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Misfire/jolt at 3k rpm only


Baconsarnie

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Brand new here mate, with or without housing:thumbs:

 

viewtopic.php?f=157&t=43466

 

viewtopic.php?f=157&t=43467

 

Alex :)

hi mate

 

cheers for the link on the great priced MAF sensor.

 

does this sound like the MAF is causing the stumble to you? or possibly another cause?

 

 

Sounds like it could be the MAF however best to get the car on Consult 2/3 to be sure. :thumbs:

 

Alex :)

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Had a car in yesterday to have a look at with the same sort of issue as your car , after investigation it wasnt the airflow meter, I feel the fitting of the de-cat pipes was making the car run very lean around the 3K rpm area especially at part throttle , resetting the ECU helped but reading the front lamba's and the amount of self learn tune the car was using the car was still to lean in that area.

 

So I was wrong :surrender: with saying it was an air flow meter problem, sorry.

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95 regular. But Just filled right up with shell vpower incase it was a a fuel issue. Do these HAVE to be run on super? I thought uk models could accommodate 95 Ron?

It - HAS - to be run on Super (98RON in handbook/filler cap, but 97 is ok). You will be running the high det map and probably getting knock from 5k to redline, if not below when the knock sensor does not work. The knock sensor only works up to 5k RPM on the 350z.

 

Hopefully you havent done any serious damage.

+1 especially with decats, breathing enhancements cause the car to run lean etc and can cause det/knock problems.

 

A car should be remapped when being fitted with decats etc as the car will eventually revert the map back once it see's the afr's have altered. This results in absolutely no power gains until remapped with uprev.

:thumbs: anybody looking for a pro mechanic ?? Call this guy <------------ :lol:

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1st time I have seen a car mis-fire/stumble due to De-cats being fitted thou, they run lean but not to the point that they have a mis-fire/stumble.

 

The AFR in the AFR layout map in the stock ECU are this area is 14.5 so the car should run around that figure, the car is adding fuel around that area to make the required AFR number but I am extremely surprised to see this problem.

 

Something to note I feel.

 

But NeilP if you having a dig at me getting something wrong whys that? We all aren't perfect and we all make mistakes and without seeing a car the crystal ball can be wrong sometimes.

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1st time I have seen a car mis-fire/stumble due to De-cats being fitted thou, they run lean but not to the point that they have a mis-fire/stumble.

 

The AFR in the AFR layout map in the stock ECU are this area is 14.5 so the car should run around that figure, the car is adding fuel around that area to make the required AFR number but I am extremely surprised to see this problem.

 

Something to note I feel.

 

But NeilP if you having a dig at me getting something wrong whys that? We all aren't perfect and we all make mistakes and without seeing a car the crystal ball can be wrong sometimes.

Wasn't having a dig mate, more surprised I got something right.

This happened with my car also that's why I said it, now it seems to be happening more, so people should take note.

 

No dig at all just having a laugh I was correct for once

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mmmmm strange;

 

you got your car at the moment? try disconnecting the front lambda's putting the car into no closed loop lambda control see if this cures the stumble?

It's been mapped since at rs and it was running very lean throughout the rev range, especially mid range. I have afr graph at home of pre and post map afr's, I'll post it later.

 

I'm running an aem series 2 now for the nitrous to run correctly, it's not mapped in yet though as work is ongoing.

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It's been mapped since at rs and it was running very lean throughout the rev range, especially mid range. I have afr graph at home of pre and post map afr's, I'll post it later.

 

But that is only a full throttle run , this problem is at part throttle.

I was getting this issue when driving normally though and once mapped the problem disappeared

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update: fitted the new MAF sensor, and disconnected the battery for a few hours. took it for a drive last night and it seemed alot better. no messing about with revs and much smoother. im hoping this cured the fault instead of the ecu resetting the fuel tables etc. ill update after a few drives to see if its any different.

 

cheers for all the help though guys! :thumbs:

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update: fitted the new MAF sensor, and disconnected the battery for a few hours. took it for a drive last night and it seemed alot better. no messing about with revs and much smoother. im hoping this cured the fault instead of the ecu resetting the fuel tables etc. ill update after a few drives to see if its any different.

 

cheers for all the help though guys! :thumbs:

 

 

Any further updates on this??

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apologies for the lack of updates. been busy with work.

 

Well....its back :lol: looks like its the decats causing the miss on part throttle. but as im not looking to get a remap/mod further (decats were added purely for noise) im going to take them off and refit the cats, :angry: the noise is amazing :rant:

 

its annoying not having the car run right and im not sacrificing the running of the engine for a bit more noise, especially if its making the engine run lean. so they will be up forsale soon. perfect for someone looking to get an uprev :teeth:

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apologies for the lack of updates. been busy with work.

 

Well....its back :lol: looks like its the decats causing the miss on part throttle. but as im not looking to get a remap/mod further (decats were added purely for noise) im going to take them off and refit the cats, :angry: the noise is amazing :rant:

 

its annoying not having the car run right and im not sacrificing the running of the engine for a bit more noise, especially if its making the engine run lean. so they will be up forsale soon. perfect for someone looking to get an uprev :teeth:

 

 

Thanks for the update, let us know how it runs when you take them off. :thumbs:

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