Hello, i have a 2004 Hyundai Elantra which i have recently replaced the high pressure power steering hose, 2 new belts, spark plugs, air filter and battery.
after this my car ran fine for a day, next day i noticed the idle surging and dropping which was causing power loss , clicking sound near dash each time the CEL light came on then off again.
I installed a new crank sensor, cleaned the MAF the proper way. Checked for any and all possible vacuum leaks. Tried pulling codes, got 1 for 02 sensor bank 1, low battery voltage, and a couple others i cant remember at the moment. I also switched out fuel pump relay. And lastly unplugged my CTS, which caused it to idle high but after that it drove well for over and hour, but sadly stalled again in my driveway.
Tested battery with multi meters and showed 14.8v, turned on heater it dropped to 14.5. i also ended up with a lot of PS fluid in my alternator when changing out line. My heads a mess on all the possible issues that could cause this so just really hoping someone out there can help shed some light on this and possibly direct me in the right direction. Theres possibly things i left out but ill add what i can as it comes to mind.

 

You might purchase a can of electrical contact cleaner. Spray that into the alternator and it should remove most of the oil residue . Give it time to dry out. do it twice. Wait at least an our or two before starting vehicle

You did clean the battery cables before attaching them to the battery, right? Also make sure the negative battery cable that mounts to the engine is clean and tight.
You might look for wires that are connected to sheet metal for grounds .Remove them one at a time , clean under them and reinstall to insure a good connection.
Many times the corrosion is hidden under the connection and it can look good , but still not make good contact where mounted.

 

Yes i cleaned all cable connections, ran a body ground from negative terminal to block, only other ground i see is going to the rear firewall which i cleaned up and reconnected. Just got it back from the shop, they put their snap on scanner on and only got the same 4 codes i got, he swapped main relay and figured he had it, ran good for 10 mins, left it for 2 hrs, started it, ran well 10 mins then stalled again. Sprayed the alternator a few times with an hour break between. Same issue.
Shop guy said to look at wiring under the fuse box beneath the main relay, i honestly dont think thats it but ill try it. Tyvm for your reply.

 

So now three weeks in and still doing process of elimination.
checked 3 times over for vacuum leaks, changed TPS, IAC, found large ground under fuse block, cleaned and replaced. Changed MAF sensor, cleaned throttle body, all relays tested good, redid all electrical connections with diolecic grease, and quite a lot more, now just got new fuel rail and injectors, engine coolant temperature sensor, coil packs and wires. Will install them tomorrow. As of now car still starts, tach needle shoots up then down rapidly as CEL light flickers each time with the same clicking sound until it soon stalls again. So seems like IAC, vacuum leak or Short, not sure what to test or look at next if these don't fix the issue. Any input would be greatly appreciated.

 

I am aware you replaced the crank sensor, however, the tach needle jumping around is an indication of intermittent signals from the crank sensor.

I would suggest looking for a poor or loose connection in the crank sensor circuitry.

 

Thank you for your fast reply. I'll take any suggestions available, and i will test and check all wiring from the crank sensor, ill let you know if i find an issue.

 

Checked and tested all wiring , ground, power and single all looked good, did a smoke leak test today and that showed nothing, tomorrow im changing TPS, MAF sensor and both coil packs.

 

I have an 04 Elantra 2.0L that has had the very same issues I have replaces the maf, plugs, wires, tps, entire evap system, purge valve & soloinoid. Crank sensor, coil pads, 02 sensors. I was finally able to get it to start start, but after about 10 mins it would die & now it's dead. It's in the shop now & they're saying that my can sensor is bad & it's throwing wrong info to the pcm also that the pigtail that connects to the fuel pump is bad n breaks contact, causing it to die.
still a work in progress. Maybe this might help.

 

Thanks for the update.

It is better to leave the diagnosing to the person that has the vehicle in front of them.

I don't know how the wire connections were checked, but to do it right we pull gently and if there is any unusual movement , that has to be investigated. Sometimes a poor connection gets corrected by just disconnecting the connection and reconnecting it.
I get a little uneasy when someone says they "looked good" I hope you were not just "looking " at them.
Some components are in places that getting your hands in there is next to impossible, but that is why it gets expensive for someone to do the job right.



If a scan tool that is providing live data is utilized, we just look for what changed at the time the engine decides to stall.