Hard start and shifting issues and high RPM's

Tiny
SPYNTRAK
  • MEMBER
  • 2007 JEEP COMPASS
  • 2.4L
  • 4 CYL
  • AUTOMATIC
  • 150,000 MILES
Hi, I have this problem with my vehicle, when starting the vehicle it takes couples of seconds to turn on? Also when it's on it sounds smooth and good but then when I shift to drive it jerks pretty bad, and when I press on the gas the rpm's is going on 3,000 close to 4,000 and speedometer is barely going 10 mph why is that? It has to reach 3,500 to 4,000 to change gears what can it be? I changed the MAP sensor, crankshaft position sensor, changed 2 ignition could, did an oil change, and charged the battery.
Wednesday, April 15th, 2020 AT 11:56 AM

7 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
This sounds like possibly two different issues. First the hard starting is most likely a fuel issue. Try to cycle the key a few times before cranking the engine and see if the hard starting stops. If it does then most likely the fuel pump is failing. We can confirm this by testing fuel pressure. Here are guides that will help explain this in more detail:

https://www.2carpros.com/articles/engine-cranks-excessively-before-starting

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

As for the high RPM, is this a CVT transmission or which transmission do you have in this vehicle? Can you send a video of the shifting issue that you are seeing and that may help us understand what is happening a little better which will help us figure this out. Thanks
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Wednesday, April 15th, 2020 AT 3:05 PM
Tiny
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As far as transmission is concern am not sure if it is a CVT, all I know is a dual VVT 2.4L.
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Saturday, April 18th, 2020 AT 4:06 PM
Tiny
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  • 36 POSTS
Am sorry, yes it is a CVT transmission.
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Saturday, April 18th, 2020 AT 4:19 PM
Tiny
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  • 36 POSTS
I tried the key cycle and same results takes a few seconds to start. When I turn to on position I heard the fuel pump, but then the other 2 times I really didn't hear anything. I also noticed that the traction lights up on the dashboard while it's on idle. When I turn on the car check engine light is on but what's weird is that Every time I do that I get different codes I get the o2 senor, crankshaft position sensor and a misfire but when I erased them and turn on the car I would get only One code regarding the o2 sensor.
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Saturday, April 18th, 2020 AT 4:23 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Okay. With that information I suspect the crank sensor is the issue. What happens when these begin to fail is they do not report the engine position for the PCM to fire the plugs and injectors at the correct time. However, if you crank the engine long enough and the PCM learns the engine position off the cam sensor it will start the engine. Normally when this happens it will set the crank sensor code that I assume you are getting.

Can you provide the actual crank code you were getting and we can test this to confirm it is the sensor? I you want to go ahead and replace the sensor that would be fine as well because I am pretty sure that is the issue.

However, if you do replace this sensor, you need to have a learn procedure run with a scan tool after it is replaced or you will have a lot of different issues like misfires and various other performance issues.
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Sunday, April 19th, 2020 AT 9:57 AM
Tiny
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  • 36 POSTS
I actually did replace the crankshaft sensor. How do I go about doing the learning procedure?
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Sunday, April 19th, 2020 AT 1:36 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Unfortunately you need a scan tool capable of performing a Cam/Crank relearn procedure. If you have one it is an actual procedure that you select and the scan tool does it with the PCM to relearn the sensors.

I am sorry I missed that when I read it the first time. Can you send me the codes that you are getting when you start the vehicle? Let's not erase them when they come back because that is going to tell us what we are dealing with.
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Sunday, April 19th, 2020 AT 7:32 PM

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