Knock sensor issue (1 Viewer)

[alaw]

One other thought: since the knock sensor plug only has one wire, it must make a good ground connection when threading into the engine block. If your threads for the knock sensor are rusty or oily or dirty it is possible there is a higher electrical resistance than what the ECM is looking for, leading to the CEL.

The amount of times I have removed these knock sensors I doubt the threads are dirty .
But I will check

 

[alaw]

when you say that you rewired di you run a new wire from the sensor to the ecu or just do a continuity check on the harness? if you did run a new wire the wire has to be shielded as it can pick noise and cause a bad reading. this is from a us spec ewd but I would expect that the aus spec would be similar

View attachment 2169871

I did run a wire back to the ECU , but it wasn't shielded.

 

[WCBlueSky]

I'm not saying dirty threads is a likely problem, but you have ruled out everything else that is likely!

 

[alaw]

I read on another post of a guy having same issues, turns out it was his EGR VSV ,not opening or closing properly.
apparently this can cause pre detonation.

 

[WCBlueSky]

Are you in limp mode? My understanding is that code 55 means a knock sensor is out of spec, not that the engine is knocking. I'm working on fixing the same code, but in my case someone smashed up the rear knock sensor and the plug is totally gone so it was pretty obvious what is wrong.

 

[alaw]

Are you in limp mode? My understanding is that code 55 means a knock sensor is out of spec, not that the engine is knocking. I'm working on fixing the same code, but in my case someone smashed up the rear knock sensor and the plug is totally gone so it was pretty obvious what is wrong.

Yes it goes into limp mode
I hear what your saying, but I have checked everything ,it has to be the motor

 

[bigredmachine]

I did run a wire back to the ECU , but it wasn't shielded.

the shielding could be as issue but I doubt it if you were running the wire as a temporary fix or just to rule some things out. if you can get to some of the shielding on the harness check for continuity to ground

 

[bigredmachine]

if your thinking that its the morot have you recently filled up, maybe it was a tank of bad of petrol. how many km on the truck, time for a tune up maybe? is the timing set correctly on the truck? you can pull the plugs and see what the tops of the cylinders look like with a bore scope. im sure that youve already checked these things but just have to ask the stupid questions

if you need some more screen shots of hte ewd let me know and i can post them up

 

[Azca]

Post up more information. Mileage, have the heads been off, has the engine been rebuilt, what general maintenance has been done? Is it burning oil and if so, how much?

Next, one post it seems to you say if it was knocking, it would throw a 053 code. Is it knocking? Is the error code recent? If knocking, how long? Your location says Vic, does this mean Victoria South Africa? Reason I ask it that it should be getting warm/hot there. If it is knocking, the heat will make it worse.

If it is knocking, and you have not had the heads off, and you have a lot of mileage on it, carbon build up on the pistons is probably the culprit. Let us know more info so the pros can assist.

 

[alaw]

the shielding could be as issue but I doubt it if you were running the wire as a temporary fix or just to rule some things out. if you can get to some of the shielding on the harness check for continuity to ground

Cheers I'll try that

 

[alaw]

if your thinking that its the morot have you recently filled up, maybe it was a tank of bad of petrol. how many km on the truck, time for a tune up maybe? is the timing set correctly on the truck? you can pull the plugs and see what the tops of the cylinders look like with a bore scope. im sure that youve already checked these things but just have to ask the stupid questions

if you need some more screen shots of hte ewd let me know and i can post them up

It's done only 240,000 kilometers
It did have a head gasket done recently
I do plan to have a look down the cylinders.
Sorry what is hte ewd

 

[alaw]

Post up more information. Mileage, have the heads been off, has the engine been rebuilt, what general maintenance has been done? Is it burning oil and if so, how much?

Next, one post it seems to you say if it was knocking, it would throw a 053 code. Is it knocking? Is the error code recent? If knocking, how long? Your location says Vic, does this mean Victoria South Africa? Reason I ask it that it should be getting warm/hot there. If it is knocking, the heat will make it worse.

If it is knocking, and you have not had the heads off, and you have a lot of mileage on it, carbon build up on the pistons is probably the culprit. Let us know more info so the pros can assist.

It's done 240,000 kilometers, it's recently had a head gasket.
We have only just purchased it
We are in Australia

 

[Azca]

Not too many miles on it, when the head gasket was replaced, how did the top of the pistons look? If there is carbon build up on the pistons and valves, it can cause pre-detonation. I had that issue before I rebuilt my engine but, only when it was over 95 degrees and heat soaked.

 

[alaw]

Not too many miles on it, when the head gasket was replaced, how did the top of the pistons look? If there is carbon build up on the pistons and valves, it can cause pre-detonation. I had that issue before I rebuilt my engine but, only when it was over 95 degrees and heat soaked.

Gasket was done just before we bought it
I'm gonna get hold of a bore scope

 

[bigredmachine]

Sorry what is hte ewd

electrical wiring diagram, its the wiring schematic. I can only get it for na spec vehicles but it may be able to help with certain things on the truck or at least get you started looking in the right direction.

240k is not really a lot and if the head gasket was replaced recently if there was some carbon on the piston tops I would have expected who ever did the job would have cleaned them off as best as they could. does the truck have egr, in the us spec trucks sometimes the wire harness can melt on the erg tube and cause wiring issues. if you don't have egr than this is obviously not something to worry about

 

[alaw]

electrical wiring diagram, its the wiring schematic. I can only get it for na spec vehicles but it may be able to help with certain things on the truck or at least get you started looking in the right direction.

240k is not really a lot and if the head gasket was replaced recently if there was some carbon on the piston tops I would have expected who ever did the job would have cleaned them off as best as they could. does the truck have egr, in the us spec trucks sometimes the wire harness can melt on the erg tube and cause wiring issues. if you don't have egr than this is obviously not something to worry about

Cheers I have a wiring diagram
It does have EGR and I've read that the egr VSV can fail which can cause pre detonation

 

[bigredmachine]

It does have EGR and I've read that the egr VSV can fail which can cause pre detonation

that's possible as when the egr is operating correctly some exhaust is flowing into the intake when the egr vlave is open under certain operating conditions. exhaust gases in the intake mean less oxygen which means less combustion and lower combustion temps, egr is used to control nox emissions. if its not operating correctly and you have high combustion temps it could cause a knock. have you tried to swap the egr vsv for another one, fortunately most of the toyots vsv connectors are the same or close enough that you can use them for testing purposes.

check the harness around the egr pipe, the harness clamps can get brittle, break and cause the harness to rest on the pipe

 

[alaw]

that's possible as when the egr is operating correctly some exhaust is flowing into the intake when the egr vlave is open under certain operating conditions. exhaust gases in the intake mean less oxygen which means less combustion and lower combustion temps, egr is used to control nox emissions. if its not operating correctly and you have high combustion temps it could cause a knock. have you tried to swap the egr vsv for another one, fortunately most of the toyots vsv connectors are the same or close enough that you can use them for testing purposes.

check the harness around the egr pipe, the harness clamps can get brittle, break and cause the harness to rest on the pipe

I don't have another one unfortunately , I'm going to try to test the one we have .
I will check out the cable I've read this can also be an issue.
My son is away with the car until Friday, I will check these things out then
Thanks heaps

 

[bigredmachine]

and your ground location for the shielded wires will be on the intake, youll see multiple wires crimped together for one ground point

 

[bigredmachine]

I don't have another one unfortunately

just try to swap one that you know that is currently on the truck, such as the purge vlave. if both valves operate the same way (normally open or normally closed) then it will work for testing purposes