Need help
02-24-2012, 09:09 PM
#4
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Torque converters don't spit and sputter. Engines do. Please be more specific. Torque converter failure on these Jeeps is extremely rare.
02-25-2012, 12:33 AM
#6
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Year: 90,84
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Engine: 4.0,2.5
Had a tune up lately? before you can find what's wrong you want your plugs, ect. square. If it hasn't been done conciser a fuel filter. That's stuff you need to do time to time anyway. Also take look at your vacuum lines and wiring.
02-25-2012, 04:32 AM
#7
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Year: 1990
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Tune up parts need to be in good shape. Have you ever replaced plugs, wires, cap and rotor? Fuel filter? Flontstone is right. This stuff needs to be known good or you could end up chasing your tail.
These problems are rarely a single sensor failure.
These problems are rarely a single sensor failure.
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02-25-2012, 09:40 AM
#8
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I have to change plugs and wires. I have change fuel filter, fuel pump, rotor cap and button, CPS, TPS, map sensor, and checked vacuum lines. It's odd that it acts up around the same speed every time. It's not random
02-25-2012, 11:02 AM
#9
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Year: 1996
Model: Cherokee
Engine: 4.0 HO Straight Six
Champion copper spark plugs gapped to .035 and quality wires. Also pull the throttle body and idle air control valve and give them a nice cleaning (with throttle body cleaner). Then report back. That's not your torque converter though
02-25-2012, 11:20 AM
#10
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I'm still learning here, Cruiser and and a number of others are sharper than me.
Do you have a meter? That new TPS you installed has an adjustment. I haven't done it on mine (yet), but it sounds like something that looks intimidating but really is easy. Our 90 and earlier Renix Jeeps are known to have wiring issues, particularly problems with grounds. Below is a TPS procedure. Really, you would likely benefit by spending a couple hrs going through the wiring connections. More on that later!
Here are two writeups , first 5-90"s, Then Cruiser 54's
TPS proper.
TPS output voltage should be 17% of input voltage, I will invariably use the manual transmission test outlined in the FSM (1990 FSM p. 8D-33.) This works on vehicles with the AW4 as well, and I consider it to be more reliable than the procedure for the automatic - since the automatic uses the "transmission side" to test, and the automatic TPS is two sensors in one body, a "good" test on the transmission side is not necessarily a "good" test on the engine side. And the engine side is more important.
Begin by measuring the input voltage to the TPS, between pins A and B on the three-pole cnx. Should be ~5.0VDC (experience shows that 5.0VDC +/- 0.5VDC is about right, so 4.5-5.5VDC. It's a regulated supply, and regulators do deteriorate with age.)
Calculate 17% of the input voltage. For correct 5.0VDC, that would be 0.85VDC. For, say, 4.83VDC, that becomes 4.83 x 0.17 = 0.8211VDC. (Yes, use a digital voltmeter, unless you're very experienced with an analogue and have one known to be reliable. It's that important.)
Backprobe pins B and C (positive lead in C) and read output voltage at closed throttle. Loosen the two screws, adjust to reach the figure calculated earlier (17% of input.) Hold the TPS in place (usually, pressing with your thumb will do) and tighten the screws to retain the adjustment. I like to dab a bit of fingernail enamel on these screw threads as an ersatz threadlocker - it has a few advantages:
- It's actually less strong than even LocTite #222, so you don't risk snapping off the screws
- It's just as waterproof.
- It does a better job of coating the threads.
- It may be "gently broken" to allow for adjustment, and will retain the screws without needing to reapply.
- You have a longer initial work time.
However, it is vital that you not use a fixed value for calibration - it is only 0.85VDC nominal output if the reference voltage signal supplied is 5.0VDC! A reference voltage of 4.5-5.5VDC is considered "acceptable," I'd start thinking about a replacement ECU below 4.25VDC.
Any main ground should experience a resistance of less than two ohms (good condition) or even as much as ten ohms (average condition) between that point and the ultimate ground point (battery negative terminal,) depower circuit to measure this. (Removing the battery positive lead is typically sufficient.)
For a function test of the TPS, an analogue ohmmeter is required. Absolute resistance values are not necessary, nor are they given.
What you do is you disconnect the three-wire plug, connect in to the TPS side for pins A & C or B & C, and then slowly and smoothly sweep the wiper arm on the sensor. The resistance reading should vary smoothly as you move the wiper arm - adjust your ohmmeter range setting until you get a reading that makes sense and varies with the position of the wiper arm. You can not use the typical DMM for this test, as a DMM has buffer circuits inbuilt into it that will work to stabilise a reading - and cause a delay in showing a reading change. Analogue ohmmeters do not have buffer circuits, and respond instantly (to demonstrate, set a DMM and an analogue multimeter to the 200VAC range, and connect both to a house outlet. You'll probably see the needle on the analogue waver slightly, while the digital tends to "seek." The analogue response is instant - and knowing this is the first step toward using an analogue multimeter correctly for diagnosis and troubleshooting. I've been using them for thirty-odd years, so I've gotten used to it. I ignore it if I don't need to know, and process it if I do. I've never gotten rid of my analogue, so I have an analogue and a digital handy.)
TO MAKE BACKPROBE PINS:
- Go to your wife's/girlfriend's/SO's/mother's sewing kit.
- Find the two longest, heaviest straight pins in there (quilting pins are good, hatpins are better.)
- Ask for them nicely. (If you end up having to, just go to the craft store and pick up a packet.)
- With a stone (like you'd use to sharpen a blade,) blunt the point of the pins. You want to round it off nicely with no burrs - the lack of burrs will help to preserve insulation and seals. You should be able to press the tip against your skin without penetrating.
The pins slide in the backside of the connector alongside the wire, so you can take a reading without disconnecting (which sometimes eliminates the possibility of taking a useful reading.)
Backprobe pins may also be purchased at electronic supply houses, but they're cheaper to make and easy enough, and you can make a dozen or so for less than what purchasing two would cost. Just don't let the metal bits touch once you've got them inserted - I've made a set and found heat shrink small enough (in various colours) to have a set of a dozen or so that are colour-coded - I used floral pins (about 2m/m thick, about 3" long) and left the 3/4" or so nearest the point uncovered. The heat shrink was cut short enough and located so that I can attach a small crocodile clip or a five-way test lead clip directly to the pin shaft, but the rest of the exposed metal is covered (and the heat-shrink helps to colour-code the things so I can keep them straight on sight. I should probably start making more sets...)
And Cruiser's Renix TPS adjustment.
And Cruiser's Renix TPS adjustment.
Here's another set of TPS instructions.They're not better, just different. And certainly nowhere as comprehensive as 5-90's. I wish I'd seen his before I put the work into these.
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: 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.
If you see more than 1 ohm of resistance 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 a three-wire TPS mounted on the throttle body.
This manual transmission vehicle TPS provides data input to the ECU. The manual transmission
TPS 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. Adjust the TPS until you have achieved this percentage. If
you can't achieve the correct output voltage replace the TPS and start over.
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--FOR 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.
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. If you have TRANSMISSION issues check the four-wire
connector side of the TPS. If you have ENGINE issues check the 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.
Do you have a meter? That new TPS you installed has an adjustment. I haven't done it on mine (yet), but it sounds like something that looks intimidating but really is easy. Our 90 and earlier Renix Jeeps are known to have wiring issues, particularly problems with grounds. Below is a TPS procedure. Really, you would likely benefit by spending a couple hrs going through the wiring connections. More on that later!
Here are two writeups , first 5-90"s, Then Cruiser 54's
TPS proper.
TPS output voltage should be 17% of input voltage, I will invariably use the manual transmission test outlined in the FSM (1990 FSM p. 8D-33.) This works on vehicles with the AW4 as well, and I consider it to be more reliable than the procedure for the automatic - since the automatic uses the "transmission side" to test, and the automatic TPS is two sensors in one body, a "good" test on the transmission side is not necessarily a "good" test on the engine side. And the engine side is more important.
Begin by measuring the input voltage to the TPS, between pins A and B on the three-pole cnx. Should be ~5.0VDC (experience shows that 5.0VDC +/- 0.5VDC is about right, so 4.5-5.5VDC. It's a regulated supply, and regulators do deteriorate with age.)
Calculate 17% of the input voltage. For correct 5.0VDC, that would be 0.85VDC. For, say, 4.83VDC, that becomes 4.83 x 0.17 = 0.8211VDC. (Yes, use a digital voltmeter, unless you're very experienced with an analogue and have one known to be reliable. It's that important.)
Backprobe pins B and C (positive lead in C) and read output voltage at closed throttle. Loosen the two screws, adjust to reach the figure calculated earlier (17% of input.) Hold the TPS in place (usually, pressing with your thumb will do) and tighten the screws to retain the adjustment. I like to dab a bit of fingernail enamel on these screw threads as an ersatz threadlocker - it has a few advantages:
- It's actually less strong than even LocTite #222, so you don't risk snapping off the screws
- It's just as waterproof.
- It does a better job of coating the threads.
- It may be "gently broken" to allow for adjustment, and will retain the screws without needing to reapply.
- You have a longer initial work time.
However, it is vital that you not use a fixed value for calibration - it is only 0.85VDC nominal output if the reference voltage signal supplied is 5.0VDC! A reference voltage of 4.5-5.5VDC is considered "acceptable," I'd start thinking about a replacement ECU below 4.25VDC.
Any main ground should experience a resistance of less than two ohms (good condition) or even as much as ten ohms (average condition) between that point and the ultimate ground point (battery negative terminal,) depower circuit to measure this. (Removing the battery positive lead is typically sufficient.)
For a function test of the TPS, an analogue ohmmeter is required. Absolute resistance values are not necessary, nor are they given.
What you do is you disconnect the three-wire plug, connect in to the TPS side for pins A & C or B & C, and then slowly and smoothly sweep the wiper arm on the sensor. The resistance reading should vary smoothly as you move the wiper arm - adjust your ohmmeter range setting until you get a reading that makes sense and varies with the position of the wiper arm. You can not use the typical DMM for this test, as a DMM has buffer circuits inbuilt into it that will work to stabilise a reading - and cause a delay in showing a reading change. Analogue ohmmeters do not have buffer circuits, and respond instantly (to demonstrate, set a DMM and an analogue multimeter to the 200VAC range, and connect both to a house outlet. You'll probably see the needle on the analogue waver slightly, while the digital tends to "seek." The analogue response is instant - and knowing this is the first step toward using an analogue multimeter correctly for diagnosis and troubleshooting. I've been using them for thirty-odd years, so I've gotten used to it. I ignore it if I don't need to know, and process it if I do. I've never gotten rid of my analogue, so I have an analogue and a digital handy.)
TO MAKE BACKPROBE PINS:
- Go to your wife's/girlfriend's/SO's/mother's sewing kit.
- Find the two longest, heaviest straight pins in there (quilting pins are good, hatpins are better.)
- Ask for them nicely. (If you end up having to, just go to the craft store and pick up a packet.)
- With a stone (like you'd use to sharpen a blade,) blunt the point of the pins. You want to round it off nicely with no burrs - the lack of burrs will help to preserve insulation and seals. You should be able to press the tip against your skin without penetrating.
The pins slide in the backside of the connector alongside the wire, so you can take a reading without disconnecting (which sometimes eliminates the possibility of taking a useful reading.)
Backprobe pins may also be purchased at electronic supply houses, but they're cheaper to make and easy enough, and you can make a dozen or so for less than what purchasing two would cost. Just don't let the metal bits touch once you've got them inserted - I've made a set and found heat shrink small enough (in various colours) to have a set of a dozen or so that are colour-coded - I used floral pins (about 2m/m thick, about 3" long) and left the 3/4" or so nearest the point uncovered. The heat shrink was cut short enough and located so that I can attach a small crocodile clip or a five-way test lead clip directly to the pin shaft, but the rest of the exposed metal is covered (and the heat-shrink helps to colour-code the things so I can keep them straight on sight. I should probably start making more sets...)
And Cruiser's Renix TPS adjustment.
And Cruiser's Renix TPS adjustment.
Here's another set of TPS instructions.They're not better, just different. And certainly nowhere as comprehensive as 5-90's. I wish I'd seen his before I put the work into these.
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: 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.
If you see more than 1 ohm of resistance 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 a three-wire TPS mounted on the throttle body.
This manual transmission vehicle TPS provides data input to the ECU. The manual transmission
TPS 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. Adjust the TPS until you have achieved this percentage. If
you can't achieve the correct output voltage replace the TPS and start over.
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--FOR 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.
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. If you have TRANSMISSION issues check the four-wire
connector side of the TPS. If you have ENGINE issues check the 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.
02-26-2012, 12:11 AM
#13
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Year: 1996
Model: Cherokee
Engine: 4.0 HO Straight Six
Originally Posted by DFlintstone
I almost want to say "WHOOPS!, didn't mean to scare you off!" Lol. Happy trails, 
I'd do my TPS to pay penance, but I don't have any source of straight pins ether. (I aint sellen)
02-26-2012, 06:25 AM
#15
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Nice job Flintstone. Truth and logic scares another one off.