Yea I guess I should buy that, Im just cheap lol
I dont think the non-renix tps are adjustable but I will look into thanks

Thanks for the help, deff going to pick up a tps first thing tomorrow when the parts store opens
I agree with the O2 wiring I am just a lazy ***

 

Lazy+cheap a bad combination for XJ ownership....

 

LOL after having a huge sugre and spending:
$50 cam sensor
$350 oil pump drive (broken)
$500 on diagnostics for PCM wiring
$150 PCM (fried)
$50 TPS
And thats all just recently, doing all the labor myself except for a wiring issue I couldnt pin-point. So I really am just searching for some help with this one.
So I guess cheap wasnt a great word to use, more like broke and loosing hope.

But about the issue I am having
Update: TPS is replaced with napa part.
Jeep still has similar issues. Minus the bucking, now all thats happening is the following:

At idle it will ocassionally idle rough. The best way I can describe it is a big cam motor idle.
It sounds cool but is clearly running rich I can smell the fuel.

Also while keeping a steady throttle,
(mostly while engine is cold but still does occasionally when warmed up)
The Jeep will accelerate normally up to about 5mph, then it will fall flat.
And literally not respond to anything except 100% throttle.
If I give it anything from lets say 20%-95% throttle I hear a slight pinging noise that will happen randomly only during the issue.
Not sure where its from but only happens when I am attempting to get the car to get out of this "limp" accelerating

It seems like it doesnt happen as often if its colder outside.
But again its completely random and nothing can trigger it.


Also no codes at all. So I am beyond stumped on this one.

Anyone with any ideas I would greatly appreciate it.

 

Try testing the following:

Map and O2 sensors for Rich running conditions

Fuel pressure for pinging/throttle lag.

Have you replaced your fuel filter before? Its simple and a cheap item to go along with the maintenance side of the jeep.

 

I havent replaced the filter myself,
I figured the base pressure 50psi would be an indicator that the fuel pressure is alright?

But seems to make sense. Im guessing I have to drop the tank to get to the filter?

So why would I have a rich idle and then lean above idle?
Am I missing something here?

 

Faulty map sensor or O2 readings. TEST before wasting money!

Depending on the year the filter should be along the driver side unibody rail. May not effect fuel pressure but may steady the acceleration out.

Id definitely look into the things that could adjust air and fuel ratios which would be O2 and Map sensor.

 

Do a vacuum test for restricted exhaust.

 

If you are interested in testing your MAP sensor, read the following data, then do the test outlined at the end of the data. Refer to the attached pic. You will be back probing the MAP sensor connector while it is attached (pic). You will be using a digital voltmeter set to 20 Volts DC.

I use safety pins for back probes but you can use any sutable probe, as long as it can reach all the way into the connector next to the wire(s) without damaging the connector or the wire(s).

The test data gives the wire colors for the pins so you won't be confused about pin numbers.

Before testing the sensor, visually inspect the rubber connector under the MAP sensor. Verify it's there and connected. Verify it's not cracked or rotted.

If you used a scanner that shows live data, it will show MAP and engine load, as well as O2S switching activity.

Back Probing the MAP sensor connector:



MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR—PCM INPUT

OPERATION
The MAP sensor is used as an input to the Powertrain Control Module (PCM). It contains a silicon based sensing unit to provide data on the manifold vacuum that draws the air/fuel mixture into the combustion chamber. The PCM requires this information to determine injector pulse width and spark advance. When manifold absolute pressure (MAP) equals Barometric pressure, the pulse width will be at maximum. A 5 volt reference is supplied from the PCM and returns a voltage signal to the PCM that reflects manifold pressure. The zero pressure reading is 0.5V and full scale is 4.5V. For a pressure swing of 0–15 psi, the voltage changes 4.0V. To operate the sensor, it is supplied a regulated 4.8 to 5.1 volts. Ground is provided through the low-noise, sensor return circuit at the PCM.

The MAP sensor input is the number one contributor to fuel injector pulse width. The most important function of the MAP sensor is to determine barometric pressure. The PCM needs to know if the vehicle is at sea level or at a higher altitude, because the air density changes with altitude. It will also help to correct for varying barometric pressure. Barometric pressure and altitude have a direct inverse correlation; as altitude goes up, barometric goes down. At key-on, the PCM powers up and looks at MAP voltage, and based upon the voltage it sees, it knows the current barometric pressure (relative to altitude). Once the engine starts the PCM looks at the voltage again, continuously every 12 milliseconds and compares the current voltage to what it was at key-on. The difference between current voltage and what it was at key-on, is manifold vacuum.

During key-on (engine not running) the sensor reads (updates) barometric pressure. A normal range can be obtained by monitoring a known good sensor. As the altitude increases, the air becomes thinner (less oxygen). If a vehicle is started and driven to a very different altitude than where it was at key-on, the barometric pressure needs to be updated. Any time the PCM sees Wide Open Throttle (WOT), based upon Throttle Position Sensor (TPS) angle and RPM, it will update barometric pressure in the MAP memory cell. With periodic updates, the PCM can make its calculations more effectively.

The PCM uses the MAP sensor input to aid in calculating the following:
· Manifold pressure
· Barometric pressure
· Engine load
· Injector pulse-width
· Spark-advance programs
· Shift-point strategies (certain automatic transmissions only)
· Idle speed
· Decel fuel shutoff
·
The MAP sensor signal is provided from a single piezoresistive element located in the center of a diaphragm. The element and diaphragm are both made of silicone. As manifold pressure changes, the diaphragm moves causing the element to deflect, which stresses the silicone. When silicone is exposed to stress, its resistance changes. As manifold vacuum increases, the MAP sensor input voltage decreases proportionally. The sensor also contains electronics that condition the signal and provide temperature compensation.

The PCM recognizes a decrease in manifold pressure by monitoring a decrease in voltage from the reading stored in the barometric pressure memory cell. The MAP sensor is a linear sensor; meaning as pressure changes, voltage changes proportionately. The range of voltage output from the sensor is usually between 4.6 volts at sea level to as low as 0.3 volts at 26 in. of Hg. Barometric pressure is the pressure exerted by the atmosphere upon an object. At sea level on a standard day, no storm, barometric pressure is approximately 29.92 in Hg. For every 100 feet of altitude, barometric pressure drops 10 in. Hg. If a storm goes through it can change barometric pressure from what should be present for that altitude. You should know what the average pressure and corresponding barometric pressure is for your area.

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR TEST
To test the MAP sensor only, refer to the following:

(1) Inspect rubber L-shaped fitting from MAP sensor to throttle body. Repair as necessary.

CAUTION: When testing the MAP sensor, be sure that the harness wires are not damaged by the test meter probes.

(2) Test MAP sensor output voltage at MAP sensor connector between terminals 1 and 2. With ignition switch ON and engine OFF, output voltage should be 4 to 5 volts. The voltage should drop to 1.5 to 2.1 volts with a hot, neutral idle speed condition.

(3) Test MAP sensor supply voltage at sensor connector between terminals 1 and 3 with ignition ON. The voltage should be approximately 5 volts (+/- 0.5V).

Terminal 1: Sensor Ground (Brown wire/Yellow tracer)

Terminal 2: MAP Sensor Signal to PCM (Dark Green wire/Red tracer)

Terminal 3: 5V Supply from PCM (Orange wire)

 

Ken, excellent info. I'm saving it.

 

Exactly what I want to do lol. But I couldnt locate a filter on the feed anywhere. So I am guessing in-tank

No cats anywhere in my exhaust, its an offroad only vehicle

Going to do this right now, You always give the best information

 

pre 97 had in line, post had in tank..

 

Addendum to post #23.

Here's a pic of the voltage reading of 1.67 volts (within the 1.5 to 2.1 volts) from my MAP sensor at hot idle (note vacuum reading).

You may want to advance your throttle while you have the voltmeter hooked up to see if the voltage reading falters any.

 

If, like you say, your truck is an off road vehicle and has no Cat, what was this rear O2S hooked to?

Although, during open loop the PCM ignores the O2S signals (like during acceleration or deceleration), the downstream O2S has a roll in determining rich/lean activity of the PCM, so don't discount it.

If your downstream O2S is actually installed but the wiring is dicked up you should fix that.

Concerning all the O2S codes:

Generally the first thing to do is check the O2S Heaters fuse in the PDC (shown in the pic). Your truck uses relays to power the O2S heaters. One for the upstream O2S and one for the downstream. Both relays get their power from fuse F17 in the PDC.