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wrscpc07 07-24-2013 07:36 PM

Weird tps CEL..im desperate
 
488 Attachment(s)
Ill keep this short..

My jeep was off the road for a year. I put it back on two days ago and to say it runs like crap would be an understatement.

Cel reads tps sensor according to advanced auto. I had purchased a tps sensor from them a year ago with lifetime warranty so I figured I'd just replace it, it's easy. Unplugged battery for a few hours, code pops up immediately upon start.

The jeep is bogging like crazy, can't get past 50, backfiring, bucking, you name it. It isn't idling extremely high but it jumps. It never shuts off due to this tho like I read in some other threads.

I changed my fuel pump about two years ago, changed tps, I even unplugged the sensors from my clock spring because I read that it could be related but after resetting the computer from that the code still doesn't even go away.

This problem eating my gas, 40 dollars in two days and it's going to get me hit on the highway.

Any advice would be helpful. Im lost :thumbdown:

Note, I swapped my 2.5 tb to a 4.0 tb a few days ago but when I started it and it was runny crappyi took it off bc I thought the 4.0 tb was at fault but even with my 2.5 tb back on and new gasket it still didn't change..

97 2.5 wrangler

CJ7-Tim 07-25-2013 05:31 PM

Exactly what CEL code number was downloaded ?

Cheap crappy "Lifetime Warranty" parts are often out of specification or even failed right out of the box. Many times they have a short service life before they fail.

Always buy top quality replacement parts and genuine Jeep sensors.

wrscpc07 07-25-2013 06:35 PM

488 Attachment(s)
Quote:

Originally Posted by CJ7-Tim (Post 15718845)
Exactly what CEL code number was downloaded ?

Cheap crappy "Lifetime Warranty" parts are often out of specification or even failed right out of the box. Many times they have a short service life before they fail.

Always buy top quality replacement parts and genuine Jeep sensors.

I have used this sensor before from advanced and never had a problem with it. And my sensor was fine when i started it up in my driveway one day, and then when i drove it the next day, the code popped up..so I am not sure how it even went bad. Usually I will ruin a tps by getting it wet but my jeep has been parked in the driveway..

wrscpc07 07-25-2013 06:36 PM

488 Attachment(s)
I am getting PO123

Holder350 07-26-2013 02:11 AM

Have you disconnected the clock spring connectors yet to determine if the clock spring is shorted internally?

The horn circuit can sometimes bleed over into the switch sense circuit and pull the tps circuit voltage high and cause the pcm to throw that code

wrscpc07 07-26-2013 04:42 AM

488 Attachment(s)
Quote:

Originally Posted by Holder350 (Post 15720221)
Have you disconnected the clock spring connectors yet to determine if the clock spring is shorted internally?

The horn circuit can sometimes bleed over into the switch sense circuit and pull the tps circuit voltage high and cause the pcm to throw that code

Yupp did that twice. Didn't help

Holder350 07-26-2013 06:45 AM

I would check voltage at the TPS and verify its reading smoothly as you open the butterfly.

Only other thing I can think it might be is bad wiring to the PCM

Sent from my phone

wrscpc07 07-26-2013 06:57 AM

488 Attachment(s)
Quote:

Originally Posted by Holder350 (Post 15720474)
I would check voltage at the TPS and verify its reading smoothly as you open the butterfly.

Only other thing I can think it might be is bad wiring to the PCM

Sent from my phone

I'm going to check the voltage more thoroughly today..if the voltage is wrong though, how do I fix it?

Anyway to test the pcm?

wrscpc07 07-26-2013 07:13 AM

488 Attachment(s)
I just looked up symptoms of a bad pcm..but I don't have those. My jeep never shuts off on me due to this issue. It never stalls when I start it or while I'm driving. It's just driving crappy like its starving for fuel.

I'm going to be really lost if the voltage from the tps harness is ok..I guess I should replace the Tps one more time?..

Holder350 07-26-2013 07:18 AM

Let's figure out what's wrong then we'll figure out how to fix it.

Only good test for the PCM is a replacement.

Sent from my phone

wrscpc07 07-26-2013 07:43 AM

488 Attachment(s)
Quote:

Originally Posted by Holder350 (Post 15720560)
Let's figure out what's wrong then we'll figure out how to fix it.

Only good test for the PCM is a replacement.

Sent from my phone

I'm definitely not going to replace the pcm without knowing haha but I'm pretty confident its not.

I'll check the voltage and go from there. I started to do that and the middle wire read 5.12 with the key turned on. I didn't have a second person so I don't know what it reads with the butterfly open

Holder350 07-26-2013 08:00 AM

Borrowed from CJ7-Tim


Quote:

Originally Posted by CJ7-Tim (Post 5747652)
DOH, wrong document.

TPS TESTING

TPS TEST

You should have 5 volts going into the Throttle Position Sensor (TPS). It is best to use an analog meter (not digital) to see if the transition from idle to WOT is smooth with no dead spots. With your meter set for volts, put the black probe on a good ground like your negative battery terminal. With the key on, engine not running, test with the red probe of your meter (install a paper clip into the back of the plug of the TPS) to see which wire has the 5 volts. At idle, TPS output voltage should be greater than .26 volts but less than .95 volts. Move the throttle and look for smooth meter response up to the 4.49 at WOT. The other wire will be the ground and should show no voltage.

Perform the test procedure again and wiggle and/or tap on the TPS while you watch the meter. If you notice any flat spots or abrupt changes in the meter readings, replace the TPS.


The TPS is sensitive to heat, moisture, and vibration, leading to the failure of some units. The sensor is a sealed unit and cannot be repaired only replaced. A TPS may fail gradually leading to a number of symptoms which can include one or more of the following:

-Poor idle control: The TPS is used by the ECU to determine if the throttle is closed and the car should be using the Idle Air Control Valve exclusively for idle control. A fault TPS sensor can confuse the ECU causing the idle to be erratic or "hunting".

- High Idle Speed: The TPS may report faulty values causing the engine idle speed to be increased above normal. This is normally found in conjunction with a slow engine return to idle speed symptom.

-Slow engine return to idle: A failing TPS can report the minimum throttle position values incorrectly which can stop the engine entering idle mode when the throttle is closed. Normally when the throttle is closed the engine fuel injectors will be deactivated until a defined engine RPM speed is reached and the engine brought smoothly to idle speed. When failing a TPS will not report the throttle closed and fueling will continue causing the engine to return to idle very slowly.

-Engine Hesitation on Throttle Application: The TPS is also used by the ECU to determine if the driver has applied the throttle quicker than the Manifold Air Pressure sensor can read. The fueling is adjusted accordingly to cope with the sudden increase in air volume, however a faulty sensor can cause the ECU to ignore this data and the engine will "hesitate" when applying the throttle. In extreme cases with the engine at idle, a sudden application of full throttle can stall the engine.

- Engine Misfire: A faulty TPS can report values outside the acceptable range causing the ECU to incorrectly fuel the engine. This is noticeable as a slight misfire and can trigger the misfire detection software and/or Malfunction Indicator Lamp (MIL) light on the dashboard. Extreme cases can cause excessive misfires resulting in one or more cylinders being shut down to prevent engine and catalytic converter damage.


wrscpc07 07-26-2013 09:03 AM

488 Attachment(s)
Quote:

Originally Posted by Holder350 (Post 15720664)
Borrowed from CJ7-Tim

I read that last night before testing voltage. Helpful, but going to need a second person help me out tonight

Holder350 07-26-2013 11:29 AM

You need to check voltage drop from the negative battery terminal to the ground on the sensor also.

Sent from my phone

wrscpc07 07-26-2013 11:48 AM

488 Attachment(s)
Quote:

Originally Posted by Holder350 (Post 15721343)
You need to check voltage drop from the negative battery terminal to the ground on the sensor also.

Sent from my phone

Will do. I read another thread on a forum and the guy had wired his back up lights without a relay and when the fuse blew he replaced the fuse with another and the culprit to this same issue was a larger fuse and it was drawing to much voltage or something like that..

Out of my 4 sets of lights, one is not wired with a relay and I did blow the fuse once and replaced it with another and I wonder if that has anything to do with it..it's an inline fuse, not sure if that makes a difference but I am going to give that a try after work too. I'll take the fuse out to the fog light, take cables off battery and see if it makes a difference..I guess that make sense, if my fog lights are pulling a lot of power that makes less power for things like tsp..correct?


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