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Discussion Starter · #1 ·
I have a thread going on the LX Forum. Down on power/cam timing

If anyone can help me out, I'd appreciate it. But my most recent question has not been answered and is as follows:>>>>
I've got some race gas headed my way next week. In the meantime I reckon I ought to check compression. Can anybody help me with step 3??

1 warm the engine a bit
2 pull a plug from each cylinder
3 somehow disable the fuel pump and asd relay (fuses?)
4 put the throttle on the floor and let it crank a bit with the compression tester in
 

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There should be a fuse in the panel under the hood I believe to disconnect the fuel pump power which disables it.

Sent from AutoGuide.com Free App
 

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Discussion Starter · #3 ·
Any idea which fuse? I have the full manual and it doesn't help much in regards to the fuel shut down and the asd relay.
 

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50 HP with a 40 degree difference on two different dynos done months apart may not mean you have an issue other than your KNK. Do you have the logs from both pulls? See what your actual timing cyl #1 was for both pulls. Should be 20 to 22 degrees at WOT over 4K RPM with a 91 octane tune. See if your ECU is pulling more timing on your second run. Your A/Fs were different enough to make me suspect the dynos are vastly different and that there may not be a mechanical problem.
I would think you would pull a couple of plugs and see what they look like or scope your piston tops to see how much carbon you have built up. That will cause KNK. Flattop can contest to that.
Other causes for false KNK can be exhaust rattles, driveshaft vibration, loose KNK sensors.
All it takes is one injector to not flow properly and it can cause KNKs too. Having your injsectors flow tested is also very beneficial when tracking down KNKs.
 

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Discussion Starter · #6 ·
The AF is different between dynos because Johan leaned it out with a tune revision for the second run. It was about 11.2 at WOT on the Mustang dyno and about 12.5 on the Dynojet. I have a picture of a few plugs uploaded on the second page of that LX thread. The actual spark seems to be about 14-18 through the 4K WOT range. That's also where the kr is.

I have tried to check my exhaust. I think it's all tight. Definitely don't hear any rattling. I plan to check my knock sensors, if I can locate them, next time I have it on the lift.
 

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I was plagued with a pesky 1.0 ST KNK right as I shift into third running a custom tune and couldn’t for the life of me get rid of it with 93 octane and a little race fuel. Octane Boosters didn’t help but I was able to quench it with water/meth fogging. The ECU would pull two degrees every time it rang up 1.0 ST KNK and took way too long to recover. Best to prevent the ST KNKs in the first place, gives you more overall timing during a pass than if the ECU detects KNK, pulls timing and tries to recover.
 

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Discussion Starter · #8 ·
Dumped in some VP Racing MS109 race gas and the end result... 0 STKR and 0ltkr.



Strangely the car felt the same and seemed to have the same power. I'll see if the kr comes back when I get back on 91 octane. Guess only a dyno run again will tell.
 

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Not sure if it matters now but the fuel pump fuse is in the panel located in the trunk, I had to pull it to tap the fuel line for the nitrous install. If you want to know which fuse it is just let me know but it sounds like you found your issue.
 
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