Dedicated fuel pump circuit.

[DeLorean03]

Here is a brief mention of the new pump/sender current for reference: http://dmctalk.org/showthread.php?38...%2FSENDER+AMPS It seems comparable to a stock pump.


Jeff

Excellent - thank you! I am running John's 957 pump, which I read somewhere on here pulls 10A or so. It is nice to know my current may actually go down a lil' bit with the upcoming pump/sender combo!

[DeLorean03]

So I wrapped up this project/mod tonight. Took the car out for a good drive - all seems well and sound! Here's the remaining photos showcasing the steps.


100_5448.jpg

Here is the RPM relay - nothing special. Just was photo-documenting the configuration of the wires. Wouldn't want to put these on the wrong way o_O.

100_5455.jpg

Here is the RPM relay with the new wires installed. Due to the insulation of the newly crimped wires, there was no way the spades of the RPM would reach the unaltered terminals left in the female socket. The only choice I could make really was to remove the female connector. I have wrapped the connectors in about 5-7 strands of electrical tape, and I plan to put velcro on the RPM relay body and the electrical compartment to keep it from "wondering around."

100_5456.jpg

These are the new 12 gauge wires that will go directly to the fuel pump's terminals. Yes, lots of excess wire; it was trimmed accordingly with a "little play" in it for safety purposes.

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Here is where I put the ground for the fuel pump; this is the inner-most bolt of the horn bracket on the driver's side. It is a 13mm bolt with a washer on it. I utilized this bolt under the advice of Dave Swingle and Casey Barlow. The yellow is the insulation of the ring connector I used to establish a ground at this bolt.

Ground wire.jpg

This is a picture of the ground wire. It goes behind the driver's side radiator bracket, away from the coolant pipe and past the master cylinder. It does have a little play in it just to be safe. These kinds of things I never want to have "just enough" wire.

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This is a picture of the new wires installed, ready to go! Of course, the old terminals were individually wrapped in electrical tape about 14 times as well as the old terminals at the RPM relay (old brown and purple/white wires)

100_5463.jpg

You would never know (: ....

Remember, I also installed a wire with a fuse extender housing a 20A fuse directly from the battery to terminal 30 of the RPM relay. This is - in essence - a fuse I'm adding to the system which I cordially call "Fuse #7A" . Now, the fuel pump has its own circuit - no more stressing out fuse #7 - it is now responsible for the FV and lambda ECU only.

I took the car for about a 1 hour drive - basically errand running. Everything went smoothly - so far - no issues! Due to my trouble-shooting, I did uninstall Bitsync's SS RPM relay temporarily. Once I am satisfied with my results (more driving), it will be re-installed as his SS relay is far superior to the analog RPM relay and probably gives off WAY less heat.

So, there you go, gang. Nothing extremely fancy - just added a new fuse, upgraded the 16 gauge wire to 12 gauge, and took some stress off fuse #7. Anyone who wants to do this as well, please, go for it. I will be driving my car down to Ken Koncelik's for the winter for storage, and I'll check fuse #7 to see how hot or cool it is with this mod.

If anyone wants to do this as well and has questions, please feel more than welcome to contact me. I will be glad and happy to answer any questions regarding this mod.

Mods, if you feel this is worthy of a "resource" to help de-stress fuse #7, please feel free to move it to the appropriate "resources" or "how-to" file!

Thank you Bitsync, Dave Swingle, Toby Peterson, and Casey Barlow for your time, help, and attention. I definitely appreciate all who helped me with this mod!

And thank you Ron, for providing me the amperage/length of wire chart - that definitely helped persuade me to use 12 gauge .

I can measure the wire I have left of both red and black to give everyone an idea of how much wire I used for this mod. Take care everyone!

And to cover my butt - if you choose to do this too - you DO SO AT YOUR OWN RISK. I'm not responsible for anything that happens to you or your car as a result of following my instructions.

[Bitsyncmaster]

Good work. I don't think our OEM wires are ever 16 AWG. It's more like 18, 14 and 12 AWG. Europe wire standards are based on strand count but I have done measurements and calculations to convert to AWG.

Glad your testing without the SS relay. I've stopped selling the starter relay because when people have installed a new starter they have blown them (bad starters).

The test of your wiring is to measure the voltage over the two terminals of the fuel pump when the engine is running. Then compare that voltage with the voltage you read at the engine "jump" terminal. That difference is the voltage drops of the wiring and connectors.

[Chris4099]

One suggestion. Have you thought about grounding your RPM relay through the inertia switch? That way you restore a critical safety feature but don't have much of a load going through that switch as well. Basically if you are in an accident, the inertia switch trips and kills ground to the RPM relay. The relay should then shutoff and kill power to the pump.

I don't have my schematic in front of me, but you might even be able to utilize the old fuel pump wiring. Connect the two old pump leads together so now the wire running back to the RPM relay is grounded via the inertia switch. Reconnect the wire to the RPM relay but on the ground terminal instead. This is assuming nothing else is connected to the pump power lead which I can't verify at this moment.

[Bitsyncmaster]

One suggestion. Have you thought about grounding your RPM relay through the inertia switch? That way you restore a critical safety feature but don't have much of a load going through that switch as well. Basically if you are in an accident, the inertia switch trips and kills ground to the RPM relay. The relay should then shutoff and kill power to the pump.

I don't have my schematic in front of me, but you might even be able to utilize the old fuel pump wiring. Connect the two old pump leads together so now the wire running back to the RPM relay is grounded via the inertia switch. Reconnect the wire to the RPM relay but on the ground terminal instead. This is assuming nothing else is connected to the pump power lead which I can't verify at this moment.

I've thought of the same thing. You would probably need to have a pullup on the RPM relay ground pin so the ground pin would not float if the inertia switch opened. I would try a 1 meg ohm pull up from the RPM power pin to the ground pin. If that works it would only have about a 100 ua. drain on the battery. I would have tried this but then you need to run a wire back to the relay or move the inertia switch to the relay compartment.

Another option is the switch can turn of the key on signal into the RPM relay.

[nkemp]

This all started when I was having some random intermittent lack of power issues while driving around Dayton. From time to time - completely and totally randomly - my car if going from 0-15MPH, would just randomly stall. If I was going say - 20mph and over - the car would buck - almost as if it was about to die, but the car would hang on and I could keep going. It started in September 2012, went away for all of Oct and Nov 2012, and then decided to resurface in Dec 2012. I tracked down nearly anything I could - lambda relay, rpm relay, air/fuel mixture - finally it came down to the connectors to the fuel pump and terminal 87 of the RPM relay.

Resurrecting an old thread but I had similar problems as described above. Some times the car would die and I'd roll of to the side of the rode and would get a flatbed ride back home. Then it would start the next day as if nothing had happened. I replaced the inertia switch with a Ford Mustang inertia switch and now I have no more bucking and stalling (knock on stainless). I went with the Mustang part since I will only give the original parts so many tries before switching.

YMMV,
Nick

[DeLorean03]

Good stuff, Nick. My inertia switch had been completely bypassed by the DPO (dreaded previous owner), so that's how I knew it was "one or the other". Just about drove me nuts.