[s-cars] Additional Fuel Pump Relay Installation Results

[Dave Forgie]

S-gruppees:  Two heads are better than one.  Sean Douglas and I have just
proven that.  Sean has just implemented the fuel pump relay idea we hatched
last night. Its amazing what you can do with a nice garage and lots of  tools
when your family is away!!  Anyway, here are Sean's results.  I think we need
to give Sean a round of applause.

Sean Douglas wrote:

> Dave:
>
> My test results are attached, the relayed fuel pump does produce more
> pressure and I would expect it to be even more with the car running with
> 13.4 V. [Note: Sean had attached an Excel spreadsheet with the simulated
> static boost pressures at the non-relayed and relayed voltages of 11.75 V
> and 12.4 V (engine off) - example results: 20 psig "boost" (via an air
> compressure connected to the FPR) - should be 78 psig, at 11.75 V it was 72
> psig; at the relayed battery voltage of 12.4 V it was 75.  At 28 psig boost,
> the target was 86 psig with 80 psig at 11.75 V and 83 at 12.4]
>
> I hooked up the relay temporarily and went for a test drive. I did
> several 2nd gear pulls at WOT. The first one, I actually detected a very
> slight ping, but much less than before. On the next 2nd gear pulls I did
> detect a ping, but even less, almost imperceptible, it could have been
> nothing, and my ears may be playing tricks on me. I did 3 more in 2nd
> gear up to 3rd and nothing! On the 99 freeway, I did 3rd and 4th gear
> pulls, redline in 3rd, but not 4th, but I did see 1.8 bar (about 26 psig)
> [On his new 2 5/8" Greddy backlit boost gauge]  on all occasions and no
> pinging! At high speed it works better to have the windows closed otherwise
> the wind noise drowns out any pinging. This is contrast to when I came over
> to your house up the Alex Fraser hill in
> 4th gear when I was "racing" that Infiniti M45 and it was really
> pinging.[Note: Sean is very responsible and would never race anybody - he
> would, however, pass them at any speed]
>
> I came back home and tidied up the wires and put new ring terminals on
> it. I used the "American" plastic loom and heat shrink on all
> connections. I managed to feed the new loom into the rubber grommet next
> to the existing wires, so it looks neat and tidy.
>
> So it looks like the relayed fuel pump has solved 99% of the pinging.
> I'll keep and eye (ear) on it over the next few days and keep you
> informed. Maybe the ECU will adapt to the "new" fuel pressure/volume and
> it will be gone for good (fingers crossed).
>
> You can let the list know of my results.
>
> Sean

***************

CONGRATULATIONS SEAN!!  I THINK YOU HAVE PROVEN THAT OUR PINGING ISSUE WAS NOT
SOFTWARE RELATED BUT HARDWARE - FUEL PUMP PROBLEM.  NOW YOU'RE GOING TO NEED
NEW BRAKES AND SAMCO'S IN A HURRY.

Now I have to relay mine and catch up to you.  We should do a write up with
photos for the rest of the group.  They may want to see photos of your
pressure testing apparatus as well.

Dave F.