anj Posted August 14, 2011 Report Share Posted August 14, 2011 Hi all I recently bought a 87 STX that I have been cleaning up. I drove the car to work and ran well, this morning when I went to start the car the fuel pump was running and the battery was dead. I got a ride home and returned the other vehicle. Tried to boost the car but had no power, no interior lights, no chimes. Checked all the battery connections and turned on the headlight and it barely came on. After checking all the relays above the fuse power was back to operate the lights etc. After a few clicks the car started fine and drove home. Car is in garage and when I checked at 1630 the fuel pump was humming and car was dead. Disconnected the battery . The pump is warm and the wiring from positive terminal is warn. After charging the battery, when I connect the ground to the battery the fuel pump switches on. I switched the fuel pump relay with another relay and it stops. My best guess is that the fuel pump relay is gone. Is this relay used in another car that I can cross reference? Any help would be appreciated. Arun Quote Link to comment Share on other sites More sharing options...
N9TE Posted August 14, 2011 Report Share Posted August 14, 2011 The OEM yellow Cartier relays have the normal "87" and "87a" poles connected. Wherein the "standard Bosch" relay has 87 & 87a in an "or" relationship. 87a normally (relay coil non-energized) closed. 87 closed when relay is energized. However, since according to my manual (1988/1989 Electrical) the fuel pump relay doesn't use pole "4" (the center one) you can use a standard Bosch relay. As it is now, it's stuck in the "on/energized" position. You can test that with a multi-meter with the unit off the car. 5/87 -- 1/86 | -- | 2/85 4/87a | 3/30 Verify that there is no wire attached to the center spade on the relay socket. If so, I'd be comfortable swapping another Bosch unit (or equivalent). Quote Link to comment Share on other sites More sharing options...
anj Posted August 15, 2011 Author Report Share Posted August 15, 2011 The OEM yellow Cartier relays have the normal "87" and "87a" poles connected. Wherein the "standard Bosch" relay has 87 & 87a in an "or" relationship. 87a normally (relay coil non-energized) closed. 87 closed when relay is energized. However, since according to my manual (1988/1989 Electrical) the fuel pump relay doesn't use pole "4" (the center one) you can use a standard Bosch relay. As it is now, it's stuck in the "on/energized" position. You can test that with a multi-meter with the unit off the car. 5/87 -- 1/86 | -- | 2/85 4/87a | 3/30 Verify that there is no wire attached to the center spade on the relay socket. If so, I'd be comfortable swapping another Bosch unit (or equivalent). Quote Link to comment Share on other sites More sharing options...
anj Posted August 15, 2011 Author Report Share Posted August 15, 2011 Thanks I will pick up a relay in the am and try the switch. Arun Quote Link to comment Share on other sites More sharing options...
Bean Posted August 15, 2011 Report Share Posted August 15, 2011 Do you know if that car has the starter relay mod? I seem to remember something funny with the STX cars with this relay mod, but I'll have to search it. There was something about it back feeding another circuit, and it may have been the FP. Verify what Koll has showed as it could simply be a defective relay that's keeping it energized. Did you make sure the pump was not running when you parked it - and it came on later? Or was it not something you checked? The other thing would be to check the wiring to make sure there's no shorting out between wires, and also make sure the power distribution off the positive battery cable is in good shape. Did you get a chance to fuse them yet? Rabin Quote Link to comment Share on other sites More sharing options...
anj Posted August 15, 2011 Author Report Share Posted August 15, 2011 Rabin, This morning when I parked it, I didnt check. I checked at 1530 and I could hear the pump. I put a charger on the battery and disconnected the ground. Pump came on any time I made contact. All the wires seemed OK. The fuse had not blown so I didnt think it was a short. I will pick up a few relays tomorrow and replace all of them. On a side note the parts car I purchased doesnt run due to a similar issue. It may be a similar fix. Arun Quote Link to comment Share on other sites More sharing options...
N9TE Posted August 15, 2011 Report Share Posted August 15, 2011 Hey Rabin, how did you go about re-wiring the primary wiring so it was fused? It's really a bizarre setup with some bad choices. You can fuse each #10 wire coming off the distribution block. But it seems weird to fuse a wire for a 16 inch trip - to a fusebox. That combined with the general mess in that part of the engine compartment has made me hesitate and not do this job. I could be literally playing with fire! Plus, you had a meltdown with a fan switch hot lead? That should be job #1 on my 89. Quote Link to comment Share on other sites More sharing options...
anj Posted August 15, 2011 Author Report Share Posted August 15, 2011 Hey Koll Rabin has some inside knowledge about my car and that is that I was planning on relocating the battery to the trunk and using Singer HPM 4 Gang MIDI Fused Distribution Block in the front. Quote Link to comment Share on other sites More sharing options...
Bean Posted August 15, 2011 Report Share Posted August 15, 2011 When I did the 86 TD wagon, I just put in a fuse box with 20A fuses on each lead. (It melted down the harness when the injection solenoid wire grounded out against the throttle assembly on the injection pump and melted the wire back all the way to the ignition switch.) It's not as pretty as I wanted as the only fused districution block I could find had the one hot incoming, and then it had six spade connectors, three on each side of the fuse box. (I wanted 6 on one side) I then dismantled the factory distribution block and the wires there already had the female blade connectors, so I refurb'd them with electrical cleaner, snugged the terminal up, and filled with dielectric grease before plugging them into the new distribution block. I was in a rush to get the car running and into storage, so I didn't get any pictures. Shortly after getting the wiring sorted out I discovered the injection pump was totally loose! For the 89' - I've been searching for a better fuse box that would have much better sealing to locate in the same place as the OEM block, or I want to run a single large wire into the fuse box and locate the fused distribution box inside it out of sight. It's such a mess in there though, and tight space wise... It'd take a major undertaking to sort it all out, reloom the harnesses, and re-route wires better, while at the same time having a nice solution for that factory distribution block. For now I've just soldered in an inline fuse on the power wire to the fan after I rewired that whole front harness. I definitely need to overhaul the wiring harness in the 89' though, as I want to get rid of all the taped harnesses, re-route what I can, and loom it all nicely. I also want to replace as many of the crap unsealed electrical connectors as I can! Rabin Quote Link to comment Share on other sites More sharing options...
Bean Posted August 15, 2011 Report Share Posted August 15, 2011 Rabin, This morning when I parked it, I didnt check. I checked at 1530 and I could hear the pump. I put a charger on the battery and disconnected the ground. Pump came on any time I made contact. All the wires seemed OK. The fuse had not blown so I didnt think it was a short. I will pick up a few relays tomorrow and replace all of them. On a side note the parts car I purchased doesnt run due to a similar issue. It may be a similar fix. Arun Wiring short could be between the hots - not a short to ground. This would effectively bypass the relay entirely and feed power to the pump all the time. Simple to check though would be to hook the battery, verify the pump is running, then pull the relay. If there's no effect it's the wiring, if it stops you know the relay is at fault. Replacing all of them is likely a good thing to do as well. I looked for a while on replacing that crappy plastic bag they decided to use to "protect" the relays, but since it also traps condensation - their "fix" is also one of the culprits. I figured a Gore-Tex bag would be a great replacement, but have yet to find anything suitable. I also looked to see if there were any sealed relay boxes, but struck out again with that as well. Rabin Quote Link to comment Share on other sites More sharing options...
anj Posted August 16, 2011 Author Report Share Posted August 16, 2011 Thanks to Koll and Rabin I plugged the new relay in and the car started right up. The relay is a no name brand so I will check to replace all of them with Tyco or Bosch. Great feeling to be able to track down the problem and fix. Arun Quote Link to comment Share on other sites More sharing options...
Bean Posted August 16, 2011 Report Share Posted August 16, 2011 So no more pump running with the car off I assume? I thought the no-start was just dead battery? Regardless - if it was just the relay at fault that really was an easy fix! I've resumed researching a proper solution for that relay bundle, and as always, it's got the potential for an "upgrade" that could get out of hand! Rabin Quote Link to comment Share on other sites More sharing options...
N9TE Posted August 16, 2011 Report Share Posted August 16, 2011 Glad to head it was an easy fix! Quote Link to comment Share on other sites More sharing options...
Ikenna Posted August 17, 2011 Report Share Posted August 17, 2011 The OEM yellow Cartier relays have the normal "87" and "87a" poles connected. Wherein the "standard Bosch" relay has 87 & 87a in an "or" relationship. 87a normally (relay coil non-energized) closed. 87 closed when relay is energized. However, since according to my manual (1988/1989 Electrical) the fuel pump relay doesn't use pole "4" (the center one) you can use a standard Bosch relay. As it is now, it's stuck in the "on/energized" position. You can test that with a multi-meter with the unit off the car. 5/87 -- 1/86 | -- | 2/85 4/87a | 3/30 Verify that there is no wire attached to the center spade on the relay socket. If so, I'd be comfortable swapping another Bosch unit (or equivalent). N9TE, Please am trying to learn something from what you have explained. I dont understand what you mean by saying no. 5 closes when coilis energised and no. 4 normally closes when the coil is not energised. I know that no. 3 has wire connection directly from the + battery terminal, no 1 & 2 have wire connections from ground & power feed or ignition switch. Then no 4 & 5, 87a & 87, wires feeds fuel pumps or whatever the relay is supposed to power. What I want to understand from you are the words "closed & energised". My questions are: when dose the relay coil energised? Is it when no 85 & 86 supplied + & - to the relay (on)? Or is it seconds after the relay has been on? Then, what do mean by the no. 87 closing when the relay has been energised? Ikenna. Quote Link to comment Share on other sites More sharing options...
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