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The mkiv Supra Owners Club

Misfire on boost over 5krpm - Single Turbo Setup


harryww89

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I took the Supra out last night for a few pulls and took note of the detail.

 

Length of running now doesn't effect the problem - Straight away from initial running the hesitation is present above 5000rpm (Obviously warmed up to minimal operating temps). Engine Management/Check engine light comes on as soon as the affected load site is reached.

 

Fuel Pressure is a healthy 3.5bar throughout WOT above 5000rpm - The needle does seem to jump bounce around from 3.4-3.6 when in the effected area.

 

Again Oil pressure is a healthy 7bar on WOT.

 

I'm struggling to find an igniter at the minute. As a precaution, I have bought a new set of coilpack Clips - The currents all look in good condition, but it's just another factor to cross of the list, these should arrive today and I'll install them this evening and try again.

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  • 2 weeks later...

Hi All,

 

I have finally found the problem with misfire - All of the symptoms came together last night as I was setting off to leave for the Nurburgring and ended up with a 5 hour limp to drive 60miles back home.

 

Basically, the issue with the vehicle only misifiring when 'warm' was down to the fuel pump. There is an external Aeromotive A1000 fuel pump in the boot, to which yesterday, I believe the heat from the car being sat in the sun all day finally sent it over the edge, The fuel pump would not prime, only upon cooling the pump down with water/ice pack would the car start and run very poorly, reading up on this thing, I believe the adhesive on the magnets on the pump can fail?

 

Eitherway, I believe this was the source of the issue - I'm unsure now as to what replacement to go for? Another A1000 or amend the set up to run twin bosch 044's?

 

Are there any other fuel pumps on the Market that can support 700bhp that people would recommend?

 

Many thanks.

Harry

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Walbro 450lph pump will do it just about or 2 if you want some headroom.

 

Hi Paul,

 

Would this be an Intank pump?

 

Here is a picutre of the set up - Ideally i'd like to keep the same fittings and swirl pot system - Just replace the A1000 With something else, whether this be 2 external pumps or another large single.

 

image

 

 

Cheers,

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Hi Paul,

 

Would this be an Intank pump?

 

Here is a picutre of the set up - Ideally i'd like to keep the same fittings and swirl pot system - Just replace the A1000 With something else, whether this be 2 external pumps or another large single.

 

http://img.photobucket.com/albums/v471/vfs72/IMG_8086_zpsadpj6okn.jpg

 

 

Cheers,

 

Replace it with another Aeromotive for easy of installation and no remap required then either? I bet thats noisy sitting in the back of the car like that!

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Are you using the stock pump in the tank as the lift pump? I find the Bosch pumps the most reliable units on the market, so always go for the 044. I am not sure I would fancy having no firewall between myself and that swirl pot and plumbing. In a competitive environment the scrutineers would send you packing. Seen the Oz pick up truck photos posted on the forum earlier.... ?

 

 

My thoughts are, is there a chance the huge main pump is slowly heating the fuel to vapour point? Was the problem evident with a low fuel load in the main tank? I don't like running main pumps any bigger than needed due to fuel heating. If this *IS* your problem you could use a cooler in the return line (*NEVER* in the pressure line. Running a DC pump slower can sometimes helps, but occasionally a pump will run the fuel hotter at a lower than design RPM.

Edited by Chris Wilson (see edit history)
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I'm running a bosch 044 fuel pump at the moment at BPU and it is pretty noisy.

 

However, I am getting the same issue as harryww89 where the car holds back slightly on the 2nd turbo when warm (first 20mins driving it is fine) and thought it may be the pump also. It has been in there around 5 years now but as Chris mentions, they are reliable so I'm now thinking it may not be the pump.

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  • 1 month later...

Hi Chaps,

 

For anybody who's interested, it turned out to be the in tank pump which was the failure, it was not even a Supra pump in tank, Turned out to be a Skyline pump in there:blink:! I re-plummed the system to run on the Skyline pump, and the car wouldn't start due to extremely poor fuel pressure. I believe the engine is still in one piece thanks to the Aeromotive and swirl pot and pressure gradually losing instead of completely shutting off.

 

image

 

Anyway, new Walbro 450lph fitted, car started first time after being stood for 6 weeks and runs well, although I have yet to take it on a long run, off to Torque Developments Next week for some tinkering so we will see how we go!

 

image

Edited by harryww89 (see edit history)
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