Too Much Fuel?

[mjestes17]

can anybody tell me why my jeep feels like its drowning when I accelerate? once I get going at about 35-40mph it runs fairly smooth but as soon as it drops into fourth gear, it shakes violently and I'm scared to drive any faster because I'm worried it will fall apart. Somebody please help this noob!!!!!

 

I have recently installed a new gas tank, fuel pump, fuel filter, TPS, IAC Valve, and 4-port fuel injectors. It was acting up before I installed the new injectors and once I installed them it idled fine and I finally got it on the road after installing every other part with no prevail. Please help!

[cruiser54]

Did you adjust your new TPS?

How old are the tune-up parts including the cap, rotor and wires?

[mjestes17]

would the tps cause all of this to happen? no i didn't adjust it but i will if you tell me how :D I bought the truck back in june/july and the HEI aftermarket distributor was already installed with new wires and all that so i couldn't tell you :???:

[87MJTIM]

Does the whole MJ shake up and down? or does it shake like the engine is missing?

 

If the whole MJ shakes, I would recommend looking at the U-joints. I had and '89 XJ that did that. During exceleration the XJ would shake violently. I would pull over and stop, (let my heart rate get back to normal), then drive on. It wouldn't happen again for awhile.

 

Just my $0.02.

[mjestes17]

it shakes like the engine is missing. its hard on acceleration like it doesn't want to go anywhere but then it smoothes out. i just want to know why it feels like it doesn't want to take off and why it won't let me go into fourth gear without bucking like a bronco (the horse, not the truck).

[Keyav8r]

Search "TPS adjustment" in MJ Tech forum. There are two posts on adjusting in the thread, Cruiser54's is the latest version.

[cruiser54]

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: With the Key OFF, and 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 parallels the valve cover and also over near the MAP sensor on the firewall. If you see more than 1 ohm of resistance, or fluctuation in your ohms reading, 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 only a flat three-wire TPS mounted on the throttle bodyand it provides data input to the ECU. It 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. Loosen both T-20 Torx screws attaching the TPS to the throttle body and rotate the TPS until you

have achieved your desired output voltage. Tighten the screws carefully while watching to see that your output voltage remains where it is supposed to be. If you can't achieve the correct output voltage, replace the TPS and start over.

Sometimes, after adjusting your TPS the way outlined above, you may experience a high idle upon starting. If that happens, shut the engine off and reconnect your probes to B and C. Start the engine and while watching your meter, turn the TPS clockwise until the idle drops to normal and then rotate it back counterclockwise to your desired output voltage.

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, as outlined above—FOR ALL 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. THIS SQUARE FOUR WIRE CONNECTOR IS USED FOR TRANSMISSION/SHIFTING RELATED ISSUES ONLY. 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.

FOR AUTOMATIC TRANSMISSION RELATED ISSUES: Check the square four-wire connector side of the TPS.

If you have ENGINE ISSUES check the flat 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 09-22-2012