Tuesday, September 05, 2006

Pressure? What pressure?

I popped down my hydraulics place again, saw Steve (we're mates now) and got a union and hose to attach my pressure gauge to the metering unit - now we can see what's going on. Sure enough there it is, a problem - only 80 PSI. It needs to be between 100 and 110 psi. ASdjusting the PRV and swapping out the PRV made no difference - the pump (spare) is not delivering enough pressure at tickover.
So with the gauge gaffer taped to the dash and the pipe coming out of the bonnet I took it to the TSSC meeting and for a blast - at no point did the pressure get over 90 psi and at full throttle under load it dropped to just over 70 psi (and the car felt strangled) As the injectors trigger at 60 psi (sp the book says) I suspect that's getting close to their limitation.
So, stuff to try - change the pump for the original, the one that draws more amps than the spare and see what that does. Can't do it now, need some sleep as I'm off to Norwich for a 9am meeting another re-organisation, I wishe we could get it right for more than 12 months!
Nevermind :-)

1 comment:

VitesseEFi said...


Following the fuel pump story with interest and some alarm as it all gets more and more complex.

I know my injection setup only needs 45psi but I simply have a Bosch pump (from scrapyard Pug 405)mounted under the boot floor and fed from a banjo attached to the tank drain. This banjo does have an extension tube to stick up above the tank floor to stop it picking up too much crap and I have a disposable inline filter downstream. Nothing in the boot at all. Has now done in excess of 6K without any problems. No reason you couldn't do the same - just use a pump from one of the CIS (K jetronic cars) like Audi 100, volvo 240 /760 which can do the higher pressures and still maintain a reasonable flow.

Some pictures on my website