ditch your air meter contact and FP round relays

[boosted79]

Figured I'd make a separate post for this from my build thread for those who are interested. There seems to be so much trouble with the FP circuit, this gets rid of all the nonsense. Note the FP's will run as long as the ignition is on with this setup, you can install a toggle switch in the FP relay coil supply to shut them off with the key on for troubleshooting,etc. EDIT - this is for a '79, the later years have that speed relay which complicates matters.

No more air meter contact or silly round relays in the pumps circuit.

Ford Taurus inertia switch between 30 and 87a of the air meter relay socket opens the ground side of the pump relay coils. 86 is jumpered to 85 to supply switched 12v to the air meter switch plug which I used to supply power to the Pierburg valve. The ground side of the Pierburg is switched open by the rpm switch.






Two 40A Hellas up front

[T77911S]

I will keep mine.
go thru the solder joints on the yellow relay and speed relay and you are good to go.
unless you soldered those crimps I think you are asking for problems.
just my opinion.
I also like to keep mine looking factory.
I split the 2 relays over to 2 fuses instead of one., if you look at it, you cant tell.

I use to do auto electric work, saw a lot of problems with those crimps.
I buy the bare metal crimps. I crimp then solder then heat shrink.

did you leave the over boost cut out and speed relay for the rev limiter?

[boosted79]

No speed relay on a '79, overboost switch is still there. Use a good crimper, no worries. The pins for the relay sockets are tinned #8 AWG solid soldered to the wires. I forgot about stock along time ago...

[Rawknees'Turbo]

No need to solder crimps that are done properly and there is zero benefit to doing so.


Man, boosted, that looks like some really good, creative thinking on your part - very nice. Question - so do you still have overboost protection with this setup? I see that you said the overboost switch is still there, but how does it work without the relay functioning?

[boosted79]

Rawknee - the overboost is just a pressure switch that opens to interrupt the ground side of the FP relay coils.

[Rawknees'Turbo]

Yep, I understand how the switch works, butt on my 1987, I don't think it functions without the yellow relay in the loop. I need to scope this out more, as I am really disgusted by the convoluted fuel pump/overboost circuit on these cars and would like to follow your lead on modifying it once and for all. And like you, I couldn't give two sharts about it looking stock or not, either.

[1979-930]

Nice upgrade.

Between the fuel pump and the other fuse panel and relay up-grades needed I have thought about converting a power distribution from a later model car into the Porsche.
I did that with my 70 Bronco when I put the 92 Mustang 5.0 in it back in 94. I used a Explorer Power distribution center with plenty of relays and fuses for the EFI conversion and all my accessories. The switches in the cab all became ground triggers for the relays.

[boosted79]

I looked at the '87 schematic, wow, they sure figured out how to complicate it. The boost switch is tied into that speed relay on that year. 1979-930, yeah, you can get a lot of good stuff at a pick-n-pull.

[flightlead404]

Originally Posted by T77911S

I will keep mine.
go thru the solder joints on the yellow relay and speed relay and you are good to go.
unless you soldered those crimps I think you are asking for problems.
just my opinion.
I also like to keep mine looking factory.
I split the 2 relays over to 2 fuses instead of one., if you look at it, you cant tell.

I use to do auto electric work, saw a lot of problems with those crimps.
I buy the bare metal crimps. I crimp then solder then heat shrink.

did you leave the over boost cut out and speed relay for the rev limiter?

Properly done crimps with good connectors are superior to a solder joint. Those don't look like good connectors. Get the ones that have an interior aluminium barrel that goes all the way under the insulation, and use a crimper that crimps twice, once on the bare wire and once at a different depth to crimp the barrel over the insulation for support.

I put about a 5lb tug on them to test.

[Rawknees'Turbo]

Originally Posted by flightlead404

I put about a 5lb tug on . . . to test.

???

!!!

[S1000RR]

I still use the front red relays and the over boost switch, but eliminated the yellow relay/air flow switch.

[flightlead404]

Originally Posted by Rawknees'Turbo

???

!!!

dammit! lol how'd I let that go?