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So my Tucson has had intermittent studdering on start up and a check engine light that would come and go. Drove to work on empty a couple weeks ago and wouldn’t start up after.

With 190k miles and an original fuel pump that I couldn’t hear cycle on I assumed (after switching around fuses and the relay) that was my issue...nope. After installing a new pump assembly still no start.

Tried starter fluid in the throttle body and it hiccuped so pretty sure I’m getting spark. My electrical expertise is somewhat limited but I’m not getting 12v back at the pump or at the relay (I assume it should get 12v while cranking). Opened up the fuse box and the dash by the ecu to look for obvious corrosion or a loose wire but nothing found.

Feeling more and more like I’m gonna have to have someone professionally diagnose it but hoping there’s something simple I’m overlooking or just doing wrong.
 

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Do you have a dvom and know how to use it?
 

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Drives : Nissan NV200 Flies : Rans S6ES
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Remove the fuel pump relay from the engine bay fusebox...see below.
Switch the ignition on and use your voltmeter to measure the voltage on the 4 terminals of the relay socket on the fusebox.
You should have 2 terminals showing 12V.

Also check the two fuses highlighted below. There are known issues with the wiring on the crank sensor on the 2.7 engine that can blow the sensor fuses.

 

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Seen a few with wiring on underside of box corroded, sometime ready to break.. you wont see anything looking at top of box.

You state you seen MIL.. lets scan it and find out what the PCM seen to have fault,, If I recall, we would find an odd low voltage DTC
 

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Discussion Starter #5
So I did remove the fuse box and inspected the wiring underneath and everything seemed intact and no corrosion that I could see. The two fuses mentioned are also good. I was able to use a jumper in place of the relay and did get power to the fuel pump but still wouldn’t start up. Probably need to confirm that I’m for sure getting spark but also wondering if a bad crankshaft sensor might kill that circuit? Didn’t get any error codes on my code reader either though.
 

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So I did remove the fuse box and inspected the wiring underneath and everything seemed intact and no corrosion that I could see. The two fuses mentioned are also good. I was able to use a jumper in place of the relay and did get power to the fuel pump but still wouldn’t start up. Probably need to confirm that I’m for sure getting spark but also wondering if a bad crankshaft sensor might kill that circuit? Didn’t get any error codes on my code reader either though.
Do you get rpms during cranking?
 

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Did you check the voltages on the terminals of the pump relay socket as I suggested earlier? You need voltage on two of the terminals or the relay wont work.

The PCM wont trigger the ignition coils if it's not receiving a crank sensor signal. But if there isn't voltage being supplied to the fuel pump relay control circuit there wont be a crank sensor signal (meaning no RPMs during crank). You bypassed the relay and the pump ran, which tells you the load side of the relay is good. But you need to also have power (and ground) to the control side of the relay (the relay coil) so I'd suggest checking the relay voltages before getting involved in anything more complicated if you haven't already done so.
 
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