Car trouble - need advice (mechmike are you here?)

[Markel]

I just arrived in the northern Atlanta area (Dunwoody) for my son's club volleyball nationals (July 1-4). I'm driving what was Nate's 2000 Hyundai Elantra (116,000 miles). We don't have any idea of the maintenance history because we just got it a year ago or so.

Things were going great (getting about 36 mpg) until I was about 20 miles from my destination. I then noticed the car sounding like it was occasionally missing. It started getting worse, then I could hardly give it any gas when going uphill or it would almost die. It got continually worse - I was sputtering along on the shoulder, hoping to reach my hotel. At one point the engine completely died, and when I restarted it it was running completely normal. I went a few miles and the sputtering started again, so this time I pulled over on the shoulder and shut off and restarted - running good again. This got me to my hotel, but I definitely don't want to leave for Chicago on Saturday afternoon without knowing what's going on. The behavior makes me suspect that it might be a clogged fuel filter, but I guess there's always the timing belt to be concerned about.

Any suggestions? Hopefully I can find someplace to take it to tomorrow afternoon. The hotel I'm at runs a shuttle to the mass transit station that takes me down to the volleyball venue (Georgia World Congress Center - right next to the Georgiadome) so that will help if I need to leave the car off someplace. (I see that there is a Goodyear Auto Center just up the road, so I might give them a visit.)

I should add - no check engine lights or such. Just rough running, especially under load.

[mechmike0034]

There guys are good: http://mcculloughautocare.com/

They are in Sandy Springs - right at I-285 at Exit 25 at the top of the ramp. They are right next to Ruth's Chris on the left as you are headed north on Roswell Rd.

[Markel]

Left the car off there this morning. Volleyball ran late (7pm instead of 2pm due to my son's team having to play some extra matches in order to stay in the running for the top bracket - which they did by winning both extra match4es) so I didn't get a chance to check back with them (I'm using the light rail to get from the hotel to the volleyball venue, so the car isn't essential at this point). I'll try giving them a call tomorrow.

It REALLY helps to have a recommendation rather that a shot-in-the-dark in a "strange" city. THANKS for the guidance, mechmike!!! (McCullough's is only 3 miles from my hotel, so that is especially great.)

(I'm wondering if I might have gotten some bad gas at my last fillup in N Georgia - it was a BP station, but you never know....)

[mechmike0034]

You are lucky enough to be close to a shop that I know fairly well. I am confident they'll treat you right.

Hopefully the problem is nothing major. I am always happy to be of assistance.

[Markel]

When I called them this afternoon, they said they couldn't find anything wrong. (Not a big surprise based on my experience with it running fine after shutting off the engine.) I explained a bit more over the phone what had been happening, and they said they would check again. Hopefully if there is anything wrong they can figure it out and get it fixed by the end of business tomorrow, because I'll need to pick up the car by then in order to check out on Saturday morning.

The engine restart "resetting" the problem is what is strange to me. If it was a clogged fuel filter, the restart wouldn't change anything.

[Daedalus]

Did they actually hook up a pressure gauge to the fuel line and drive it around? I like your clogged filter theory, and I can think of a couple related causes. A lot of cars have dual or triple-voltage fuel pumps. Battery voltage on start-up and WOT, and lower voltages at othe times. If the pump is going out the fuel line may get full pressure at start-up on high voltage, then slowly bleed off pressure over the next few miles as the pump on a lower voltage cannot keep up with demand.

It could also be the fuel pump controller. As electric pumps age they draw more current. A solder joint in the controller can get hot enough to melt, causing problems. As soon as you stop the car it cools and solidifies. This one can drive you crazy trying to troubleshoot. Look for signs of melting and heat discoloration at the connectors.

[Markel]

Well, they never could get the problem I has having to occur. They did find that the fuel filter was at least partially clogged, so they installed a new one. Hopefully things will be working when I leave for home tomorrow afternoon.

[mechmike0034]

Well, they never could get the problem I has having to occur. They did find that the fuel filter was at least partially clogged, so they installed a new one. Hopefully things will be working when I leave for home tomorrow afternoon.

I hope you get back to Chicagoland OK... My sister and her family (including my Mom) moved to Park Ridge in April.

Sorry there wasn't a more definite outcome. I can relate to their taking a conservative approach. That is much less expensive than throwing parts at the problem (we in the repair biz call this "diagnosis by inventory") like darts at a dartboard.

[Markel]

5 hours on the road this afternoon/evening without any problems.

[brainsmile]

Nice one mechmike0034.... Love it when someone you trust gives you a recommendation!

[mechmike0034]

5 hours on the road this afternoon/evening without any problems.

Outstanding! - I'll let them know next time I get over there. Glad you made it home OK.

[Markel]

Made it home fine today (yesterday was just the first leg of the drive) except for accident and construction traffic jams that turned the 11 hours of driving into 12.5 hours.

I took a few of McCullough's business cards and left them with the hotel front desk. I told them that if anyone ever inquires about a local mechanic that they came highly recommended by an industry insider.

[Markel]

I got a call today from McCullough's asking if everything was ok on my car. This is only the second time that I have had a followup call after an auto repair, and I think it shows great customer service.

[johnnymk]

That is rare in today's world.

[Markel]

Not sure if it is in any way related to past problems, but yesterday I turned onto the road to my work (1 mile to go after 17 miles of driving) and my car stopped dead (no sputtering or anything - the engine just died). I tried cranking it for quite a while but there was no sign of life (as if it was not getting fuel or spark). I called AAA and arranged for a tow, and as I was waiting I would occasionally try to start the car. About 45 minutes after it died, it started right up (but the check engine light was on). I went on to work (after canceling the tow) and after work drove home and dropped the car off at my mechanic. Today he told me that the problem (from the check engine code) was a bad crankshaft sensor.

[Daedalus]

Not sure if it is in any way related to past problems

I think it's possible. Bad CPS can cause both, though I would have expected a MIL the first time. I wonder if it was indeed the sensor and not just an intermittent harness connection problem.

[johnnymk]

I think it's possible. Bad CPS can cause both, though I would have expected a MIL the first time. I wonder if it was indeed the sensor and not just an intermittent harness connection problem.

salt? corrosion?

[mechmike0034]

The Crankshaft Position Sensor on this vehicle is a variable reluctance type, which is essentially a coil of wire wound around a bar magnet. Several things can happen to these over 100K plus miles of vibration and thermal cycling.

Some will fail when hot and work OK when cold, as you've seen.

Hyundai Service Information online is free for that car, BTW - all you have to do is register.

Here's the factory schematic showing the signal wires and shield wire. Here's another view...

I can't find any enable criteria (what has to happen for a crankshaft position sensor code to set) in their service information - they just define the P0335 code as "Crankshaft position sensor circuit malfunction" and note that it does turn on the MIL (malfunction indicator light, commonly called a "check engine" light...).