SVX Won't Start... Fuel Pump?

[daristotle]

My SVX died on me in the middle of road yesterday and wouldn't start. Had to get towed back home. It cranks and sometimes catches but then immediately dies. (But, mostly just cranks.) It has done this twice before this past summer. The first time it started back up again after 10 or 15 tries. The second time it started up after I had a friend come over to look at it and we had barely begun to diagnose it. I've checked the fuses, replaced the battery, replaced the fuel filter, and tried swapping the MAF sensor with a known good one.
What should I do now? Where can I check to see if the fuel pump is getting voltage? (I think it has a relay under the steering wheel.) Or is it probably something else entirely?
Thank you for any help.

UPDATE: I just got code 37 for the oxygen sensor. Would this cause my problems?

[daristotle]

Alright, so today I tried starting the car several times, checked for codes, then checked for voltage at the main relay. There was voltage. I then disconnected the 'in' hose to the fuel filter put it in a bottle and turn the key to the on position. No gas came out. Then I removed the rear seat and checked for voltage at the wiring harness there. I got voltage. I tried starting the car and it fired right up. Let it run for a minute then turned it off and then back on. Ugh. What should I be checking next here? I really don't want to stall out in rush hour traffic again.

[Mr. Claret]

Not sure if this relavent but I believe my problem like this was something to do with the fuseable link.

Just a thought

[daristotle]

I checked the fuseable link and it seemed good. I drove the car today to the auto parts store to have the alternator tested. (It tested good.) On the way home the check engine light came on and I got code 37. (Oxygen Sensor No. 2, Left Side, On SVX.) I was still able to drive the car home and the performance didn't seem any different. Could this be the source for all my problems or yet another problem?

[SeanD]

I started having similar problems just today coming home from work. First my car feels like it wants to shut off while driving, and honestly the closest thing I can compare the feeling to is when my other cars electronic speed governor came on and shut off the fuel to the engine. Exact same feeling. Then when I get home and it wants to stall constantly. Any advice would be welcome.

[legacyau]

fuel pump relay? shouldn't you get 2 x 12 volt readings at the pump connector under the seat? one for the pump and one for the gauge?

[Jonnycash]

Originally Posted by legacyau

fuel pump relay? shouldn't you get 2 x 12 volt readings at the pump connector under the seat? one for the pump and one for the gauge?

The blue wire should have 12v onlY when the key is on. Yellow should have 12 all the time. Green is the switching wire from the ecu that should turn on the relay and then there is a ground. I would start by checking the yellow, and move along from there. Make sure you have power at blue at the pump. If all is good, you may just have a bad pump.

[SoCal LS-L]

Dont forget to check the fuel pump modulator in the trunk. Sometimes it can get bumped by stuff in the trunk.

[daristotle]

Thanks. I'll recheck those wires when get some time. Where exactly is the fuel pump relay or is it just the main relay? Does anyone have a part number? I can't seem to find it on any parts site. And where is the fuel pump modulator located? I can't find that either.

[Gamesy]

double check your fuses under the dash board, specifically the E/G IGN Airbag fuse,
same thing happened to me that fuse was blown.

[oab_au]

Originally Posted by SoCal LS-L

Dont forget to check the fuel pump modulator in the trunk. Sometimes it can get bumped by stuff in the trunk.

Yes, also the ground wire from the modulator, if that is bad it won't supply a ground for the pump.

Harvey.

[SoCal LS-L]

Originally Posted by daristotle

Thanks. I'll recheck those wires when get some time. Where exactly is the fuel pump relay or is it just the main relay? Does anyone have a part number? I can't seem to find it on any parts site. And where is the fuel pump modulator located? I can't find that either.

Click here to see where it is. I would download this for future reference.

[Jonnycash]

Originally Posted by daristotle

Thanks. I'll recheck those wires when get some time. Where exactly is the fuel pump relay or is it just the main relay? Does anyone have a part number? I can't seem to find it on any parts site. And where is the fuel pump modulator located? I can't find that either.

If it turns out to be the relay, you should be able to match it to another at the parts store.

[daristotle]

Originally Posted by Jonnycash

The blue wire should have 12v onlY when the key is on. Yellow should have 12 all the time. Green is the switching wire from the ecu that should turn on the relay and then there is a ground. I would start by checking the yellow, and move along from there. Make sure you have power at blue at the pump. If all is good, you may just have a bad pump.

Alright, so here are the findings. Under the rear passenger seat I get 12v with the key turned on for a few seconds, I get nothing at all from yellow. Without the key in, with the key in, and with the key on - I wasn't able to get any voltage from yellow. At the connector to the pump I got 12v on blue again. I checked the modulator and got a solid 12v ground. Rechecked the fuses and all looks good.
So is it just a bad relay then? I've been able to drive it around. Is the fuel pump relay the silver cylinder one with the blue and yellow wires going to it from the harness under the drivers side? Part number 056700-5260 12v 22A. Should I go ahead and replace the main relay as well?

[Jonnycash]

Originally Posted by daristotle

Alright, so here are the findings. Under the rear passenger seat I get 12v with the key turned on for a few seconds, I get nothing at all from yellow. Without the key in, with the key in, and with the key on - I wasn't able to get any voltage from yellow. At the connector to the pump I got 12v on blue again. I checked the modulator and got a solid 12v ground. Rechecked the fuses and all looks good.
So is it just a bad relay then? I've been able to drive it around. Is the fuel pump relay the silver cylinder one with the blue and yellow wires going to it from the harness under the drivers side? Part number 056700-5260 12v 22A. Should I go ahead and replace the main relay as well?

Yes that is the fp relay that you have located. I'm pretty sure if the main relay were bad, the starter would not work. I just went through a similar thing on my 92. I'm pretty sure it was the yellow wire feeding the relay that was energized all the time. If you have no volatage at that wire, I don't know where the pump is getting it's power. I am not looking at a wiring diagram and it's been a while since I was under the dash... maybe somebody else could confirm these wires before you go any further.