Emission control system

Tiny
STEPHEN KARANJA
  • MEMBER
  • 1998 ACURA RL
  • 3.5L
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 233,000 MILES
This car runs then all of a sudden stalls and dies. The check engine light shows po1201 code on all cylinders. The other shows ignition misfire sensor failure on all cylinders.I cant find a misfire sensor on this vehicle the only thing close is ignition module. I don't think its got a vacuum leak but I could be wrong. Definitely whatever is going on is affecting all cylinders. How can I begin to pinpoint what the issue is?Is it a fuel issue or misfire.
Sunday, March 27th, 2016 AT 6:49 PM

5 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 34,165 POSTS
I don't have a listing for that fault code, but there is no such thing as a misfire detector. Misfires are detected by the Engine Computer seeing the rotational speed of the crankshaft slowing down for an instant when a power pulse goes missing. When it's bad enough, that is the same thing that allows you to feel a misfire.

With all misfires, the place to start is with the basics, meaning spark plugs and wires. Then, especially at the mileage you listed, compression and worn camshaft lobes are good suspects. Typically the last thing to suspect are fuel injectors. Once you've eliminated the spark plugs, it's best to do some tests first to identify if the problem is being caused by a single cylinder, and which one that is. If the fault code is for "random" or "multiple cylinder misfire", look at what they all have in common which is fuel quality, fuel pressure, fuel / air mixture, and things like that.
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Sunday, March 27th, 2016 AT 9:55 PM
Tiny
STEPHEN KARANJA
  • MEMBER
  • 47 POSTS
Thanks for your reply. But only helps me partially. The result from one of the error codes says."Replace ignition failure sensor" (IFC) P1201 on all cylinders. AlsoPO300. What does ignition failure sensor mean. Could it be spark plugs or something else. Thanks. Sorry on my 1st query I wrote PO1201instead of P1201
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Monday, March 28th, 2016 AT 12:24 PM
Tiny
CARADIODOC
  • MECHANIC
  • 34,165 POSTS
I have never heard of that sensor, but the bigger problem is the fault code did not say to replace anything. They never do. They only indicate the circuit or system that needs further diagnosis or the unacceptable operating condition.

Where did you come up with that code number? Was it from an aftermarket code reader, a full scanner, or the dealer's scanner?

AHA! I found this fault code on a different site. It is "misfire detected, (fuel related), cylinder 1". That makes sense, but I've never seen that code where it specified whether it was fuel, spark, or compression-related. Those three things can be determined by looking at oxygen sensor signal wave forms, but those have to be interpreted by engine performance specialists with a diagnostic scope.

What I would do is swap the injectors between cylinder 1 and one other one, erase the code, then see if a code sets for the cylinder you moved the injector to. If it does, consider installing a flow-matched set of rebuilt injectors.
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Monday, March 28th, 2016 AT 8:24 PM
Tiny
STEPHEN KARANJA
  • MEMBER
  • 47 POSTS
I'm glad you were able to find the fault code.P1201 on webspace.
But my problem is not just one cylinder it seems to apply to all the cylinders.I've already checked spark plugs and their fine. What I did notice though they all were coated with gas and smelled of it. Like I said the car starts just fine runs for a while than stalls when it gets to normal operating temperature. At the same time the check engine light shows up TCS sign flashes on dash board. The car does start up again after that with check engine light on. My question is what would normally affect all cylinders at once I don't think compression is a problem. It has to be something that's applicable to all cylinders like fuel.I doubt all injectors would fail at the same time. Please your knowledge of this situation would be highly appreciated. If it would help i'll send image of test results from shop. Lastly but not least what is IGNITION FAILURE SENSOR you will see it listed on top of image. You said there was no misfire sensor. Thx apparently I can't add image. But it simply says.'ignition failure sensor'then p1201, up top p1206 misfire detected.
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Wednesday, March 30th, 2016 AT 9:53 AM
Tiny
CARADIODOC
  • MECHANIC
  • 34,165 POSTS
Could you be reading a fault code description that someone typed onto a repair order or entered into their computer manually? The code is for misfire "detected", not misfire "detector".

Regardless, misfires don't cause engine stalling. The CAUSE of a misfire might cause stalling when it gets bad enough, but it's not the misfires you need to be looking for right now.

Stalling that occurs regularly at predictable intervals is typically caused by a failing crankshaft position sensor or camshaft position sensor. Those don't always have enough time to set a fault code as the engine coasts to a stop. The best way to find those is to view live data on a scanner and look for an indication similar to "no" or "present" listed for each sensor.
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Wednesday, March 30th, 2016 AT 8:40 PM

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