false knock

[BrianJ]

what is the best way to find false knock? When I get over 7psi the ecm is seeing knock and taking 20 deg of timming out? This is a brand new eng and its not knocking help please.

 

[leroy]

Re: false knock

A few ideas:

You can relocate the knock sensor.

Make sure the knock sensor is torqued to 14 ft. lbs.

Eliminate mechanical noise.....lifter adjustment, exhaust leaks, loose brackets, flywheel bolts, etc.

Make sure base timing is correct.

Use all the correct and fresh tuneup parts.

Tune it with a wideband.

Jim

 

[protosy]

Re: false knock

just another thought, but try some race fuel. like c16 or something.

 

[BrianJ]

Re: false knock

A few ideas:

You can relocate your knock sensor
.
Make sure the knock sensor is torqued to 14 ft. lbs.

Eliminate mechanical noise.....lifter adjustment, exhaust leaks, loose brackets, flywheel bolts, etc.


Make sure base timing is correct.



Use all the correct and fresh tuneup parts.

.
Tune it with a wideband.

Jim

I relocated it to the front of my intake but it doesent screw in but only 3-4 threads cause it hits the water neck, also I ran an overlay wire from the connector(at the ecm) to the sensor I thought that might be my problem but wouldnt I have a light on all the time? (it does come on and I do get a knock code but only about every 3-or 4 times I drive it


I do have a rattiling noise I can hear in the car but not outside the car or comming from under the hood I suspect its comming from my transmission because my shifter is slightly misadjusted.


Timming is set a t 0 this is correct ?



I have new wires and plugs in it. Cap and rotor are not in bad shape.

I dont have a wideband to tune with
thanks for the help

 

[BrianJ]

Re: false knock

just another thought, but try some race fuel. like c16 or something.

I added some octane booster to my 3 gallon fill (2 bottles of octanebooster) and it ran better up till I hit 7-8psi then it layed over still.

Putting this eng in and transmissin in was a complete pain in the ass it's making me hate this car. All that work and it runs like this WTF
sorry I had to vent.

 

[leroy]

Re: false knock

I relocated it to the front of my intake but it doesent screw in but only 3-4 threads cause it hits the water neck, also I ran an overlay wire from the connector(at the ecm) to the sensor I thought that might be my problem but wouldnt I have a light on all the time? (it does come on and I do get a knock code but only about every 3-or 4 times I drive it


I do have a rattiling noise I can hear in the car but not outside the car or comming from under the hood I suspect its comming from my transmission because my shifter is slightly misadjusted.


Timming is set a t 0 this is correct ?



I have new wires and plugs in it. Cap and rotor are not in bad shape.

I dont have a wideband to tune with
thanks for the help

You should never get a check engine light for knock. Follow the diagnostics at http://www.syty.org/old/d&e-code43.html .

I'm not sure what you mean about only being able to screw it in 3 or 4 threads. The hole in the intake is 3/8-16 and the knock sensor is NPT. (3/8 I think). I welded a pipe cap on top of a short 3/8-16 bolt. Tighten the bolt securely. Then thread the knock sensor in to 14 ft. lbs. I never had a clearance issue with the water neck. I've run a shielded wire to the knock sensor in another application.

Timing is set at zero, with the tan wire disconnected. The outer ring on stock balancers tend to slip and may be off by quite a bit. There are 2 marks on the balancer. Make sure you are using the right one. You can use a piston stop to find true tdc.

HTH,

Jim

 

[BrianJ]

Re: false knock

You should never get a check engine light for knock. Follow the diagnostics at http://www.syty.org/old/d&e-code43.html .

I'm not sure what you mean about only being able to screw it in 3 or 4 threads. The hole in the intake is 3/8-16 and the knock sensor is NPT. (3/8 I think). I welded a pipe cap on top of a short 3/8-16 bolt. Tighten the bolt securely. Then thread the knock sensor in to 14 ft. lbs. I never had a clearance issue with the water neck. I've run a shielded wire to the knock sensor in another application.

Timing is set at zero, with the tan wire disconnected. The outer ring on stock balancers tend to slip and may be off by quite a bit. There are 2 marks on the balancer. Make sure you are using the right one. You can use a piston stop to find true tdc.

HTH,

Jim

does the problem I am having sound like its comming from the knock circut?
I bought a knock sensor from napa it has a different size stem comming out of it when I screw it into the front of the intake the biground part hits the waterneck. I have a friend that has a knock sensor that you discribe and it still lays over at 7-8 psi.
Asfar as the balancer slipping how can I tell by looking at it?

 

[leroy]

Re: false knock

You have a problem with the knock circuit or you wouldn't get a check engine light. It may be intermittent, and you may have other problems.

You can't tell if the balancer has slipped by looking at it. You need a piston stop to find tdc.

HTH,
Jim

 

[turrrbo6]

Re: false knock

I had the same problem on my build. Old gas in the tank from the truck sitting a while and I was getting some knock. Best to check with a wideband to make sure its not real knock.

 

[gjp]

Re: false knock

There are different sensors for the 4.3. Make sure you got the right one. Octane boosters dont do much. Zylene IMO is the best way to see if the Knock is real. Do you get knock if you rev in park or neutral?

 

[BrianJ]

Re: false knock

ever heard of insolating the knock sensor?

 

[Slow-Clone]

Re: false knock

Sorry to butt in.. is it safe to drill/tap the hole to the left of the thermostat out so the sensor is a direct fit?

 

[BrianJ]

Re: false knock

Sorry to butt in.. is it safe to drill/tap the hole to the left of the thermostat out so the sensor is a direct fit?

that is where mine is and its hitting the waterneck the big round part is to big.

 

[leroy]

Re: false knock

ever heard of insolating the knock sensor?

No, but I've heard of insulating it. j/k

Teflon tape on the threads are supposed to have some impact.

Jim

 

[turbodig]

Re: false knock

what is the best way to find false knock? When I get over 7psi the ecm is seeing knock and taking 20 deg of timming out? This is a brand new eng and its not knocking help please.

Just a personal observation.....

Out of several dozen trucks that I've worked with in the last 12 years, I've seen 2, maybe 3 trucks that knock wasn't real.

My .02.