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The mkiv Supra Owners Club

Over Fuelling


Benjy

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After putting her on a rolling road at a shoot out day yesterday, it was pointed out to me that the car's running @ 10.6:1 air/fuel ratio which obviously is horrendously rich giving me a serious lack of BHP.

 

The car has got a Power Boost Valve on it, and apparently i have two options. 1) Adjust the boost valve and get the AFR right or 2) Bin it and replace it with a standard Fuel Pressure Regulator.

 

Anyone got any ideas of my best route??

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Yikes! I've finally fitted my fuel pressure gauge against my FSE - I'm getting massive overfueling on boost too.

 

This supposedly "constant rate" FPR returns, guess what:

 

Anywhere from 3.2 to 5.5 bar pressure!!

 

FSE? More like FFS!

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3.2 bar (fuel) off boost, but the pressure is rock steady.

 

Up to >5 bar (fuel) at less than 1 bar boost. Only fitted the gauge last night, so I haven't given it a bootfull of 1.2 bar boost yet. I'll try to do a more thorough test and post up.

 

Bear in mind that my AFRs on the dyno get down to about 10.2!!

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i haven't got the old standard FPR, the bloke that fitted the Power Loss Valve binned it i believe. i need a new FPR and banjo bolt too, luckily he didn't remove the original fuel metal fuel pipe that runs under the inlet manifold!!

 

could you source a relatively cheap one Chris?

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Yikes! I've finally fitted my fuel pressure gauge against my FSE - I'm getting massive overfueling on boost too.

 

This supposedly "constant rate" FPR returns, guess what:

 

Anywhere from 3.2 to 5.5 bar pressure!!

 

FSE? More like FFS!

 

Why you using one of these Chris? or was it fitted when you got the car?

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Why you using one of these Chris? or was it fitted when you got the car?

 

It was on the car when I bought it, as fitted by Thor, along with a pump and a couple of other bits and bobs. Apparently the car showed a flat spot during dyno testing before fitting it.

 

Anyway, I took a few readings last night and got:

 

0.26 bar on cold start and hot idle

0.24 bar on closed throttle (engine braking)

3.2 - 3.8 bar @ 0 bar boost

4.6 bar @ 0.68 bar boost

4.8 bar @ 0.88 bar boost

4.8 bar @ 1.03 bar boost

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  • 3 weeks later...

Well I tried the +B / FP diagnostics bridge to check and set my FSE fuel pressure. Following the workshop manual, I should get 226 - 275 kPa (33-40psi). I got around 350 so I trimmed that back to about 300 Kpa.

 

Stage 2 in the manual procedure is to un-bridge the diagnostics, start the engine and remove the manifold pressure reference from the FPR. Should get 226-275 kPa - I got about what I had above.

 

Stage 3 is to re-connect the reference pipe. Should get 167-216 kPa (27-31 psi) - I got about 170.

 

So, in summary at static the FSE is set about 7 psi higher than the workshop maximum, but as soon as the engine is started, pressure falls to the minimum allowed by the manual. What a piece of crap.

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  • 1 month later...

Guys,

 

Does anyone have a spare OEM FPR lying around, or would you know the part numbers for all the bits that I need to remove an FSE and replace with stock???

 

I've got an FSE unit on my car, and I want rid pronto. I'll also need to get someone to fit it for me. (probably ToyotaGT) I don't want the risk of running anything like the FSE that seems to have a bad track record.

 

The car is fully decatted and BPU, so from my understanding I don't need anything more than the stock unit.

 

Even part numbers would be good if you have them! Thanks!

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