theorie

iTrader: (31)

I was using a Tyco 12v 20/30A relay (part number V23234-A1001-X036)

Had to ghetto-rig my fuel pump power to move the car...then just left it disconnected after I shut the car off. I just ordered a new Bosch relay from eBay, so just waiting for that to come...

Is it normal for these relays to fry themselves? I've only had this one for about 6 months.

I did have some alternator issues in the recent-past - at one point it was charging 16v and fried my headlight bulbs. Perhaps the damage was done then but the relay just finally **** the bed?

arghx

iTrader: (3)

looks like a short to me

theorie

iTrader: (31)

yeah i thought it might have been a short, but i dont see how it could have shorted...

i had everything connected up really nice with no exposed wires... maybe the shielding on one of the wires melted off and then it shorted?

i have noticed that the relay gets really hot. i have it mounted in the passenger's side rear bin, where there's no airflow. perhaps it got too hot?

Speed of light

iTrader: (8)

If you were noticing that the relay was hot then a bad connection or crimp likely caused the heating. (i.e., too much resistance; it is possible that the relay had an issue.) Replace it and check for heating, it should only be warm, NOT HOT.

arghx

iTrader: (3)

one thing I will say... the wire you were using on the harness that came with the relay was utterly pitiful. It was maybe 12 or 14 gauge but that is shitty 12 gauge wiring. It's much more insulation than copper. It looks like it has as much copper as good 18 gauge. I have a friend who installed car audio professionally. He has demonstrated to me many times that not all "x gauge" wire is created equally. You could have simply overheated the wire on there because there just isn't enough copper, and that in turn burned out the relay. Better the wire than the pump though IMO.

I would run good quality 10 gauge wire and use spade connectors that are designed for 10 gauge.

gracer7-rx7

iTrader: (16)

Got an online source or recommendation for us that can't tell good from bad?

Speed of light

iTrader: (8)

Now that I look at it, that wire is rather small. Wire gauge (AWG) sizes are supposed to be rated by the cross-sectional area of the conductor and are designed for acceptable heating and loss. #10 is good for 30amps, #12 for 20A, #14 for 15A, #16awg for 10amp circuits, etc.. You can always use a larger conductor, but should not use a smaller one or excessive heating and voltage loss will occur.

The approximate diameter of Common wire sizes are as follows: (this is for the copper conductor portion only) These are typical ratings for continuous operation at 60 deg C..

#4 = 5.19mm/.204" (70 amps)
#6 = 4.12mm/.162" (55 amps)
#8 = 3.26mm/.129" (40 amps)
#10 = 2.59mm/.102" (30 amps)
#12 = 2.05mm/.081" (20 amps)
#14 = 1.63mm/.064" (15 amps)
#16 = 1.29mm/.051" (10 amps)
#18 = 1.02mm/.040" (~8 amps)
#20 = 0.81mm/.032" (~4 amps)

If in doubt about your wire size, measure the diameter of the copper portion of the wire and compare to above table! (Note that larger wires such as the #4 are often used to carry substantially higher loads, e.g., starters, where the draw is typically for a short period of time.)

arghx

iTrader: (3)

It's basically installer lore that I am referring to, I don't know of any guides off hand. I remember him showing me Phoenix Gold (good stuff) and then Tsunami (I think he said that was ok) and then Raptor. I think that's what he showed me anyway, it's been a while. All of them were supposed to be 10 gauge, audio-grade wire, but I think it was the raptor that was just a bunch of shitty insulation with a few strands of coppor on the inside in comparison to the others. The raptor in comparison to the phoenix gold was like night and day... he sold me a Phoenix Gold amp wiring kit at manager discount and I used that to wire up my fuel pump.

I know there are "standards" for wire but from what I have seen, you can't always trust the advertised wire gauge. Following that table ^ might work, I'm not sure.

dguy

iTrader: (8)

If you're looking to build a bullet proof wiring system use Tefzel milspec wire.

theorie

iTrader: (31)

alright so i went to home depot tonight and picked up some female spade connectors that were rated for 10g:



the power wires that i ran to/from the fuel pump were 10g copper stranded which were purchased from a car stereo shop, and it seems to be good wire.

i think you guys are right that the harness was at fault here. i believe the harness used only 16g wiring (and it was a cheapo made in china harness.

i'm going to re-wire everything using the spade connectors and only the 10g wire. perhaps the relay is fine and it was just the wiring, but i'm still going to swap the current relay for the bosch relay when it gets here.

let this be a lesson to those rewiring their fuel pumps - don't use the $%*(#& harness that comes with the relay! hard wire it with female spades that are rated to the right amperage (sp?).

cheers
tom

IRPerformance

iTrader: (41)

Get a 40 amp relay. Better to overbuild this one. Also make sure the wires on the connector are at least 10 gauge.

theorie

iTrader: (31)

yeah the one i ordered says, "HD SPDT 30/40 Amp 12VDC Automotive Relay with Harness" and my wiring is all 10g so i think i should be good once i get it all hooked up again.

theorie

iTrader: (31)

ok so today on my lunch break i went out to re-wire every thing...

here's how it came out:



however, when i reconnected the battery and went to start the car, i had no fuel pressure (meaning the pump is not getting power)...

i'm sure i hooked it up correctly...

here is how i have it wired: (the same way it was connected before, this time without the shitty harness...)



maybe the relay is dead? hopefully the new one comes soon...

Uncle Hungry

iTrader: (2)

Hey Tom, when you melted your relay did you pop the fuse? Also if you ran the lines out of fuel when it died, it takes a while to fill them back up. I usually just jump the pump in the diag box.

theorie

iTrader: (31)

well the inline fuse that i added (between the battery & the new relay) was not popped...

could it have popped the fuse under the hood? i'll have to check when i get home from work.

theorie

iTrader: (31)

ok so all the fuses are fine. i checked all the wiring between the pump and the battery and that's fine as well.

apparently it is the relay - 100% dead.

i just happened to have this 12v illuminated rocker switch rated to 30a, so i'm going to use that as a manual on/off for my fuel pump until the new relay comes.

check it out in action.

turned off:


turned on:


it's only so i can move my car around on the street since the street sweep comes every on opposite sides of the street.

as soon as the new relay comes i'll swap it out.

theorie

iTrader: (31)

little update...

the new relay came today. i hooked it up and.........no fuel pressure.

turns out it's the factory fuel pump relay that has fried - the one under the hood. (at least, that's what i'm assuming now...)

no matter...i bypassed it: i remembered that the cig lighter only turns on when the key is clicked forward into the "run" position (second click forward), so i tapped into that. i don't use the cig lighter because i have a mount stuck into it for my pfc commander, so i think it will be fine as a power source for my relay.

the fuel pump is still getting direct power from the battery via 10 gauge power cable; that's the important thing.

here is how i have it wired now:


everything works great now. thoughts?

Uncle Hungry

iTrader: (2)

I'd imagine since your only using the factory pump power as a signal that you wouldn't need a relay there anyway.

theorie

iTrader: (31)

yeah that's what i figured too. the power source for turning on/off the relay doesn't need to be a heavy duty line - just enough to turn activate the relay (similar to how you only need a very small power line when hooking up an amp for a stereo system).

evilg

I could be wrong here, but the way I understand it is that the factory FP feed (The one you had wired to 86 in your first diagram) undervolts up until a certain RPM point, in order to preserve the fuel pump. Past that point it gives the pump the full 12 volts.

I can't remember the exact figure but I think it was 8-9 volts.

Your new relay that you purchased (having slightly beefier contacts) probably needs the full 12 volts in order to operate its coil.

The way you have wired it is okay, however the Cigarette lighter will operate when your keyswitch is in the "ACC" position. (Standard fuel pump operates in the "ON" keyswitch position) So your fuel pump will be operating then too, which whilst isn't ideal, shouldn't be a cause for concern.

There are a couple of solutions I can think of to get this wired in the correct manner.... you could remove your factory fuel pump relay, and bridge the coil feed side of that, to the wire that heads into the rear of the car. That would be my solution anyhow.

theorie

iTrader: (31)

yep, you were right: the cig lighter gets power when you turn the key to the first position.

can anyone suggest a better (constant) 12v that comes on only with the second key position (run)?

here's a pic of how i have it wired up now. i'm still using the switch, but now it's on the 12v line coming from the cig lighter. i figure i'll keep it in there for safety and security...



also, here is my current wiring configuration...


cheers.

Uncle Hungry

iTrader: (2)

You can still use the factory fuel pump relay. All you need to do is jump the fuel pump speed relay, or jump the fuel pump resistor. Walla, constant 12v. If you take power from somewhere that only switches on in the run position , your pump won't prime. Hope that helps Tom

theorie

iTrader: (31)

ok good you can show me where that is tomorrow

Uncle Hungry

iTrader: (2)

No doubt

FD3S2005

iTrader: (11)

Wait, what's the power from the cig lighter for if your getting it from the battery?