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The mkiv Supra Owners Club

Wierd juddering at 5krpm +


Lurch
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Hello, I wonder if anyone can help me with a problem I've got. When I accelerate at full boost it judders almost like its not getting enough fuel. I'm BPU @ 1 bar boost. New sparkies, new walbro. Decat and 1bar restrictor ring. Could it be a faulty fcd? It doesn't do it when on 0.8 boost

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did you fit the right sparks? right gap?

 

Yea I've got colder plugs, NGK BCPR7ES

 

Do you have a boost gauge ? whats it boosting to ? What FCD have you got ?

 

Just went out to check, as I wasn't sure and I noticed this... (not my photo but same item)

image

Would this be the reason, does it need to be adjusted or mapped? I dont even know what it is lol. Tried researching but could only find the f con v pro which I do believe is different?

 

yea I have got a boost controller, its running 0.97 bar of boost. (just under a bar)

 

:badidea:

 

You got enough fuel? When mine is on the warning light and I floor it it will judder and cut.

 

Yea lots of fuel, it does feel as though it has something to do with fuel though.

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Thats a piggy back. Have a go at removing that unit and just going through the stock ecu and see what happens. If its that ecu I don't think there are many places that can map them in this country as I have the same fitted.

 

Yea I've got colder plugs, NGK BCPR7ES

 

 

 

Just went out to check, as I wasn't sure and I noticed this... (not my photo but same item)

http://i.ebayimg.com/14/!BkW55Kw!mk~$(KGrHqYOKigEsm+VcgY7BL(MD5ebY!~~_35.JPG

Would this be the reason, does it need to be adjusted or mapped? I dont even know what it is lol. Tried researching but could only find the f con v pro which I do believe is different?

 

yea I have got a boost controller, its running 0.97 bar of boost. (just under a bar)

 

 

 

Yea lots of fuel, it does feel as though it has something to do with fuel though.

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I had the Fcon V on my car when it was BPU (it was on it when imported, and i didnt know until i removed carpets for painting) and every other TT or BPU TT owner i ever took for a drive commented how fast it was. If you change fuelling and ignition you can change the spool characteristics. When 2nd turbo came in when mine was BPU it felt insane. No juddering or issues though.

 

IIRC, dont they also have a crude FCD effect? So maybe you fitting another may have confused it and led to juddering?

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No, it didnt have a FCD. It was the f-con that stopped the fuel cut.

 

Im not sure i follow.

 

Im pretty sure the juddering wasnt fuel cut, the feeling you get with fuel cut isnt a judder, but more of a 'head through the screen' type thing!

 

All i can say is my car was BPU, Had an FconV, didnt have an FCD, boosted to 1.2bar, and didnt hit cut.

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Sorry, lazy typing again. What I mean is that I didnt have an FCD and F-con ecu together like you thought I did. I assumed I had a FCD as my car never hit boost cut until I had a look and found the f-con. So the juddering wasn't caused by a conflict of having and FCD and the F-con ECU. But its hitting boost cut now as I've removed the F-Con but the juddering has stopped. I luckily have a FCD to fit. :thumbs: Hope that makes sense, I'm rubbish at explaining things :rolleyes:

 

 

Im not sure i follow.

 

Im pretty sure the juddering wasnt fuel cut, the feeling you get with fuel cut isnt a judder, but more of a 'head through the screen' type thing!

 

All i can say is my car was BPU, Had an FconV, didnt have an FCD, boosted to 1.2bar, and didnt hit cut.

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