fluffydawg

hey everyone, I am new to jeep I have owned everything else but these so I could you some help. I am haveing issues with the rpm's being to high. I am sitting around 750rpm in gear and park and neutral about 1200-1500 rpm. when you go from drive to reverse it is like you are doing a tranny drop. the other issue is that the tranny is very rough on the shifts is this normal or is there something I should be investigating so that I don't cause damage to anything. So far I have replaced the tps and switched out the sensor just to the left of the tps, not sure what it is called. I know that the solanoid in the tranny is putting up a code on the computer aswell. not sure if that is the cause of the rough shift. any and all help would be appreciated.

XJ Stryker

Damn I would say check your TPS lol. Did you adjust it any. TPS is not an item that you can just install you must adjust it with a multimeter for it to work properly. You really shouldn't be getting any codes on anything if you own a 90 unless someone swapped the motor the 90 would be renix which is the multimeters favorite engine. Have you cleaned out the throttle body or IAC. Seafoam works miracles on there pour a lil in the throttle body while its running and rev it up slowly you should also get some nice White smoke out the exhaust lol.

theangler

sorry to jump this thread, but where can you buy sea foam?

drakan1908

Advance Auto,Auto Zone and I think I have seen it at Walmart.

XJ Stryker

Just about anywhere you could buy auto parts now-a-days it is about 6-7 bucks a can but well worth it.

BlueXJ

Fluffy did you simply install a new TPS without adjusting it? If you did I am surprised you can even drive it. The adjustment will help with both the idle and that tranny shifting problem. Check also for vacuum leaks. You have 3-4 things that effect the type symptoms you describe.
1- TPS adjustment
2- Vacuum leaks or kinks.
3- O2 sensor
4- MAP sensor.
That being said you may find others but those are the cheif culprits in a Renix Jeep.
HTH and you may find the TPS adjustment write up on here (check stickies) but if you don't and still need it then post up and I will be happy to post it again

mike

listen to blue and xj they were a lot of help for me. and as far as the shifting being rough, if this is normal. no i can bearly feel mine shift. you can check posts by me and blue sent me the link for adjusting the tps, helped alot.

fluffydawg

I installed the tps and tryed moving it a bit but I don't have a multimeter. Time to buy one I guess. What is this RENIX that you refer to. I haven't cleaned out the throttle body or IAC as I am not a good trouble shooter. Thanks for the help

I am going to try all of these things that you mention. is there a way to test the 02 sensor or the map sensor with the multimeter. if there is is there a link to the web or to some other post that has the meter readings that I will need to know if there are working correct or not. thanks for all of your help

BlueXJ

Renix is the Jeeps from 87-90 that used the Renix computers. They had no OBD ports and stored no data. Most people do not have the factory diagnostic scanned but they cqn easily be diagnosed with a $4 multimeter.

Testing data:
TPS :

Located on the right side of the front of the throttle body. To test, disconnect the connector at the TPS. Check the voltage at TPS connector pins B (Ground) and A (5.0 volt supply) with the ignition on. If you see about 5 volts, hook up the connector again. and check the voltage at TPS terminals C (positive) and B (Ground) with the ignition on and the throttle plate closed. You should notice approximately 0.8 volts. If you see that voltage, your TPS and wiring should be ok. If not, you'll have to adjust the TPS to get that voltage. If you cannot adjust the TPS to get that voltage, you'll have to replace the TPS and adjust the new one properly. Also, with the voltmeter hooked (terminal C) up and the ignition on, move the TPS arm down and back up slowly and watch the voltage. The change should be increasing and smooth. If there are any dead spots or it is not smooth, it probably needs to be replaced

Adjustment of TPS:

Adjustment is simple though backward by most TP standards. With the
harness connected, test the voltage on pins A, B & D. The voltage on
pin A (reference voltage) should be approx. 5v

Voltage on pin D (ground) should be less than 0.1v. If the voltage is
higher, an additional ground wire can be spliced into the circuit.

Pin B is the TPS signal to the controller. The voltage on pin B should
be 4.0 - 4.4v at closed throttle. At full throttle, the voltage should
be 0.2-0.5v. The TP sensor has elongated holes for the hold-down screws which allow it to be ajusted.

Adjustment is as follows: (comments in brackets are mine)

1. Turn the ignition switch to the "ON" position

2. There are 2 wire harness connectors attached to the TPS. Inout/output voltage is checked at the SQUARE, FOUR TERMINAL CONNECTOR (though it only actually has 3 pins). The terminals are identified by the letters A,B,C,D molded into the connector.

3. Do not unplug the connector. The voltmeter leads must be inserted through the back of the connector to make contact with the terminals. Connect the positive lead to terminal A and the negative lead to terminal D.

4. With the throttle plate in the closed position, note the "input" voltage. It should be approx 5.0 volts

5) Remove the voltmeter positive lead from terminal A and connect it to terminal B. The "output" voltage should be 4.2 volts - 82% of input voltage. (NOTE: on my XJ, the input voltage was only 4.6 volts so I had to adjust the closed throttle output voltage to 3.8 volts as this is 82% of 4.6)
If this is not the case, continue with this procedure

6. Adjust output voltage as follows: with the voltmeter leads still attached to, carefully loosen the sensor mounting screws and slowly rotate the sensor until the output reading is 4.2 volts with the throttle closed (or 82% of your input voltage). Then, toghten the sensor mounting screws securely.


MAP Sensor:
Located on firewall behind valve cover. To test, using a voltmeter with the ignition on/engine off, voltage at terminal B should be 4 - 5 volts. The voltage should drop to 1.5 - 2.1 volts with a HOT, neutral idle engine. Supply voltage can be checked at terminal C with the ignition on. Voltage there should be 5 volts + or - 0.5 volts (Terminal A is the ground wire).

O2 Sensor:
Located in the exhaust manifold. To test, using an ohmmeter, disconnect the O2 sensor connector. Connect the ohmmeter test leads to connector terminals A and B of the sensor connector. Resistance should be between 5 and 7 ohms. Replace the sensor is the ohmmeter displays and infinite reading. I don't know about you, but this test is pretty vague. They say it should be between 5 and 7 ohms, but infinite is bad. What if you get a reading of 13 ohms or 100 for that matter? I wasn't too fond of this test as I found it is a test of the O2 sensor heating element!. One other thing you can do with the O2 sensor is hook up the voltmeter to terminals B and C (I can't remember if those are the right letters, but you want to get the sensor wire (believe it was blue) and the ground wire, or just ground to something else) with the connector hooked up and the engine on, warm, and idling. You should notice the voltage jumping up and down in about 2 second or less intervals. If it doesn't jump up and down considerably or takes longer than 2 seconds to do so, change it.
(Hint* Use an appropriate socket which is a slotted deep socket)

Hope this is the info you needed fluffy.

fluffydawg

damn that is lot of good info. Thanks. I went to a friends place and we got the tps set to the right specs but it is still hesitating on take off. I will try some of these other things first. I have found that the rpm is down to about 500ish rpm when stoped and in gear and park and neutral is around 1000 rpm. at 80kmh I am down about 700 rpm which is good. tranny still clunking going into reverse.

BlueXJ

That clunking going into reverse may be a bad u-joint in the driveshaft. or it may be a bad tranny mount on the rear crossmember. Check those possibilities out.

89xjgrey

Not that it would help, but also check the adjustment of the kickdown cable...if nothing else, it's good maintanance. :-)