blog:escort:work:lift_pump [Target-Earth]

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====== Escort Work Log - Lift Pump & Swirl Tank ======

{{:blog:escort:work:lift_pump:img20240725151959.jpg?600|}}

==== Date ====

Work took place mainly throughout July 2024 and finished August 4th 2024.

==== Parts ====

   * Torques 1.5L swirl tank
   * Facet fuel pump
   * Hi OTP044 injection fuel pump (258 - 378 litres/hour)
   * Various AN fittings and additional braided fuel hose
   * 12v relay
   * Miniature SPST latching toggle switch

==== Overview ====

Unfortunately, despite very few running miles on the car, the Bosch fuel pump we installed as part of the Cosworth engine conversion (a very expensive new part!) started to fail - intermittently not running. This would manifest as the inability to start the car, and when we were able to run the car on the road (in the very few times we tried it) it would stumble, hesitate and refuse to build any boost at all.

Eventually the car just refused to start, and the pump showed no signs of life - no priming noise when turning the ignition on, and no sounds of running when cranking.

=== Original Design ===

The original fuel system we installed when undertaking the Cosworth conversion was the [[https://www.proalloygroup.co.uk|ProAlloy]] fuel tank into a pre-filter, into a Bosch 0580254044 injection pump, out through a post-filter and to the fuel rail and back. The ECU was solely responsible for running the fuel pump via its normal fuel pump signal wire and a relay (since the battery is in the boot it's simple to run the pump directly from it, controlled via relay). 

It's a relatively simple setup and one we though would be fine, given the car is no longer for track days or rallying.

{{:blog:escort:work:lift_pump:p1060121.jpg?200|}} {{:blog:escort:work:lift_pump:p1060123.jpg?200|}} {{:blog:escort:work:lift_pump:p1060124.jpg?200|}} {{:blog:escort:work:lift_pump:p1060125.jpg?200|}}

In hindsight, the original design possibly helped to kill or at least damage the high pressure fuel pump, since it was susceptible to fuel starvation and possible drawing of air into the pump under acceleration. It's highly likely that drawing air is what killed the pump.

{{:blog:escort:work:lift_pump:fuel_system_no_swirl_tank.png?700|}}

=== Modified Design ===

In the modified design we added a low pressure, high flow lift pump (Facet 480532E, 6-8PSI, 170 litres/hour) filling a 1.5 litre swirl tank, and the (replacement) injection pump then pulling from there.

{{:blog:escort:work:lift_pump:img20240725151959.jpg?400|}}

The theory is that the injection pump then always has a constant source of fuel to pull from, so should not be damaged by occasional fuel starvation under acceleration or cornering. Since the Facet pump is literally just filling the swirl tank which then overflows back to the main tank, it requires very little effort and thus should not be overworked.

{{:blog:escort:work:lift_pump:fuel_system_swirl_tank.png?700|}}

In addition to the main diagram above, a small toggle switch was added in the +12v IGN Live line (and mounted under the dashboard) to the low pressure pump relay, in order that the constant pump running could be switched off whilst electric/diagnostic work was being undertaken that didn't need the pump constantly running (which would be needed in normal operation).
==== Outcome ====

So, does it work? __Yes__, the car now starts and runs again. The car drives much more smoothly (but is still not perfect) and will now build boost when accelerating from 2nd to 3rd gear - showing approximately 0.7Bar on the boost gauge; something we had never been able to achieve previously.

The next steps are to revisit the fuelling setup - attach the wideband O2 sensor from AEM again - and recheck the base CO% / fuel trim% of the ECU, and adjust the idle screw. We don't have a working ISCV control (since the aftermarket parts are junk and don't work), so setting the idle is a compromise to get a stable idle whilst cold, vs not too high when warm.