Shane

Anyone have a picture showing knock sensor locations on the S4 and up?

Have an idea rolling around in my head, now that we have the LH2.2 and EZF Sharktuner. I'd like to use a knock sensor with the octane loop on the EZF to retard ignition if knock is detected.

John Veninger

No picture, but in the "v" of the block under the intake.

Shane

Ok sorry for the bad illustration but do they bolt to the locations that I point out with white arrows in this pic:

atb

Shane, I think there are 3 plugs total, with the front and rear used for the knock sensor and the middle one left plugged. It looks like you are pointing to the middle and rear ones.

Shane

Correct Adam, I was limited on pictures to choose from. I believe that the '85-86 have three locations but can't remember, and this pic only shows two.

Rob Edwards

Here's an ok shot from my '90:

Shane

Excellent! Thanks Rob!

Now to find out if using the stock S4/GT sensors will work for the application I have in mind.

atb

You've got some seriously high standards there Rob.

PorKen

Only the front one would work pre-87, AFAIK. You'd have to get a threaded plug for it. The middle one is covered by the U, and the rear one has the rubber bumper for the U.

IIRC, Louie said he was able to detect knock reliably from either of the sensor positions. I think two sensors were used either to be extra safe and/or it made it easier to design the EZK circuitry.

When I get around to refreshing the intake on the new 86.5, I'm definately going to install an S4 sensor, for a future knock light.

I think you could easily put in a retard as part of the TempI (air temp) input. The octane loop grounds the input from the TempI. A separate box could insert a specific resistance via the TempI pin, and that value would be programmed with the EZF ST for ~6º retard. You could even program increasing levels of retard, using different resistance inputs.

Shark_gts

Working on a 1987S4 intake job & it had the front sensor cable routed through/to the passenger side of the oil filler neck/Coolant bridge.

It would seem better & easier to rout the cable to the driver side as shown in Rob's photo.

Any issues with me doing that?

Also I am not sure I am going to hose clamp the ISV connections, as the drawing shows no clamps there. Must be a reason for that - vibration/rattle perhaps?

dr bob

The bracket for the front knock sensor connector is in the front on the left (left is left side of car, driver's side in US cars) near the flappy solenoid. The rear sensor connector is under the right (passenger side on US cars...) fuel rail cover at the rear where the cover humps up.

davek9

If you are replacing the rubber w/ new (I would) always recommend it, than they are not required as the rubber is a Tight Fit on the Barbs.
Vibration and noise have nothing to do w/ this part, it's more like staying put and a great seal.

Dave K

Edit: you need to keep the cables where they are, else they won't fit/route correctly onto the Engine harness and the mounting brackets.

Rob Edwards

Proper routing for the front knock sensor is under the driver's side of the water crossover, here's a pic of the L-shaped bracket and gray omega clip that holds the cable off the rear water crossover bolt:

Shark_gts

Thanks - that's exactly what I was looking for. The intake on this car was off before and the sensor cables were wrapped in friction tape.

The front was routed so weirdly through the P-side that I just cut the cable.

I also did use hose clamps on the ISV. I was referring to clearance for the clamps and there is lots there.

The intake is refin'd and built-up ready to drop in now. I used compressed air, sanded etc, some compressed air. Latex primer or paint grips well too. Color coat found a Krylon Nickel we had in the shop here. Satin clear - 3 coats of Rustoleum 2x cover - great paint for a can...

Rob Edwards

That's a good looking Speed Yellow 911.