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Discussion Starter · #1 ·
Hey. Obviously new here. But not new to online forums. They are invaluable. So, that said, my mother in law just bought a new car and gave us her old trusty 2001 Santa Fe. Its a clean little SUV, Sandstone Metallic, GL with aftermarket leather and 2.4/auto.

So here goes.

Currently it has 154k on it. Also Currently the CEL is on (P0300, P0446, P0171). Interestingly, the 446 isnt in my book (Haynes) but when Auto Zone scanned it, it was an Evap code of sorts...which is consistant with the other 440's in my book. Anyway, this check engine light is on and judging by the stack of repair orders from the dealer, it likes to be on. Looking through there, for the past 6 years or so....usually the codes have had something to do with the Evap stuff, judging by what the tech did. Obviously its never been correctly fixed.

Symptoms right now when first started, the motor does not seem to have a high idle as it should...it idles slow and stutters, and will stall if you put it into gear before it has run for a few minutes. Also, when its running, it will idle fine but when first taking off it will hesitate and then just take off.. (well, as much as a 4 banger suv will take off)....generally the little motor runs fine, and sounds fine. Also when going down the highway, it will jerk once in a while.

Now, also I do know the timing belt has been replaced, and at 110k miles, the transmission was replaced at the dealer.

Also, the dealer has replaced the cat and pipes, basically looks like all behind the manifold has been replaced one time or another....

Its also got some sort of oil leak...the motor was super gunked up (in laws never ever have cleaned a motor in their lives...)...I cleaned it up to watch for an oil leak. Jiffy Lube told her it had an oil leak (because they checked the fluid and it was "very low" prior to an oil change). Of course, their barely educated techs told her it was a cracked head or a valve cover gasket or rear main. Um....yeah...anyway, I cleaned it up to see where its leaking. I doubt its a head issue, theres no overheat, no loss of power (all 4 cylinders worth), no coolant loss, no cross contamination with coolant in oil or oil in coolant etc. i'll be working on the oil leak thing once it leaks enough to see..so far (had it couple of days) nothing has shown up.

But anyway, enough about that, the main deal is, what is causing the motor to run like a carb'd motor w/ a broken choke? what's causing the hesitation/jerking on the highway and when trying to accelerate? i hate to start throwing parts at it, like the dealer has been for the CEL for the past 6 years at least.....i've read about the crank and cam sensors, and know the issues they can cause, I had one on a 96 neon I fixed up and gave to my brother in law (yeah, looks like cars get passed back and forth haha)...the cam sensor was actually split....it would cause the car to shut off and not restart until cooled down...but the 'Fe doesnt die, just jerks then goes back to normal. We'd like to keep this car and use it, she bought it new and its a decent car. The wife actually wants to sell her 07 C class benz (gets tired of making that payment for one thing) and use this as her daily driver since its got alot more room for our two babies.....so, i'd like to get the quirks worked out before we sell the other car and have only half a car........

ok sorry for the long first post....
 

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:00000732:

Camshaft position sensors are a common failure item with the SM Santa Fe. I think that would be a wise place to start. Oh and here's Code 446 courtesy of New Tiburon's master CEL list of awesomeness. :grin:

P0446 - Evaporative emission (EVAP) system, vent control – circuit malfunction Wiring, EVAP canister purge valve, ECM
 

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Discussion Starter · #4 ·
QUOTE (lovemysantafe @ Jun 2 2010, 04:41 PM) index.php?act=findpost&pid=328948
:00000732:

Camshaft position sensors are a common failure item with the SM Santa Fe. I think that would be a wise place to start. Oh and here's Code 446 courtesy of New Tiburon's master CEL list of awesomeness. :grin:

P0446 - Evaporative emission (EVAP) system, vent control – circuit malfunction Wiring, EVAP canister purge valve, ECM

cam or crank? lots of stuff i've read talk about the crank sensor....from what i've seen, the cam sensor is easier to replace so i'd rather it be that but i think its the crank sensor....
 

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2.4L Melco motor....

P-0300 : Random Misfire Detect, not harsh enough to single out a specific cylinder (01/02/03/04)--- Start by looking at plugs, wires and coil sticks (the plastic winding body where the steel loop pass real close for a large white/grey spot) for burn mark.

P-0446 : Evap - simple terms is evap cannot breath.. the canister is restricted, replace canister, close valve since it is all apart, and the vent filter as a package.

P-0171 : Lean Bank 1, look for vacuum leak, the 2.4 likes to split the PCV hose on a bunch of the 2.4 near the port at the intake manifold.. Also look for low fuel pressure, bum MAF, broken/split air tube between MAF and throttle body (un-metered air), biased ox sensor..

Who paid the $900 for the catalyst guess ??
 

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QUOTE (2001santafe @ Jun 2 2010, 07:18 PM) index.php?act=findpost&pid=329023
cam or crank? lots of stuff i've read talk about the crank sensor....from what i've seen, the cam sensor is easier to replace so i'd rather it be that but i think its the crank sensor....
I meant to say crankshaft. Sorry.
 

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Discussion Starter · #7 ·
QUOTE (lovemysantafe @ Jun 2 2010, 10:51 PM) index.php?act=findpost&pid=329060
I meant to say crankshaft. Sorry.
yeah thats kinda the PIA i was thinking haha.


sbr711....hyndai dealer did the cat under hyundai warranty...that CEL has been on forever...and always has had some sort of EVAP issue apparently....its got paperwork for last 6-7 years with it being on...no telling what all parts were thrown at it...

the CEL doesnt really bother me, nor do i put too much thought into the codes...i just want this jerking and hesitation to go away...so i'll be changing that crank sensor soon and see.....the light can stay on for all i care haha.
 

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Discussion Starter · #8 ·
Ok you experts...we just drove the santa fe down to the river for some tubing and back. approximately a 510mile round trip with the little bit of driving once there.

so..here's my observations.

the car, when first started, doesnt like throttle input at all and has a very very unsteady idle and will stall if you put it into gear before its warmed up a few minutes. its only on the cold start, as in first start after sitting all night. exactly the way a carburated motor does w/a defective choke.

second...almost always between 2300-2600rpm and occasionally a little higher rpm, it has a very pronounced jerking or misfiring...you can play with the throttle back and forth slightly to make it do it somewhat predictably. if on flat ground and cruising its no problem at all. just in that one range. if it starts jerking you can go ahead and give it more throttle and make it push through that issue...so its doubtful its a spark plug wire or plug type of misfire...waaay too regular wiht the RPMS.

only thing i can think of with regards to the throttle position being a factor, is obviously, a bad throttle position sensor. i havent checked it with the volt meter yet, my volt meter batteries are dead. oops. but i dont think its a crank sensor at this point due to just the overall feel of it and the way i can know when it will do it, and even how i can induce it a little bit...its very annoying but i dont think its a serious issue.

side note, when she gave us the car, she told us jiffy lube said she had oil leaks and cracked head and all sorts of issues. um...i doubt it. no coolant in the oil or oil in the coolant, no cooling issues, i did degrease and clean up the motor and tightened all the bolts on the valve cover and oil pans. only very minor seepage along the valve cover gasket, not enough to even notice unless you are looking for it. didnt seem to burn or leak any measurable amount of oil on that trip either. it does burn a little bit i do believe, but only when idling for exteneded periods of time...i noticed a slight oil smoke coming from the tailpipe after idlign about 20 minutes after cleaning the motor.

so anyway, i did look at the plug wires and they look like they are fairly new...i'll look to see if they are in the invoices i got from her. but has anyone had any experience with the throttle position sensor going bad and having issues like this or similar? is my thinking just way off the wall?
 

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Discussion Starter · #9 ·
OK. someone please put some more thoughts in here...hate to replace that crank sensor if its not what causes it..the sensor is almost 100 bucks and its a pain in the butt to get to apparently.


I did check the voltage on the TPS and its within spec according to my haynes manual, and theres no spikes or drops or anything throughout the throttle range so i dont think thats it after all.


more details on the misfire....sometimes when it does it, u can feel what feels like a "dead cylinder", u can hear it....and if you barely feather the throttle u can get it to get a little louder...till u give it enough gas for it to just "clear up" whatever is going on and it will accelerate jsut fine. im now thinking maybe a clogged injector or otherwise poor fuel flow someplace....ideas??? its only the random/multiple codes not a cylinder specific one so im not sure. that and the fact it will start, rev up to the high idle like it should but then promptly slow down and start sputtering and having an erratic idle...sometimes might stall out...giving it gas doesnt do much of anything except make it try to die faster....only when cold or its first start after sitting overnight. anny other start during the day, even those where it has sat for 3 or 4 hours, is fine. only if its like an all day at work type of sitting or overnight..then it acts like a choke issue on a carb'd motor. i doubt thats a crank sensor...and i feel the jerking/misfiring while driving is related...and i think it might be a fuel flow issue...thoughts from u experts???
 

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Discussion Starter · #10 ·
if anyone is reading this thread (not that anyone cares to reply....), i have now tried new ignition coils. plugs/wires, throttle position sensor, idle air control valve, cleaned the mass air flow and the dealer also tried it with a new one....replaced the fuel pump and strainer....

took it to the dealer to avoid throwing parts at it, for diagnosis. wrong idea. they immediately suggested spark plugs and wires (i did them the night before i took it in) and then ignition coils. no change. they did say however, that the fuel flow was low, and an erratic reading from TPS at times....talked to the mechanic and he said i should try a fuel pump assembly first for like 400 bucks (or get a new fuel pump and strainer for 22 bucks via ebay...duh.. and replace just the pump itself...no brainer), and the TPS...then he said the O2 sensors were reading as if the precat was partially stopped up....


so, i think it runs great now, only an occasional bogging down at 2300 rpms...and when started cold, it starts, then sputters and barely idles for a few moments...then will be fine....

im gonna pull the first 02 sensor tomorrow after i run and get an oxygen sensor socket, i cant get my wrench on it....that way it will have an exhaust leak large enough for it to not be affected if the cat is actually stopped up (actually read that online, and good idea....makes sense)....if it starts and runs fine then i'll be getting a new aftermarket precat off ebay for less than 200 bucks and be done with it. if not, well, then i dunno...

suggestions?
 

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I think you're on to something by relieving exhaust back pressure by temporarily removing the oxygen sensor. Keep in mind that the engine will run in open loop mode for the first few minutes after it is cold started. After that, when it goes to closed loop operation, the oxygen sensor not being in the exhaust flow will play havoc with the fuel mixture, so don't be surprised if it messes up big time and then throws a CEL for the sensor after 20-30 minutes or so.

The way you described your symptoms, it makes me think you have a vacuum leak somewhere, but it looks like you're mechanically savvy, so I kind of think you might have thought of that already.

Low fuel pressure will cause it to run lean with stumbling (especially when cold and fuel demand is slightly high) and misfire. If the fuel pressure is low, I wonder if the fuel pressure regulator might be one possible contributor to the drivability issue. If you pinch off the fuel return hose temporarily and drive it then, will it change the symptoms?

Just thinking "aloud".
 

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Discussion Starter · #12 ·
QUOTE (DSHornet @ Jul 14 2010, 08:56 PM) index.php?act=findpost&pid=341838
I think you're on to something by relieving exhaust back pressure by temporarily removing the oxygen sensor. Keep in mind that the engine will run in open loop mode for the first few minutes after it is cold started. After that, when it goes to closed loop operation, the oxygen sensor not being in the exhaust flow will play havoc with the fuel mixture, so don't be surprised if it messes up big time and then throws a CEL for the sensor after 20-30 minutes or so.

The way you described your symptoms, it makes me think you have a vacuum leak somewhere, but it looks like you're mechanically savvy, so I kind of think you might have thought of that already.

Low fuel pressure will cause it to run lean with stumbling (especially when cold and fuel demand is slightly high) and misfire. If the fuel pressure is low, I wonder if the fuel pressure regulator might be one possible contributor to the drivability issue. If you pinch off the fuel return hose temporarily and drive it then, will it change the symptoms?

Just thinking "aloud".
no change with the O2 sensor out on the cold start...didnt drive it cause i didnt want to call attention to it (was loud haha) and figured id be in closed loop too soon...

but did have the cats checked anyway, the exhaust place checked the flow and they are fine....so i think i might be back to a fuel pressure deal...the vaccuum leak thing i cant find any leak....who knows...

can i pinch off the fuel return hose and drive it? never thought about that....
 

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Sounds a lot like you have run into problems that nobody will be able to pinpoint. I have the same problem with my car, have had problems with the engine for over half a year and not a single mechanic is able to pinpoint the problem.
What I do know is that I have misfires as well, loads of them, engine really runs bad, but nobody knows what the cause is.

At the moment I cannot even sell the car anymore because it is running so bad. One Hyundai dealer already told me to scrap the car, repair would be too expensive, so basically he is telling me to write off a car, which I bought last November, in less than a year.
To me that sounds pretty ridiculous and am not willing to do that.

I have now bought a spare ECU, will try it this week and after that I will take a look at the crank shaft sensor again, plus the complete vacuum system. The misfires tend to increase when the engine has to work, which means the timing adjustment is not working properly. Question is ...............why ?

Hope you find some solution, am curious to hear what it was, may give me some ideas as well.

In all I can safely say that this Hyundai is the worst car I have had in my life. I will be so happy to get rid of this car and go back to the non-electronic Mercedes Diesel with a simple Bosch fuel pump, no electronics, easy to fix and difficult to break down.
 

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Discussion Starter · #14 ·
well i hate to jinx myself but the wife has been driving it for the past week solid to and from work and she reports no issues at all with starting it nor any "jerking" while driving. so no misfires i assume. i ran up to fill up my propane tank for my gas grill saturday at the local muffler/inspection/propane place and had them check codes and all i am getting is the evap code now...(same code thats been there for 6 years apparently....dealer has replaced the evap canister and all valves with no fix so they just lived with it), so i assume the misfire deal is taken care of for good....when i drove it the short distance it ran really well and didnt give me no trouble either. i did have one weird code, on the printout it said unknown code and i googled it and it showed to be a reverse something or other trans code...but we've never had any issues....so, anyway, if it starts being a POS again i'll work on it some more, for now i'll just drive it as is...i did change the oil in it tonight...which was refreshing....i can change the oil with a 5 qt jug and filter from wally world for less than 20 bucks haha. havent been able to do that on a car we've owned in years...the benz uses almost 10 quarts of that euro spec mobil 1 synthetic and a MB only filter cartridge and u have to drop the belly pan or suck it out top side...the tundra is almost as big of a pain, holds a ton of oil and has a pain in the butt skid plate to remove....the santa fe took all of 15 minutes...just easy to get to and take care of business. im gonna like the simple life for a while.
 
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