Another e30 electrical problem thread

[e30manny]

would the external fuel pump cut the power from the fuel pump?? or from the fuel pump relay

i do have power in the relay prong but its like it cuts it off to the direction of the fuel pump :hitler:

[e30manny]

So after all that headache it ended up being a simple loose connection on the external fuel pump!! I feel like such a noob. Thanks for everybody's help on the situation.

In the mean time, I think I am going to invest in a new internal/external fuel pump and filter. Probably do the timing belt and spark plugs and all the corresponding maintenance required. I will keep you guys posted on the progress.

would the external fuel pump cut the power from the fuel pump?? or from the fuel pump relay

[e30manny]

i am having the same problem i noticed that the fuel pump wont get power until i remove the fuel pump relay and put a wire direct to make the fuel pump work, but even if i do that its like i am not getting any power in the injectors . I change the two Crankshaft Position Sensor and still noting

[DaveSmed]

Nice, glad to hear you got it sorted!

[white04wrx]

So after all that headache it ended up being a simple loose connection on the external fuel pump!! I feel like such a noob. Thanks for everybody's help on the situation.

In the mean time, I think I am going to invest in a new internal/external fuel pump and filter. Probably do the timing belt and spark plugs and all the corresponding maintenance required. I will keep you guys posted on the progress.

[browntown]

Speaking of which, how old is that fuel filter? Might have some crap trapped inside it. Good time to replace it.

[DaveSmed]

It kind of sucks to get to, but if you jack the car up a bit and look up under the car in front of the drivers side rear tire, you will see your fuel filter. Above that is your fuel pump.

[white04wrx]

from searching around the forums, it seems like the external fuel pump is on the rear driver side wheel well. What do you recommend is the fastest way to getting to that to disconnect it?

[white04wrx]

I have not had time to look over the car today. Hopefully I can find time tomorrow to try that trick that davesmed recommended. I will keep you guys posted on the progress as soon as there is some. hahah

[StereoInstaller1]

update?

[StereoInstaller1]

Start your testing at fuse 11.

No power at fuse 11, head to fuel pump relay.

No power to FPR, head to main relay/DME

If 11 has power, head to the pumps.

Test every bit with a testlight.

Always look for the "central debarking" point...almost always in the fuse box, on virtually every ELECTRICAL issue.

[DaveSmed]

Here's a trick I use to make relay related diagnosis in an E30 easier.

http://r3vlimited.com/board/showpost.php?p=2318700&postcount=2

If you look on the bottom of the relay, you will notice it has an odd layout, and terminal 30 is not where it usually is on relays of that style. That's why that trick works.

Once you do that, the fuel pumps should be running constantly. If the fuse simply pops again, unplug the in-tank pump and disconnect the external pump then feed it a new fuse.

If all is well, reconnect the external (since the internal usually goes first) and if you hear it pumping, try starting the car. It will run with the external pump only (for a little while anyway) Then plug in the internal pump and see what happens.

Here's a diagram for a late model E30, showing the fuse AFTER the relay and main engine connector (C101). The only difference is one pump instead of two. There really is nothing else that can pop that fuse.

And as jlevie mentioned, the relay is only closed when the engine is turning. Use that fuse trick to make life a bit easier and bypass the relay.

[white04wrx]

I forgot to mention in my OP that after I manually tested both the relays, that the car did crank over and start. It idled for about 1~2 seconds before it died again. Ever since the car has been broken, this was the first time there was a glimmer of hope.

It probably started with the left over fuel in the lines or injectors which leads to me that there is a spark present.

[white04wrx]

Wow, I want to thank everybody for their support. One thing about owning a car is not the actual car itself but the community that welcomes you in and their willing to help you out like the problem was on their own personal cars.

Do NOT use a DMM to test fuses, get a testlight...one with an actual lightbulb.

Test fuses installed, as in powered up. Your testlight will show if the circuit has power too.

Testlights are superior to DMMs for testing simple electrical circuits like these, as a DMM can read "ghost voltage" and make you believe all is OK, while a testlight requires just a bit of current. Trust me on this!

Electrical issues = test light

Electronic issues = DMM

So your recommendation is to purchase a test light and hook it up to the power supply that feeds into the fuel pump instead of using a multimeter? Let me see if I can get my hands on one and crank the car over to see if the light comes on at all.

But from the symptoms so far, I don't think that there is any power going into the fuel pump since the engine is not getting any fuel and even though you don't recommend using one, the multimeter gave a 0 reading.

The ground point is on the left side of the car over by where the bottom of the LR passenger's seatbelt is mounted. It will be a cluster of brown wires.

Is the fuse blowing immediately when you try to start the car?

Thanks, I just double check the ground point in the back seat on the drivers side and it seems to be fine. No rust or any signs of being loose.

You may be barking up the wrong tree. As DaveSmed said earlier, the pump is only powered up when the DME sees timing data from a rotating engine. So you have to check for power to the pump while cranking the engine.

Is there spark when cranking?

Let me try hooking the multimeter to the power supply of the fuel pump while cranking the car over soon. If it still reads a zero reading, I might go ahead and try to get my hands on a testlight as Stereoinstaller recommended.

[DaveSmed]

The ground point is on the left side of the car over by where the bottom of the LR passenger's seatbelt is mounted. It will be a cluster of brown wires.

Is the fuse blowing immediately when you try to start the car?