Hi there
Im trying to fault find an issue with my engine, its running as rough as a VW Camper van! I have recently changed my cat, it cracked off at the weld, story for another thread.
After changing the CAT the car seems to have lost power, and sounds rough. I had real trouble getting both sensors off, the pre and post cat sensors. I really had to hammer and bash them off.
So, im trying to work out if I have shagged them in the process.
As you can see from above this model has two sensors, and from eper, it seems they are both the same.
looking at the following electrical circuit:
where K40 is one of the sensors, it seems the sensor is made up of a resistor, which im guessing changes with temperature, and another component, which looks like a heat sensitive capacitor or thermocouple.
So, i've been out to the car and got the following measurements:
COLD
---------------------
Pre-CAT terminals
1 - 2 Open circuit, 0V AC, 0V DC
3 - 4 Continuity, 8.4 Ohms (meter set to 200scale)
Post-Cat terminals
1 - 2 Open circuit, 0V AC, 0V DC
3 - 4 Continuity, 9.3 Ohms (meter set to 200scale)
WARM (5 mins idle)
---------------------
Pre-CAT terminals
1 - 2 Open circuit, 0V AC, 0V DC
3 - 4 Continuity, 12.5 Ohms (meter set to 200scale)
Post-Cat terminals
1 - 2 Open circuit, 0V AC, 0V DC
3 - 4 Continuity, 13.3 Ohms (meter set to 200scale)
HOT (10 mins)
---------------------
Pre-CAT terminals
1 - 2 Open circuit, 0V AC, 0V DC
3 - 4 Continuity, 14.1 Ohms (meter set to 200scale)
Post-Cat terminals
1 - 2 Open circuit, 0V AC, 0V DC
3 - 4 Continuity, 15.3 Ohms (meter set to 200scale)
I cant seem to measure any change between terminals 1 and 2, I suspect i need to scope these terminals, sadly i dont have one avaliable.
Terminals 3 and 4 are increasing in resistance in line with temperature, and both are within 1 degree of each other, i think this is negligable, but i might try swapping them over.
interestingly, having the sensors unplugged versus plugged in made no difference to the revs or noise at idle. :idea:
so my question is, is there anyone out there willing to go and measure their sensors. If you have a multimeter to hand and a spare ten mins, it would be a real bonus, not only to me, but i think this could be of interest to others. :worship:
thanks in advance.
Im trying to fault find an issue with my engine, its running as rough as a VW Camper van! I have recently changed my cat, it cracked off at the weld, story for another thread.
After changing the CAT the car seems to have lost power, and sounds rough. I had real trouble getting both sensors off, the pre and post cat sensors. I really had to hammer and bash them off.
So, im trying to work out if I have shagged them in the process.
As you can see from above this model has two sensors, and from eper, it seems they are both the same.
looking at the following electrical circuit:
where K40 is one of the sensors, it seems the sensor is made up of a resistor, which im guessing changes with temperature, and another component, which looks like a heat sensitive capacitor or thermocouple.
So, i've been out to the car and got the following measurements:
COLD
---------------------
Pre-CAT terminals
1 - 2 Open circuit, 0V AC, 0V DC
3 - 4 Continuity, 8.4 Ohms (meter set to 200scale)
Post-Cat terminals
1 - 2 Open circuit, 0V AC, 0V DC
3 - 4 Continuity, 9.3 Ohms (meter set to 200scale)
WARM (5 mins idle)
---------------------
Pre-CAT terminals
1 - 2 Open circuit, 0V AC, 0V DC
3 - 4 Continuity, 12.5 Ohms (meter set to 200scale)
Post-Cat terminals
1 - 2 Open circuit, 0V AC, 0V DC
3 - 4 Continuity, 13.3 Ohms (meter set to 200scale)
HOT (10 mins)
---------------------
Pre-CAT terminals
1 - 2 Open circuit, 0V AC, 0V DC
3 - 4 Continuity, 14.1 Ohms (meter set to 200scale)
Post-Cat terminals
1 - 2 Open circuit, 0V AC, 0V DC
3 - 4 Continuity, 15.3 Ohms (meter set to 200scale)
I cant seem to measure any change between terminals 1 and 2, I suspect i need to scope these terminals, sadly i dont have one avaliable.
Terminals 3 and 4 are increasing in resistance in line with temperature, and both are within 1 degree of each other, i think this is negligable, but i might try swapping them over.
interestingly, having the sensors unplugged versus plugged in made no difference to the revs or noise at idle. :idea:
so my question is, is there anyone out there willing to go and measure their sensors. If you have a multimeter to hand and a spare ten mins, it would be a real bonus, not only to me, but i think this could be of interest to others. :worship:
thanks in advance.