Fuel Pump Relay

[tissimo]

Anyone know what the fuel pump relay is rated at? I need a 2 way relay like the fuel pump relay to get my fans to run 1/2 speed, and dont need my fuel pump relay anymore (wired a spereate relay for it) but not sure it would handle the load of a electric fan (Fal 220s or whatever)

 

[CRE]

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&Page=115

These may be of further help:
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&Page=111
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&Page=114

 

[tissimo]

thanks, but looking to know if anyone knows if the relay would handle 30 amps from a fan? whats the fuelpump (I doubt 30 amps)

Heres my schematic

 

[CRE]

Oh, sorry, I thought you were looking for the impedence. Also keep in mind that the amount of voltage the fan sees after the resistor pack is going to depend on *actual* current draw.

 

[jetjock]

Learning about electricity are we? Don't get me wrong. I commend your efforts, it's more than most people are willing to do.

I'll let you guys figure out the apparent errors in the schematic but to answer the question a stock fuel pump pulls 4 to 6 amps. If you want to know for sure just use a meter in place of the jumper in the diag block. If you've rewired it you'll have to go inline some other way or use a current probe.

tissimo: It's called a Form 1C relay but most people refer to it as SPDT (single pole double throw).

CRE: There can be no impedance in a DC circuit.

 

[bigaaron]

The fuel pump relay is not sufficient for fans, it's probably good for about 10 amps.

 

[tissimo]

Learning about electricity are we? Don't get me wrong. I commend your efforts, it's more than most people are willing to do.

I'll let you guys figure out the apparent errors in the schematic but to answer the question a stock fuel pump pulls 4 to 6 amps. If you want to know for sure just use a meter in place of the jumper in the diag block. If you've rewired it you'll have to go inline some other way or use a current probe.

tissimo: It's called a Form 1C relay but most people refer to it as SPDT (single pole double throw).

CRE: There can be no impedance in a DC circuit.

I just whipped that up in ms paint in a couple minutes, but what are the errors I'm curious..

I didn't think the fuel pump relay was up to the task, I'll look around and find one..

 

[bigaaron]

Bosch relays are pretty good, use one per fan like your diagram shows.

 

[jetjock]

Hey, at least he's making an effort. It's not all that bad and may even work. He just didn't supply enough info. That's why I said "apparent" errors. Tissimo, what ECU is that and what pins are you using? Why are you using the HPS of the A/C and why is it connected to the ECU? I don't recall that as being normal on the stock TCCS. It's not a very elegant way to do things either and it needs over current protection to boot. I assume you know the fans are in series because you want them that way.

Ampacities of Toyota relays are marked on the case but the fuel pump relay is a special animal. It's not a true Form 1C and needs to be wired corectly but yeah, it won't handle 30 amps. At least not for long. Even if the contacts could a quick look at the pigtail shows it can't. I'd get me some standard Bosch like Aaron said if I was gonna do this but then again I'd rather have control of fan speed over the entire range or even feedback control based on temp. Not hard to do. I've done it on my other car and two others like it.

 

[tissimo]

I want to run in series to run at 1/2 speed..

The two pins on the ecu are to be determined, but I have an aem ecu and they will be ground switches (programable at the ecu) I have the Pressure switch (I dont remember if it grounds when it closes or if there are 2 wires to it) on there so with the AC pressure is high itll turn the fans to full speed.. or when temp reaches xx (prob 195-200*f, controlled by the ecu)

And of course there will be fuses.. Each positive for the fan will be ran seperate with a 40 amp fuse.. again the drawing was a quickie while im bored at work..

I figured I might be able to get away with using what I have instead of finding another relay and I had the fuel pump relay sitting here, so thought I would ask..

edit: and I realize that the wiring on the 2nd fan relay shouldn't come after the 1st fan relay.. just a quick drawing again..

 

[CRE]

CRE: There can be no impedance in a DC circuit.

ROFL.... I can't believe I wrote that.... my uncle would kick my ass. I do know better. I thought he was looking for the resistance not the dissipation it was capable of. :3d_frown:

Never claimed to be a pro... I know just enough to get myself in trouble and usually back out.

As for this application wouldn't a voltage regulator be a better bet? They're simple, can handle the current (depending on how they're built), and can be made inexpensively (again depending on how they're built). Otherwise consider using two resistors setup as a potential divider. (Is that more accurate JJ? :icon_bigg )

 

[jetjock]

Yeah, I figured you put them in series for speed. I'm not a fan of series strings but as long as you're aware of the lose one lose all it's no big deal. I thought you might be using the stock ECU and the original FP output for control and tied the HPS in by mistake. My bad. You're good to go but there are nice fan controllers out there for not much more than a handful of relays will cost you.

CRE: No problem. Divider networks are old school plus you have to dissipate the losses. Current regulation would be better. Better still would be some thyristor action. An SCR for example, it'd make for infinite control