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Discussion Starter #1
Heading down the freeway, the car dies. Middle lane in heavy downtown traffic. State cop pushes me to the side of the road and there I sit, waiting for a tow. Bad news.

When a friend shows up and we're ready to tow, I try again and it starts. He follows and the car makes it maybe 3 miles and dies again. We wait awhile and it won't start so we tow it to my house. It starts and runs so I put it in the garage.

Now, what can cause this kind of behavior? There's no sputtering like what you might expect with fuel flow problems, still it seems like it might be fuel related. Maybe something with the computer shutting off the gas, or some such.

Don't work on cars, or at least not often and never on anything like this. Can anybody point me in a direction?
 

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Discussion Starter #2
I forgot to mention; about 30 seconds before the car died, there was a convulsive lurch accompanied by a pretty loud noise.
 

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If you mean the engine shuts down and will crank, but not start then what you described are symptoms that are often characteristic of a bad crankshaft position sensor (...not guaranteed that it is though). If you have a tachometer, pay attention to it next time it dies. Whenever you start the car, you should see the needle bounce slightly while the motor is cranking. If the tach needle doesn't move when the motor is cranking then that likely means the crankshaft position sensor isn't sending a signal to the ECM and the motor will not run. This is even better seen if you have an OBDII scanner that reads live data. Just select the engine speed (RPM) datastream and if the crank sensor is bad, it will read 0 RPM when the motor is turning over.

You said the car lurched and made a loud noise before it stalled? Did this happen every time you had this run/stall sequence or just once? What did the noise sound like?
 

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Discussion Starter #5
Well, I ordered a reader gizmo and it should be here Wednesday.

Most guesses I got at the Gold Wing forum were also the crank po sensor, but I don't want to start replacing parts without a pretty good idea they're bad.

I'll need a heap of advice when I get started.
 

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Have a look at timing belt.... LC Accent will break if not replaced in timely manner
 

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Have a look at timing belt.... LC Accent will break if not replaced in timely manner
Always sage advice with these cars.

You initially suspected the fuel pump--when the car wouldn't start did you try spraying starter fluid in the intake manifold? If the motor fires up with starter fluid then that suggests a fuel delivery problem with the fuel pump the likely culprit although you'd need to test the fuel pressure to be certain (...a special adapter needs to be hooked up to the fuel rail that you can attach a fuel pressure gauge to). Also, did you check to see if you were getting spark from the ignition system?

On a side note, I see you're in AZ, but your Hyundai is still 16 years old so double-check all your grounds for corrosion just in case.
 

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When the engine won't start, check for spark at plugs
And check for fuel injector pulses
If both are missing then it is a good indicator that the crankshaft sensor is faulty
Not unusual to see the crankshaft sensor fail when engine is hot
Cools off and it works for a while again

 

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Discussion Starter #9
Well, codes are P1703 ... Manufacturer Control.

and P0727 ... Engine Speed Input Circuit no Signal

Does that make any sense?
 

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Well, the engine speed input comes from the crank position sensor, so the 727 code seems to confirm what rusty & avisitor have already told you.

Did you follow they're advice and check for spark when the engine wont start?
You should also check to see if the fuel pump is being switched on DURING CRANK.
No spark and no fuel delivery are the common symptoms of crank sensor failure. So if you confirm the symptoms and you have a code for a crank sensor too, I think you can be pretty confident your not wasting money by replacing the sensor. Any further diagnosis really requires tools you probably wont have access to (oscilloscope).
 

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Discussion Starter #11
The car starts and runs so those observation tests don't really pertain to the problem. I would have to take it out and drive it until it fails again, then try to check for spark and fuel etc., over a hot engine in 110 Arizona heat.
 

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The car starts and runs so those observation tests don't really pertain to the problem. I would have to take it out and drive it until it fails again, then try to check for spark and fuel etc., over a hot engine in 110 Arizona heat.
Your right, there isn't any point to testing it when the engine is starting, so you either need to test it when the fault is present or just replace the crank sensor and see what happens.
 

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Discussion Starter #13
Yeah, I'll order the sensor.

I put the car in the driveway and ran it a half hour idling with the A/C going and it didn't so much as flinch so I putted around the neighborhood a bit and again, all was fine.

Did I just imagine last Friday?
 

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Yeah, I'll order the sensor....
You need to be aware that a problem (with or without a code) does not automatically mean that a sensor is bad. Every sensor has associated connectors and wiring, and very often the problem is caused by one of those. So the (highly) recommended approach is to first examine the connector(s) and all visible wiring related to a suspected sensor, before considering replacement. Additionally, the best diagnostic approach is to test the sensor circuit, before replacing the part. You can do some basic testing with a multi-meter, although a scope is required to evaluate the waveform produced by a crank/cam sensor.

... Did I just imagine last Friday?
I'd put money on the problem returning, probably in the near future. However I also wouldn't hang on a new crank sensor before doing everything possible to check out the circuit first.
 

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Discussion Starter #15
Can anybody explain to me why the codes show as transmission, not engine problems? Is that a malfunction in my new reader?

And why isn't there a standardized chart for codes and what part(s) the code refers to? After 2 days of searching I haven't found a chart that definitively names the crankshaft position sensor for a P0727 code.
 

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The two codes you've posted don't seem to be valid for your car (UK models at least) so that would seem to point to an issue with your generic scan tool.

They aren't valid codes so there isn't any diagnostic test plan relating to them in the workshop manual.
 

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Or they are/were pending codes from the "lurch" you experienced. Which again may have been set due to your engine dying all of the sudden and PCM going "I just don't have the power, captain". Scott can probably do that in the actual accent :).

Cool thing about OBD codes is that there's a different code setting criteria for various cars/makers. So that's why when you look them up, it'll list various things that could be wrong but it never tells you exactly what you need to replace. It's all about how the various systems are interpreting what's happening and triggering errors when various things are out of bounds.

The Crank sensor is a hall effect so the signal may not be out of bounds when the engine is running. After heat soak, things expand, lose integrity... etc and all of the sudden the ECU is not getting the right signal or one that's correct to be able to start the engine.
 

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Did you try looking on YouTube for some videos? avisitor linked one in a previous post.

A couple of things that can give you some extra space (if you haven't done this already):
- Remove the engine cover (it protrudes just enough to get in the way, esp. for light/visibility)
- Disconnect the O2 sensor connector that's attached to the same bracket as the crank sensor connector. You can even take the O2 sensor wire out of its bracket, which is attached to the exhaust manifold heat shield and just move it out of the way.

Penetrating oil on the sensor itself may help with actually getting it out--remember, it's been stuck in the engine block for 16 years so it's probably not going to come out easy. Don't forget to get the old o-ring out. You might need a pick and mirror if it remains lodged in the block when you get the sensor out.
 
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