freep

I have a 89 4.0 xj and it will not rev over 3500 this all started after I had the transmition rebuilt I have a mechanic from jeep over my house for 3 days he could not figure it out do you guys have any idea

freegdr

why would ya wanna rev that high ? pinched fuel line tps been checked

freep

I take it to glamis most of the time need all the rpms I can get this is only a toy not a dd. yes tps is fine and fuel line is fine

freegdr

no rev limiter correct, factory style tranny,tranny shop informed? just going thru basic stuff questions wise trying to get a total picture....

3hounds

Plugged exhaust ?

tjwalker

Clogged cat is a possibility. Rule it in or out with some simple vacuum testing.

And unless you swapped in a different one to verify, the throttle position sensor is still in play.

freep

factory tranny, have removed cat,changed cpu tried 3diff ones, changed tps , no rev limited that I know of before tranny rebuild was fine I'm wondering if the shop bent the flex plate and would that cause that or if they use the wrong bolts on the crank shaft positioning sensor witch was changed too

freegdr

fuel issue maybe ?

cruiser54

If it starts and runs, unlikely it's the CPS. Have you checked it's output?

Did you adjust the TPS you put on? If so, how? The "engine side" can be bad on your tPS but if you set it with the "trans side" you would be unaware of the issues on the "engine side". Did the ground strap from the back of the head to the firewall get stretched/broken when the engine hung freely while removing the trans?

freep

I will check the ground. I don't under stand what you mean about the engine side of the tps ? but the tps was adjusted by the guy from jeep

cruiser54

This will make it real clear.

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: Set your meter to measure Ohms. 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. Wiggle the wiring harness where it runs parallel to the valve cover and also near the MAP sensor mounted on the firewall. If you have an 87 or 88 with the C101 connector mounted on the firewall above the brake booster, wiggle it, too.
If you see more than 1 ohm of resistance, and/or fluctuating 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 03-13-2012