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  #1  
Old 23-12-2014, 01:41 PM
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Default MOT fail/misfire
Ok where do I start?

Car has a misfire under load, I can't drive it any distance due to no MOT or tax.

Fuel is around a year old engine was rebuilt and reinstalled with 15w 40 semi synth oil (as per builders instructions). New plugs fitted as well.

Emissions are through the roof! Always passed after second test with the sports Cat in place.

Fast idle CO = 0.505, HC = 417, Lamda = 0.965
Natural Idle CO = 1.593

What do I check first? Syvecs ECU with Wideband.
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Old 23-12-2014, 02:16 PM
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I would be dumping the old fuel as it will stagnant and putting clean fuel in it as you've not used it in a while
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Old 23-12-2014, 02:28 PM
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I'm thinking of a drop of octane booster/fuel cleaner in the old fiel and run it through before topping up with clean. Only pain is I can't drive it to the petrol station so lots of cans needed!
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2005 Spec B 6MT - KiDO tuned (~270Bhp)
Custom exhaust - Cosworth filter - Samco Intake - Tints - Bilstein B8/B6 & STI springs - SuperPro ALK - Whiteline positive shift kit, rack mounts, rear adjustable camber bushes, front ARB mounts & strut brace, 20mm rear ARB with AVO mounts, - Hardrace Gearbox and pitch mounts - Prodrive PFF7's - Front Brembos - Kenwood CarPlay - 1/2 carbon grille - STI front splitter
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Old 23-12-2014, 02:40 PM
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Either drain or several bottles of octane booster and then a fresh 20l on top

I've had similar misfire issues with other cars that have been sat for a year or more.
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  #5  
Old 23-12-2014, 03:57 PM
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As above dump the fuel , I'd also rebook a mot at frosts in Shoreham
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Old 23-12-2014, 04:58 PM
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Hoping that I can get the misfire sorted soonish so I can get a retest for free. Only problem is I can't drive the car, otherwise it should be simple. I've also got to sort the brakes as they were a fail but only really due to lack of use.

Anybody with a Syvecs able to tell me what their wideband readings are at idle and 2500 rpm so I can see if my Lamda sensor is working?
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2005 Spec B 6MT - KiDO tuned (~270Bhp)
Custom exhaust - Cosworth filter - Samco Intake - Tints - Bilstein B8/B6 & STI springs - SuperPro ALK - Whiteline positive shift kit, rack mounts, rear adjustable camber bushes, front ARB mounts & strut brace, 20mm rear ARB with AVO mounts, - Hardrace Gearbox and pitch mounts - Prodrive PFF7's - Front Brembos - Kenwood CarPlay - 1/2 carbon grille - STI front splitter
Last edited by SpecB; 23-12-2014 at 05:00 PM.
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Old 23-12-2014, 05:26 PM
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Quote:
Originally Posted by BlueBugEye View Post
Hoping that I can get the misfire sorted soonish so I can get a retest for free. Only problem is I can't drive the car, otherwise it should be simple. I've also got to sort the brakes as they were a fail but only really due to lack of use.

Anybody with a Syvecs able to tell me what their wideband readings are at idle and 2500 rpm so I can see if my Lamda sensor is working?
Idle and 2500rpm should be 14.7AFR or ocscillating from around 14.3 to 14.9 if using 02 feedback.
If they are not then it will fail MOT.

If using a wideband it depends where the probe is and what exhaust is fitted.
If the probe is in the downpipe/header it should read fine. But if you have a dustbin of a tailpipe and the probe is only in the tip of the exhaust then the idle and light cruise readings are worthless.
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Old 23-12-2014, 06:25 PM
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I've calculated that a reading of 0.965 lambda is an AFR of 14.19 meaning the car is running rich. Is this likely with poor fuel? The Syvecs should be correcting the fueling based on the wideband sensor so it should be able to cope with old fuel?
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2005 Spec B 6MT - KiDO tuned (~270Bhp)
Custom exhaust - Cosworth filter - Samco Intake - Tints - Bilstein B8/B6 & STI springs - SuperPro ALK - Whiteline positive shift kit, rack mounts, rear adjustable camber bushes, front ARB mounts & strut brace, 20mm rear ARB with AVO mounts, - Hardrace Gearbox and pitch mounts - Prodrive PFF7's - Front Brembos - Kenwood CarPlay - 1/2 carbon grille - STI front splitter
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Old 23-12-2014, 10:36 PM
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Mine was miss firing when it came on boost while i was having it mapped it turned out to be a faulty plug id only fitted them the previous day stuck a new set of plugs in and it was fine
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Old 23-12-2014, 10:43 PM
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If that AFR rock solid, as 14.19AFR is fine if it is the lower level of the oscillation.
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Old 24-12-2014, 06:25 AM
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I'll get out there again today and get the readings as AFR as I think I can switch the units. My wideband is in the downpipe so should be reading correctly.
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2005 Spec B 6MT - KiDO tuned (~270Bhp)
Custom exhaust - Cosworth filter - Samco Intake - Tints - Bilstein B8/B6 & STI springs - SuperPro ALK - Whiteline positive shift kit, rack mounts, rear adjustable camber bushes, front ARB mounts & strut brace, 20mm rear ARB with AVO mounts, - Hardrace Gearbox and pitch mounts - Prodrive PFF7's - Front Brembos - Kenwood CarPlay - 1/2 carbon grille - STI front splitter
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Old 29-12-2014, 05:13 PM
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Haven't figured out how to change the units but have got some better fuel into the car and got the following readings at fast idle (2500) direct from the Syvecs Lambda fluctuating from 0.99-1.00 and at natural idle fluctuating slightly around 0.930.
The only error 'code' found was Engine coolant 1, low after warm up.
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2005 Spec B 6MT - KiDO tuned (~270Bhp)
Custom exhaust - Cosworth filter - Samco Intake - Tints - Bilstein B8/B6 & STI springs - SuperPro ALK - Whiteline positive shift kit, rack mounts, rear adjustable camber bushes, front ARB mounts & strut brace, 20mm rear ARB with AVO mounts, - Hardrace Gearbox and pitch mounts - Prodrive PFF7's - Front Brembos - Kenwood CarPlay - 1/2 carbon grille - STI front splitter
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  #13  
Old 29-12-2014, 05:42 PM
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Dead coolant sensor will make it run a touch rich when warmed up.
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Old 29-12-2014, 06:19 PM
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I am going to be putting my Miltek downpipe on soon, is it worth me/can I put a wideband in? Not sure what currently have without looking and will be going aftermarket ECU eventually most probably. Thought might be good for mapping if nothing else?

What make should I get? Where from?

thanks.
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Old 29-12-2014, 06:47 PM
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Cheers Scott, I'll have to get the sensor readings from cold to see if they make sense to double check but it sounds a good and reasonably cheap fix.

SI, I got mine from JT innovations with the correct Syvecs Lead, I don't think the STD ECU can use one though.
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2005 Spec B 6MT - KiDO tuned (~270Bhp)
Custom exhaust - Cosworth filter - Samco Intake - Tints - Bilstein B8/B6 & STI springs - SuperPro ALK - Whiteline positive shift kit, rack mounts, rear adjustable camber bushes, front ARB mounts & strut brace, 20mm rear ARB with AVO mounts, - Hardrace Gearbox and pitch mounts - Prodrive PFF7's - Front Brembos - Kenwood CarPlay - 1/2 carbon grille - STI front splitter
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  #16  
Old 29-12-2014, 08:25 PM
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Quote:
Originally Posted by Wagon_Si View Post
I am going to be putting my Miltek downpipe on soon, is it worth me/can I put a wideband in? Not sure what currently have without looking and will be going aftermarket ECU eventually most probably. Thought might be good for mapping if nothing else?

What make should I get? Where from?

thanks.
Innovate LC-1 is a popular choice, although they seem to of now updated this to an LC-2 http://www.innovatemotorsports.com/products/MTS.php

Check out Ebay, normally a few bargains and I think some Innovate comes in from Latvia. My last sensor did and never had a problem with them myself.
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