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Throttle Position Sensor and....
My 1994 Cherokee 4.0 was kicking out a code 24..TPS..It was running a
bit erratic..hesitant..etc....Went to the junkyard and found another one and cleared the code...Ran perfectly for 200+ miles and then the code and minor troubles returned.....Back to the junkayrd..Found a 1996 4.0 with only 72,000 miles on it (Whole side caved in from a wreck near the rear) got that sensor..Same thing..Ran great for several days then code 24 again...All these sensors can`t be bad...What else could cause that code to appear if the sensor is ok?...Or what could cause sensors to go bad that fast if in fact they are bad?...I read the Haynes manual about checking the sensor and it says to "back probe" (A few posters also mention this) what exactly does that mean?...Thanks |
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#2
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Throttle Position Sensor and....
Used parts, why not get a new one and eliminate the posssibility of that
being the problem. Go to autozone.com/repairinfo for the testing of a tps on that truck. > wrote in message ps.com... > My 1994 Cherokee 4.0 was kicking out a code 24..TPS..It was running a > bit erratic..hesitant..etc....Went to the junkyard and found another > one and cleared the code...Ran perfectly for 200+ miles and then the > code and minor troubles returned.....Back to the junkayrd..Found a 1996 > 4.0 with only 72,000 miles on it (Whole side caved in from a wreck near > the rear) got that sensor..Same thing..Ran great for several days then > code 24 again...All these sensors can`t be bad...What else could cause > that code to appear if the sensor is ok?...Or what could cause sensors > to go bad that fast if in fact they are bad?...I read the Haynes manual > about checking the sensor and it says to "back probe" (A few posters > also mention this) what exactly does that mean?...Thanks > ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#3
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Throttle Position Sensor and....
Shep wrote: > Used parts, why not get a new one and eliminate the posssibility of that > being the problem. Maybe I don`t want to pay $80 for a part I don`t need..I get the sensors for free and it`s something that getting a used one shouldn`t be a problem with it being good..Thanks for the non-answer |
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Throttle Position Sensor and....
The usual problem I see with the TPS and the CPS is just a dirty
connection plug. I take spray contact cleaner to them and then they work perfect again. So far 'I' have not needed to change either. I just got an 87 Cherokee and it wanted to rev at 2300 every second time it was starter. It needed a new TPS.... Ya sure it did. One quick spray of the connection with contact cleaner and it purrs at 650 rpm. I was told 6 or 7 years ago I needed a new TPS for my 88 Cherokee which now has 315K km. Again, a spray on the connection every two years or so and it is still running perfectly with the original TPS in there. They are low power computer signal connections. They can be corroded enough to still look clean but not pass the signal. A fresh plug and unplug will scratch a new contact for a very short while sometimes, but the clean is the best. That is why folks say to unplug and plug back the CPS to get a few more starts out of them... Oh, 'back probing' just means poking a meter into the back side of a live connection to try and get a voltage reading out of it. TPS voltage should be from 0.02V at idle position up to 4.8V at the full throttle position with the engine and AC off but the key in 'run'. The TPS can be tested unplugged with an ohm meter. It is a rheostat that should have even resistance all the way up. If the resistance jumps around it is a bad or dirty one. Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 http://www.imagestation.com/album/pi...?id=2115147590 (More Off Road album links at bottom of the view page) wrote: > > My 1994 Cherokee 4.0 was kicking out a code 24..TPS..It was running a > bit erratic..hesitant..etc....Went to the junkyard and found another > one and cleared the code...Ran perfectly for 200+ miles and then the > code and minor troubles returned.....Back to the junkayrd..Found a 1996 > 4.0 with only 72,000 miles on it (Whole side caved in from a wreck near > the rear) got that sensor..Same thing..Ran great for several days then > code 24 again...All these sensors can`t be bad...What else could cause > that code to appear if the sensor is ok?...Or what could cause sensors > to go bad that fast if in fact they are bad?...I read the Haynes manual > about checking the sensor and it says to "back probe" (A few posters > also mention this) what exactly does that mean?...Thanks |
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Throttle Position Sensor and....
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#7
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Throttle Position Sensor and....
Shep wrote:>>> How dare you not fix his used parts/car problem!!<<< I didn`t want someone to fix it for me but to answer some basic questions in a clear logical manner which Mike and many others always have..In his above post he explained "back probing" which is what I thought it may have been and which I am completely competent to do but I had never heard that phrase before...I also asked what else could be causing the problem other than the sensor and he suggested another possiblity..It may not be the cause but it`s something else to consider...As far as vehicles in junkyards having "junk" parts that simply isn`t true as I`ve used them for 25 years and have saved thousands of dollars by getting used but still fully functional factory parts off of "junk" cars instead of buying new after-market parts...Alternators..starters..wiper motors..fans..etc...I mean seriously..Who is going to take a Jeep to the junkyard because the TPS is bad???.......Thanks for all the useful tips and advice I get on here from time to time :-) |
#8
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Throttle Position Sensor and....
Mike Romain > wrote in
: > > Oh, 'back probing' just means poking a meter into the back side of a > live connection to try and get a voltage reading out of it. Some connectors are very hard to backprobe with the meter, as the connector conforms closely to the wire diameter. In those cases, I use a straightened paper clip to stick into the connector and make contact with the metal contact inside, then touch the VOM probe to that. > TPS voltage > should be from 0.02V at idle position Are you sure it isn't more like 0.2V? 0.02 seems kinda low. > up to 4.8V at the full throttle > position with the engine and AC off but the key in 'run'. The TPS can > be tested unplugged with an ohm meter. It is a rheostat that should > have even resistance all the way up. If the resistance jumps around it > is a bad or dirty one. Comboverfish told me that wasn't a reliable way to check, when I needed to check mine. He said voltage was the only reliable way. -- TeGGeR® |
#9
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Throttle Position Sensor and....
"TeGGeR®" wrote:
> > Mike Romain > wrote in > : > > > > > Oh, 'back probing' just means poking a meter into the back side of a > > live connection to try and get a voltage reading out of it. > > Some connectors are very hard to backprobe with the meter, as the connector > conforms closely to the wire diameter. In those cases, I use a straightened > paper clip to stick into the connector and make contact with the metal > contact inside, then touch the VOM probe to that. I have used needles and then sealed the holes with a dab of sensor safe RTV. > > > TPS voltage > > should be from 0.02V at idle position > > Are you sure it isn't more like 0.2V? 0.02 seems kinda low. The Jeep one calls for >200 MV or .02V. The early adjustable ones called for 0.026V. If it's an automatic, it actually works backward on one pin set. 4.8 at idle and 0.02 at full throttle. > > > up to 4.8V at the full throttle > > position with the engine and AC off but the key in 'run'. The TPS can > > be tested unplugged with an ohm meter. It is a rheostat that should > > have even resistance all the way up. If the resistance jumps around it > > is a bad or dirty one. > > Comboverfish told me that wasn't a reliable way to check, when I needed to > check mine. He said voltage was the only reliable way. I wouldn't argue there, but if the TPS has a 'dead' spot in the acceleration, that can usually show up on the resistance. Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 http://www.imagestation.com/album/pi...?id=2115147590 (More Off Road album links at bottom of the view page) |
#10
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Throttle Position Sensor and....
Mike Romain > wrote in
: > "TeGGeR®" wrote: >> >> >> > TPS voltage >> > should be from 0.02V at idle position >> >> Are you sure it isn't more like 0.2V? 0.02 seems kinda low. > > The Jeep one calls for >200 MV or .02V. The early adjustable ones > called for 0.026V. A millivolt is 1/1000th of a volt. A thousand of them is 1V. If you had only 200 of them, that would be .2 of a volt, not .02. Work the decimal places back and you'll see: 1.000 V (1,000 millivolts) 0.200 V (200 millivolts) 0.020 V (20 millivolts) > > If it's an automatic, it actually works backward on one pin set. 4.8 > at idle and 0.02 at full throttle. My Integra's is .3V to 4.5V through its range, from closed to WOT. > >> >> > up to 4.8V at the full throttle >> > position with the engine and AC off but the key in 'run'. The TPS >> > can be tested unplugged with an ohm meter. It is a rheostat that >> > should have even resistance all the way up. If the resistance >> > jumps around it is a bad or dirty one. >> >> Comboverfish told me that wasn't a reliable way to check, when I >> needed to check mine. He said voltage was the only reliable way. > > I wouldn't argue there, but if the TPS has a 'dead' spot in the > acceleration, that can usually show up on the resistance. That's what I thought too, but he differed and he's got a lot more experience than I do, so I checked it his way. It tested OK either way. -- TeGGeR® |
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