26 replies to this topic

[Spitfire Engineering]

This post keeps cropping up in forum searches:

 

 

Spitfire Engineering, on 12 Apr 2013 - 12:22 AM, said:

Regarding your setup, is the installation noisy? If so it allows a possibility which may help and save you a lot of money. Basically the unit has an eductor which is tuned to the output (well more accurately the return) pressure. If you just fit the Walbro without adjusting this it usually results in high pressure return fuel hitting the lid of the pump unit and flying out sideways, outside of the pump canister, this fuel normally gently flows over the top of the standpipe and into the can. What this means in reality is the return fuel which should not only be returned to the canister but also suck in fresh tank fuel via the eductor principle as well, is mostly sprayed back into the tank reducing the fuel in the canister for the next corner. We have sold loads of S2/VX units to Bernard for the Audi Elise conversions all without issue and they make similar outputs. If you are going to hard track the car at tracks with long left handers then a swirlpot or trapped tank is needed, the advantage of a trapped tank is that it keeps a single in tank pump, personally I am not a fan of several feet of HP fuel hose and several components in the engine bay.

 

 

How would I go about modifying the unit to prevent this?

 

 

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[Stig_1911]

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[Spitfire Engineering]

 

 

Not quite sure why there is such a great desire for Walbro units, outdated gear type pump, not very efficient and noisy.

 

 

 

 

A. It's on the CS SC conversion website as an optional part. B. It has been confirmed to fit our pump housing unit. C. It has been confirmed to been used succesfully without blowing up the car.

 

 

You are the first hint of using anything alternative in the 15 years the car has been out there.

 

 

Sorry Hoor, ik heb dit gemist

 

A ?

B just about any pump will fit the housing, thats a big difference from it working correctly.

C is that the criteria then?  

 

We would take that as a compliment but we have been working with these units for the same time period. and until about 5 years ago we also used Walbro.

 

Dag

[jayworth2]

 

 

 

 

 

I've put a hose clip on too which will hopefully stop it squirting off.

 

I would certainly go along with this as I've learnt, to my great expense.

 

Thought that I would save myself some money and fit the pump myself. Followed the instructions to the latter. All seemed fine after some long periods of road testing.

 

Took the car up to Courteny's on Friday for the final mapping. On the last speed run on the Dyno, the convoluted pipe from the fuel pump to the upper part of the housing, blew off. Result is that now on pin 29 of the ECU we have a positive voltage, rather than a switch to earth which would activate the K16 relay which supplies power to the fuell pump and injectors. 

 

The result was another return trip from Courteneys with the car on my trailer, and it now looks like a new ECU, or at least having it checked out by a speclist company to see if has been damaged...And this is all because I did not put a worm drive clip on the fuel pipe on either end of the pump connections.

 

To be fair to John and Mark at Courteneys they made a sterling effort to track the problem, putting in some extra hours to fault find.

 

So make sure that a worm drive clip is installed at both ends of the uprated pump!

 

 

It may be worth considering, IMHO of course, that if you are not sure of what you are doing the HP fuel system is the last thing you should be tampering with  

How did you come to the conclusion you needed a more powerful pump in the first place?

Why did you select a Walbro?

 

How did a drop in fuel pressure (which is all you would have seen) possibly damage the ECU??

 

On my last vist to Courtenys, to fit a modified K06 turbo, and 3" exhaust, testing on the dyno showed a 1 bar drop in fuel pressure at full power runs. So John/Mark's suggested in fitting the 225. Which I did. Noise wise there was no detectable difference over the OEM pump.

 

The the pumps internal supply pipe, blew off on the final mapping run on the Dyno. TRhe fuel pump was rememved and the convoluted pipe reconnected and secured with clips.

The car could not be started unless the activation coil of relay K16, was bypassed and connected directly to an earth. Currently there is a 12 volt+ existing on pin 62 of the ECU, where there should be a connection to earth, activated by the ECU.

There exists a possibiulity that there is a fault else where, so I will have to, remove the ECU and test whetere 12 volts still exists on the coil part of the relay. 

 

So the conclusion was that under full power with the fuel pipe blowing off there was a current surge that damaged the ECU.

 

OK, I think you need to look elswhere for the problem, sudden failure of this pipe would result in a reduction of current from about 11A down to 6A which is pretty minimal, (about half the load difference of turning the pump on and off in the first (or flashing your lights) and without the spike, as the pump is still pumping fuel and the mass needs to accelerate to the new fuel flow speed.

 

Did you check for a back pressure in the return pipe? this is one of the issues of not modifing the unit to match the new pumps output specification.

 

Gaz

 

 

 

Thanks for the suggestions Gaz. I'm not too sure whether John or Mark checked the back pressure in the return pipe. It would be great if there might be another cause other than a damaged ECU.

The problem is getting the K16 relay to trigger. Everything works if you connect pin 4 to earth and the relay engauges. However, the ECU then throws up an error code. As part of the fault finding I've got to check the continuity of the white/violet cable from pin 4 on the relay to pin 62 on the ECU. I also think that a sudden loss of pump capacity,  and the subsequent sharp drop in the amperage demand from the pump should not have damaged the ECU...but then I've got no experience in this!  

 

 

[jayworth2]

I have same fault now where if I ground  pin 4 of fuel pump relay car starts 1st time but have no voltage on the white/violet wire & no 12V at injectors, FCO switch is good fuses are ok and have swapped grey relays around also checked Loom of doom. Was this an ECU fault?

[Spitfire Engineering]

I have same fault now where if I ground  pin 4 of fuel pump relay car starts 1st time but have no voltage on the white/violet wire & no 12V at injectors, FCO switch is good fuses are ok and have swapped grey relays around also checked Loom of doom. Was this an ECU fault?

 

Bit confused, how is it running if you have no power on the injectors??

[jayworth2]

Its the 12V solenoid signal i'am missing. By grounding pin 85 of fuel pump relay this switches the power on to the fuel pump & injectors & then fires up.