I was wandering if the rest of you renix owners have had bad luck with after market tps' like autozone,napa etc. ? I have only replaced one from autozone since having my 90'. That was about a year ago,and it is acting up already.I know they dont like to be pressure washed,ask me how I know.It has actually been mild weather here not much rain at all, big puddle splashes not a issue.I dont remember brand I got, but does anyone know who makes the oem ones ? I call stealership in morning to see how far they want me to bend over for there stock one. :worship:
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Tps For Renix ?
- Thread starter MACH90XJ
- Start date
martin
NAXJA Forum User
- Location
- Huntsville, AL
I got mine at the dealer for my 88 XJ. You have two choices at the dealer the normal and the high altitude CPS. My dealer stocked and changed the same price for both versions.
The high alt version gives you more advance which translates into more power. You don't have to worry about ping since your engine has a knock sensor. If you get knock after replacing the CPS with a high alt version you will need to replace the knock sensor. You can now get the knock sensor on the aftermarket.
I would go with the dealer for the CPS, as far as I know they are the only one who carry this high alt CPS. The normal CPS has the sensor mounted on the center of the bracket, the high alt has the sensor mounted off center on the bracket. When you pick up a CPS you will know instantly which version you have in your hand.
The high alt version gives you more advance which translates into more power. You don't have to worry about ping since your engine has a knock sensor. If you get knock after replacing the CPS with a high alt version you will need to replace the knock sensor. You can now get the knock sensor on the aftermarket.
I would go with the dealer for the CPS, as far as I know they are the only one who carry this high alt CPS. The normal CPS has the sensor mounted on the center of the bracket, the high alt has the sensor mounted off center on the bracket. When you pick up a CPS you will know instantly which version you have in your hand.
martin
NAXJA Forum User
- Location
- Huntsville, AL
Sorry there, that what I get for reading a post first thing in the morning. I now relook and see he asked TPS. I replaced my TPS on my 88 XJ with a new one I got from rockauto.com. It was a starndard brand TPS and has worked well. The pain of a TPS on a Renix XJ is calibrating the new sensor, lots of posts on that issue.
I messed up read it at "cps" instead of "tps".
I messed up read it at "cps" instead of "tps".
martin said:
Okay, thanks for clarifying. I respectfully disagree about TPS adjustment needing the OEM scanner or Snap On system. FSM doesn't mention it so where is that coming from? The trouble, I believe, is most folks don't use "sensor" ground when calibrating the TPS so the voltmeter method will be wrong and may cause driveability issues after adjustment.
I've tech'd my Renix system for years and never had a problem with any of the FSM procedures and I've even hooked up an o-scope and measured injector firing pulse width, blah, blah, blah. But, I do have an electronics tech background and that helps me avoid the little pitfalls like "sensor ground" vs. vehicle ground for example.
For the OP - I'm at over 260k miles on my '89 and have never replaced the TPS or CPS yet. Wiring/connectors and people spraying carb cleaner into the TPS are more of a problem than component wear/tear. The only thing that should be used on a TPS is potentiometer cleaner/lube. An analog volt/ohm meter can sometimes help diagnose a bad TPS. Look for erratic movement in either resistive or voltage checks of the TPS range. Trouble is, you gotta know about Ohm's law to understand what that means.
The best adjustment procedure I've used is to 1st setup a warm base idle with the throttle plate. For that, the IAC must be fully closed, then adjust the TPS per FSM procedure referencing "sensor" ground with the DVM.
Works great for me.
martin
NAXJA Forum User
- Location
- Huntsville, AL
XJXJ that statement when I say it comes from my personal experience. I replaced the TPS on my 88 XJ using the Multimeter method. I did an spread sheet so I would just look up output value paired with the "source" value. I then take it to the dealer for a problem that turned out to be a stickey EGR. The mechanic told me my TPS was out of adjustment and set it right for me. I only paid him for the EGR, no charge for the TPS adjustement.
I then buy the snap on tool MT2500 scanner since I read on here it the only tool beside the dealer tool which can read the computer on a Renix. I plan to keep the XJ and was worried the dealer tool may 'disappear".
I have the tool and my buddies with older vehicles I offered to hook up the MT2500 to see what going on with their vehicles. I hooked it up to a 85 Vette, and the following with the GM 3.8/3800 V6: 87 buick Century, 88 buick Le Saber, 88 buick park Ave, 88 Olds 98, 90 buick le sabre, and 91 buick le sabre.
Three different people owned those vehicles, each had installed a new TPS and used the multimeter method to set the TPS and were happy with the result. I hooked up the MT2500 and discovered the value read at the computer was lower than the published spec. The 85 Vette was to be set at 0.6 v, and the GM 3.8/3800 was to be 0.4 volts but across the board they were all 0.2 volts low. The Vette was 0.4 volts and the 3800s were like 0.2 or 0.22 volts.
The guy with the Vette had been out showing me how it ran, we came back to the house and checked and adjusted the TPS, then less than 5 minutes later we went back out to see what the difference. With the owner driving we pulled up to a stop light and pulled away when it was green. He said "Oh yes, it did make a difference!!!"
The 4 of us talked to why the voltages were lower and we concluded the Multimeter method does not account for the voltage drop from the TPS to ground. This would expain the difference between the DVM method vs the MT2500 scan tool. With the computer reading a lower voltage from the TPS the computer will not give the full amount of fuel for best power. Remember by the TPS measurement the computer determines how "open" the throttle body is. If the computer thinks the throttle is less open than you will have less than optimal performance.
By all means using the mulitmeter method is the way to go it you don't have access to a scan tool. Just passing on the lesson I learned.
I then buy the snap on tool MT2500 scanner since I read on here it the only tool beside the dealer tool which can read the computer on a Renix. I plan to keep the XJ and was worried the dealer tool may 'disappear".
I have the tool and my buddies with older vehicles I offered to hook up the MT2500 to see what going on with their vehicles. I hooked it up to a 85 Vette, and the following with the GM 3.8/3800 V6: 87 buick Century, 88 buick Le Saber, 88 buick park Ave, 88 Olds 98, 90 buick le sabre, and 91 buick le sabre.
Three different people owned those vehicles, each had installed a new TPS and used the multimeter method to set the TPS and were happy with the result. I hooked up the MT2500 and discovered the value read at the computer was lower than the published spec. The 85 Vette was to be set at 0.6 v, and the GM 3.8/3800 was to be 0.4 volts but across the board they were all 0.2 volts low. The Vette was 0.4 volts and the 3800s were like 0.2 or 0.22 volts.
The guy with the Vette had been out showing me how it ran, we came back to the house and checked and adjusted the TPS, then less than 5 minutes later we went back out to see what the difference. With the owner driving we pulled up to a stop light and pulled away when it was green. He said "Oh yes, it did make a difference!!!"
The 4 of us talked to why the voltages were lower and we concluded the Multimeter method does not account for the voltage drop from the TPS to ground. This would expain the difference between the DVM method vs the MT2500 scan tool. With the computer reading a lower voltage from the TPS the computer will not give the full amount of fuel for best power. Remember by the TPS measurement the computer determines how "open" the throttle body is. If the computer thinks the throttle is less open than you will have less than optimal performance.
By all means using the mulitmeter method is the way to go it you don't have access to a scan tool. Just passing on the lesson I learned.
Jeep839
NAXJA Forum User
- Location
- Highlands, New Jersey
i have a 90 and have had a TPS from Napa for about 3.5-4 years no problems yet just remeber to make sure that the turpedo connectors are lubed and tight, bc mine has lossened up on me and it was giving me some problems and then i just lubed it and bent the connectors so they would grab on alot stronger and no more problems................. yet............
Spanky414
NAXJA Forum User
- Location
- North Bay, Ontario, Canada
XJXJ said:
Maybe he ment voltage drop going from the TPS all the way back through the harness to the ecm? Wouldn't that be more acurate to measure the values right at the ecm?
I only go by what is said/typed. Far be it for me to put words into somebody's mouth.
But, if you are interested in the effect of wire resistance you may find this helpful -
http://www.sci-journal.org/reports/vol3no2/v3n2a3.html
But, if you are interested in the effect of wire resistance you may find this helpful -
http://www.sci-journal.org/reports/vol3no2/v3n2a3.html
DrMoab
NAXJA Forum User
- Location
- The Utah Backwater
You guys are all making this too hard on yourselfs....Just plug it in....adjust till it drives right and call it good.
GO redneck or go home! :laugh3:
GO redneck or go home! :laugh3:
Spanky414
NAXJA Forum User
- Location
- North Bay, Ontario, Canada
XJXJ said:
Well I'm not talking about the wire specificaly but all the connections it has to go through, corrosion and all that.
