PDA

View Full Version : HELP! Fuel pump relay?



A4Rob
06-27-2009, 03:25 AM
Does anyone here have alldata or know which relay is for the fuel pump? It is 4:30 AM and I really really want to start my car "tonight". Thanks AZ! [az]

mattiouti
06-27-2009, 08:02 AM
this is in a 1.8t which im assuming u have... im guessing its behind the driver's kick panel

Fuse & Relay Arrangement on the Relay Panels

Micro Central Electric Panel - behind the storage - driver's side
Micro Central Electric Panel

Relay Location


1 - Dual Horn Relay
2 - Load Reduction Relay
4 - Fuel Pump (FP) Relay
5 - Wiper/Washer Intermittent Relay
6 - Wiper/Washer Intermittent Relay

mike-2ptzero
06-28-2009, 09:46 AM
Relay 372 above the clutch pedal, well if your car is like mine.

ghost6303
06-28-2009, 10:13 AM
on my 98 1.8t, you look thru the little opening just above the fuse pannel and its the closest one you see thru the hole, i think it says 230 on it.

JK35
08-20-2009, 10:50 PM
Relay 372, above the clutch pedal is definitely for the fuel pump in mine too, Mike, but... something seems wrong.
I have the wires back at the tank tagged and positively identified. the green with yellow stripe is fuel pump positive, the brown next to it is fuel pump ground (the brown across from the green is ground for the fuel level sender and the smaller violet -w- black stripe is positive for fuel level sender)

OK, Multimeter set to read voltage. key to run= I get 2 volts, engage starter and voltage jumps to 9v (I need to charge overnight as it's been doing alot of sitting and cranking, but not much running, batt voltage is 11.5v)

when I pull relay # 372 I still have 2 volts in the run position and while I try to crank it, so it is definitely a fuel pump relay, but I am not understanding why I still have 2 volts/1.9v with #327 removed with key in run or start)?

Also, I cannot hear this fuel pump running at all. There's a SHITLOAD of dynamat throughout the entire car and it is the quietest car I have ever been in, but with the access panel open, windows up and in a closed (air conditioned) garage, I just can't hear the damn thing run... what conditions activate the pump to prime, and what conditions to run? If the 2v is a prime, could there be another relay for this? (but why doesn't it stop after a few seconds static in the run position (not running)

I thought it would be simplist to just run my "fuel pump #1" trigger wire to the fuel pump relay, and remove the existing trigger wire from the fuel pump relay

(AEM race box EMS installation, and this is a 97 stroked/built, BT B5 QTM)
at this point I am a bit reluctant to remove the factory trigger wire from relay #372, and replace it with the trigger from my AEM, because there seems to be more going on here than a simple fuel pump relay circuit...

does anyone here understand this circuit, and if so would you be kind enough to explain it?

-the big box of Bosch relays/sockets/Tefzel wire are looking like a pretty good idea right about now, as I can just rewire it off my standalone to operate as logically as I care to set it up... -But I would rather understand how and why it operates as it does (or if mine has been malfunctioning)

thanks
Kyle

PS any info on the cooling fan relay would be a big help too (which relay is it, where is it located?)

handyvorb
08-21-2009, 12:15 AM
Relay 372, above the clutch pedal is definitely for the fuel pump in mine too, Mike, but... something seems wrong.
I have the wires back at the tank tagged and positively identified. the green with yellow stripe is fuel pump positive, the brown next to it is fuel pump ground (the brown across from the green is ground for the fuel level sender and the smaller violet -w- black stripe is positive for fuel level sender)

OK, Multimeter set to read voltage. key to run= I get 2 volts, engage starter and voltage jumps to 9v (I need to charge overnight as it's been doing alot of sitting and cranking, but not much running, batt voltage is 11.5v)

when I pull relay # 372 I still have 2 volts in the run position and while I try to crank it, so it is definitely a fuel pump relay, but I am not understanding why I still have 2 volts/1.9v with #327 removed with key in run or start)?


The ECM often sends low voltages down the "wrong direction" on wires as a diagnostic measure, and is often how the ECM determines specific open/short faults, relay failures, etc...

The positive wire going to the fuel pump (supplied by the fuel pump relay) also goes to several other solenoids, such as the purge valve as wastegate bypass valve. Looking at the wire diagram you should be able to verify this by removing fuse S229 (fuse 29 in the fuse panel by driver, 20A). This is the fuse separates all those other solenoids from the fuel pump power wire.

But, basically what I'm saying is ignore this small voltage.

Your battery voltage of 11.5v seems likely to be the culprit, as this is almost a fully discharged battery. When you crank the starter it's not a surprise your voltage at the fuel pump is only getting 9v, I bet that's what you will see at the battery too while cranking on such a low charge.

Get your proper voltage at the battery before attempting any electrical component checks, the car may also start.

handyvorb
08-21-2009, 12:21 AM
With these quite fuel pumps I've found it easy to check to see if they are running at all by putting a finger on the fuel supply line at the fuel pump flange while turning the key on (assuming you have the seat out and the cover off of course).


[edit: just saw you were running an aftermarket ECM, is it plug and play or did you have to splice some wires?]

aytheory
08-21-2009, 12:23 AM
if you need a relay let me know

JK35
08-30-2009, 09:15 AM
[edit: just saw you were running an aftermarket ECM, is it plug and play or did you have to splice some wires?]

AEM doesn't make a plug and play EMS for our cars, I'm using the 30-1900U and a twin fire CDI ignition, harness is almost complete (started from scratch with a bare connector body/crimp pins, and built from Tefzel wire, surge tank setup is done and fits under a lexan panel in the spare tire well (and I can still fit a full size spare, PLUS 20# nitrous cylinder, PLUS sound system (well... not really but I am rebuilding the subwoofer enclosure/amp racks to accomodate that as we speak... here are a few pics

BTW, I decided to totally bypass all the factory shit, as my factory ECU/relays/fusing are all coming out anyway... (no one really seems to have a clue about the electrical systems on these cars, and there's really no need to add frustration to an already complicated install/setup. everything I try to integrate is like pulling teeth... The factory ECU's do a great job at running a stock car or are fine for those who want a "chip" but the AEM EMS I've chosen is a standalone. it doesn't need or want the factory ECU interfering with anything (it told me this about a week ago ;) )
nor am I f-ing around with 12 year old relays + wiring. [;)]



http://i207.photobucket.com/albums/bb224/kntstealth93/photo-1247.jpg
http://i207.photobucket.com/albums/bb224/kntstealth93/IMG_0023.jpg

http://i207.photobucket.com/albums/bb224/kntstealth93/IMG_0022.jpg

http://i207.photobucket.com/albums/bb224/kntstealth93/IMG_0018.jpg


http://i207.photobucket.com/albums/bb224/kntstealth93/IMG_0031.jpg

http://i207.photobucket.com/albums/bb224/kntstealth93/IMG_0027.jpg

A4Rob
08-30-2009, 10:48 AM
Wow nice setup!



if you need a relay let me know


I have parted out over 50 B5's at work..

handyvorb
09-01-2009, 10:08 PM
Yeah JK35, that is indeed a very nice setup, makes me want a 1.8t to make fast [:d]