r2srvnews

I have a 87 jeep Cherokee that misses under light acceleration lower rpms,you can let off a little runs fine,or acceleration through it runs fine again, a sputter like miss,, anyone encountered this?

all new tune parts ,including ngk plus,,I can duplicate the miss everytime ,it acts like when the thottle is in a certain position it cuts some fuel or a injector is acting up?

captainwoot

How is your tune - up ? spark plugs, wires and dist cap, rotor?

cruiser54

Yep. Champion copper plugs or NGKs, dizzy cap and rotor with brass terminals and new good quality plug wires every 30,000 miles. Start there.

r2srvnews

all new tune parts ,including ngk plus,,I can duplicate the miss everytime ,it acts like when the thottle is in a certain position it cuts some fuel or a injector is acting up?

Mech17

I think checking the injectors would be a good idea. thats kin of what mine did and it was an injector/fuel pump combo.

r2srvnews

the strange thing is going down the freeway I can let off the throttle and hold it at a certain speed and it will keep missing ,but once again i just give it gas or let off a little more it goes away....?

cruiser54

Could be a bad spot in the TPS on the engine side.

RENIX TPS ADJUSTMENT
Before attempting to adjust your TPS be sure the throttle body has been recently cleaned.
It's especially important that the edges of the throttle butterfly are free of any carbon build-up.
IMPORTANT NOTE: Using the positive (red) lead of your ohmmeter, probe the B terminal of the flat 3 wire connector
of the TPS . The letters are embossed on the connector itself.
Touch the black lead of your meter to the negative battery post.
If you see more than 1 ohm of resistance some modifications to the sensor ground harness will be
necessary. The harness repair must be performed before proceeding.
I can provide an instruction sheet for that if needed.
MANUAL TRANSMISSION:
RENIX manual transmission equipped XJs have a three-wire TPS mounted on the throttle body.
This manual transmission vehicle TPS provides data input to the ECU. The manual transmission
TPS has three wires in the connector and they're clearly embossed with the letters A,B, and C.
Wire "A" is positive.
Wire "B" is ground.
Key ON, measure voltage from "A" positive to "B" ground by back-probing the connectors..
Note the voltage reading--this is your REFERENCE voltage.
Key ON, back-probe the connector at wires "B" and "C". Measure the voltage. This is your
OUTPUT voltage.
Your OUTPUT voltage needs to be seventeen percent of your REFERENCE voltage. For
example: 4.82 volts X .17=.82 volts. Adjust the TPS until you have achieved this percentage. If
you can't achieve the correct output voltage replace the TPS and start over.
AUTOMATIC TRANSMISSION:
RENIX automatic transmission equipped XJs have a TPS with two connectors. There is a flat three-
wire connector, same as the manual transmission vehicles have, and it is tested the same as the
manual transmission equipped vehicles--FOR ENGINE MANAGEMENT RELATED ISSUES.
However, the automatic TPS also has a square four-wire connector clearly embossed with the letters
A,B,C, and D. It only uses three wires and provides information to the Transmission Control Module.
Key ON, measure voltage between "A" positive and "D" ground. Note the voltage. This is your
REFERENCE voltage.
Back-probe the connector at wires "B" and "D". Measure the voltage. This is your OUTPUT
voltage. Your OUTPUT voltage needs to be eighty-three percent of your REFERENCE voltage.
For example 4.8 volts X .83=3.98 volts. Adjust the TPS until you have achieved this percentage.
If you can't, replace the TPS and start over.
So, if you have an automatic equipped XJ your TPS has two sides--one side feeds the ECU, and
the other side feeds the TCU. If you have TRANSMISSION issues check the four-wire
connector side of the TPS. If you have ENGINE issues check the three-wire connector side of
the TPS.
For those with a MANUAL TRANSMISSION--the TPS for the manual transmission XJs is
stupid expensive. You can substitute the automatic transmission TPS which is reasonably priced.
Revised 11-28-2011

r2srvnews

thanks i will try that ,problibly just get a new one only 56.00 dollars ,I will repost a reply if this works fine ...if not of course be back with more questions LOL

cruiser54

Be sure to adjust your new one.

r2srvnews

Installed the new tsp and the hesitation is gone, i adjusted the tps till it accelerated nice . but when i test drove it the trans didn't shift down ...

cruiser54

See post # 9 and # 7.

tjwalker

Follow cruiser's recommendation. Test and adjust the new one.

But, it is not at all uncommon to get a flaky aftermarket throttle position sensor. Where did you buy yours?

I have answered more threads than I can ever remember about problems with aftermarket engine management sensors. Because of that, I will buy no sensors unless they are MOPAR and recommend that to others as well. The little extra money you spend is insignificant in the reliability AND longevity of an OEM sensor.

r2srvnews

I readjusted the sensor and it works great now ,,,thanks for everyone's input....

cruiser54

Thanks for posting back and congratulations.