knock with the hypertech. Thats why I took it out. Everyone on here stated that the hypertech was old school technology and it was outdtated and turbo tweak was the way to go. I will say a lot of guys that replied to my info said that increasing the injector size in conjunction with the chip might solve the knock issues. With the stock chip I didn't experince much knock on the guage. It only went into the upper yellow or red for a sec and that was right around the shift point, which most told me was not as much an issues because the engine was not under load at that point and some knock is acceptable during shifts. If you have the time and money I would recommend new injectors. The problem is your new chip is probably set up for stocks, so that would need to be upgraded to reflect the new injector size. Hope this helps. Take it easy and have fun. I move to Oklahoma at the end of the month, but I will still be creeping the halls of the message board even though I don't have my car anymore. Maybe I'll get another one later down the road.

Jim

 

[fast]

Thanks Jim,

We are enjoying the car! It looks great all waxed up!

Thanks for your replys. Hope everything goes well with the move.

Take Care,

David

 

[BRAD_PADGETT]

Fast- Listen to ES1. I have both the Caspers Knock as well as the scanmaster. The knock gauge measures the signal to the computer and the Scanmaster measures the ECM response to the signal. I also have found the flooring the car when I get abouve 5 lbs boost puts the chip into WOT and knock goes away due to added fueling. I also suspect you fuel pressure is to low. My o2 run into the 800's. Every car is different. Take care-Brad

 

[fast]

Hey Brad,

That makes sense. Thanks! The fuel pressure is now at 44psi. Would you go up to 45 and see what happens?

So would the new chip be not allowing the ECM to adjust and thats why I don't see anything on the scanmaster? I know Eric said he set it not to react to false knock in certain places such as wheel spin.

Also, is there any chance of this being false knock....I read a lot of the old threads....I just don't know where to start.

I just really think it must be false knock due to everything being set conservative.

I'll up the pressure and see what that does.

Thanks,

David

 

[salvageV6]

You should be able to bump the pressure to 46psi. static, hose off reading, with no issues and do a couple of more tests.

Make sure you zip tie the hose back on after you take the reading.

I run my Turbotweak chip at 45psi. as well as my Extender Extreme chip in the other car I have.

It won't be an issue, just make sure the fuel pressure goes up properly to 61psi. if you are running 15psi. boost.

Proper in car gauge (isolated or electrical), or one taped to the windshield, or a hood installed gauge, is about the only way you can verify this easily.

I believe the turbotweak chip is adjustable but I'd do the baseline fp. increase first.

 

[fast]

Thanks!!!

Hey Guys,

I turned up the fuel pressure to around 45-46.

I also noticed the IAC was a little off...so I got it right...then fixed the TPS....then fixed the IAC....boy that was process.

Anyway....it runs great now!!! 16lbs of boost. I get hardly any knock on the caspers gauge and it only read about 2.0 on the other gauge one time. GREAT.

Thanks again,

David