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        General >> Problems >> 24 valve Missfire at Idle.
        
(Message started by: Nunnspoet on May 7^th, 2009, 9:04am)

Title: 24 valve Missfire at Idle.
Post by Nunnspoet on May 7^th, 2009, 9:04am

;D ;D . She passed her MOT yesterday without any problems:

Fast Idle Test:

Descritpion Min Limit Max Limit Actual value Pass

RPM 1/min 2500 3000 2560 Pass

CO ....... 0.200 0.007 Pass

HC ....... 200 0.008 Pass

Lambda 0.970 1.030 1.014 Pass :-/

Second Idle Test not done

Natural Idle Test:

RPM 1/min 450 1500 711 Pass

CO ....... 0.300 0.083 Pass :-/

I don't know too much about the figures but I am a bit suspicious about the closeness to a fail on the ones marked with :-/.

She has a tendency to hesitate/misfire sometimes when Idling for more thatn 20secs. I renewed the Bank 1 (nearside) Lambda some months ago but the lead on the Bank 2 is too short and I left it as I was not well :(, then I forgot it till I read the Lambda readings on the Mot. ::) Could this be the cause of the missfire hesitation

I have been puzzling about this for sometime also there is a recent thread about this on Simplelists.

When I renewed the Spark Plugs a couple of weeks ago I noticed that the Bank 1 Plugs were in a much better condition than Band 2 which were slightly oily. Is that telling me something?

Whadda you think? :)

Mike

Title: Re: 24 valve Missfire at Idle.
Post by Nunnspoet on May 7^th, 2009, 9:11am

:'( :'( Oh Dear!! The figures have moved around between typing and Posting. I do hope you can follow them. I had them all laid out as per the Test Sheet.

I should have "Previewed" my posting. Sorry. If you can't follow the figures I will start again.

Mike

Title: Re: 24 valve Missfire at Idle.
Post by NiceMan on May 7^th, 2009, 1:45pm

One what can make is catalytic... my cos both is broke and idle speed hc is 260-403 ... but fast idle its drop to 55
Now i just make new pipe and put new catalyt them see what change...

Title: Re: 24 valve Missfire at Idle.
Post by martin_rowe on May 7^th, 2009, 3:38pm

Nothing wrong with those numbers at all.

Title: Re: 24 valve Missfire at Idle.
Post by Nunnspoet on May 8^th, 2009, 9:01am

:) Thanks for your replies Nice man and Martin, much apreciated.

I think the offside cat is quite old but there is no rattling or anything like that going on ::). The nearside Cat is not very old. Without looking it up I believe it was replaced by Eric R in 2005'ish and has not done a load of miles since then. Interestingly it was the offside set of Spark Plugs that were quite oily when I renewed them. The nearside plugs looked good.

Thanks for the reassurance regarding the "fume" figures Martin. I was a bit concerned with the Lambda readings but I will relax now 8).

Would a failing pre-Cat Lambda cause the oiling of the Spark Plugs on that Bank folks???

Mike

Title: Re: 24 valve Missfire at Idle.
Post by martin_rowe on May 8^th, 2009, 1:29pm

depends on what you are calling 'oiling', according to the emission readings you have no running problems, or were the plugs covered in oil when you removed them (cam cover gasket leak)

Title: Re: 24 valve Missfire at Idle.
Post by Nunnspoet on May 8^th, 2009, 4:57pm

When I renewed the plugs the plugs on the offside bank looked fine around the electrodes and the cones, but were quite oiled up around end of the screw ends whereas the nearside bank really were in top condition.

Maybe I should just stop fussing. It's just that slight missfire that annoys me and getting to the bottom of that niggle is difficult without an OBD readout though it does make me stretch the brain hence my question:does the performance of the offside pre Cat sensor affect the fuelling of the offside bank and vice-versa regarding the nearside bank and pre cat sensor?

Mike

Title: Re: 24 valve Missfire at Idle.
Post by scorpio_man on May 8^th, 2009, 5:09pm

hi mike

sounds like you have a slight spark plug gasket leak.

i wouldn't worry too much unless it's a fair wee bit of oil in each plug hole.

hth

Title: Re: 24 valve Missfire at Idle.
Post by Nunnspoet on May 9^th, 2009, 8:59am

:) :). Thank's for all advice recieved :-* .

My mind is now much easier.

Mike :)

Title: Re: 24 valve Missfire at Idle.
Post by NiceMan on May 11^th, 2009, 6:05pm

Problen solvet? ;-)

Title: Re: 24 valve Missfire at Idle.
Post by Nunnspoet on May 12^th, 2009, 9:24am

Not as yet, NiceMan :-/. There was oil around some of the plugs when I removed them so I could re- install the Spark Plug Gasket which is new. but the Plenum has since been removed and repalced since then.

I have been considering the Lambda sensor on that bank. I bought 2 new pre Cat sensors some time back, but when I came to fitting them I found the leads too short. I was able to peel back the car loom on the nearside enough to fit that side sensor but this is not possible on the offside as the Loom goes around the front of the engine. I could cut out a length of the insutu Lambda sensor and splice that into the new sensor loom but I am a bit wary of doing that, thicko me might get it wrong :-/, I may do it anyway. The reason I'm considering the sensor route is that I've been reading EricR's article on the site concerning the sensors and their influence on the fuelling (Stoichmetric input ?? ). It is about the readings taken from both pre-cat sensors whereby the pcu works out the correct fuel trims, and as one of my sensors is brand new and the other could be many thousands of miles old there could be an imballance in their combined input to the pcu which the pcu could not cope with manifesting itself in a creeping missfire/hesitation at tickover.

The sensors I bought are NTK/NGK 4 wire Part No. OZA448-E44.

Title: Re: 24 valve Missfire at Idle.
Post by NiceMan on May 16^th, 2009, 9:09am

http://www.ngkpartfinder.co.uk/car_commercial_extra.php?id=1190

Sensor is right.
I have same in my cos... both front is new but make that "Misfire" or something in my car too.
Today i plan look fuel system etc... soon i not know what is problem...

Title: Re: 24 valve Missfire at Idle.
Post by NiceMan on May 16^th, 2009, 9:39pm

I find problem in car.. ing 3 and 6 change place... now looks works normal... i wish ;-)

Title: Re: 24 valve Missfire at Idle.
Post by Nunnspoet on May 18^th, 2009, 8:45am

Sorry for not replying sooner NiceMan :-[. life got a bit hectic for a few days. And with this lousy weather I have not been around the Scorps, which are all outside in the wind and rain.

Have you managed to improve your Scorpio ?

When I first ordered the Sensors I was given
2 of the NTK/NGK 4 wire Part No. OZA448-E44 which are the same length and as the distance from the plug to the exhaust is futher on the offside of the car than on the nearside it will not reach ::)

I went to my friendly Part suplier here in Chard and explained the situation to him. At first he could not believe that the 2 Sensors could be different lengths but after searching his Database he found that I was correct ::) and he then ordered up the correct Sensor for the offside :)

So when ordering up Pre cat. Sensors from NTK (whch are NGk) you need;

1 X OZA448-E44. Stock No. 0293

1 X OZA448-E42 Stock No. 0271

Mike

Title: Re: 24 valve Missfire at Idle.
Post by NiceMan on May 18^th, 2009, 5:13pm

I have same leng both side... =) One is little too long but works.
Tomorror i have Mot test... Them see what they say...

Title: Re: 24 valve Missfire at Idle.
Post by Nunnspoet on May 19^th, 2009, 10:32am

:)Good luck with the Test. I look forward to hearing all about it NiceMan

Mike :)

Title: Re: 24 valve Missfire at Idle.
Post by NiceMan on May 19^th, 2009, 4:10pm

Test past ;-) No any problem.
HC idle 22, Fast 6 ;-)

Other i not remember but i tell them later.

Title: Re: 24 valve Missfire at Idle.
Post by Nunnspoet on May 19^th, 2009, 5:35pm

:) :) Well done. Scorpios Rule ;D

Title: Re: 24 valve Missfire at Idle.
Post by NiceMan on May 19^th, 2009, 6:34pm

Thanks ;-)