Melrose 4r

I would test the sensor with a DVM on AC voltage with the engine running. Look for a spike as you tap the area of the block surrounding the sensor. See if you get a response. I haven't tried it myself, but should work. I'd also run with it disconnected then see if the condition changes and it does throw a code. If these tests check out then I would consider it working normally.

One other comment, I was convinced I was hearing pinging on my daily driver Honda and could make it happen under the conditions you would expect, high temp, high load, etc. However, it turned out to be a heat shield rattle on the cat. Are you sure you are hearing pinging?

RASALIBRE

Knock sensors work in Hz, plus I don’t know how I’d keep anything connected, while trying to read the dvm, while driving at 2500-3000 rpm.

I’ve thought the very same thing about the rattle. It’s not unless it’s valve rattle... which it could be. But the same very slight noise at certain rpms, becomes the same noise only louder at certain rpms when the timing is set higher.

Melrose 4r

You wouldn't be reading Hz via a Frequency counter. Just looking for an AC spike... I didn't mean while driving...

RASALIBRE

Trying to answer these while on the job site. Yeah, just at idle and tap on the block just to see if it registers. I follow now. I was thinking while trying to reproduce the ping...

I’m gonna button her all back up, smoke test her for leaks again and then see what’s up. If the ping is still there I’ll do some further investigation of the knock sensor. I’ll probably start by unplugging the knock sensor to see if I get a code and then go from there.

Thanks for the help and ideas

RASALIBRE

Yeah, I just mentioned the octane rating because that’s usually most peoples first response. This is EFI...

Thanks for the heads up on the knock sensor shield.

My take on the ping is either a true lean situation or hot spots from carbon build up.

RASALIBRE

Bored the intake manifold out to 60mm.

RASALIBRE

Two more tanks of gas through her.
18 mpg on the first and 23mpg on the most recent.
First tank had a lot of idling time chasing vacuum leaks, afm, and timing adjustments. I was also reving her out to 4500+ in every gear. Second tank was just daily commute.
She’s been my daily driver for the last week and a half.
Big bore throttle body and manifold make 5th gear much more useable. Hold 65mph in 5th on a hill I encounter daily, where I use to have to down shift and rev the piss out of 4th. Can also casually merge onto the highway and pass in 5th now. Acceleration from 65mph up to 80mph in 5th is a breeze. 4th gear 3000 on up is a pretty fun sweet spot too. Low end seems to have just as much torque and power as before. I’m pretty satisfied.

RASALIBRE

Still getting 21-23mpg, though probably not this tank... Got the Supra AFM as dialed as currently possible. No pinging in +95* heat. I have an adjustable fuel pressure regulator and wide-band O2 with gauge on the way to try and fine tune her.

84 yota dude

Stock gearing and tire size? 95 is moving!

Any info on your smoke test system for vacuum leaks?

Also did you consider built up carbon on the head for the cause of pinging? After seeing the EGR build up.

RASALIBRE

Stock gears and the tires were 235/75/r15 at the time. She’s back to being a dog on 235/85/r16 now. Though I have gotten the tires to give a pathetic but fun bark once or twice.
Yeah, that thought definitely crossed my mind with the pinging. She’s got pretty bad carbon problems. I’ve put a scope down each cylinder though and the tops of the pistons aren’t too bad at all, I can’t see the faces of the valves though. The egr port for cylinders one and two was completely blocked too.


Chucked up equal lengths of braided steel cable

Fished into the port while the trans was out

RASALIBRE

Vacuum hose to check depth. Yellow marks showing progress of depth. Spare bad head used to reference correct depth. Exhaust manifold was off.

Smoke pump is a cobbled together pickle jar with harbor freight soldering iron, a valve stem, and a ball point pen body epoxied into the lid, mineral oil on old rags, some tube, a latex glove, and a bike pump. Pour some mineral oil on the rags, plug the iron into the wall, hose clamp the glove to the throttle body and pump in the smoke. Look for leaks. Works like a champ. Cost less than $20.

84 yota dude

Awesome.

Love your creative thinking on the repairs.