satch

iTrader: (1)

At the bottom of "your" pic is a green plug. Well right behind it is the plug I speak of for it is covered with a rubber boot and the actual plug is yellow and there are only two terminals to the plug and it is shaped in the form of the letter "T"

EDIT: ""Then tested the blue wire that is one of four(?) that connects the fuel pump to the harness (on the speaker tower). Was this right? I got a reading 2.92 jumped and 2.94 not jumped (which makes me think I jumped the wrong connectors.""

When you say one of four I'm assuming you're saying that of the four wires only one of them is "blue." Is this correct.

HAILERS

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satch

iTrader: (1)

^ Now find his variable resistor but don't go blind looking for it!

MastrChase

LOL, thanks Hailers. Got it. And yeah satch, thats what I meant about the blue wire. (My variable what?)

2.59 jumped. 2.69 not jumped. Good? Bad?

satch

iTrader: (1)

If you look back at the pic you provided to show the plug you jumpered, well just to the right there is a triangular piece of metal with a hole in it towards the end of it. This is where the variable resistor should be and it allows you to control the fuel mixture, rich versus lean, when the car is "idling." It is used to set the idle speed on S4's.

satch

iTrader: (1)

So you jumpered the yellow plug that Hailers, I, Hailers provided and your blue wire which leads to your fuel pump measures out at 2.69 volts? The reading should be at or close to 12 volts.

EDIT: was the reading done with the key to "ON."

MastrChase

Er.. I assume even NA S4s have these? Well, like I've said before, my car ran great as a DD before, so unless one of my friends took it off for some reason when we were doing the swap... its never been there(?). Which really makes no sense. Could you provide of pic of the variable resistor? Thanks. I can look around for it, but I'm not sure why it wouldn't be there.

Yeah the reading was done at ON both times.

So I need a fuel pump resistor relay right? (Or rewire to bypass it?) And I'm assuming a variable resistor too?

I like finding things that are wrong/that I'm missing b/c we could be getting close to figuring out why its not running!

satch

iTrader: (1)

An NA uses just the circuit opening relay to control the fuel pump. On your turbo it uses the relay aforementioned, and the fuel pump relay resistor which is somewhere in hiding. Now the voltage reading you got is very low and I'm not sure if three volts is enough to run your pump which might very well explain why your car is not starting. Next thing up on the agenda would be to locate the circuit opening relay under the dash right near the steering wheel column and it houses 5 wires and is very small and I think the color of the relay is yellow perhaps but the color of the 5 wires are as follows; Blue, Black, Brown, and two Black with White stripes. Black is ground (constant), Brown is also a ground provided by the AFM but is not constant, Blue sends 12 volts to the pump which is the wire you checked, and the B/W wires provide power to the two coils located inside the relay. You need to focus on the Blue wire and probe it to check the voltage as it comes out of the relay and it should be 12 volts with the key to on.. Also check the voltage of the "large B/W wire" as one is larger in gauge as compared to the other B/W wire in the relay. Check this larger B/W wire with the key on as well and it should read 12 volts also.

MastrChase

Okay. I think I found what you were talking about. However the blue wire ("top" right, has two blue wires) had 0.02 vdc's at ON and the black and white wire(center) had ~11.56. I was using the black and red wire("top" left) as ground. I'm guessing this is bad, lol. (Which is good!)

The pic is of the connector I was testing. The blue wire is also what I'd wire a fuel cut off switch to right?

MastrChase

I thought the fuel pump didn't come on until you tried to start it. Though I'm guessing it should still show vdc's?

satch

iTrader: (1)

On some cars instead of two B/W wires there are one B/W wire and the B/R wire ( usually found on cars with auto transmission or ABS) but both have 12 volts to them so using the B/R as a ground is incorrect. Below the B/R wire should be a Black wire and this is your ground but it appears in the pic that there are two of these wires, is this correct? Also, can you tell where both of the blue wires run off to? With your voltmeter place the red lead on the B/W wire and the black lead to a "known" ground. On each "side" of the console at the very "bottom" where the ash tray is there is a plastic panel that has a screw. Remove this panel and push away the carpeting a bit and you will find where the console bolts to the body of the car. This bolt you will find is an excellent ground source to use. Try using this as the ground when measuring voltage from the B/W wire and also when measuring the voltage from the blue wire(s). Both the blue and B/W wires should have 12 volts with the key to on. After getting these two readings take the readings again using the black wire underneath the Black/Red wire and see if this wire is properly connected to ground.

MastrChase

Yeah there are two wires below the B/R wire. Two grounds? I'll test it again. Thanks.

satch

iTrader: (1)

Remove the jumper wire which you did at the yellow plug in the engine bay when you do these measurements. Is there or did you rig up a fuel cutoff switch?

MastrChase

Retested: reading were the same. Blue wires at ON were 0.01 and the B/W wire was ~11.50ish The jumper wires hasn't been there. No fuel cut off switch yet. My 7's stick and a "sport" model, which I don't think has ABS. But it doesn't really matter. Thanks for the bolt suggestion!

satch

iTrader: (1)

The blue wire is supposed to be carrying voltage to your fuel pump and if your voltage reading is correct then your pump is not receiving voltage therefore cannot run! Your blue wire "HAS TO HAVE VOLTAGE!!!!!!!!!!!!!" Now if the blue wire does not have voltage where you are testing it then how you got a small voltage reading in the back by the pump yesterday is confusing to say the least. As far as the blue wires in the plug up front that you are testing are they combined into "one" terminal or "two" separate ones?

satch

iTrader: (1)

The only reason that makes sense to me why there are two blue wires and two grounds is there was at one time a fuel cut switch rigged up at some time. Anyway, take a real long section of wire and connect one end of it to the positive terminal of your battery and connect the other end of it to the rear of the car where the blue wire mates with the harness coming from the fuel pump. Remember where you took a voltage reading yesterday in the rear where the pump is where you found the blue wire underneath the rear hatch carpeting. Just take the end of the long wire that is not connected to the battery (+) and snuggly stick it into the place where the blue wire resides in the plug. Then try to start the car. This will bypass the circuit opening relay and if the car starts let it run for a while and don't shut it off immediately. Good luck!

MastrChase

If the pumps not running, how can I be smell fuel so strongly. I'll double check that I did it right. OK!

satch

iTrader: (1)

Also check if the B/R wire has voltage with the key to on as well.

EDIT: What you could do as well is to take the jumper wire you have and place one end in the B/W wire and the other end in the Blue (l) wires and this will take the voltage that you are getting from the B/W wire and pass it on to the Blue wire. Then go to the rear hatch and pull the carpeting up and test the voltage at the blue wire. And what ground source are you using back there?

satch

iTrader: (1)

When you test for voltage of the B/R wire in the circuit opening relay it should be done with the key to "START" and not "on" as mentioned previously. With the key to start the voltage should be around 9 to 12 volts or so. The voltage reading should be similar to the reading you got when you tested pin 3B some time back, for this wire should be coming from that same pin.

MastrChase

Oh okay. I'll have to test it all in a few hours. My friend and I are replacing a wheel barring on my wifes car and the battery on my 7 is super low.

satch

iTrader: (1)

When conducting some of these tests you could have your car battery jumpered by another car battery if need be to provide the proper battery power to conduct these tests just in case your battery was low to begin with.

MastrChase

Yeah I usually do. I thought there was enough in there.

satch

iTrader: (1)

Getting back to testing the relay, check for voltage of the B/R wire with key to "start" so to do that just use the bolt for the center console (pointed out earlier) as your ground, and the red lead from the voltmeter to the B/R wire and you should see close to battery voltage.

Also use the jumper wire you have and put one end in the B/W cubby hole and the other end in the Blue terminal and with the key to "on" check for voltage at the relay coming from the blue wire and also in the rear hatch area at the same blue wire.

Edit: when checking the blue wire for voltage at the relay itself after the jumper is in place and key to on make sure that your red lead of the voltmeter "is not" coming into contact with the jumper wire but just the blue wire itself if possible.

MastrChase

Thanks satch, will do. It'll have to be late tonight, b/c our second car has run off with my wife. I didn't have a chance to charge my battery any. ^_^

wvumtnbkr

I just wanted to clarify something.

YOU HAVE TO HAVE A JUMPER WIRE IN THE YELLOW TEST CONNECTOR WHILE CHECKING FOR VOLTAGE ON THE BLUE WIRE.

I know satch and HAILERS mentined it, but I am not confident that BravePotato caught this.

If I remember correctly, the pump should only run for a few seconds while the key is in the start position. After that, the AFM door must be open at least 1/8" or the yellow test connector must be jumpered.

Just use a paperclip and bend it into a "U". Shove this "U" so that each leg goes into the test connector.

Re-check voltage on the blue wire with key at start or "on".



Better yet, put a fuel pressure guage in line where you can see it. See what kind of pressure you have. Does it bleed off overnight?

This would also tell you if you have fuel.