1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Suzuki Fuel Pump Wiring

Discussion in 'Suzuki Carry' started by jliltd, Jul 19, 2007.

  1. rugerman

    rugerman Member

    The fuel pump will shut off when it pressurizes the carb. SO will your truck fire up and keep running?

    A typical fuel pump start will click 3-6 times then the relay clicks behind the dash and the pump stops until it calls for fuel again when the motor starts cranking.
     
  2. SpankyNFla

    SpankyNFla New Member

    That sounds just like what happened to me. Where did you find the relay? What is it behind? What does it look like?
     
  3. Settewongse

    Settewongse New Member

    1990 Suzuki Carry
    SOLVED - It was the relay after all! - Read on.
    RELAY LOCATION: It is located behind the glove box. You have to remove the glove box and then you will see it. It is NOT the relay located under the passenger seat by the ignition coil, that's the fan relay. I'm re-attaching a pic uploaded by Piterix (pg 3 of this post). That is the FUEL PUMP Relay in the pic.

    Initial problem: Truck running fine and sputtered to a stop as though it ran out of gas. Five minutes later it started and made it home but sputtered a bit. Then it never started again. It cranked over. I checked for spark which it had. I then pulled the fuel line to the carb and saw that no fuel was pumping through the line when cranked. After several days of chasing the problem and replacing: fuel pump, fuel filter, relay under passenger seat, battery, battery cables, spark plugs, plug wires, distributor cap and rotor I saw that pic and looked behind the glove box.

    FUEL PUMP & FILTER LOCATION: It's located by the gas tank just behind the rear wheel on the driver side. Attached to the frame rail with two bolts. It has two fuel lines attached to it. The fuel filter is located about 6" next to it.

    TESTING FUEL PUMP: I tested my fuel pump by unplugging the relay plug (black in that pic but white on my truck). I then connected a wire to the (Brown with thin Black Stripe) socket on the plug directly to the + Positive on the 12V battery. I made a 6ft long jumper wire to test. I then turned the key and Tic,Tic,Tic,Tic real fast non stop from pump. I tried it with my old pump and it went tic only once, hmm? Also I bought the $25 replacement pump on eBay. When I looked prices were from $25-$365. Not sure why but it was and exact replacement for a DB51T.

    TESTING FUEL PUMP HAS POWER (Fustration!): OK so if the relay behind the glove box is bad you might have what I had. I tested the two wires going to the fuel pump, at the pump several times. Sometimes it would show 12V with key turn for a sec. Other times nothing. Sometimes 12V and then flash on and off different numbers. Was it getting power, was it not - ARG! Just test it as above or run + and - from the battery directly. If the fuel pump tics like crazy it's working.

    REMOVING THE RELAY: Without taking off the dash it's impossible to get to the screw. I couldn't pull it off the gold post either. I just used a tiny chisel and wedged it under where it slides over the gold post and broke the plastic slides. It came off but put a tiny hole in the plastic housing.

    RELAY PART NUMBER: My part number is 38860-76D10 but it looks like there are 2-3 different relays depending on your chassis number. I would check your relay, it's marked.

    CHEAPER AFTERMARKET: I have not found a cheaper OEM alternative or a cross reference after about 2hrs of looking online. If you find one tell us. However, you can and I did completely replace it with a Bosch style relay.

    Fuel Pump Relay AND Under Passenger Seat Relay are NOT the same: I tested the two relays the best I could and they click when completely different post have 12V. You cannot interchange them.

    HOW I THOUGHT I FIXED IT: I took my fuel pump relay out. Since I accidentally put a hole in the back I decided to shoot electrical contact cleaner inside it. I then tap it on the counter lightly. Shot more in, taped and then blew it dry with canned air. I cleaned the plugs and post with electrical contact cleaner. Plugged it back in and the fuel pump started ticking when the key was turned and the truck started. Then the next day it stopped after 5 minutes. Relay dead :(

    ........ a few days later.

    HOW I DID FIXED IT - OEM Relay replaced with Bosch Style 5 Pin Relay.

    So mapping the OEM relay was somewhat successful in that I learned enough to completely replace the OEM fuel pump relay with a Bosch style relay. I installed an aftermarket relay panel under the dash. This allowed me to replace the fuel pump relay and have extra relays relays to go for future plans I have. Worked perfectly and cost me about $60 with everything. You could easily replace it with just a Bosch style relay with harnesses sold on Amazon for $10. The OEM relay is a 4 pin relay. You can replace it with a Bosch style 5 pin relay. You just don't use/ wire up the middle pin.

    WHAT I DID: The quick DIY: (Do at your own risk if you feel confident)
    1. Unplug the + and - cables on the battery.
    2. Find the fuel pump relay behind the dash and unplug it.
    3. Map/ identify the wire in that plug going directly to the fuel pump. Just look at the color of the + wire plugged into the fuel pump. Mine was a brown/black stripe.
    4. Map/ identify the wire in that plug with a test light that is the ignition wire. When key is off no power/ key turned on power.
    5. Now run a 14awg 100% copper red+/black- line directly to the battery.
    6. The Bosch relays will have numbers on the pins.
    7. CONNECT: Red+ from battery to pin 30 on Bosch relay using harness. Make sure you have a 15amp inline fuse between the battery and relay harness.
    8. CONNECT: Black - from battery to pin 85 on Bosch relay using harness.
    9. CONNECT: Ignition wire to pin 86 on Bosch relay using harness. I made a solid adapter/ jumper from my OEM plug.
    10. CONNECT: Fuel Pump wire to pin 87 on Bosch relay using harness. I made a solid adapter/ jumper from my OEM plug.
    11. Reconnect the + and - cables on the battery.
    12. Turn key and :) OR wait for it all to catch fire if you made a mistake :(

    Only took me a week of being super frustrated :/

    NEW Relay Box added to the passenger footwell. It's really small and not in the way and easy to get to.
    [​IMG] [​IMG]



    Inside the box: It has room for 6 relays. The Fuel pump is the only only currently in use. I plan to install a lightbar and a backup camera so I added one for those plus a future extra. I also have an extra 15amp fuse in there.
    [​IMG]


    Back of the new relay box.
    [​IMG]



    Behind the glovebox: On the 91 Suzuki when you remove the glovebox you will see the old stock relay (small black, not in this pic) located where these wires are. I tied into the old wiring to the stock fuel pump relay to feed the new relay box. I choose to wire it in a way that left the OEM fuel pump stock plug in place. You could easily just cut it out and wire it directly.
    [​IMG]


    This is the OEM Old Fuel pump relay on the 91 Suzuki.
    [​IMG]
     

    Attached Files:

    Last edited: Feb 25, 2021
  4. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    That looks like a standard “Bosch” Pattern cube relay. did you happen to take any pics with it out?
     
  5. Settewongse

    Settewongse New Member

    I have pics. I'll upload them this week. It's not the standard Bosch pattern 4 pin. The Omron relays that it uses also do not have the post marked or a diagram on them. The ones in the mini truck look exactly like the ones used on Suzuki 1000cc motorcycles. However I know which post goes to the pump and which is the negative. So I only need to map constant power and power when key is turned. I'm going to map the OEM relay and then try and remove it and install a Bosch style waterproof relay on Amazon $10. I'll upload full detailed pics and instructions.
     
    Last edited: Sep 8, 2020
  6. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    My guess would be that it contains an impact/rollover cutoff.
     
  7. Settewongse

    Settewongse New Member

    That is not the fuel pump relay. I believe it's the fan relay. The fuel pump relay is located behind the glove box. You have to remove the glove box to see it.
     
  8. Settewongse

    Settewongse New Member

    So mapping the OEM relay was somewhat successful in that I learned enough to completely replace the OEM fuel pump relay with a Bosch style relay. I installed an aftermarket relay panel under the dash. This allowed me to replace the fuel pump relay and have extra relays relays to go for future plans I have. Worked perfectly and cost me about $60 with everything. You could easily replace it with just a Bosch style relay with harnesses sold on Amazon for $10. The OEM relay is a 4 pin relay. You can replace it with a Bosch style 5 pin relay. You just don't use/ wire up the middle pin.

    WHAT I DID: The quick DIY: (Do at your own risk if you feel confident)
    1. Unplug the + and - cables on the battery.
    2. Find the fuel pump relay behind the dash and unplug it.
    3. Map/ identify the wire in that plug going directly to the fuel pump. Just look at the color of the + wire plugged into the fuel pump. Mine was a brown/black stripe.
    4. Map/ identify the wire in that plug with a test light that is the ignition wire. When key is off no power/ key turned on power.
    5. Now run a 14awg 100% copper red+/black- line directly to the battery.
    6. The Bosch relays will have numbers on the pins.
    7. CONNECT: Red+ from battery to pin 30 on Bosch relay using harness. Make sure you have a 15amp inline fuse between the battery and relay harness.
    8. CONNECT: Black - from battery to pin 85 on Bosch relay using harness.
    9. CONNECT: Ignition wire to pin 86 on Bosch relay using harness. I made a solid adapter/ jumper from my OEM plug.
    10. CONNECT: Fuel Pump wire to pin 87 on Bosch relay using harness. I made a solid adapter/ jumper from my OEM plug.
    11. Reconnect the + and - cables on the battery.
    12. Turn key and :) OR wait for it all to catch fire if you made a mistake :/
    FYI - There is a more detailed post by me a few post up on pg 5.
     
    Last edited: Sep 16, 2020
  9. Billy_Retired

    Billy_Retired New Member Supporting Member

    FYI. The fuel pump controller/relay on a 1993 Carry DD51T is behind and underneath the Speedo/instrument cluster. It's a real pain to get to (drop steering shaft, remove heater control knobs, remove dash bezel, remove instrument cluster clear cover, remove instrument cluster, remove right vent duct) and then you can unplug and remove the controller/relay.

    Suzuki calls it a "fuel pump control module" I dissected the old one and it is truly a controller (several IC chips, resistors, capacitors, and diodes) see attached pictures.

    I'm guessing that because of where and how it's mounted (perfectly level front to back, and side to side with the vehicle) that there is some safety features integrated.

    I am choosing to follow Settewongse's path by wiring in a separate relay mounted in a much more accessible location.

    IMG_0568.jpg IMG_0569.jpg
     
    Last edited: Feb 25, 2021
  10. Settewongse

    Settewongse New Member

    That looks like the same relay as the 91 (behind glove box) with a slightly different mounting bracket. Good to know that they moved it's location on the 93. I just added pics to my post above of my new aftermarket relay box.
     
    Last edited: Feb 25, 2021
  11. ed nap

    ed nap Member

    Hi guys, after 4 months of fun with my '94 Carry, I had trouble with her this weekend. After about 30 miles of a couple of high speed runs for a few nonstop miles it started to miss, lose power and finally died. Seemed like a fuel starvation issue. I had just topped up the tank about a hour ago prior to starting the trip. This was the first long trip I had taken in the truck so even though I had just changed all the filters over xmas holidays, if seemed like not enough fuel was getting pumped up to the carb. After letting her rest a few minutes I managed to limp home and I figured I likely stirred up some some dirt in the tank and it was clogging the filter. I thought I would drain and clean the tank, restore all the old hoses, and add a new filter. The next day I tried to siphon out the tank and got most of the new gas out. I then disconnected the hose coming out of the outlet of the pump and hooked up a longer quarter inch line and led it onto the empty container. I thought when I turned the key on that it would help to empty the tank but after a couple of clicks, the pump went silent. I removed the old pump and attempted to bench test it. Mine is a 3 wire pump. Is has a black, which I assume for ground, a brown wire with a black stripe , which is 12V positive, and also has a black with a white stripe. I don't have access to a wiring diagram so what is the black wire with the white stripe for...? I hooked the pump up to a 12 V power supply, but I can't even get the pump to respond. WhHen I climb under the vehicle and test the electrical connector with a test lamp, it has steady 12V power on the Brown/ Black wire. So what is the Black wire with the White stripe for?
     
  12. Billy_Retired

    Billy_Retired New Member Supporting Member

    It should be a trigger wire. I've heard that the 1994s and up had a rollover switch (if the vehicle rolled over, the pump would be disabled even if the ignition switch was still on). In theory you could bench test it. 12v ground to black wire, 12v positive to brown wire with black stripe, and 12 v ground to black with white stripe. Or put 12v positive on both brown wire and black with white stripe and 12v ground on black wire. If the pump runs with either, that's it.
     
    Last edited: Mar 2, 2021
  13. ed nap

    ed nap Member

    Any idea where the roll over switch might be ? Since I have the whole fuel system apart I might as well go poke around the check its operation... For some reason the two wire fuel pumps are $25-$150 (likely Chinese parts) , but the 3 wire pumps are averaging $350 !
     
  14. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    If you have a multimeter, you can try to figure out what the wires to the pump, and on the pump are.

    If you check the feed wires to the pump with the power off, you should have continuity to ground on grounded wires, and not on hot wires. Then double check with power on, find your hot wire(s), by checking for voltage to ground. And, the grounds shouldn’t have anything.

    Once you have done that you can then check for continuity through the pump wires. You should know which wires are hots, and grounds from the connector on the truck. Now hook the multimeter up in the Ohm mode and you should have resistance from the hot to one of the grounds. this identifies the winding on the motor, and you can probably bench test the pump using those two wires.
     
  15. ed nap

    ed nap Member

    Thanks. I will follow your advice, roll my sleeves up and dive in. Nothing beats a lessons learned opportunity! I ordered another fuel pump but curiosity has the best of me so tonight I will try to dissect and diagnose the old pump to see why its failing.
     
  16. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    Hopefully you don’t figure out it is a wiring issue after you install the new pump.
     
  17. ed nap

    ed nap Member

    That's why I was asking if anyone knows where the roll over switch might be located. I would like to test that switch as long as I am already this deep into it. Does anyone know if its an actual pendulum operated switch, or something else ? I could not easily locate the fuel system relay either. I took out the glove box to look at the front firewall where others indicated it might be located, but mine has a plastic box from the HVAC system in that location. Others were suggesting to remove the speedo head, and look down to the left , but that's also a chore to remove (I already previously tried to remove the speedo to clean it). I don't see anything that resembles a relay under the passenger seat (the 3 rd possible location). I might just go the route of a new dedicated switched hot wire, with a fuse and a hidden anti-theft switch.
     
  18. ed nap

    ed nap Member

    I cleaned up the electrical connector on pump assembly, removed the plastic pump from the electric motor just to see what makes it tick. The electric motor has a large rubber diaphragm on top, which pulses up and down to flow fuel. The plastic pump assembly has a few check vales in it to hold the fuel pressure once pumped up by and past the diaphragm. I screwed it all back together and re-plugged her back into the truck's wiring harness, without hooking up any of the original fuel lines. Now, when I switch the ignition to ON, the pump runs for a second and then shuts down. Tried this multiple times. I started the truck and let her run on the gas remaining in the carb. The pump seems to keep on running. Seems normal. I tested that sequence several times, and the pump keeps running as long as the engine runs. I still can't locate fuel pump relay. So I am going to hook everything back up and see what happens over time. I am hoping it might have simply been a poor electrical connection in the connector.
     

Share This Page