I have no injector Pulse or fuel pump prime

Tiny
AWARES25
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  • 2006 HYUNDAI SANTA FE
  • 3.5L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 158,000 MILES
Replaced timing belt and crank sensor/sprocket. I have no injector pulse or fuel pump prime. I tested the fuel pump via the fuel pump relay. The fuel pump relay itself gets 12v and ignition 12v. Side note; does anyone know what those 3 relays are for in the interior fuse panel?
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Friday, June 12th, 2020 AT 8:31 PM

12 Replies

Tiny
KASEKENNY
  • EXPERT
Were the injectors pulsing prior to the crank sensor and sprocket replacement? If they were then I suspect we either have a timing issue or crank sensor issue. Take a look at the attached info about this system. The PCM using the crank signal to pulse the injectors.

I also attached the info about about the fuse panels for your review.

Let me know and we can go from there.
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Saturday, June 13th, 2020 AT 9:27 AM
Tiny
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Thanks for the quick reply. Full story: While replacing the harmonic balancer stupid ripped the sprocket off along with it thus throwing timing off and having me replace the belt. I replaced crank sensor timing belt and crank sprocket. I only replaced the crank sensor when I noticed the fuel pump and the fuel injectors where not priming when ignition in on position. As of right now I m already at TDC on the compression stroke marks all lined up accordingly. And still nothing.
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Saturday, June 13th, 2020 AT 10:21 AM
Tiny
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On a side note; if I unplug the crank and cam sensors it s not even throwing a code on my scanner only will throw a code when I unplug a sensor connected to intake manifold.
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Saturday, June 13th, 2020 AT 10:32 AM
Tiny
KASEKENNY
  • EXPERT
So you were just replacing the balancer for another reason and that happened none of this was happening? In other words, it was starting fine before the harmonic balancer issue?

Then how are you confirming you are not getting injector pulses?
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Saturday, June 13th, 2020 AT 8:01 PM
Tiny
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Initially was just replacing the balancer because it was coming apart, pulled to hard and crank sprocket cam off with the balancer, along with the timing belt. This is probably my third time lining up everything making sure all my marks are spot on. I noticed I lost injector pulse and fuel pump prime when turning the key to "on" position, which led me to replace to crank shaft sensor. It s been sitting for about a year now while I only work on it when I have downtime. The car as of right now is sitting at TDC (compression strike) all marks in the correct orientation I have not tried to start it because no prime/pulse from injector/pump. Fuses/relays are all good. It s like I m missing the signal to turn the injector and the pump on, the injectors have 12v as well as the crank sensor with key on.
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Saturday, June 13th, 2020 AT 9:14 PM
Tiny
KASEKENNY
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Okay. Let's address the fuel pump first. The crank sensor only controls injector pulse and does not trigger the fuel pump to come on. So if the fuses and relays are okay then the pump should be coming on and creating fuel pressure. The injectors may not fire if the crank sensor is bad but that pressure would still be at the rail waiting for the injectors to open.

I attached a complete fuel pump test. Let's run through it and pay particular attention to the jumping power to the pump and see if it comes on.

If it does then we need to check for pressure to make sure the pump is able to not only turn on but build the needed pressure. This asks you to pinch the fuel line to see if there is pressure. That is fine for an initial test but we need the pressure gauge to make sure it is building enough pressure.

Once we know we have proper fuel pressure, we can come back to the injectors.

Let me know what questions you have and we can go from there. Thanks
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Sunday, June 14th, 2020 AT 6:58 AM
Tiny
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Thanks for the input, I m going to run out today and get a gauge to test fuel pressure. I do know that if I jump the fuel pump via the relay I get fuel at rail.
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Sunday, June 14th, 2020 AT 8:28 AM
Tiny
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Also does the pump need pressure to preform the prime function? I know the pump is good and it pumps fuel. I will try/check pressure check and power at the harness. Thanks for the help!
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Sunday, June 14th, 2020 AT 8:38 AM
Tiny
KASEKENNY
  • EXPERT
Okay. If we can confirm the pressure is correct (I attached the spec for your pressure) then we can take the next step.

As for the priming of the system. That is what the pump is supposed to do when you first turn the key on. So basically the pressure begins to bleed off about 5 minutes after you shut the engine off. So once the pressure bleeds down and you turn the key on again, it primes the system again and sends fuel back to the rail. Then the pressure regulator will ensure it is not too high.

So once you go key on and the pump turns on, you should have proper pressure at the rail in about a second. If you can hear the pump coming on when you jump it and have fuel at the rail then we just need to find out if the pressure is correct. If it is then try to start the engine when you have the fuel pump relay jumped. If it starts then shut it off and we need to figure out why the pump is not getting turned on.
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Sunday, June 14th, 2020 AT 6:44 PM
Tiny
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So getting fuel at the rail, I sprayed a squirt of starter fluid in throttle and turned the engine over. I fired up then cut off, shot a little more in ran until I turned key off. Was running kinda rough and the rpm fluctuating but was consistently running. Cam has signal, and I m assuming crank sensor is working if it started. Pump is 4.4-4.6 volts the pump assembly is getting like 11.6 at one terminal. Sorry for late reply. In the meantime I m going to put back at TDC on compression stroke and see if any marks moved.
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Tuesday, June 16th, 2020 AT 11:37 AM
Tiny
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I m kinda leaning towards timing is off or slipping, but I ll know tonight.
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Tuesday, June 16th, 2020 AT 11:42 AM
Tiny
KASEKENNY
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This is possible that the timing is slipping that that will not cause a fuel delivery issue which is what it appears you have. If you spray starter fluid and the engine starts then that is meaning we need to chase down the fuel issue. What have you replaced as it relates to this and we can go from there. Thanks
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Wednesday, June 17th, 2020 AT 5:17 PM

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