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Discussion Starter · #1 ·
Hi

I have a strange problem with my car. When there is no boost the car is misfiring badly, and is loosing power, but as soon as i get boost, from around 0.2bar it pulls like hell, and everything is fine. Drove my car on the track, and everything is fine as long as i have boost.

Doesn't matter cold or warm, low rpm and high rpm... the problem is there only when off-boost.

Does anybody have any clue to what this could be??
 

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could be something with your lambda sensor, since the problem only occurs in the closed loop. when you're on boost you the engine switches to open loop. Could be worth chekking, disconnect the lambda sensors and check the difference.
 

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Discussion Starter · #3 ·
fabianGTR34 said:
could be something with your lambda sensor, since the problem only occurs in the closed loop. when you're on boost you the engine switches to open loop. Could be worth chekking, disconnect the lambda sensors and check the difference.
Ok, thanks, will try that later on today.

Anybody else have any info??

Asim...
 

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Discussion Starter · #4 ·
fabianGTR34 said:
could be something with your lambda sensor, since the problem only occurs in the closed loop. when you're on boost you the engine switches to open loop. Could be worth chekking, disconnect the lambda sensors and check the difference.
Thanks for the tip.
I disconnected them and the misfire is gone... i have a spare set i will put on.

I just cant believe i didn't try this earlier hehe... :p

Asim..
 

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I've got a gtst and the lambda sensor is that sparkplug looking thingy in the downpipe from my turbo yes? theres a plug goes into it too and the rest of the pipework appears to be the exhaust leading to under the car.

If I disconnect this whilst running a pfc what would happen? I'm just curious as I'm getting slightly dodgy idling and erratic ignition signal. Not getting misfires at all though.
 

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lambda sensors do need replacing every once in a while. They will tend to cause erratic idling if not working properly.

The sensor produces its own voltage and readings according to the 02 levels it picks up, and when it starts ageing, then it does not produce these accurately.

http://www.gtr.co.uk/forum/upload/showthread.php?t=55445&highlight=lambda
post # 7
 

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yep I read that one only half an hour ago rasonline :) very good explanation but as you can see ...it went into my muppet brain... minced about for a bit then went to get a toasted sandwich :/

so basically get a new one if I'm getting strange and erratic idling!
 

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yeah lookin for one for my 33gtst now - seen lambdasensor.co.uk and they seem to do a specific one on there but not sure if I'll have to do any wire cutting an soldering - would much prefer straight unplug/swap fitment really :/
 

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oh you rotter hehehe! yeah I think I'll order one at end o the month for the car - rather have new than 2nd hand with an item like this - no-one would think o putting 2nd hand sparkplugs in as a service item so dont think it'd be a smart idea to get one of these things 2nd hand :/
the chaps from just-lambda's came back and said the plug is designed to fit the skylines - it was just whether the unit was a titania or zirconia based unit. If it needs a 17mm spanner to remove the old one then its a titania and the unit they sell isn't suitable - pretty sure mine is the zirconia unit.
 

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Discussion Starter · #15 ·
should be ok to run but your fuelling settings will be way out and the car won't run well off boost. It will tend to run rich off boost.
I have been running mine since i posted this, and no problem, the only thing is that the idle is a littlebit higher....
No misfire og black smoke offboost, if anything, the car did run bettre hehe... but that was because of defect lambda`s...

Asim...
 

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Sorry for a bit of a highjack, but I have a similar problem. My car runs fine in the lower gears when off boost. If I try to put her 1/2 throttle, I get alot of sputter/pop. Once I hit about 3800rpm, no issues at all. I can't use 5th gear on the highway as she wont even hold speed until 140km/h. Once I hit 140km/h (or about 3700rpm) Away she goes, even off boost. I've got a t88 turbo and a remapped original ecu with no O2 sensors. Checked the resistance on the coilpacks (all at 1.0) but I'm not sure how accurate my multimeter is. Still running factory gap on the plugs with no issues all the way up to 2.0 bar....
:squintdan
 

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i just came across the weirdest situation.

sometimes wires become brittle. If the wire is close to a place which generates a lot of heat, then the following might happen:

When cold, the wire makes proper contact. when hot, the wire expands and has a loose/broken contact. when it cools off again, the contact is restored.

Had me baffled for weeks until we figured it out.

PS.. Please post up the solution to your problem once it is fixed.
 

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If you are running off the original ECU then you will almost certainly require the O2 sensors to be fitted and working. It runs good over 3700 / 3800 rpm because thats when the ECU starts running open loop i.e not using O2 sensors.
 

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The O2 sensors were definitely left out intentionally. They are not wrapped up anywhere. Also, the downpipe has 2 plugs in it which are for the O2 sensors if required. The performance of the car below 4000rpm gets progressively worse in the higher gears, so I thought it may be an AFM issue. I've located some splitfires locally and I'm going to have a go with those. Any other suggestions would be helpful. By the way, does anyone have a pic of the plugs that the O2 sensors plug into. Are these the ones ???

 
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