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Mikuni Throttle Bodies onto 4EFE


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Hi guys!

As the title suggest its something that I plan on doing for my 'Starfire' project; that is a 4EFE engine in a '71 Triumph Spitfire. At the moment I have the stock inlet manifold and throttle body fitted but I'm hoping to swap this out for a set of Mikuni throttle bodies from a Honda CBR.

Has anyone ever done this? Anyone point me towards info sources? Is it a simple enough swap if say I leave the Toyota fuel rail and injectors in place (save having issues with ECU??). What should I be looking out for in regards to electrics, sensors, plugs etc...

Any help at all to get me started would be appreciated!

The project: http://www.boards.ie/vbulletin/showthread.php?t=2057197258&page=20


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Its been done with some triumph tt600 throttles the tps even fits with a little bit of trimming to the plug, cut of the inlet leaving just the bottom as you planned, add some vac ports and stick some silicone joiners on to the bike throttles.

Run a all the vac feeds to a vac chamber, then from that to the Map sensor fpr and if your car has it, brake booster assist.

The oem ecu will fuel ok but could be made better with a piggy back like emanage or even a apexi Safc.

Chris green on here has a 5efe ep91 with them throttles, he has a build thread on here.

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Hello mate nice project you got going in terms of intake I haven't seen that done before to an 4efe. I have seen ITBS from a triumph tt600 put on an 5efe engine worked pretty well you can modify the throttle position sensor and everything else from the old intake to fit so you can run it from the ecu but will need to be remaped to get it running to its full potential.



Tez.


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A lot of the clio boys and the volvo drift boys put bike carbs out of the R6 on the earlier Renault 1.8 16V that you could find in the Mk1 Clio 16v - not a Starlet I know but helpful for some of whats needed in the conversion (such as FPR etc)


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Cheers for the help and info guys. Been looking for that build thread by Chris Green, cant seem to locate it, can anyone direct me to it?


I made a mistake in relation to the tb make, they are actually Keihin tb's, if that makes any difference, they are relatively simple, similar to the ones pictured below:

3cdd334d2559305fda81588161447364c.jpg
2b5b37eb1a20a30db26050b88bfdc288b.jpg

I've removed the fuel rail, injectors and accompanying wiring. Do I remove and try to refit the TPS from the standard Starlet manifold, or leave the Keihin one in place and modify the plug?

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Heres chris' thread buh.

http://www.ukstarletowners.com/topic/46823-remixd-5e-fhe-sportif-operation-refresh/page-15#entry1167238

The tps on the thriumph throttles was the same as a starlets just there was a lug on the side that stopped it fitting once that was filed/cut off it fit on directly. The shape of that plug is different so wouldnt clip in, also not sure what the voltage range would be on that but the 4efe ecu will need the correct range so might need to find out or retro fit the 4efe tps.

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Heres chris' thread buh.

http://www.ukstarletowners.com/topic/46823-remixd-5e-fhe-sportif-operation-refresh/page-15#entry1167238

The tps on the thriumph throttles was the same as a starlets just there was a lug on the side that stopped it fitting once that was filed/cut off it fit on directly. The shape of that plug is different so wouldnt clip in, also not sure what the voltage range would be on that but the 4efe ecu will need the correct range so might need to find out or retro fit the 4efe tps.

The TPS on both the Starlet and the Keihins are Denso's so I'm hoping it should be an easy swap, I've yet to take them off to have a good look though.

Hey bud I have Chris' old ITB's just changed the vac ports for better ones and I use my standard tps just with a little like adapter plate for it

5C04FE96-514A-45E0-A4D5-7BB70C81F2D6_zps

Looks great! Got any pics of the tps mounting?

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No pics bud could get some if you want it's literally a thin metal plate with holes drilled for the bolts and tps trigger to sit in

Cheers. On further inspection it looks like the inners of the Keihin and Toyota TPS's are different, so I'll have to stick with the one thats currently on the bike carbs.

From what I've seen both are 5V and both are three pin, so, thats a good start! Simple case of changing over the wires then. Maybe someone could correct me on this, but the three wires going to my TOYOTA tps are as follows (and what I believe the pin out is):

Pin 1 - Yellow w/ red tracer = ECU IDL (Throttle closed sensor)

Pin 2 - Brown w/ white tracer = E2 (Ground)

Pin 3 - Light Green w/ red tracer = PSW (Variable posistion sensor)

My research on the Keihin TPS is that:

Pin A - Green wire = DC negative (ground)

Pin B - Red wire = DC signal output to the ECU

Pin C - Yellow wire = 5V DC positive

What I have come up with is the following match, if anyone could confirm, deny or help me on this one that'd be great!

Pin 1 + Pin B

Pin 2 + Pin A

Pin 3 + Pin C

Edited by SplitfireIV
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  • 2 weeks later...

Pointless trying to use the oem ecu. Vacuum reference for fuel will give you poor drivability and mileage. At 0 to 5% throttle(tps) your map sensor will think you went from 30inhg to 0inhg(full throttle) use a full engine management and tune in alpha -n or a hybrid alpha n. https://youtu.be/5jvmLzHtWDY

Edited by Sudden
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