Hesitation. Cured by replacing CO2 sensor?
18 March 2002, 10:43 AM
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Has anyone had the hesitation problem cured by replacing the CO2 sensor?
I read a few weeks ago that a guy called Steve had the hesitation problem and PE replaced the lambda sensor which cured this. Has anyone else done this with the same results?
I have the same hesitation on a MY98 between 2500-3000 rpm but dont know how to test my lambda to see if it is working correctly. I recently had an MoT and it passed the emissions test fine but I dont think that will pick up the problem that Steve had. Its something to do with the voltage. Its supposed to vary between 0-9 but his one had stuck at 3, correct me if I am wrong.
I was just going to replace it and see what happens but a new lambda is about £120!
Any replies will be much appreciated.
Thanks Stuart
I read a few weeks ago that a guy called Steve had the hesitation problem and PE replaced the lambda sensor which cured this. Has anyone else done this with the same results?
I have the same hesitation on a MY98 between 2500-3000 rpm but dont know how to test my lambda to see if it is working correctly. I recently had an MoT and it passed the emissions test fine but I dont think that will pick up the problem that Steve had. Its something to do with the voltage. Its supposed to vary between 0-9 but his one had stuck at 3, correct me if I am wrong.
I was just going to replace it and see what happens but a new lambda is about £120!
Any replies will be much appreciated.
Thanks Stuart
18 March 2002, 11:24 AM
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I have 2 lambdas - being lazy (& a little nervous about shredding the thread on one 
) I had a new one fitted for a replacement SS DP. Not a lot of difference. An improvement, yes, but that I think was more to do with the DP. The hesitation was still there a little.
I got rid of it with Optimax. Filled up yesterday with standard SUL (going to be mapped tomorrow & wanted SUL for it
) & the hesitation came back again.
) I had a new one fitted for a replacement SS DP. Not a lot of difference. An improvement, yes, but that I think was more to do with the DP. The hesitation was still there a little.I got rid of it with Optimax. Filled up yesterday with standard SUL (going to be mapped tomorrow & wanted SUL for it
) & the hesitation came back again.
18 March 2002, 10:23 PM
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Hi Stuart,
I am that Steve!
I don't normally recommend the 'fitter' approach - replace bits and see what happens - but you could use a 'universal' Lambda (O2) sensor as this is what PE fitted to mine as they could not obtain an 'official' one in time. This greatly reduced the cost of the replacement part and my car continues to perform fabulously again - I am sooooooo pleeeeeeeeeaaaaaaased with it.
Of course, your problem could be different but if the synptoms are the same and it is driving you as nuts as it drove me, the replacement could just maintain your sanity.
As a matter of interest, the reason that the Select Monitor does not register a fault is simply that the sensor under normal conditions outputs a voltage of between 0.1v and 0.9v and mine was 'locked' at 0.3v (well within the acceptable output range) so no error was apparent. It would seem the ECU is not clever enough to realise that the Lambda sensor output is not varying as it should do! Lambda closed loop mode is only in operation below 3000 RPM which is why nothing was found to be wrong on the emissions front.
Best of luck
Steve
I am that Steve!
I don't normally recommend the 'fitter' approach - replace bits and see what happens - but you could use a 'universal' Lambda (O2) sensor as this is what PE fitted to mine as they could not obtain an 'official' one in time. This greatly reduced the cost of the replacement part and my car continues to perform fabulously again - I am sooooooo pleeeeeeeeeaaaaaaased with it.
Of course, your problem could be different but if the synptoms are the same and it is driving you as nuts as it drove me, the replacement could just maintain your sanity.
As a matter of interest, the reason that the Select Monitor does not register a fault is simply that the sensor under normal conditions outputs a voltage of between 0.1v and 0.9v and mine was 'locked' at 0.3v (well within the acceptable output range) so no error was apparent. It would seem the ECU is not clever enough to realise that the Lambda sensor output is not varying as it should do! Lambda closed loop mode is only in operation below 3000 RPM which is why nothing was found to be wrong on the emissions front.
Best of luck
Steve
19 March 2002, 01:52 PM
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Thanks for the replies Steve/nom
I think I am going to have the bite the bullet and pay out for a new one and see what happens.
Steve did you get better fuel consumption when you changed it?
Also did it only feel better below 3000rpm and made no difference above those revs.
Stuart
I think I am going to have the bite the bullet and pay out for a new one and see what happens.
Steve did you get better fuel consumption when you changed it?
Also did it only feel better below 3000rpm and made no difference above those revs.
Stuart
20 March 2002, 03:24 PM
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Stuart,
I am not aware of any difference in fuel consumption but then I would not expect it either to be honest as the 0.3v output was making the engine run lean anyway. The problem only occurred at low loads where there is little fuel consumption anyway.
As the Lambda sensor only contributes at below 3000RPM (approx.) it's replacement should not affect performance above this and that too has been my 'real world' experience. It really did resolve the problem that was apparent in a very particular set of circumstances. If you need to know more about the specific circumstances, let me know if you feel it will assist.
I am not aware of any difference in fuel consumption but then I would not expect it either to be honest as the 0.3v output was making the engine run lean anyway. The problem only occurred at low loads where there is little fuel consumption anyway.
As the Lambda sensor only contributes at below 3000RPM (approx.) it's replacement should not affect performance above this and that too has been my 'real world' experience. It really did resolve the problem that was apparent in a very particular set of circumstances. If you need to know more about the specific circumstances, let me know if you feel it will assist.
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