Mazda Rotary Club

General => General Technical => Anything Engine/Performance/Tuning related => Topic started by: n4bes on April 02, 2007, 09:21:20 PM

Title: Knock Sensor/Heat Light
Post by: n4bes on April 02, 2007, 09:21:20 PM
Looking for some help on this Guys................................

Changed my alternator a while back and droped it on the engine, stupid idiot I know. After it was changed the heat light on the dashboard came on and has stayed on since. I know this was the knock sensor warning light and presumed that the sensor was broken after dropping the alternator.

I fitted a PF Commander today and it is picking up the following readings for knock :

30ish below boost and peaking about 65 at 5000rpm, not going any higher till I know it\'s ok.

Why would the heat light be staying on if the PFC is picking up a reading..????? I thought it was the sensor that was goosed.

Totally Confused on this one...........................
Title: Knock Sensor/Heat Light
Post by: efiniste on April 02, 2007, 09:48:51 PM
The heat light stays on if you\'ve got a faulty sensor. Check the screen on the commander where it shows you the voltages for all the sensors. One of them will be highlighted, that\'s the faulty one.
Title: Knock Sensor/Heat Light
Post by: n4bes on April 02, 2007, 10:36:39 PM
Quote from: efinisteThe heat light stays on if you\'ve got a faulty sensor. Check the screen on the commander where it shows you the voltages for all the sensors. One of them will be highlighted, that\'s the faulty one.

Thanks mate..............................................

Is there a few different sensors for knock..........??????????
Title: Knock Sensor/Heat Light
Post by: nikp on April 03, 2007, 08:10:47 AM
No, the light can meaning different errors. A quick succession of flashes is the knock reading going high, the light staying on is a sensor failure (Like crank angle, fuel temp, etc, etc)
Title: Knock Sensor/Heat Light
Post by: bin liner on April 03, 2007, 11:27:55 AM
light on with power fc can mean.

1.  Oil metering pump fault. ( if the light is on constantly, make sure the omp wires that run close to the crank have not come loose and caught on the pulley) DO NOT DRIVE until u get it fixed or add 2 stroke oil to fuel..

2. Cat sensor has broken check under car.
Title: Knock Sensor/Heat Light
Post by: nikp on April 03, 2007, 01:02:25 PM
It can mean more than just those issues. It means \'something\' is wrong somewhere - check the sensor/switch check menu to see what is flagged as having an issue.
Title: Knock Sensor/Heat Light
Post by: John_Hudson on April 03, 2007, 05:34:05 PM
might be your air temp under the UIM, mine is faulty and sometimes it stays red  for upto a couple of mins at a time after a while it goes off and i get a neg 35 reading on my commander, Im about to change it this weekend even though its been like that for months :p
maybe worth your while checking there


John-
Title: Knock Sensor/Heat Light
Post by: n4bes on April 03, 2007, 08:46:37 PM
Thanks all guys................................

I have checked the sensor menu on the commander tonite and the fuel reading is highlighted........................??????????????

Any ideas wot I need to look at next....?????
Title: Knock Sensor/Heat Light
Post by: n4bes on April 03, 2007, 09:04:59 PM
Finally got my english insruction manual and it appears that the fuel temp gauge is faulty........................................

Any Ideas....????????
Title: Knock Sensor/Heat Light
Post by: m4drx on April 12, 2007, 12:16:23 AM
Quote from: John_Hudsonmight be your air temp under the UIM, mine is faulty and sometimes it stays red  for upto a couple of mins at a time after a while it goes off and i get a neg 35 reading on my commander, Im about to change it this weekend even though its been like that for months :p
maybe worth your while checking there


John-

i get the same mate -35 sometimes, gonna do mine this weekend was just wondering if it had made much difference to the car? the air fuel ratio should obviously be more accruate but is it obvious.

also my knock reading is always 1 so im guessing its broke, any tips.

much apreciated :)

(sorry for digging up and stealing thread but looks like you guys are done)
Title: Knock Sensor/Heat Light
Post by: m4drx on April 12, 2007, 12:18:08 AM
also mine has highlighted

NTR
FPD
APR
CCR

anyone have a translation?
Title: Knock Sensor/Heat Light
Post by: m4drx on April 12, 2007, 12:27:51 AM
found the meanings of codes but i think the vmop one came on one tme i checked so i need to monitor, any views?
Title: Knock Sensor/Heat Light
Post by: nikp on April 12, 2007, 08:48:30 AM
VMOP is your oil metering pump sensor - if that\'s failed you need to get it changed asap or start using a pre-mix fuel, otherwise you\'ll do damage to your rotor housings.

I have a spare standard air temp sensor if anyone needs one?
Title: Knock Sensor/Heat Light
Post by: Ed_RX7 on April 12, 2007, 09:39:03 AM
bo**ocks...i got the same problem
Title: Knock Sensor/Heat Light
Post by: nikp on April 12, 2007, 12:34:36 PM
I had it happen before i rebuilt my engine. Got bored of putting premix in. The result was some very worn rotor housings!
Title: Knock Sensor/Heat Light
Post by: AndyGen3 on April 12, 2007, 01:14:24 PM
Damn it mines on 2... Only since i got it back from Dragon...

Will have to suss it out tonight... Dont wanna wreck the engine...
Title: Knock Sensor/Heat Light
Post by: nikp on April 12, 2007, 04:17:03 PM
Quote from: AndyGen3Damn it mines on 2... Only since i got it back from Dragon...

Will have to suss it out tonight... Dont wanna wreck the engine...

Whats on 2? :3Confused
Title: Knock Sensor/Heat Light
Post by: AndyGen3 on April 12, 2007, 04:19:57 PM
Quote from: nikpWhats on 2? :3Confused

The cat heat light... Wudnt mind i was bootin it back to make the boat and the car died and wudnt boost... Had to get the AA to bring me home..

This could be part of the problem...

When your checking the sensors will the circles be black or white if theres something wrong???
Title: Knock Sensor/Heat Light
Post by: nikp on April 12, 2007, 04:23:13 PM
No circles denote whether the switch is on or not (\'white\' circle is off, black is on). If the whole thing is highlighted in black, then it denotes the sensor/switch as bust.

A knock of 2 is very good. However, you would probably expect it to move a bit (If you look on the graph of it). I\'m not an expert on failed knock sensors, but my understanding of them is that often they give wildly high readings when they fail as opposed to low readings.
Title: Knock Sensor/Heat Light
Post by: AndyGen3 on April 12, 2007, 05:12:02 PM
haha i wasnt talkin about the knock i meant my cat light is on too "2" text speak sorry...

Highest ive seen my knock is over 200!! So i dont think it works very well...:p
Title: Knock Sensor/Heat Light
Post by: nikp on April 12, 2007, 06:44:38 PM
Oh.....ok. I\'m not very good with text talk. High knocks on the apexi can mean anything. Especially with old knock sensors. If you\'re worried, it might be worth getting it checked out.
Title: Knock Sensor/Heat Light
Post by: yamaster on April 12, 2007, 06:57:14 PM
my heat light came on there on the way home from work. it comes on when its decelerasting and is poping alot more.. as soon as i accelerate it goes of???  the tick over is also higher at about 1100rpm.  anyidea what this could be??

the car is decated
Title: Knock Sensor/Heat Light
Post by: RobbieRX-7 on April 12, 2007, 07:21:46 PM
Has anyone sucessfully removed the cat and and managed to make the heat light go off? I know some people put the sensor under the seat but thats not an option for me because mine broke when removing the cat from the car.. I read that a resistor does the trick. Has anyone done this?
Title: Knock Sensor/Heat Light
Post by: Carl on April 12, 2007, 09:13:47 PM
Quote from: yamastermy heat light came on there on the way home from work. it comes on when its decelerasting and is poping alot more.. as soon as i accelerate it goes of???  the tick over is also higher at about 1100rpm.  anyidea what this could be??

the car is decated


Hi Shane,
drop the rpm on the idle screw.Should be about 900 rpm when warm.
Regards
Carl
Title: Knock Sensor/Heat Light
Post by: Carl on April 12, 2007, 09:16:16 PM
Quote from: RobbieRX-7Has anyone sucessfully removed the cat and and managed to make the heat light go off? I know some people put the sensor under the seat but thats not an option for me because mine broke when removing the cat from the car.. I read that a resistor does the trick. Has anyone done this?


Hi Robbie,
It is an easy fix.
Under the drivers seat there is the wiring that goes to the sensor under the car.
Just disconnect the connector,and then cut the two wires and solder them to gether,then tape up with electrical tape.
That removes the constant on of the heat light for the cat,but you still get any other warning flashes.
Regards
Carl
Title: Knock Sensor/Heat Light
Post by: Carl on April 12, 2007, 09:19:02 PM
You can get high knock readings if the engine is low on compression,or it can be due to something like the power steering pump getting rattly.Sometimes sensors need changing.
If the knock is high on overrun then you have no worries,but if it comes on under hard acceleration then that can be a worry.
Regards
Carl
Title: Knock Sensor/Heat Light
Post by: RobbieRX-7 on April 12, 2007, 09:33:17 PM
Cheers carl. Your always giving out sound advice, much appreciated:cheers