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Amedee
Amedee, Chrysler Technician
Category: Chrysler
Satisfied Customers: 25244
Experience:  ASE certified Technician advanced level specialist. Wisconsin certified emissions state inspector
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Input and output speed sensor symptoms?

Customer Question

Input and output speed sensor symptoms?
Submitted: 4 years ago.
Category: Chrysler
Expert:  Amedee replied 4 years ago.
Hello!

Are you saying that the engine has a hard start at times? Does this happen intermittently? Cold hot or does this happen all of the time?

Are you saying that it will not rev up past 2500 rpms in drive or even in park?
Customer: replied 4 years ago.
Hard start every time. Will not rev past 2500 in either situation, drive or park. I'm out options, from what I've read and researched the input and output speed sensors may have a factor in this situation. Please help
Expert:  Amedee replied 4 years ago.
Are you talking about the transmission input and output speed sensors?

Have you checked fuel pressure?
Customer: replied 4 years ago.
Yes the trans input and output sensors. Yes I have checked the fuel pressure and it is at spec, 58 psi from what I recall...
Expert:  Amedee replied 4 years ago.
Ok.. got it.

Have you checked engine vacuum at idle and when trying to rev up the engine?
Customer: replied 4 years ago.
No I haven't done that. Would that affect the rpm issue?
Expert:  Amedee replied 4 years ago.
Sort of...

What ever it causing this engine to run like this would most likely cause the engine vacuum to be lower than normal. You could have a plugged converter or the valve timing could be off. You might want to check for a plugged cat and engine vacuum/engine compression to see if you get low readings. If so, you might want to check the timing marks. The timing belt could have jumped a few teeth or it could even be loose. Both will cause the engine vacuum to be low and instable. It should be well above 19 inches of vacuum at idle.
Customer: replied 4 years ago.
I thought of the timing issue and was thinking of checking that next, but once the rpm's hit 2500 it's like it hits a rev limiter and cuts out. I don't think a timing issue or a plugged converter or cat would do that. I know the cats are clear. Correct me if I am wrong...
Customer: replied 4 years ago.
And the vacuum is strong
Expert:  Amedee replied 4 years ago.
HOw much engine vacuum does it have at idle?
Customer: replied 4 years ago.
I wish I could tell you, but I don't recall the exact reading. That was one of the first few things I checked months ago... The only thing I remember was that it was at or just above spec
Expert:  Amedee replied 4 years ago.
Ok.. double check the reading at idle and at 2500 rpm when the engine is acting like it is at the rev limiter. We need to see how well the engine is breathing.

Also, don't forget to check engine compression and the timing marks if needed.

I hope this helps! Please don't forget hit the green accept button so that I may get credit for the time that I have spent with you. This is necessary for me to be paid for my work and get credit for assisting you. Your question will not close, and you will still have the opportunity to follow-up if needed. Leaving a bonus and positive feedback is not required, but doing so is certainly appreciated!

I do hope you are as honest with me about your vehicle as I have been with you. If you have any further questions or if you need more assistance, just hit the reply button and we can continue our conversation. Please remember, even if you accept my answer now, you can still reply or respond back to this thread at any time you wish at no further cost to you.

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Thanks in advance!

Best Regards

AMEDEE
Customer: replied 4 years ago.
Before I do anything I'd like to know about the trans input and output sensors as this was my original question...
Expert:  Amedee replied 4 years ago.
The transmission input and output speed sensors will not affect the engine running.
Customer: replied 4 years ago.
Last question, there is a pigtail connector coming off of the tps harness that is a 3 prong connector to a sensor somewhere in the back of the motor that isn't connected to anything but had to have been at one time recently. What would the connector possibly go to?
Expert:  Amedee replied 4 years ago.
There are lots of sensors. I would need to see a picture of this connector or you would need to tall me the color wires that go to this connector for me to point you in the right direction.
Customer: replied 4 years ago.
It is a 2 wire connector, both wires black, one with a red stripe and the other with a blue stripe
Expert:  Amedee replied 4 years ago.
It sounds like either the engine coolant temp sensor connector or the air intake temp sensor connector.
Customer: replied 4 years ago.
You are right about the IAT. Is that supposed to be on the intake tube just before the throttle body? I have an intake tube from another motore from the junk yard but it was a little short and didn't have any sensors or sensor locations on it making me believe it's the wrong part
Expert:  Amedee replied 4 years ago.
YES.. the intake temp sensor is located on the intake. SOme are on the intake snorkel and some are on the intake manifold itself.
Customer: replied 4 years ago.
Missing that sensor would cause stalling and starting issues, correct?
Expert:  Amedee replied 4 years ago.
YES.. it could!
Customer: replied 4 years ago.
It didnt work. I have a feeling the timing is off
Expert:  Amedee replied 4 years ago.
I would agree!