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Discussion Starter #1
Let me begin by stating I've thoroughly seached the forum for this issue.

2007 Elantra

The car has had stalling/no start issues lately. I replaced the fuel pump first when it was just a stalling issue thinking this was the problem. It went away for a while but came back with a vengeance to the point that it wouldn't start at all. It sat for a week not starting so I pulled the fuel pump to replace it thinking it was defective. Nothing appeared to be out of sorts so I figured I would toss it back in and try once more. It started right up. Again, a few days later it started trying to stall while driving. This time I replaced the pressure regulator. Voila! I filled up the tank, test drove it 80-ish miles and not one problem. Well now I have made it 250 miles on that tank and this morning on my way to work it stalled AGAIN!

I noticed this on the last fill up. Shouldn't there be a trap door in the top of the filler neck? Could this possibly be as simple as a bad gas cap? I'm so over this problem.
 

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Same issue as mine its 2007, ive attached a pic below ,but i think mine its the problem with the immobilizer, Like this other day i went to the mall parked normal Ill come today, just want only 20 or 10 min of ur time, i cant be loosing you over this the car and went to the shops, after that i got back to the car unlcok remotely ,whrn i turn the ignition on i hear the pump going on for few seconds,but this time it ddnt so the car ddnt start, i got off and lock and press the unlock button on the fob about 5times ,when i got in again it started right away, i guess the issue was solved right there , it does repeat the issue a number of times but after a while..... Hope this helps you
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Sorry to hear about your car issues, unfortunately I don't have enough experience to solve for you. However, check out the following video, it might help you diagnose.
Good luck!!!
 

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Let me begin by stating I've thoroughly seached the forum for this issue.

2007 Elantra

The car has had stalling/no start issues lately. I replaced the fuel pump first when it was just a stalling issue thinking this was the problem. It went away for a while but came back with a vengeance to the point that it wouldn't start at all. It sat for a week not starting so I pulled the fuel pump to replace it thinking it was defective. Nothing appeared to be out of sorts so I figured I would toss it back in and try once more. It started right up. Again, a few days later it started trying to stall while driving. This time I replaced the pressure regulator. Voila! I filled up the tank, test drove it 80-ish miles and not one problem. Well now I have made it 250 miles on that tank and this morning on my way to work it stalled AGAIN!

I noticed this on the last fill up. Shouldn't there be a trap door in the top of the filler neck? Could this possibly be as simple as a bad gas cap? I'm so over this problem.
does it stall while driving or when are at idle, at a traffic light, for example?

If the car is stalling, the first thing you would check is fuel delivery, which seems like you've taken care of. To answer your question, I doubt that a bad gas cap would cause this problem, but I’m not sure about that.

The next thing I would check is air, is it possible your car is choking due to lack of air? If the car stalls at idle, I would check the IACV. If it stalls while driving I would check your air intake and throttle body. The IACV and throttle body get carbon built up on them and can cause them to stick a bit which will cause rough idle/stalling.

I'm not sure this is the problem, but worth checking as it’s easy.
 

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Not sure but Hyundai in the United States don't have immobilizers for 2007 models.
And intermittent issues are the toughest to figure out.
When the car would not start, should check to see if the fuel pump is getting 12 volts and ground.
It could be the fuel pump relay is faulty???
Or could be the wiring to the fuel pump???
And the stalling issue could be a separate issue???
 

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Discussion Starter #6
Can anyone provide me with a wiring schematic for the fuel injection system? I have two plugs, five wires each and I don't know which wires to test on which plug.

The car died on my wife again while she was out & about. I've pulled the fuel feed line at the pump and turned the key on but no fuel is coming out so I need to make sure the pump is getting voltage before I throw away any more money on this p.o.s.
 

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The first thing you should do is switch the ignition on then use your voltmeter and check the F/PUMP & INJ fuses out on the engine bay fusebox...see below.

I've never seen a Hyundai tank unit with two connectors. So your saying there are 10 wires going into the tank? I can't think what all those could be for, but usually the fuel pump wires are thicker than the ones for the fuel level sensor.
 

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Discussion Starter #8
I have no voltage or continuity at the fuel pump fuse. Checked with the fuse removed.

Electical was not my strong suit in auto tech so please forgive my ignorance.
 

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Discussion Starter #10
I'm sorry. I should clarify. I checked the circuit first with the fuse in. Nothing. Then I pulled the fuse and checked the circuit; same thing. I also checked the fuse for continuity while removed and that was good.
 

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Next I would remove the fuel pump relay and check the power supplies to the relay :
Remove the relay from the engine bay fusebox, switch the ignition on, then measure the voltage on each of the four terminals on the relay socket in the fusebox. You should have two terminals showing 12V, one with a lower voltage (usually 3ish Volts), and one terminal with 0V.

The fuel pump fuse usually comes before the relay in the circuit on Hyundai cars. If that's the case on your car you'll only have one 12V on the relay socket.
 

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Discussion Starter #12
I tested ~12V at two terminals in the relay circuit, ~4V at another and 0V at the last.

I decided to recheck the fuse circuit with the fuse in and out and got ~12V. This time when I measured everything I used the batt NEG ground strap at the body so I know everything I tested is testing accurately.
 

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Swap the relays and when that doesn't help do a relay bypass test to see if that makes the pump run.

Remove the fuel pump relay then bridge the two terminals on the relay socket on the fusebox using a short link wire as shown below.
Remember to make sure the fuel lines are reconnected at the tank module before doing the bypass or you'll end up with a big petrol puddle under the car.
443842
 

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Discussion Starter #15 (Edited)
The wire link didn't activate the pump but I do have 12V from the wire link to the batt NEG ground strap.

I tested the voltage at the connector for the pump at various pins with the plug disconnected, key ON and I'm only getting ~11.4V or ~0/0.2V depending on which ones I test.
 

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If the pump didn't run with the relay bypassed the next step would be to leave the wire link in place then check to see if there is power being supplied to the fuel tank module under the rear seat...see below.
If there is 12V at the tank module harness connector but the pump doesn't run, that would seem to suggest your new pump is faulty.
443899
 

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Discussion Starter #17
Yep. I am getting batt voltage (12.14V) at pins 5 & 6. This was a cheapo RockAuto pump. The fuel pump housing assembly never went back together properly (one of the clamping tangs wouldn't clip back into place and caused everything to sit cockeyed when fully assembled) so my only guess would be to replace the whole assembly. I can't think of anything else that would just magically kill a pump in and of its self. I don't think trash in the tank is the culprit because everything looks clean in there with the pump removed. Thanks for your electrical help my fellow Scot.
 

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One final thing we need to consider is the possibility of high resistance in the pump circuit. In the previous test your measuring the voltage with the tank module disconnected, so there is no current flowing in the circuit. Ideally you want to check that you still have 12V when the module is connected and the circuit is under load. To do that you'd need to back probe terminals 5 & 6 with the connector plugged in and the link wire fitted at the relay socket. If you still get 12V then the fault is definitely inside the tank.

And personally I would always replace the complete tank module rather than split it to replace only the pump motor. There are lots of posts on the various forums here from folk who split the module and ended up creating a new fault in addition to the one they were originally trying to fix.
 
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