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The mkiv Supra Owners Club

Where is the MAF(?) Circuit...


Gareth Davies

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Hi guys, my Supras a bit ill at the moment... :(

 

After starting it sounds very rough, and without some revs dies off immediatly. After it warmed up it was a little better but was definatly running very rich.

 

We've been fiddling around and the fault code I get from the diagnostics is 31 (which is the MAF circuit), I presume it means a similar thing in a j-spec car (which uses a MAP system?).

 

I don't have access to the engine manual or anything funky (is there an online one somewhere?), so could someone give me a hint were i'd find the sensor in the engine bay. And what colours the wires are for the ECU.

 

I fear it can be one of two things thats killed it, the water inflow from the ab-flug bonnet (if it's exposed), or somethings gone wrong in my rats nest of wires down by the ECU. Neither being particulary good, and the local toyota people aren't exactly on my favourite persons list after royally f'in up my NA... With the greatest annoyance being it's died in Norwich rather than in MK where Leons like 4 miles away! Grr.

 

Any help greatly appreciated.

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Gareth,

MkIV.com have a large amount of info on the electrical system, namely the manual online, here.

 

Pages 72 though 77 are the ECU circuit diagram, and you'll find the MAP/MAF/boost pressure sensors on page 74.

 

The J-spec boost pressure sensor is here , it being the black thing with two bolts and the green sticker on. A small vacuum hose goes into it's underside, and a three-wire multiplug comes off it to the ECU. It's only bolted onto the manifold, nothing actually interfaces. Now, I don't know if this is classed as the MAP and used instead of the MAF on J-specs, or if the MAP is a different component somewhere else. Perhaps someone else can clear this one up :)

 

And finally, search keywords in case anyone else needs this info - ECU wiring circuit diagram MAP MAF pressure sensor

 

Hope this helps :)

 

-Ian

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Awesome, thanks guys. That thing was making a very strange clicking noise so i'll bet that's our candidate. It's at Clive Attowes now so i'll pass that on so I hope he can find whats up. I'll bet toyota don't have one in the country though...

 

I thought there was an electrical manual on MKIV.com. Couldn't find it though! Hmmm quick add to favourites.

 

Thanks again.

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Guest Martin F
Originally posted by Ian C

Now, I don't know if this is classed as the MAP and used instead of the MAF on J-specs, or if the MAP is a different component somewhere else. Perhaps someone else can clear this one up :)

 

 

Not sure if this helps or confuses, but UK\US spec also have the same MAP sensor, as well as the MAF.

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  • 3 years later...
Guest RaZerback121

SOooo, i have the engine........and a 5 speed Tranny......all i need is a 6 speed JDM ECU? I might just go with a Aftermarket ECU. Only problem is the the wire harness was meant for an Auto, not a man.......we will see how that goes >_

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