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Discussion Starter #41
Thank you for tips and help!
Yes usually once a year I would put fuel injector cleaner at fill up.
What ever is on sale/special at local auto parts/walmart store (gumout or stp brand) goes in.
Read about evap system on SFS and it DOES cycle/pulse - as you described it
 

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Discussion Starter #43
Found this page myself to...

According to step 4 that fuel pump in the tank could be responsible for a LOT of problems. Fuel filter (that is in that pump) causes low pressure in fuel line. Fuel pressure regulator (in that pump) can cause big drop in pressure. Check valve malfunction (on that pump again!) drops that fuel pressure.
Can someone confirm that part #
31110-4Z000

is fuel pump that I need (2013 - SFS sport 2.0t) ?
 

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Discussion Starter #44 (Edited)
Any of my OBD2 scanner reading for a fuel pressure are from rail (after high pressure fuel pump - that is where el.sensor is located). My little OBD2 scanner app shows 650-700 psi at idle (manual specs are 435.1 ~ 2175.6 psi range).
Now how to check that low pressure line (manual says 69.6 ~ 75.4 psi) ?
I've seen that there are spec.tools (a gauge 09353-24100 and an adapter 09353-02100). Checking prices online and they are 300-400$ online (ouch!).

Is there a generic fuel pressure kit that will quick connect to fuel line and high press.fuel pump with a gauge attached?
What type of quick connect are those? Any brands/models recommended?

STILL no codes (pending or displayed) on dashboard. Now it seems that when car sits outside for a while (after running then park it for 3-4 hrs) it will take longer to crank.

It was suggested to try to do on-off-on-off-on (not starting a car, just priming fuel pump) with start button. Every time I could hear pump starting (normal sound to me). Starting a car after it was better.
Does this mean that my pump is toasted (pump in gas tank)? Or pressure regulator (on that pump) is not regulating any more...


Cheers
 

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Any of my OBD2 scanner reading for a fuel pressure are from rail (after high pressure fuel pump - that is where el.sensor is located). My little OBD2 scanner app shows 650-700 psi at idle (manual specs are 435.1 ~ 2175.6 psi range).
Now how to check that low pressure line (manual says 69.6 ~ 75.4 psi) ?
I've seen that there are spec.tools (a gauge 09353-24100 and an adapter 09353-02100). Checking prices online and they are 300-400$ online (ouch!).

Is there a generic fuel pressure kit that will quick connect to fuel line and high press.fuel pump with a gauge attached?
What type of quick connect are those? Any brands/models recommended?

STILL no codes (pending or displayed) on dashboard. Now it seems that when car sits outside for a while (after running then park it for 3-4 hrs) it will take longer to crank.

It was suggested to try to do on-off-on-off-on (not starting a car, just priming fuel pump) with start button. Every time I could hear pump starting (normal sound to me). Starting a car after it was better.
Does this mean that my pump is toasted (pump in gas tank)? Or pressure regulator (on that pump) is not regulating any more...


Cheers
Only sure way is to have it tested with a gauge - which would show the operating psi plus you can conduct a pressure holding test to verify that the check valve is working, I'm assuming Hyundai's setup uses a check valve, it's a simple device that usually doesn't fail though, but when it fails it's usually cold start cranking that is prolonged. You could always hack the fuel line and install a check valve, probably not recommended though. . I would think that if there is an issue with the fuel pressure regulator itself it would show up under engine load conditions and here again I don't know what Hyundai uses for pressure control, some cars cars use a sensor that allows the ECM to regulate the presssure but I would think if Hyundai did that you'd be able to see the pump pressure on a scanner. I would also think you could disco the low pressure fuel line and use a rubber hose to connect a pressure gauge - making sure it's sufficiently tight to prevent pop off, but then you would probably need to supply independent of fuel pump harness 12v to the pump to do a thorough test, not sure if doing the on off is going to be a valid test. Going by what a Hyundai tech who used to post once stated - the Hyundai in tank assembly is generally very reliable.
 

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Discussion Starter #46
From service manual : "Fuel Pressure Control Valve is installed on the high pressure fuel pump and controls fuel flow flowing into the injectors in accordance with the ECM signal calculated based on various engine condition " - new high pressure fuel pump installed and according to obd2 reads it does maintain fuel pressure (high side PSIs)
But in the in tank pump there is fuel pressure regulator (non serviceable part, just like fuel filter) that is known to fail sometimes (according to other hyundai/kia forums). Reports of cracked plastic housing on that pump - few youtube videos on that to.
Hyundai did not help to diagnose these fuel pressure issues by making unusual shape/style fuel port plug in. There is NO aftermarket test kit to fit these plugs in order to test it.
I am replacing in tank pump and just ordered part (31110-4z000) from a dealer here in Canada (280 CAD/220 USD). Will post after done...
Cheers
 

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From service manual : "Fuel Pressure Control Valve is installed on the high pressure fuel pump and controls fuel flow flowing into the injectors in accordance with the ECM signal calculated based on various engine condition " - new high pressure fuel pump installed and according to obd2 reads it does maintain fuel pressure (high side PSIs)
But in the in tank pump there is fuel pressure regulator (non serviceable part, just like fuel filter) that is known to fail sometimes (according to other hyundai/kia forums). Reports of cracked plastic housing on that pump - few youtube videos on that to.
Hyundai did not help to diagnose these fuel pressure issues by making unusual shape/style fuel port plug in. There is NO aftermarket test kit to fit these plugs in order to test it.
I am replacing in tank pump and just ordered part (31110-4z000) from a dealer here in Canada (280 CAD/220 USD). Will post after done...
Cheers
I hate that its parts cannon time but sounds like you are at least closer to a lasting fix

The filter is part 31112 3Q550 (picture attached) and it lists for a Sonata but the assemblies are the same. I have one but it was broken when I got it and I never followed up with the seller to get it replaced. Tried fixing with with JB weld and it may work. Let me know if you want it.

There is also a pressure sensor on the fuel pump top would check that as well to see if values are normal it's right on top. it's part number 31435 3K600 but they are specific to VIN

Speaking of the top...neither the lock ring or seals should be reused. Suggest ordering those before you do the job. Also you can spin the ring using a brass punch and lots of liquid wrench no need for the tool.

And if I were you I'd think about replacing the sending unit as well. If you have ever seen the range to empty or mpg randomly reset between fill ups it's an indicator that its failing. Plus you have to take it off to replace the fuel pump.

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From service manual : "Fuel Pressure Control Valve is installed on the high pressure fuel pump and controls fuel flow flowing into the injectors in accordance with the ECM signal calculated based on various engine condition " - new high pressure fuel pump installed and according to obd2 reads it does maintain fuel pressure (high side PSIs)
But in the in tank pump there is fuel pressure regulator (non serviceable part, just like fuel filter) that is known to fail sometimes (according to other hyundai/kia forums). Reports of cracked plastic housing on that pump - few youtube videos on that to.
Hyundai did not help to diagnose these fuel pressure issues by making unusual shape/style fuel port plug in. There is NO aftermarket test kit to fit these plugs in order to test it.
I am replacing in tank pump and just ordered part (31110-4z000) from a dealer here in Canada (280 CAD/220 USD). Will post after done...
Cheers
Well if I ever had that issue and suspected the in tank fuel pump I'd disco the low pressure line at the high pressure pump and put 12 volts to the in tank pump, assuming one can access the wiring harness. I believe Harbor Freight has a cheapo gauge ($20) that might have the adapter so might not have to run external power to the pump.

But a least the in tank unit isn't too expensive, on some cars they are a good deal more costly and the tank has to be dropped. Good luck

 

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Discussion Starter #49 (Edited)
SUCCESS ! Replaced that pump in 2 hrs. It took more time to move/wrestle back seat out of the way then to actually take pump out. Highly recommend to get tank ring tool (under different brand names but ends with 6599). With that tool it took a strong pull on 1/2" breaker bar to unlock it without damaging it (ring or gasket).
Vehicle started normally and drove perfect - no CEL or any hiccups. Left a car overnight to sit (lately 1st start in the morning was loonger then usual). Car started this am no problem !
In old pump there was some small amount of sand on the bottom of it (in plastic housing).
New pump assembly came with a new sender unit, new filter ((y)) and a new pressure sending sensor. Later I will take this pump apart to see fuel filter debris in it.
Thank for all help on this forum!
 

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SUCCESS ! Replaced that pump in 2 hrs. It took more time to move/wrestle back seat out of the way then to actually take pump out. Highly recommend to get tank ring tool (under different brand names but ends with 6599). With that tool it took a strong pull on 1/2" breaker bar to unlock it without damaging it (ring or gasket).
Vehicle started normally and drove perfect - no CEL or any hiccups. Left a car overnight to sit (lately 1st start in the morning was loonger then usual). Car started this am no problem !
In old pump there was some small amount of sand on the bottom of it (in plastic housing).
New pump assembly came with a new sender unit, new filter ((y)) and a new pressure sending sensor. Later I will take this pump apart to see fuel filter debris in it.
Thank for all help on this forum!
Glad you found success this time!!!! And you have almost a fully new fuel system to boot.

I'd cut that filter open and see how it looks too. I know it drained out fairly dark when I did my Sonata. Really dumb how these newer cars have vital filters in hard to get at places and then claim that they dont need replacement.

Pictures would also be much appreciated (by me at least)

Get thyself a beer, you deserve it!

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Discussion Starter #51
Glad you found success this time!!!! And you have almost a fully new fuel system to boot.

I'd cut that filter open and see how it looks too. I know it drained out fairly dark when I did my Sonata. Really dumb how these newer cars have vital filters in hard to get at places and then claim that they dont need replacement.

Pictures would also be much appreciated (by me at least)

Get thyself a beer, you deserve it!

Sent from my SM-G965U1 using Tapatalk
🍻cheers
 

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View attachment 442903 View attachment 442904
This is how filter media was (yikes!)
65000kms/40000mi
Hyundai says that filter is non-replacable part ( no parts to buy here).
It's a shame you didnt photo that filter before you autopsied it. There is a part number on the top and I'd be surprise if it wasn't the one I have.

That sediment is concerning. Its blue and I cannot for the life of me think what would be and stay blue in a solvent like gasoline. Do you fill up at the same station all the time? Maybr avoid that for a while and see if your fix lasts a fee years.

It is a shame that to get to that filter it requires so much labor since it clearly seems like a regular change of it would have save you replacing the pump. Good move buying the pump assembly because all of these potential issues are now mitigated for a good while

I price out my sender and seals today and its roughly half the price of a full unit. Think I'm going to follow your example this spring.

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MSkip, did you have to drop the tank to swap the pump? Also, it's been about 2 weeks now. Is it still fixed?
 

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Discussion Starter #55 (Edited)
All fixed! I tried to edit my orig.post and put a note that it is fixed. This forum does not allow editing older posts/titles.
If you look on youtube on how to replace in tank fuel pump for sonata 2.0t it will give you idea on how it goes. No need to drop gas tank. Acces hole from top (under rear seats- they have to be removed).
Whole thing took me a couple of hours. Try to do it on very low level in your gas tank.
Now it seems that fuel economy got slightly better then before (I DID change spark plugs and did oil change - full synth.pennzoil 5w30).
Cheers
 
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