Inside of the fuel pump relay - pictures

JoeFromPA · 16th June 2012, 20:34

Hi all,

At Sailor24's request, I've taken apart my old fuel pump relay. Here are pictures:

I have no comments aside from that I couldn't see how it disassembled so I simply dremel'd one side lightly - it came loose and pulled right out.

Hope this helps in a variety of ways I can't even begin to imagine

Joe

bibledriver · 16th June 2012, 23:11

When I took mine apart, I just put two screwdrivers up the sides that seemed like you could see a clip, and then pried the bottom downward. It came out easily and I reassembled it. you would never know it was apart.

Here's my pics for what its worth

Sailor24 · 16th June 2012, 23:30

Can we get another shot of the back so that the numbers can be read off the other two processors. Just as a note we only use a very small part of this. It was designed for the Z3 that seems to use all of it. So this device can do some very cool things problem is no published wiring diagrams.

bibledriver · 17th June 2012, 00:24

Changed that last photo

It is interesting, as I've done plenty of wathing fuel pump voltages. In mine what I've seen is that both throttle and Revs have an effect on the voltage to the pump. I just watched to jigure out when it was changing and on revs alone, IIRC it was at 12.5 above 3k, as i decellerated through 3k it started dropping the voltage to the pump until at 2500 it was at 10.2.

BUT, if you are at 1500, it will be sitting low voltage and if you put throttle in, while still low on revs, it will increase the voltage too.

I wonder what the circuits that don't get used do?

bibledriver · 17th June 2012, 01:52

Here's a video to clean up where my memory was a bit fuzzy.

That is the result of this nifty "relay"

ger · 18th June 2012, 02:28

Great pictures, I was wondering what the insides looked like as it's quite expensive compared to a standard relay.
Does anyone have an idea what it can do?

Does it monitor current/power and adjust it's output (voltage and current) accordingly?

bibledriver · 18th June 2012, 05:00

Well, if you're at work, your firewall may be blocking it, but the video in the above post may answer your question.. What I do know is that the input to the relay/module is a constant feed, and that the output is varied according to throttle position and engine speeds. Don't know if that is really your question though. Maybe some electrical gurus can get a better angle on it.

Sailor24 · 18th June 2012, 05:18

Sorry dude your video does not show much. I have not finished testing so all I will say is it appears to work off of calculated load. Full current should be restored at 18-20 percent.
Bible your hot wire means you are drawing to much current, yours is likely been broken by driving the car. Stop drawing conclusions based on your car it is broken and that is not good logic.Your does not look like mine at all. When the current is reduced on your pump possibly yours will return to normal. Maybe you have another problem with your car.
That said this thing is a stupid piece of junk not a lot of consistency. It may in fact be the cause of this US car jerky throttle thing. I am going to make it activate a standard relay and have that relay operate the pump. Same idea as the euro car.

bibledriver · 18th June 2012, 16:21

We'll see. I'll be checking it all out once all is "normal" as I may have a bad pump

but not long ago, I was using "bad logic" and you were telling me "its just a switch"

So, as sailor said, my pump may be "not right" and there could be some variables. I have a new relay on the way too, and maybe that is the weak link! As I said, I will measure again in the future

But, the voltage applied is definitely shown to vary based throttle and engine speed (seems that pump condition shouldn't matter much if the car is running, the conditions of which the relay controls voltage can be tested). If that changes with a new relay, then I'll definitely see it and post it up. As for all the other details, sailor will certainly enlighten us.

Sailor24 · 18th June 2012, 16:49

It truly is still just a switch. Two position solid state switch. Mine seems to snap to the new current as soon as I hit 20% calculated load. Of coarse it could be other things as calc load is made up from other sensor readings. It might be so simple as just one of those sensors. Mine also appears to have an issue or two but performs quite well because my fuel system is in good shape. When I pinched my fuel line I got some very strange readings, similar to Bibles. That maybe normal may not be. I am not prepared to comment until I have my new alt in as that maybe what I am seeing in current and voltage. So far what I have seen I am unimpressed and don't see a reason for this at all. Mine will be bypassed.