slow_90firebird

Ok guys I need to see if anyone else has or had this problem before, its killing me. Car is bone stock besides a flowmaster 3" and open element.

Ever since I put the EBL in and got it working, I have had a major issue with knocking. The laptop makes the sound and everything.

Thanks to RBob I was able to do some learns and get a good base tune to drive the car on.

I then took that tune and reduced the Main SA table where the knock was occuring during every day driving. I richened the AFR's for closed loop, the whole open loop table, and also PE commanded. I reenabled EGR and CCP.

Car seems to run good now, and if I dont have the computer i cant hear it knock or ping at all. I run 93 octaine. Base timing set at 0 on the dist. and also in the tune.

At WOT it will knock nonstop untill I lift. I could drive all day like a granny and it would never knock, but the minute i ease into the pedal a little it will knock untill I back off. One thing I noticed was I can drive as hard as I want and it will never knock when the coolant is below about 95*F.

Two other things I tried were dropping the whole Main SA table to 0 and also making the car run very rich (this made it soot like my diesel truck lol). But neither helped the knocks at all.

I am 90% sure it is not false knock. It seems to happen at all the same times you would expect to hear a car "ping" if you were running lousy gas and had the dist. advanced way too much, but I am not doing either!

Any help is much appreciated, thanks

TZFBird

Not sure if it's worth a try, but maybe taking the Ignition Control Module in for a test. Mine took a dump on me and I ended up retarding timing to -3* and running 350 TBI injectors until I figured it out. I could hear the pinging while driving.
Just something to try. It sounds like you've gone through just about everything else. Also check the cap for carbon trails that could be causing spark in more than one cylinder?

I think you have an underlying problem or else maybe try removing the EBL to see if it goes away.

slow_90firebird

Removing the ebl won't help me because I can't actually hear pinging, so the what's up display is the only way i know about it.

The distributor is fairly new (a1 cardone), and came with a new ICM already installed. Cap and rotor Are even newer with the brass terminals. Plugs and wires are newer also.

Should I still test the ICM?

I was also thinking of running sea foam down the intake, then changing to 1 heat range colder plugs? But that's alot to do without knowing it will help

EagleMark

The EST module in the distributor of the GM EFI systems is probably the only part that has gremlins. Over and over again I have seen and read where the problems link directly to it. If you have it tested ask them to run the test multiple times. If it fails once you know it's got a problem. Everything else on these systems is very robust and either works or does not. The EST is the only one I know of that can have intermittent issues.

Also your knock counts could be other engine noise. The Knock Sensor is not fool proof. If you read a GM service manual one of the tests for it is to hit the block with a hammer! So a header tapping the frame or anything silly like that will set it off. HTH!

Ronny

iTrader: (1)

I am certain the the knock I am seeing is false. 116K on engine and AC compressor and dual ext. Yours may be as well. On brisk accel getting onto xway under load it shows KC and pulls timing. In no way is my timing overly agressive. Over 3500 rpms no knock under load. I have not yet done so but a gas station 5 miles away sells hi octane race gas that if timing related I should no longer see KC with that 100 octane gas. Just an experiment to rule out real K.

slow_90firebird

Thats a good idea I def wanna try the race gas now. A place near me sells CAMM2 its crazy expensive though so il probably try 2 gallons or so.

Anybody know if I could effectively run 7.4L 454 injectors in my 305? I mean the older ones that made 80lb at 13psi? Rbob said the reason my %DC is at 130% when I go WOT is because I need bigger injectors or more PSI. I think changing the injectors would be easier / more cost effective than changing my fuel line setup.

TZFBird

How could you be running out of DC if it's a stock 305? Are the injectors sized so close that they are almost to small for the stock application?

slow_90firebird

From what ive read that sums it up pretty well.

That is why i am hesitant to buy a set of 350 injectors because there is not alot of room for expansion going from 55lb/hr to 61lb/hr. I know the big block ones would be overkill, but I am not sure if they would be so big that they would not be spraying often enough in the lower RPM range. If I could get away with it i would rather run stock pressure and a lower DC across the board and save wear and tear.

Ronny

iTrader: (1)

80's are waaayyy too big. Maybe your fuel pump is failing or filter or injectors are not functioning properly or fuel pressure lacking under load(pump). How many miles on injectors?

slow_90firebird

Alright quick update... I am not so sure that it is real knock anymore. Maybe 50/50.

I put some race gas in tonight and drove around and it still knocked. Even on my less timing - more fuel tune. Cant see how.

Went home and let it idle in the driveway. Brought the laptop under the hood. I tapped on a bunch of stuff under the hood to check for knock counts. A few places I found that were real sensitve were engine lifting bracket, thermostat housing, intake manifold under TB, Throttle bracket that holds cables, steel brake booster vacuum line, water pump. Any of these spots, one tap with extension = 1ct.

Spots that were very in-sensitive were exhaust manifolds, valve covers, air cleaner, alternator, accessory brackets.

The weirdest thing was tapping it with the extension gave 1 maybe 2 cnts with each tap. When I pumped the throttle open with my thumb I would get 12 or 15 cnts all at once, with no audible ping. So something is way louder to the sensor that I cant hear at all! But I have to rev it hard and fast to get the cnts in neutral. While driving it dont take that much, but still only does it under load.

I checked my exhaust clearence near my SFC on that side and there is no where it appears to be hitting, or I would see the marks.

Any other ideas would be greatly appreciated! Oh btw water pump is brand new last year, alternator is 2yrs.

slow_90firebird

Alright figured something new out today. Learned that the ESC module (under hood near brake booster) is in charge of filtering engine noise picked up by knock sensor. I unplugged the module just to see what would happen, and behold the knock counts went crazy with just a tap of the gas! Not sure how this thing is wired in but somehow when you unplug it the ecm still reads the knock sensor, just unfiltered. I was hoping it wouldnt pick up any counts at all.

So is it possible that this module could be loosing its filtering ability? Or is there any other modules out there that would plug right in and provide more filtering?

RFmaster

I went through this nightmare a while back:

1) get a ESC module (JY hunt) from earlier CCC car (four pole filter vs. three pole)
2) Install 90 deg elbow before KS.
3) reduced amount of KS timing back off in BIN.

Still getting some, but not as bad as at once used to be. Engine and exhaust are noisy, but not pigging.

//RF

slow_90firebird

Cool finally someone with definative info! Can you tell me, does this esc module need to be from a qjet f-body? Or are there other GM cars to look for within a certain year span? Will this unit Plug right in?

Also what kind of elbow are we talking about here? Like something copper from the hardware store? Is the knock sensor like a normal pipe thread or something?

Thanks so much for the info!

RBob

iTrader: (1)

Yes, that will happen. The reason is that the knock filter is missing.

In this case the ECM will see run-away knock counts, and eventually toss a code. Try holding the RPM above idle and see how long it takes for a SES and the code 43 to appear.

RBob.

xch3no2

If you choose, or need, to run sans knock sensor system with your EBL,

place a 1k ohm, 1/4 or 1/2 watt resistor between pins A6-B7 to kill the knock gauge in your WUD.

slow_90firebird

Thats good to know about the resistor, however I hope it doesent come to that. I was hoping to retain the ESC system as a tuning aid to see how far I could push certain timing / mixtures without knock.

Bob, when I unplugged the sensor it immediately tripped a code 43, but I didnt get any counts untill I brought it above idle. Then they went crazy and the table was filled with 255's i believe.

It seems like GM did a lousy job with the ESC system on this car, and I was probably suffering SA retard on the old ECM but just never realized it because it wasnt enough to throw a code.

On a side note, before installing the EBL I got an occasional code 32 EGR at highway speeds, now the EBL seems to control it much better. I enabled the EGR and CCP check boxes in the option words, but I left the solenoid settings alone and it seems to be working fine.

Ronny

iTrader: (1)

I read a sensor from a 4.3L is less sensitive?