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shifting issue

poomero

NAXJA Forum User
Location
Tigard
Im sure this has been talked about a million times but i have a question.

I have a 90 xj with a 4.0 in it.

I was driving home right now and the jeep started to down shift on the freeway and would not up shift. I was on a flat freeway so it did not have to shift to gain speed or go up a hill. the jeep will not shift unless it hits redline and will not down shift now untill i come to a complete stop.

What can cause this? TPS?

Last weekend i changed the transmission fluid and filter but i have been driving the jeep all around after i did it with no problems.
 
Start with the basic, free stuff.

Check the fluid level--yeah, I know, but check it again. Check it after 20 minutes of driving, in Park.

Adjust the throttle pressure cable (it is not a kick-down cable).

Test/adjust the TPS.

Adjust the shifter cable, followed by adjusting the NSS.
 
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How do i do the NSS and where is it located?

fluid is good.

and the throttle pressure cable is correct.
 
i know i have adjusted the TPS before and i found the write up on here i cant find it now thought. can anyone post the link to a write up for me please. thanks
 
ok this is where I am at.

I have a meter and I set it to Volts to check the TPS.

I have followed these steps and I think my TPS is bad. It says turn the key to the on position and the volts should read 4.2 if the TPS is good. my meter reads 0.32 at the highest does this seam right to anyone?

I am new to electrical so I dont know if I have the meter set to the right setting or not.

TPSadjustment2.jpg


TPSadjustment3.jpg


are these steps the right steps or what way would you do it if not this way?
 
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check your meter by measuring the battery voltage to see if your meter is working correctly...make sure you are on a voltage range set higher than 12 volts... also make sure you meter leads are in the correct plugs...some meters have different plugs...one for ohms/resistance, and another for volts.
 
I did that and it was 12V when I put it on the battery.

I had it set on the 200. setting and the 20. setting. The setting was put in the V with a solid line and the 3 dots under it. This is the right one right?

The meter also has a setting with a V and a squiggley line.

it also has an ohms setting. (the horseshoe looking one)

The last setting is an A with a solid line and 3 dots under it.
 
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You have an auto.

Meter set to the closest range more than 5.0 volts--likely 20 volts.

Disconnect the 4-wire connector from the TPS. Key ON, measure the voltage between "A" positive and "D" ground. Note the value on a piece of paper--that is your "reference" voltage and should be about 5.0 (but you won't see that--don't worry about it). Ok, put the 4-wire connector back on the TPS. Key ON, back probe the connector at "B" positive and "D" ground. That is your "output" voltage. The TPS needs to be adjusted so that the "output" voltage is equal to 83 percent of the "reference" voltage. If you can't achieve that value--replace the TPS and start over.

If you don't have back probes, take a couple small paper clips and straighten one leg on each.
 
X2^^ on all the above

if paperclips are tough to get into the plug, curtain pins work great-- sharp on one end and a tight fold on the other to hold the DVOM probes
 
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