der3k

I have an 01 Prelude with a JDM H22A swap. CEL came on throwing code P0325 faulty knock sensor or circuit malfunction. Looked under the car and found a broken knock sensor. The wire connecting the sensor has been cut and a different plug has been put on. The 2001 calls for the small green square plug knock sensor which is 24mm, but this JDM engine has the larger circle plug knock sensor. I bought a 27mm deep socket but I cant get the socket onto the knock sensor to remove it from the block. I dont know if I need a special wrench or if I have to remove the intake manifold. The knock sensor is very tight under the IM with little to no clearance. Have any of you came across this problem and can you give me any advise as how to remove the knock sensor.

The car...


The Engine...

The broken sensor...


The connection plug has been changed by previous owner...

This is a photo of the broken knock sensor still in the block. You can see that there is almost no clearance to get a socket onto it for removal. I couldnt get the 27mm socket onto the sensor. If you have removed this type of knock sensor was the clearance minimal like this and were you able to finally get the socket onto the sensor?

bamaland601

iTrader: (1)

i used a 1-1/8" socket just yesturday to change mine, it helps it your oil filter is off

der3k

bamaland601 is this the same amount of clearance that you had? Seems like there isnt enough space to fit a socket in there. you can see in the picture how tight it is. I got a 1-1/8" socket... Ill let you guys know if it fits.

bamaland601

iTrader: (1)

pretty much..

der3k

Your intake manifold is different. I think that is my problem. Look at where your IM bolts are... Its hollow above them on yours. Mine has metal above the bolts. Damn... I think my intake manifold would require the small knock sensor. The big knock sensor thats on my engine my not come off with out removing the intake manifold.

snobordboy

From the picture, I would hate to say it, but you would probably be better off pulling the manifold to get that guy off. It will also give you decent room to fix the wiring, because that is ghetto, especially in an environment like the backside of the engine.

der3k

What is the large black hose that runs under the knock sensor? What will come out if I disconnect it? Is it possible to disconnect it so I could then get an open end wrench on the bottom of the knock sensor?

gstrudler

Coolant bypass pipe, so you'll need to drain the coolant before you try that as well as pull the t-stat housing.

holmesnmanny

Have you tried getting a pair of needle nose or vice grips in there and see if you can grip it ? Knock sensors aren't really on there that tightly. If you can get a thin pair of needle nose in there I would put another pair opposite against that pair of needle nose and turning might shake it loose.

You will need to pull the water pump to get to the water pipe. The thermostat side won't be a big deal but the water pump side will obviously take some work as you will need to remove the timing belts etc etc.

snobordboy

There is no need to pull the water pump to remove that pipe. If you drain the coolant, and remove the thermostat housing, all the hoses that attach to the oil cooler and heater core hoses from the cabin, and the one 12 mm bolt holding it to the block, it will come out from the back of the block. The O-ring is very snug so it takes some work, but it comes out.

If you do pull that pipe, get 2 new o-rings for it from Honda, nothing else will seal properly.

der3k

Thanks ill give it a try

der3k

Finally got the knock sensor off.

der3k

Used a grinder to grind away the outside diameter of a deep 27mm socket to compensate for the tight fit. Replaced the sensor with a new one from Amazon, its HQRP brand. It didnt work... still have a code P0325 and the check engine light is still on. Contated them, theyre sending me a new sensor free of charge. Hopefully the sensor was defective. Idk. hoping its not an electrical problem.

der3k

anyone know where the knock sensor is grounded at?

bamaland601

iTrader: (1)

its self ground. only 1 wire which goes straight to ecu.

holmesnmanny

more specifically it's grounded through the block

you may have an obd1 knock sensor...you need the obd2 one

der3k

I do have an OBDI knock sensor because I have the plug for the obdI. When then installed the engine swap the put this sensor and plug on it. I thought you could use either knock sensor as long as u had the correct plug? Idk the guy who did the swap switched the plug to an obdI plug but the ecu is still an obdII. The knock sensor did work fine until in broke.

holmesnmanny

then perhaps something wrong with how you connected the connector back on the wire

der3k

Possibly, Ill check the wiring. Maybe the connection or the plug is malfunctioning. Im still waiting for the new knock sensor, it should be here soon.

der3k

Finally got rid of the check engine light.

der3k

After contacting the HQRP brand and telling them about the defective knock sensor they sent to me, they sent me another one free of charge. I replaced the new one out with the defective one and no more check engine light. The Prelude runs great now. Shifts better, better gas mileage, and double the power that I was getting with the cel on.

Thanks for all of your help with the replacement of this sensor.

holmesnmanny

Ya it will run in limp mode with it throwing the knock sensor code. Nice to see you got it fixed.