Speedometer is off 25 mph after re-gear: Should I be worried?

Justin03X

Justin03X

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Joined
Apr 23, 2018
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31
Location
Wildomar, CA, USA
I just got my TJ regeared two days ago. 42RLE with 33's went from 3.73 to 5.13 thanks to forum members. Night and day difference! Only thing that worries me is my speedometer is almost 25mph off. When I hit exactly 70mph on the freeway my whole engine bogs down everytime. I guess my question is, do we have a speed limiter that keeps bogging it down? BTW I am waiting for a speedo gear in the mail.
 
I'm not sure I need to play around with it I guess, all I know is I was using my GPS and literally right when it hits 70mph it would lose power. I could try turning OD off and hitting 70mph and see if it does it.
 
You won't hurt anything to my knowledge... I bet it pulls great now.
 
rouxbicon said:
Agreed...although I have never tested it myself, I have read more than once that TJs are governed at around 93 - 95 mph by the pcm. So even if the gps says 70, but the pcm sees 95, it would start restricting probably either spark or fuel. Proper speedo gear should solve it
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Thank you, and yeah it is exactly at around 93-95 mph it bogs down.
 
Swap the speedo gear as mentioned. That will also fix your odometer and we will avoid a thread in the future of "why is my mileage so low".

My JB Conversions sensor was loose. The speedometer was starting to go wild and would shoot to 100+. It wasnt often but every now and then when that happened I would feel a surge and loose power for a split second.
 
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tworley said:
Swap the speedo gear as mentioned. That will also fix your odometer and we will avoid a thread in the future of "why is my mileage so low".

My JB Conversions sensor was loose. The speedometer was starting to go wild and would shoot to 100+. It wasnt often but every now and then when that happened I would feel a surge and loose power for a split second.
Click to expand...
Thank you, and yeah what was freaking me out was loosing power while on the highway.
 
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