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No ignition (no spark) on four cylinders

Tiny
FANI4MIKE
  • MEMBER
  • 1997 CHRYSLER TOWN AND COUNTRY
  • 3.3L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 200,000 MILES
My can sensor went bad and I replaced it, now the car starts runs perfect for six to seven minutes then shuts off. While in no start I have tested both crank and cam sensors with volt meter and hand turning the motor both sensors produce a good signal. While cranking the motor it shows signal to fuel injectors (are least the three in front). I only have spark in two of the six cylinders, testing the pulse signal two of the signal wires drop to 0 and no pulse one of the three signal wires pulses three or four times then drops to 0. Before and after cranking pulse wires have 12 volts. After fifty minutes or so car starts runs perfect again for six or seven minutes. Could it be anything other than the PCM?
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Sunday, February 24th, 2019 AT 5:18 PM

19 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
Hi and thanks for using 2CarPros.

What you described sounds like a bad crankshaft position sensor. Take a look at this link:

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

What I need you to do is check is this. Plug in a live data scanner and go to engine RPM. See if the RPM signal stops when the engine stalls. Also, see if there is an RPM signal when cranking. If the RPM signal stays consistent, chances are the sensor is good. However, that leads to the next concern, the PCM.

Here is the information related to the PCM for the ignition. It indicates which pins should have power, ground.
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Sunday, February 24th, 2019 AT 6:48 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi and thanks for using 2CarPros.

What you described sounds like a bad crankshaft position sensor. Take a look at this link:

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

What I need you to do is check is this. Plug in a live data scanner and go to engine RPM. See if the RPM signal stops when the engine stalls. Also, see if there is an RPM signal when cranking. If the RPM signal stays consistent, chances are the sensor is good. However, that leads to the next concern, the PCM.

Here is the circuit operation information related to the PCM for the ignition / crankshaft position sensor. It indicates which pins should have power, ground... You will need to confirm the specifications listed to determine if there is a problem with the PCM. Keep in mind, there could be a weak connection, corrosion, or other issue at the plug. Make sure to disconnect the battery before you remove the harness from the PCM. Once it is removed, you can reconnect the battery. Prior to reconnecting the PCM connector, disconnect the battery again to prevent any damage to the PCM.

CIRCUIT OPERATION
Circuit K7 supplies 8 volts from the Powertrain Control Module (PCM) to the crankshaft position sensor. The K7 circuit originates at cavity 44 of the PCM connector.

Circuit K24 from the sensor provides an input signal to the PCM. The K24 circuit connects to cavity 32 of the PCM. On vehicles equipped with an electronically controlled automatic trans axle, circuit K24 splices to the transmission control module.

The PCM provides ground for the crankshaft position sensor signal (circuit K24) through circuit K4. Circuit K4 connects to cavity 43 of the PCM.

_____________________

Let me know if this helps or if you have other questions.

Take care,
Joe
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Sunday, February 24th, 2019 AT 6:52 PM
Tiny
FANI4MIKE
  • MEMBER
  • 10 POSTS
Thank you Joe,
For your response, trying to keep simple I didn't mention I live in Brazil parts are not easily available here for Chrysler, but it is worth trying a new cam sensor. It will take about ten days to receive this part, tomorrow I will check the rpm gauge and pins at the PCM. I have checked the crank sensors when engine wouldn't start with good readings at the sensor. I wonder if hand turning the motor might cause less heat and give a good reading when cranking the motor might have a bad signal? Will also check wire resistance from PCM to crank sensor. This I have done with injectors and ignition circuit both are good. To my understanding the cam is only used at start up on this car and would not cause a stall unless obvious reasons like a short. Is this true? At this point a scanner would be hard and near the cost of a PCM. I will keep you posted.

Thank you again,
Michael
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Sunday, February 24th, 2019 AT 9:56 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
Welcome back:

That sounds like a plan. However, I still question the crankshaft position sensor. Regardless, let me know what you find.

Take care. Also, if you are getting parts online, make sure you get a quality brand. Off brands are not very reliable.

Take care,
Joe
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Monday, February 25th, 2019 AT 8:30 PM
Tiny
FANI4MIKE
  • MEMBER
  • 10 POSTS
Hi Joe,
just saw your response, I made a mistake telling you "cam sensor" I meant to say crank sensor like you suggested. Yesterday I checked the wiring from crank sensor to PCM even opened the harness wiring is sound less than 1100 of a ohm even wiggled them with no issues. When I went check volts at PCM my battery was dead. I also ordered a new crank sensor will be here in about ten days, also decided to buy the cam sensor with it. Thought it would be nice to have at the house if need;) I post again after the parts come. (Sure hope the PCM is good was replaced three years ago.)

Thanks for being here for those in need,
Michael
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Wednesday, February 27th, 2019 AT 2:52 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Welcome back, Michael:

I'm happy to help. I just hope it does help. It's not as easy diagnosing when I'm not in front of the vehicle.

Let me know what you find and good luck.

Take care,
Joe
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Wednesday, February 27th, 2019 AT 7:51 PM
Tiny
FANI4MIKE
  • MEMBER
  • 10 POSTS
Hi Joe,
received both sensors three days ago, the first night I had about thirty minutes. So I changed out the cam sensor, car ran great for about thirty minutes and stalled again the next morning I changed the crank sensor (you were right on) car has been running fine for two days (about eight hours of driving) today the car started rough idling and poor acceleration not able to drive, spits and sputters tachometer bounces up and down can hold the pedal about one third down and engine will level off at about 2,000 rpm. Seemed like a vacuum issue but no visible lose hoses. Turning my hair gray over here. Any ideas?
Thanks,
Michael
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Wednesday, March 13th, 2019 AT 2:40 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
Welcome back:

Okay, we are getting there. A rough idle as you described can be a vacuum leak, a coolant temperature sensor, stuck injector, bad fuel pressure regulator and the list goes on.

Here are a couple links that show how to check for a vacuum leak, check fuel pressure, and one last thing, how to check if a catalytic converter is plugged. Start with vacuum. Also, let me know if it cleared itself up and ran good after this happened. If it did, I have other thoughts.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

_____________________________

Let me know if any of this helps.

Take care,
Joe
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Wednesday, March 13th, 2019 AT 5:56 PM
Tiny
FANI4MIKE
  • MEMBER
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Hi Joe,

just like you mentioned this morning I went to look for the problem and the car is running good again :). I should mention the car is equipped with propane, so I can bypass fuel injectors, gas pump line pressure etc. I guess this eliminates vacuum lines also? Now that it runs. Last night I disconnected the battery. So i´m thinking temperature sensitive problem or ECM reset related. Yesterday I ran the A/C for maybe twenty minutes and ten minutes after it was turned off the problem came. I don't know if this could be part of the problem. (This was the first time I turned the A/C on since replacing the sensors.) Looking forward to your thoughts I´m running out of them and tired.
Thanks again,
Michael
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Thursday, March 14th, 2019 AT 10:10 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
Welcome back:

If you have access to a live data scanner, I need you to check the engine coolant temp sensor (ECT). When the engine is cold, using a scanner see what temperature the sensor is telling the computer. Do the same when the engine is warm. I have a feeling the sensor is indicating the wrong temp and since it is indicating a temp (right or wrong) the computer thinks it's working.

For example, if the sensor tells the comp that it is -40 degrees F and in reality it is 70 degrees F, the computer will make the air fuel mixture extremely rich so the engine can run in cold temps. The result can be a no start, stalling, misfire, poor running condition and the list goes on. Are you able to get your hands on one? I didn't realize the was a natural gas vehicle. When you switch back to gasoline, the computer determines how long the injectors stay open (to adjust fuel mixture). It may be dumping fuel.

It's a theory at this point, but if you can get your hands on a scanner to do this, it will take one minute to check it.

Let me know.

Joe
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Thursday, March 14th, 2019 AT 5:49 PM
Tiny
FANI4MIKE
  • MEMBER
  • 10 POSTS
Okay back again. :)

Managed to scan with a elm327 on my lap top. Coolant temperature sensor shows -40 continually. I think that's a problem. Set off 3-codes po 118, 108 and 353. 353 shows ignition coil problem on circuit 3, tested signal wire 3 and resistance on the ignition coil all seems equal to the other two, even read a led pulse at the ECU. I´m guessing next step is a new ECT. Could the ECT set off the other codes?
Want to thank you again your web site is one of the few that has real answers.
Michael
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Sunday, March 17th, 2019 AT 2:58 PM
Tiny
FANI4MIKE
  • MEMBER
  • 10 POSTS
Went back a second time and bypassed the ECT with a piece of wire PCM responded and raised the temperature on the scanner to 127c. Bypassing had no effect on the way the car runs. Tested the ECT sensor resistance its open. Is their a way to add a resistor to test the car? Will take seven to ten days for new ECT sensor, I am guessing both open and short are off the scale for the PCM to use the information. Anyway, let the car run for a while and the po108 and 353 were both gone, but the problem stayed. :( Sanner did show po117 and 118 (to hot and to cold).
Dipping back in the pocket for new sensor.
Michael
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Sunday, March 17th, 2019 AT 7:25 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
Welcome back:

The sensor works off resistance, so if it is open, it's bad. I have no other option than replace the sensor. Let me know what you find when you get it.

Take care,
Joe
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Sunday, March 17th, 2019 AT 7:42 PM
Tiny
FANI4MIKE
  • MEMBER
  • 10 POSTS
Hi Joe i´m back (not to scare you);),

Okay, new temperature sensor came yesterday installed last night couldn't wait, hooked up the elm to the obd2 port to read temperature, started scanning at 40c and ran up to running temperature. About 60c started to misfire could not keep car running no codes went off. Today car started right up ran good until running temperature (no codes). Let car cool about four hours ran good again, this time I shut the car down turned fuel pump off and put a LED light on cam signal while cranking. Did the same with crank sensor signal and ignition signals. Then turned on fuel pump started car let it run until it faulted, stalled and would not start. Then tested signals again with LED light sensor signals stayed the same as when it ran and pulse signals to ignition also stayed the same. I am using a limited trial version program, if I upgrade what live data should I be checking? If you any other ideas I am ready.
Thanks,
Michael
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Thursday, March 28th, 2019 AT 1:11 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
The temperatures that you started with, 40°C, that is really hot. Are you located in an extremely hot climate? Also, the 60°C isn't hot enough for engine operating temperatures. Operating temperatures should be just above 90°C.

With that, you checked both crank and cam sensors and they were the same if the engine ran or not. Have you checked for spark at the plugs?

https://www.2carpros.com/articles/how-to-test-an-ignition-system

When it ran, did it run good until it failed? Also, will it start even for a couple seconds if you use starting fluid?

Let me know.

Joe
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Thursday, March 28th, 2019 AT 5:36 PM
Tiny
FANI4MIKE
  • MEMBER
  • 10 POSTS
Great news Joe,
today went to compare signals to the ignition and test for spark, while waiting for the engine to cool down I decided to pull and cool the crank sensor down quickly and put it back in and see if it made a difference, well guess what the motor worked fine with a cold sensor even with a hot engine :) after it warmed the problem started to come back but this time the car kept running. Loosening the sensor I backed it out maybe 1 to 1.5mm further than the spacer and now the car runs 99% better and is usable. I think the after market sensor is the only problem. It feels like the timing is slightly advanced and the car only has a problem with heavy acceleration. I can not find oem or original parts here in brazil and yes it is hot here. I have a friend coming from the U.S. At the end of april who can bring quality parts for me can you recommend a brand and/or place to buy?
Thanks for all your help,
michael
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Friday, March 29th, 2019 AT 2:30 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
Welcome back:

Those things can really be a pain. It does sound like you found the issue. As far as parts, because if where you live, I would recommend having your friend get an original equipment part. He/she will have to get that from a Chrysler dealership.

Let me know if I can help or if you have other questions.

Have a good weekend,

Joe
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Friday, March 29th, 2019 AT 8:52 PM
Tiny
FANI4MIKE
  • MEMBER
  • 10 POSTS
Hi Joe,
wanted to give a update, could not wait for oem parts bought another crank sensor. (Still waiting for oem) traded it out and have been using car running excellent. Crazy enough after about five days car began to act up. Next day car would start and shut off about 1 second after starting. After pulling all my hair out putting old sensor in with no change, I stopped and recalled when the problem started remembering the instrument panel went out I pulled it out and disconnected the wiring, hooked up battery without panel and car started perfect and ran great. I have read many issues with the instrument panel on line but no one mentions if you think the problem is the instrument panel you can disconnect it and test car without it| already have a second panel so it was easy for me. I hope to be done working on this car for awhile and just drive it:) I want to thank you for your help its good to have someone to help direct you when you don't know what to do next.
Thank you for this site
Michael
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Saturday, April 20th, 2019 AT 9:12 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
Welcome back:

You are very welcome. I honestly didn't realize the IP went out on you. Any more, so much is tied together. I'm glad you got it going. Let me know if you have any other issues.

Also, if by chance it happens again, check the automatic shut down relay (ASD). This component is actuated in the event of an accident to shut down the engine. I attached a pic for you. It is in the power distribution box under the hood.

You are welcome to come back as many times as you want. However, I realize that means you are having problems, so rather than saying I hope to see you again soon, I will end with a simple, take care.

Joe
PS: Happy Easter
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Saturday, April 20th, 2019 AT 5:05 PM

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