Knock counts

[Maverick87]

I did a search and got some info..... but still am a little confused.

Built motor ,code 59, and ostrich.

Ok goes like this I am getting knock counts at an idle and pretty much every where else. But out of gear I can rev it to 2400-3000 and it will start pulling timing and bounce around between 12 and 18 deg. of retard. You can even disconect the knock sensor and the counts still rise. Checked the memcal and it has been and still is in right. What might it be.

Man I love this truck

 

[WyoSyclone]

Re: Knock counts

I did a search and got some info..... but still am a little confused.

Built motor ,code 59, and ostrich.

Ok goes like this I am getting knock counts at an idle and pretty much every where else. But out of gear I can rev it to 2400-3000 and it will start pulling timing and bounce around between 12 and 18 deg. of retard. You can even disconect the knock sensor and the counts still rise. Checked the memcal and it has been and still is in right. What might it be.

Man I love this truck

Sounds like a question for Dig, Paul, or Jeff.... did you post this over on the Code59 site?

 

[ZMann]

Re: Knock counts

Wow, you get knock counts even when the knock sensor is disconnected? Weird. My truck will never show an ounce of knock, sounds like I've got the opposite problem as you.

 

[sy#2921]

Re: Knock counts

what I have been told is knock counts are events picked up by the computer but aren't considered knock. To have knock retard while out of gear says false knock from somewhere there are a ton of reasons listed on the board. But for knock to occur while the sensor is disconnected is weird. Maybe a bad memcal even though it is seated correctly.

 

[JSM]

Re: Knock counts

If your getting counts with sensor unplugged I suspect ECM/Wiring/Memcal

 

[turbodig]

Re: Knock counts

If your getting counts with sensor unplugged I suspect ECM/Wiring/Memcal

x2. Bad ECM would be the first thing to check.

 

[Maverick87]

Re: Knock counts

k did a little more checking and this is weird. You can un plug the ks and it still keeps counting knock but if you give it just a little throttle it stops. But as soon s it gets below 1000rpm it starts counting again. I have a new coputer coming should behere tomarro. Then just have to put in the drivers and try it out. Would be nice if it fixed the knock problem I have had sence I got the truck back going.

 

[Flyin Ryan]

Re: Knock counts

k did a little more checking and this is weird. You can un plug the ks and it still keeps counting knock but if you give it just a little throttle it stops. But as soon s it gets below 1000rpm it starts counting again. I have a new coputer coming should behere tomarro. Then just have to put in the drivers and try it out. Would be nice if it fixed the knock problem I have had sence I got the truck back going.

It's somehow counting down the life of your motor

seriously though I have no clue

 

[Syclone#2960]

Re: Knock counts

I'm having the same issue. All though I'm not running code59. I tried different ECMs & memcals. I get knock counts as soon as I start the truck and just keeps reading just like the O2 readings. I even Disconnected the knock sensor and the wire that goes into the ECM and I still get knock counts.
I'm going to try running the same set-up in my other truck & see if it does the same thing.

 

[turbodig]

Re: Knock counts

I'm having the same issue. All though I'm not running code59. I tried different ECMs & memcals. I get knock counts as soon as I start the truck and just keeps reading just like the O2 readings. I even Disconnected the knock sensor and the wire that goes into the ECM and I still get knock counts.
I'm going to try running the same set-up in my other truck & see if it does the same thing.

The really odd thing about this, is that if you pull the knock sensor wire, you should get a ESC code immediately.... are you?

When it doubt, go back to basics. Stock chip (no adapters/piggybacks), stock ECM.
(unless you need modded drivers.. not much of a way around that, other than stick a set of stock injectors in, just as a test.)

Most trucks will run well enough on a stock chip (even with big injectors) to tell whether the knock issue is there. You can also mod a stock chip by halving the F77 table, to work with injectors 72 and above. This isn't a chip you want to drive around on, but it should tell you what you need to know.

If you still get counts, you've got a very serious noise issue.

GM ECMs are notorious for lifting pins on the SMD devices on the board. Many "remanufactured" ECMs just have 1 or 2 pins reflowed.

 

[Maverick87]

Re: Knock counts

Well I replaced the ecm with another one and it does the same thing. When you first start it it doesnt strat counting the the first time you touch the gas it starts counting. I have now tried 2 ecms and 2 chips and both do the same thing. even with the ks dissconected it still counts knock. And yes It does get the code as soon as you unplug the sensor.

 

[dgoodhue]

Re: Knock counts

I didn't see this before. With the C4 Corvette ECM's and the knock sensor disconnected, you will see approx 4 degrees of knock retard. I would be surprised idf the 749 is the same way.

 

[Maverick87]

Re: Knock counts

Yeah once you get to 1800 rpm it shows 4 deg. of knock.

 

[Syclone#2960]

Re: Knock counts

Yeah once you get to 1800 rpm it shows 4 deg. of knock.

Same thing here with the KS unplugged. I read somewhere you will lose 4* of timing w/ the KS unplugged. I found out I have a bad valve guide on the #5 cylinder that is causing the excessive valve train noise.

 

[Syclone#2960]

Re: Knock counts

I year later still trying to figure this out. Maverick did you ever get this resolved?

 

[Syclone#2960]

Re: Knock counts

I disconnected the knock sensor in the ty to see if it does the same thing as the syclone & it does.
It gets a Code 43 and when you give it a rev the knock automaticly retards to a max of 4 degrees but the knock counts do not change.