POS hyundai elantra lol

[Matthew Naffziger]

so my car recently took a crap on me. its a 2000 hyundai elantra and ive never had an issue with it in thr 8 years ive owned it. (other than a busted power steering line)

it just started a couple weeks ago, i felt like i was losing a lot of power and my rpm wouldnt go above 6000 (later and now not above 4500-5000 rpm and even more power lose. i owned a geo prism that did the same thing and it ended up being the timing had jumped so it had to be reset and a new belt put on.

this elantra has 144k on it (bought at 62k) so i figured it was time for a change anyway so i took it apart to check and it was still in time. i replaced all the belts anyway, so with time set it still wont go above 4500-5000 but i also found if i hold the throttle wide open, it slowly looses rpm, it went from 4500 down to 4000, then down to 3500 (in about 5 seconds. back it idle it seemed to idle pretty rough, just below 1k. (yeah im pretty rough on the car lol)

i tried new spark plug wires and plugs, new air filter, cleaned the mas air flow. just trying little things that i keep hearing about but now im wondering why it would lose rpm like that..

any thoughts or suggestions are appreciated!!

Topic

[Its me]

Start by checking your fuel pressure…. Also do you have an in line fuel filter on it?

At WOT your fuel pressure regulator should be wide open (full fuel pressure)… Check the vacuum line to it and ensure there are no fuel leaks into your vacuum line from your Fuel pressure regulator (leaking fuel pressure regulator diaphragm) and that the vacuum line has no vacuum leak…

May want to check for random vacuum leaks (rough idle)… Are you getting any codes?

The fuel pressure regulator is the gold circular thing that has the vacuum hose on the right of the fuel rail in this pic…

-Karl

[Matthew Naffziger]

i was thinking of that myself when i told my friend about what had happened, i thought, if fuel pressure cant keep up, it could go down i suppose. i was looking at the regulator like the one in the pic, wiggled the line but i couldnt really see/feel anything.

as for codes, my check engine light hasnt come on at any point during this whole thing, so apparently my car thinks its running fine lol

would it be possible to feel the regulator move when throttle is opened? like running my fingers underneath it?

[Its me]

[quote=”naffziger” post=70408]i was thinking of that myself when i told my friend about what had happened, i thought, if fuel pressure cant keep up, it could go down i suppose. i was looking at the regulator like the one in the pic, wiggled the line but i couldnt really see/feel anything.

as for codes, my check engine light hasnt come on at any point during this whole thing, so apparently my car thinks its running fine lol

would it be possible to feel the regulator move when throttle is opened? like running my fingers underneath it?[/quote]

I don’t think you will feel anything with regard to the regulator, but I cannot be 100% certain of that…. It is best to inspect it as posted earlier….

I suspect a fuel delivery issue…. If you have an in-line fuel filter, it may be restricting fuel flow….

The best check is a fuel pressure gauge hooked into the rail/fuel line as close to the engine as possible…

Also, never discount bent or kinked fuel lines somewhere… That can cause issues where the pressure seems fine, but the vehicle has fuel delivery problems…. Also a weakening fuel pump can cause issues…. But that is further along in diagnosis….

-Karl

[Matthew Naffziger]

this might add a little fuel (haha) to the fire about a pressure issue, but when i first start the car it would go to 6k, but every time after that it wont get above the previously posted 45-5000 rpm.

ill check the fuel lines tomorrow when i have some light.

thanks karl!

[Its me]

[quote=”naffziger” post=70414]this might add a little fuel (haha) to the fire about a pressure issue, but when i first start the car it would go to 6k, but every time after that it wont get above the previously posted 45-5000 rpm.

ill check the fuel lines tomorrow when i have some light.

thanks karl![/quote]

That makes absolute sense…. When you first turn on the key, the fuel pump will cycle up to pressure for a couple of seconds for your initial start… If the engine does not start (from Crank position sensor signal) the fuel pump does not remain on as a safety feature…. This is probably allowing your first start to have the highest pressure of fuel for that initial 6k rpm… The lowering of maximum rpms afterward is probably due to a lower fuel pressure for reasons not yet determined.

Good luck tomorrow and keep us posted…

-Karl

[Matthew Naffziger]

well i did an inspection of my fuel lines and they all seem good, and i even saw the hyundai logo on my fuel filter, which made me wonder if it had ever even been changed. so i bought one and changed it, but while i had the lines off, i cycled the key a few time and not a drop of fuel came out of the lines? i was actually hoping to catch some and look to see if it was filthy or had water in it, but nothing came out.

subsequently when i put on the new filter, an o-ring went missing and fuel was spraying everywhere out of the top of the filter cus it wouldnt seal lol had to buy a universal set of o-rings and it sealed up nice now.

tomorrow when i get paid ill probably buy a regulator to put on to see if that changes it. i hit the gas after i got the filter to stop leaking and it did the same thing. 6k, then dropped to 4500 then 4k then 3500. but if i back off the throttle just a bit, it came back up to 4k. i did it a few times to see if it was a fluke. but every time i mash it WOT it bogs down to 3500 but when i let off it comes back up. probably from too much air rushing in?

i might just go car shopping soon lol

[Bill]

It’s possible that the catalytic converter is plugging up. What goes in has to come out.
LoL. You might try removing the oxygen sensor or even disconnecting the exhaust pipe and give it a try.

[Matthew Naffziger]

thats not the first time ive heard that actually lol one of my friends said that first thing. either cutting it out and straight piping it or just run a pipe down through it.

would it happen that fast though. i mean one week it was fine, the next its crap? i just cant see it acting up that fast.

[Bill]

Yeah….They melt inside or fall apart and the small pieces plug up the good parts that are left.

Worse thing for a converter is an engine misfire and second worse is running rich.

[Matthew Naffziger]

ill be taking the car to work with me monday so i can take off the exhaust manifold after i get off. if the car runs better with out the exhaust ill know if there is a restriction in there somewhere. and if there is ill cut it out and put in some new pipe lol

[Author]

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