car died on way home. suspect fuel pump, need help

[Wingsuit]

Took the car to the shop to get it safety inspected. Inspection came back almost clean just a brake booster problem that they fixed, and some small electrical tweaks and an alternator belt change that I elected to take home and do myself to save shop labour.

Halfway home the car all of a sudden felt like it lost power and died. I restarted it, it ran for 3 seconds and then died. After that it wouldnt start. Through the choke on and got 1 last second of engine running before sputtering and dieing.

I noticed I wasnt hearing a familiar noise. Normally with the key in the on position I hear the fuel pump running. This time, nothing. At first I missed it cause of the traffic noise. Got the car towed home.

p/o has installed a mallory series 110 electric pump, and looks like disconnected the flow guide valve. I'm guessing the can before the pump is likely a fuel pressure regulator?

I'm new to these cars so I'm doin my best to research as best I can. My question is basically about diagnosing this correctly. obviously right now the pump isnt running cause I was able to hear it before. Do these cars have a tank located pump as well (71 240z)? Makes me wonder if the shop left the key in the on position when doing their work and maybe overheated and wore out the fuel pump? It was running fine the day before I took it to the shop, drove a good 40 miles with no problems. though I also know old stuff breaks.

The ****ty part is I'm under a time crunch. After inspection you have 1 month to fix and show fixes, otherwise you go back to square one (which means the next inspector might not overlook a few things this one has). All I had to do was alternator belt and get side markers working (they worked a week ago) but now I have to sort out this issue.

Would it be a simple job to just buy a new fuel pump, install, and see what happens? Is there other things I should be checking just in case (**** in fuel lines etc) ie is there something that might have caused the pump to fail that I should look into? I have a home garage but not a lot of specialty tools. (fuel pressure guages etc)

[siteunseen]

That looks like a Napa fuel filter to me, isn't that what it says on the side? You may have blown a fuse for the fuel pump, hopefully that is, instead of burning it up. Can you straight wire 12 volts to the pump and listen for the whirling sound? or pull the out bound hose to the carbs and see if it flows fuel out into a jar or something. If it had plenty of gas in the tank I wouldn't think leaving the key on would burn it.

My '72 has a mechanical pump on the front passenger's side of the valve cover. They don't have pumps in the tank.

Edited August 15, 2013 by siteunseen

[Wingsuit]

car is at home, but I'll check that after work. They way it quit I hadnt even thought of fuse. thats why its always good to check with others thanks. and yeah you are right on the napa fuel filter.

[zKars]

wingsuit:

Congrats on the inspection (near) pass! Driving time coming real soon!

No in-tank pump on any S30. All 240 had mechanical pump on the engines, some had addition electric pumps back by the tank. THat can next to yours is filter.

The fuel pump quit for sure. Most likely problem is the +12 power to it has been lost. Blown fuse, bad connection most likely. Plugging wouldn't burn the pump up quickly.

The red wire attached to it runs somewhere, likely to the ignitions switch of something that gets power when the key is in the ON position. Just trace the wire back and see where it goes, then it might be obvious why its not connected anymore (like loose or blown fuse in-line).

First test, turn the key to the On position and test for +12v at the red wire on pump. There is no exposed wire at the pump, so trace it back where it goes until you can get a bare end to test. Or expose a tiny bit of the copper on the wire near the pump, or slice into with a razor blade to touch the core wires and touch you probe to the blade.

Check the black ground wire too. It has to be connect to car metal somewhere or the - side of the battery.

If you can't figure out what went wrong, just re-wire that red wire to a new spot. Find a fuse position that gets +12 when you turn the key on, and temporarily connect the red pump wire to the fuse connector by tucking a bare end under a fuse. Make this VERY temporary, it will get you running. Make sure you put that wire under the terminal closest to the CENTER of the fuse box or you may risk blowing that fuse with the extra pump current. Worst case, just connect it straight to the battery +12.

Having the pump up front like that is a poor idea in general. Pumps are good pushers, not all are good suckers. The inlets tend to need to be below the bottom of the tank. That particular pump is a decent sucker, but it belongs in the back with the tank. Later!

Good luck. Call to chat if you need to!

Edited August 15, 2013 by zKars

[Wingsuit]

well that was a ****ty way to spend money (referring to the tow) traced the fuel pump wire. negative direct to battery, positive going to the ignition with a inline fuse that was tucked way up in the dash so I missed it. fuse had blown. wonder what would have caused it?

oh well, every experience helps teach me about the car, fired right up.

time to put a very extensive fuse kit in the car so I potentially avoid that situation in the future.

[siteunseen]

Glad you got it back running. You mentioned something about your mechanic doing some electrical tweaking, maybe he burnt it by accident. You might want to turn on everything else and make sure you have all your accessories, lights and wipers etc.

Edited August 16, 2013 by siteunseen

[Stanley]

If my car was ok and I took it in for an inspection, and it died afterwards, I'd never go back. It could be a coincidence but why take a chance.

[Wade Nelson]

and it died afterwards, I'd never go back. .. why take a chance.

D'oh! Because if you don't pass the inspection they don't give you your license plates / sticker.

[beermanpete]

What size is the fuse that failed? How did the break in the element look? Was it melted wide open and have black/smoky marks on the glass, or did the fuse look ok at first glance and turn out to have a small crack in the element?

[Wingsuit]

yeah exactly I need to take it back to get the inspection signed off on. After finding what broke I don't think it was a shop problem, probably just bad timing.

I've now fixed everything left fixing so I've got an apt mon to get it all signed off on so I can get it registered and insured here.

The part that got me was I checked all fuse in the fusebox and didn't see any troubles. But after I got it home I traced the wire from the fuel pump and found one of those inline wire fuses that input a 10amp blade fuse, that one was where the fuse blew. the wire was tucked up under the front dash and then joins in a wire coming from the ignition switch which is why I missed it when it happened.

The fuse was melted with slight blacking on the elements either side of the break, but no blacking on plastic housing. I'd say a .5-1mm break in the fuse element.

Edited August 17, 2013 by Wingsuit

[siteunseen]

I like fuses.

[beermanpete]

The 10 amp fuse is a suitable size for that pump. Mallory recommends 7.5 amps. The wide gap in the fuse along with the black spots indicate a short circuit type of overload. Considering this type of fuse failure you might have an intermittent short due to a bare spot on a wire somewhere or perhaps something in the pump itself. If you have a recurrence inspect the wiring.