QuestionQUESTION: Hi,on my 1999 Hyundai sonata recently lost the ignition spark. I got a code reader and the code said that it had crankshaft sensor circuit a malfunction, so I replaced the crankshaft sensor, and the timing belt while I was in there. It still has no spark. What other things could it be?
ANSWER: Since you replaced the timing belt while replacing the sensor, I'm assuming you have the 2.4L four cylinder engine. I can't think of a single instance on this engine where I had a code for the crank sensor that the issue was not related to the crank sensor or timing belt.
To start, I'm going to ask you some questions that'll hopefully give me a better idea as to what's occurring.
1. What was the condition of your timing and balance shaft belt when you removed them? Were they broken or were any teeth missing?
2. Was the plate between the crankshaft sprockets in good condition?
3. Is it possible you installed the plate backward? I typically use the markings on the plate made by the sprockets as a guide.
4. Is it possible you installed the crank sensor backward? The plate should go between the two halves of the crank sensor.
5. Is it possible you routed the crank sensor wire routing incorrectly and it got cut by one of the moving components?
6. Does your engine crank faster than normal?
7. How did you determine that you have no spark?
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QUESTION: 1 The condition of the timing belt was worn it had a couple of missing teeth.2 Yes the plate between the crankshaft sprocket appeared to be in good condition.3 No the plate should be on correctly because I did not replace the balance shaft belt and did not have to remove it.4 No the crank sensor only goes one way. 5 No I took extra care that it was routed exactly like the one that was removed because every thing is very close in there.6 No it has good compression it has over 120 psi. on every cyl.7 I pulled a spark plug out and stuck it in the plug wire grounded it with a grounding lead to the negative battery post and crank the engine over while watching for spark, and there was nothing. PS. Yes it is a 2.4L.
AnswerIt does sound like you've done a good job checking everything.
One of the reasons for failure of this crank sensor is that the teeth that come off the timing belt can get wedged between the sensor plate and the sensor, damaging or breaking the sensor. It's possible that if you didn't get all the old broken off belt teeth out that one of them has broken the new sensor.
If you can, I'd recommend checking the crank sensor output. First, verify you have power and ground to the crank sensor. With the ignition key in the on position, you should have battery voltage between the pink and black wires in the harness connector for the sensor. If that's okay, you'll then need a scope if you want to check for the actual square wave on the yellow wire (when plugged in). An alternative is to use a meter that will check frequency and voltage. On DC Volts, you should probably be somewhere between zero and battery voltage while cranking, and the reading will probably vary. On AC Volts, I'd expect something around 8.5V. And you should also get a frequency measurement while cranking.
