tickover issue?

[Dartmoor_Lad]

Hi, I have just had a new exhaust and lambda sensor fitted now the tickover is very low. Any suggestions guys? Is there anysort of reset/learning procedure to learn the new sensor levels etc?

 

[clivvy]

how low??

 

[Dartmoor_Lad]

how low??

So low that its hardly moves the needle on the rev counter or doesn't actually tickover

 

[solarman216]

do not adjust anything till you have done a few miles of varying driving, I have just fitted a new lambda to the wifes T2 and it was pretty much the same, took it to the cheapest fuel station to fill up only 5 or so miles now it is running much better, the brain has to learn the new readings and ditch the old, Rick

 

[solarman216]

incidentally was the new sensor complete with plug or was it a short lead version needing cutting and joining the wires, if so worth checking the connections are good and white to white X2 and black to black, Rick

 

[Dartmoor_Lad]

do not adjust anything till you have done a few miles of varying driving, I have just fitted a new lambda to the wifes T2 and it was pretty much the same, took it to the cheapest fuel station to fill up only 5 or so miles now it is running much better, the brain has to learn the new readings and ditch the old, Rick

Took it for a thirty mile run to see friends and got back in after an hour it wouldn't even tick over! Will check connections in the morning....

 

[dan]

Check connections on the low range wire, high range is ok as it runs, low range takes over at idle - may not be connected properly.

 

[solarman216]

Check connections on the low range wire, high range is ok as it runs, low range takes over at idle - may not be connected properly.

Can you expand on that a bit more, are you saying one white wire is low and one is high? or are you referring to something else, Rick

 

[dan]

A lambda sensor is a dual circuit device. You have Low Range, and High Range. Wires are usually 6 in number, 2 low, 2 high and 2 for power supply/earth.

When the vehicle starts and is 'cool' it will use low range circuit - this allows a richer burn, until warm, where the high range circuit takes over and runs much leaner. Low range is effectively telling the ECU to allow the vehicle to have a bit of 'choke' as it were.

If the low range is badly connected, the ECU will be given only info from the high range, thus thinking the vehicle is warm and giving less fuel/air mixture, which could be the problem accompanied by the ECU not being able to 'learn' a new signal.

In most cases of Lambda faults, the signal is intermittent - which causes the 'hunting' and it is usually the high range that fails (as it sees more use) and this gives a richer mixture (as low range is operating), and causing the cat to overheat giving the eggy smell.

Think of it as an electronic version of a thermostat - low is 'closed' and high is 'open'

 

[Dartmoor_Lad]

A lambda sensor is a dual circuit device. You have Low Range, and High Range. Wires are usually 6 in number, 2 low, 2 high and 2 for power supply/earth.

When the vehicle starts and is 'cool' it will use low range circuit - this allows a richer burn, until warm, where the high range circuit takes over and runs much leaner. Low range is effectively telling the ECU to allow the vehicle to have a bit of 'choke' as it were.

If the low range is badly connected, the ECU will be given only info from the high range, thus thinking the vehicle is warm and giving less fuel/air mixture, which could be the problem accompanied by the ECU not being able to 'learn' a new signal.

In most cases of Lambda faults, the signal is intermittent - which causes the 'hunting' and it is usually the high range that fails (as it sees more use) and this gives a richer mixture (as low range is operating), and causing the cat to overheat giving the eggy smell.

Think of it as an electronic version of a thermostat - low is 'closed' and high is 'open'

I only have 3 wires... 2 white and one black

 

[dan]

That is nothing to worry about, works on the same principle, just a Zirconia Sensor - they produce their own power through heat induction, so only need one earth wire, and the two sensor wires. low circuit should read 0.45v and high 0.50v - if higher or lower than this, that sensor range will be the faulty one!

 

[Dartmoor_Lad]

That is nothing to worry about, works on the same principle, just a Zirconia Sensor - they produce their own power through heat induction, so only need one earth wire, and the two sensor wires. low circuit should read 0.45v and high 0.50v - if higher or lower than this, that sensor range will be the faulty one!

So lets pretend your talking to an idiot who has no idea how to test it, actually you won't haveto pretend! How would you explain to him the test procedure. I was given a MAstech MAS-345 digital multimeter which I have no idea how it works apart from the very basics, would it be any use in testing this?

 

[Dartmoor_Lad]

Checked all the connections this morning, where the garage had put the new connectors and covered them with little rubber sleeves it looks like as they replaced the cable protector it slid all the protective sleeves off and they bared all the wires which have been touching for the last 24 hours.
Could this have damaged the sensor? I can't imagine it doing it any good!

Maybe best if I just buy another one with the plug attached and change the whole thing over.

 

[dan]

It shouldn't have, but would have given you the short that was causing your problem! Reconnect properly, and fire her up!:thumbs

Just cut and shut the wires, solder them if you can - failing that use some crimps and make sure you insulate well.

 

[Dartmoor_Lad]

It shouldn't have, but would have given you the short that was causing your problem! Reconnect properly, and fire her up!:thumbs

Just cut and shut the wires, solder them if you can - failing that use some crimps and make sure you insulate well.

Done all that and cleaned a few bits and pieces, its now ticking over when warm at a steady 500rpm, a tad low I reckon but at least it's doing it! :clap

 

[clivvy]

ECU may just need to re learn now, tickover should be approx 750 rpm, a good drive may sort it out...good result so far though.

 

[Dartmoor_Lad]

ECU may just need to re learn now, tickover should be approx 750 rpm, a good drive may sort it out...good result so far though.

Took the MAF sensor out and cleaned it, didn't look to bad to be honest but whatever I did over the last two days has worked. Mother now starts ad ticks over better.

Now anti roll bar bushes.....