HAHAHAHA, Cruiser Im starting to wonder if you dream about the TPS adjustment and Ground Refresh procedures in your sleep.

 

Well, from my experience if more people would address the ground issues with their Renix Jeeps they would have fewer nightmares about spending money and wasted time unnecessarily on sensors.

I lived that nightmare at the dealership when these Jeeps were new.

 

Or just pull the vacuum line off of the FPR, and see if pressure remains stable. That way, you're not crushing the return line hose (just block off the vacuum line when the engine is running. You don't need to do anything with the FPR. I've done this just by pulling the vacuum line and rapidly putting my thumb over the hose end.)

 

I'm curious. If a piece of something, (say a shaving of fuel line from pushing it onto a nipple), lodged in the FPR, couldn't that let fuel past the diaphragm/valve regardless of what the vacuum was doing?

 

Potentially, if the regulator is supposed to be "deadheaded" at any particular time ("deadhead" = diaphragm fully shut.)

I'm not sure of the internal arrangement of the RENIX FPR, so I can't really attest to more than that.

 

Stoki, you can ignore 9/10 ths of what the meter does. (I do). You just want a DC volts scale. The one you want is probably 20. (or 2 for checking flashlight batteries. (I can them down around 1.25)).(before rechargeable got cheap)

Then AC volts. For a Renix CPS you are just looking for 1/2 a volt, so a 2, or 200 scale is fine. (also on 200 you could check an outlet in your house. On your cloths dryer it will only flash a "1", and you will need to go up to the next scale)

Then ohms, (is continuity, how much resistance). Resistance makes the equivalent of friction. Handy for a car's cigarette lighter. Not handy for a starter cable. Has the symbol that looks like headphones. I rarely try to use the scales with a "K". The ground at my dipstick tube probably has less than 200 ohm's resistance, so the 200 scale is high enough.



Now what they have done for some, ...For DC...they have a straight line, looks a minus sign.(--), after the "V", (signifying "even", I guess)
And for AC, after the "V" is the wavy deal, (~), (signifying "wavy" I guess. AC IS wavy)

The black lead goes where is says "COM", and might have a downward arrow like symbol. The red goes where there is a V and the headphone, (ohm's) symbol.

WARNING! If you have the red in the "A" (Amps) socket, and say, try to check your battery, it will blow the fuse, trip the breaker, melt your leads, or smoke your meter! (the amp's circuit anyway). That's a dead short as the current can go right through. You could put, say the Positive output of a solar panel through it, or the power to a small inverter, (or other small 12v load), and read the current flow in Amps. In 30 years off the grid, I've forgotten to put my red back in the volts socket a few times.

 

DC voltage is steady, and runs at a (theoretically) fixed level. +5VDC will always be at +5V, if nothing's wrong.

AC voltage constantly varies within a range, following a sine wave pattern (remember your middle school geometry? Residential supply - 115VAC - runs a predictable pattern from +115V to -115V.

The straight line indicates DC voltage, the wavy line is supposed to be indicative of the sine wave, indicating AC voltage.

AC/sine wave is also the form for a radio wave signal, although it's measured somewhat differently (I won't go into the difference between root-mean-square and peak-to-peak wave measurement here, I shall leave that as independent study for the apt pupil.)

The typical multimeter is only good for measuring either DC voltage (straight run) or AC voltage (60Hz sine wave - alternates sixty times per second.) A square wave output (as in a Hall Effect sensor, or some mobile inverters) is something that a multimeter won't measure well. That's when you're starting to get into oscilloscope territory...

 

Hey guys Im back finaly. I installed the new fuel pump and had a hell of a time with reintalling the locking ring. It did fix my problem though the Jeep runs well now. Now my gas gauge stopped working. I read in my Haynes manual that if you knock the pump around it can damage the sending unit. How hard is this to do? Is it possible to fix if this is the case or will I have to replace it?

Also I may try to adjust my TPS with the voltmeter but it seems pretty complicated to me.

I also have some general axle questions. Ive done lots of reading latly and have read about "Dana" axles. What is this exactly and are they better than my stock axles? if so why?

 

The lockring takes a bit to reinstall, but it's doable. I like to paint the surface with never-seez before it goes on, and I use a brass mallet and drift rod to drive it into place (no sparks.)

The sending unit is on the "stinger" that mounts the fuel pump - it's possible you may have bent the rod for the float when you put it back in, I've known it to happen. Generally, replacing the float sensor usually means replacing the stinger assembly - the pump gets moved over from the old one to the newer one.

The TPS is easy to adjust - suggest using a digital voltmeter if you don't have practise reading an analogue.

You'll have to adjust the TPS with it plugged in and with the key on (engine not running!) which requires backprobing. Backprobe pins may be made from paper clips or straight pins (I prefer straight pins,) just take a minute with each wire to round the end off using a stone or sandpaper. The wire is then inserted into the backside of the connector, under the grey insulating boot, alongside the wire. Go as far as you can gently push it - you should see the wire go in about a half-inch or so, which should put it in contact with the terminal inside.

You can also puncture the wire jacket to read that way, but some advice there:
- It's better to use a "bed-of-nails" test clip, which increases the chance of your hitting the wire.
- Don't punch through the insulation on wires near each other - keep some space between the puncture spots (have a linear half-inch or so between them.)
- Cover the puncture site after you're finished - friction tape works, silicone (black or clear) coating it should work better. You could also use a drop of liquid electrical tape (this is one of the very few times I'd recommend the stuff) or something like Plasti-Dip - cover the puncture site completely, so nothing can get into the wire.

(As you can see, it's easier to use backprobe pins - less work after-the-fact.)

You'll use something like a T10 Torx driver to loosen-tighten the screws if they're OEM - most aftermarket replacements come with Philips head screws (and usually take a #1 Philips screwdriver instead.)

As something to help keep adjustments fixed, I like to put a drop of rubber cement on the posts under the sensor. This will create friction enough to keep the thing from moving randomly, but won't harden and fix the thing permanently to the throttle body. Hold the sensor in place and monitor the adjustment while you tighten the screws, go back-and-forth across the sensor, tightening each screw a bit at a time, and you'll be okeh.

(Gawd knows how many times I've done this job...)

Bear in mind that the voltage target is not an absolute! The closed throttle adjustment for the engine side of the TPS should be 17% of the input voltage - if it's still 5.0VDC, you'll want to get to 0.85VDC. If the regulator for the reference voltage has started to drift, calculate your target beforehand (if the input is less than 5.0VDC, and you set it to 0.85VDC, you'll get spurious readings.)

For instance, if your sensor reference voltage has dropped to, say, 4.83VDC, then you'll set the TPS idle output to 17% of that - 4.83*0.17=0.821VDC. I've lost count of how many people take the "0.85VDC" figure as absolute, then come over to me because their reference voltage has drifted and their rig is acting screwy...

EDIT - Oh, and "Dana" is an axle manufacturing company. You'll hear axles made by a few different vendors:
- Dana is an "non-corporate" axle manufacturer - they make driveline parts, but not entire vehicles. Dana axles are identified by model number (30, 35, 44, 50, 60, 61, 70, and 80 being common for light trucks and now - they've been doing it for a while); location of the axle (front or rear - I don't believe any Dana light truck axles are meant for "tandem/tridem" use,) and whether they have a vacuum disconnect for the front axle (which is usually referred to as "disco.") Also, note that axles through D70 could be used front or rear - they usually share differential parts (except in the case of a "high pinion" or "reverse spiral" front axle, where the spiral for the gear teeth runs in the opposite direction. These may be identified by the centreline of the pinion being above the centreline of the halfshafts, typically it lies below.) Low Pinion fronts use the same gearsets as rear axles, and there is otherwise a good deal of parts commonality. Front axles have been referred to as "fronts" (by hobbyists like us,) or as "drive steer axles" (by the manufacturers.)
- "Corporate" means that the axle was made by (or on contract for - American Axle & Manufacturing makes a lot of contract corporate axles) the company that made the rest of the vehicle. Corporate axles are usually identified by the outfit they're made by/for (General Motors, Ford, Chrysler/Dodge) and ring gear diameter or number of screws securing the cover (the latter can cover two or three ring gear sizes, so the ring gear size is best.) Also, GM has a couple of ring gear sizes that are shared between passenger cars and light trucks - just to add to the confustion. Ergo: A "Ford 9-inch" is a rear axle made by/for Ford Motor Company (FoMoCo,) and has a 9'" ring gear. (This axle is also easy to identify by the housing being built-up from sheet steel instead of cast, and the lack of a differential cover - the whole assembly drops out of the driveshaft side.) The Chrysler 8.25" is the rear axle that sporadically replaced the Dana 35 in the back of the XJ, 1991-2001.

Other manufacturers include:
- American Axle and Manufacturing (AAM). These guys make their own axles, and produce a number of "contract/corporate" axles for GM and Dodge.
- Eaton. Strictly heavy-duty axles, usually for Class 5 heavy trucks and larger, and often set up for tandem/tridem use.
- Rockwell. You'll hear about "Rockwells" under Jeeps - this refers to the 2.5-ton axles, usually salvaged from under an M35. However, that's probably the lightest-duty axle that Rockwell makes - and it can be set up for solo or tandem operation (all three axles under an M35 are Rockwell 2.5-ton units - the tandem rear drives and the front steer axle, all "live" axles.)

These are the common ones. Of course, there are also Toyota axles, Nissan axles, and Isuzu had their own (and also used the D44 in the Amigo, Trooper, and pickup.)

Confused yet?

Since you've got a RENIX-era XJ (1987-1990, last of the AMC specs,) you'll have a Dana 30 front steer/drive axle. Your rear axle is likely a Dana 35 (which is okeh - at least it's a true semi-float, and not a C-clip,) but some AMC-built XJs (through AUG1988) with the trailer towing package may have the coveted Dana 44 rear axle - if you sell the truck and the axle is still straight - keep it! Or, give it to me, I want to go D44 fore and aft under my 88, geared to about 4.27:1...)

In short, Dana axles are your stock axles - but you could do better. Depends on what you're trying to do. I've blown four Peugeot gearboxen in my 88, but I'm still steaming along on the factory D35 that's in there (probably because it's horribly mismatched in gearing to the BA-10/5 or AX-15, so I don't strain it much.) You'll get a lot of complaining about the D35 axle - and it is relatively weak (which is why I want to go with D44s, but I want to refit as a work truck...) and a number of swaps are common (which is why I'm writing Swappology - I've decided to try to make a few bucks out of my Jeep hobby, and Swappology is my "second book" - even though it will probably end up being three: AMC, IHC, and Jeep.)

Common swaps under the XJ? The D30 is often left in place, and the rear axle swapped out for:
- Ford 8.8", as found under the Explorer. This can also net you rear disc brakes. The Ford 8.8" has the advantage of being dirt common and relatively strong, but it's a C-clip axle - if you're going to push the thing, you're best off getting a C-clip eliminator kit for it. Usually requires having a driveshaft made.,
- Ford 9". Hell-for-strong (partly due to the 9" ring gear, partly due to the third pinion shaft bearing on the pilot, inside the ring gear, and partly due to the high hypoid offset; I believe it's 2.375", instead of the more typical 1.25"-1.75") This is the legend in light axles, parts are everywhere, and even aftermarket full 9" axles are made (like the Currie "Hi-9.") And, for its weight, it's strong.
- You can swap out the later XJ Chrysler 8.25" for the D35 - same caveats as the Ford 8.8, but less work. Grab the driveshaft as well, making sure it's from a 4WD XJ (the 2WD shafts are longer, and will tie up on you without some lift. I don't know how much.) Also C-clip.
- Dana 44 rear. Advantage? Everybody used the D44 at some point, some are still using it, and I don't think a C-clip D44 was ever released. The 8.5" ring gear makes it stronger than the D35 or C8.25 and puts it on a par with the Ford 8.8". This axle also has the most extensive aftermarket support - so getting upgrade parts is not REPEAT NOT a problem! Want 4340 shafts? Easy! 8620h gears? Sure!

(The D44 is also readily available in front/steer versions, open or closed knuckle. However, these are harder to modify in width than rears.)

- The D60 is used under most GM and Dodge 3/4-ton and 1-ton light trucks, which makes them fairly easy to find as well (Ford, GM, and Dodge all used D60 steer axles as well.)

The primary limiting factor for swapping axles, realistically, involves:
- Moving/welding the assorted bracketry.
- Upgrading your central brake hydraulics, if the cylinders are significantly larger (common.)
- Adapting the handbrake cables
- Adapting the driveshaft, or having one made (I like that the Ford 8.8" often uses a "companion flange" instead of a yoke. About the only thing I like about it - I'm not wild about Ford or Ford parts.)

Critical data for axles?
- Ring Gear diameter - bears directly on axle overall strength.
- Halfshaft diameter - bears directly on halfshaft strength.
- Side splines - more is usually better (due to the standard pitch being used, you need a larger shaft to fit more splines. Also, this means that the drive force is spread out over more material, which gives the splines a bit of a break.)
- Pinion splines - you sometimes have a choice (D44, D60, and C9.25" all had "transition years" with various pinion spline counts - again, generally, more is better. The nut on the pinion shaft keeps the yoke from walking off and keeps preload on the pinion bearings, but it's the splines that handle the power transfer!)

Of course, this is "all else being equal." This doesn't take material into account. A 1541h shaft is stronger than a 1541 shaft (the "h" is vacuum-melted, which eliminated entrained oxygen and hydrogen embrittlement,) and a 4130 or 4340 is going to have a 1541h beat all hollow. Standard gear steel for OEMs is usually 8620, but there are better alloys out there as well (these numbers denote AISI steel alloys - you can look them up, if you want to know the properties.) Given the same material and section, also, a forged shaft will be stronger than a wrought shaft. (I really don't want to go into metallurgy right now - it's late.)

If you have more questions - fire away! I'll answer them as best I can, but I don't know everything. However, I'm sure there will be some people here who would be happy to fill in whatever I miss (I'm just a half-assed engineer who's had to learn everything the hard way - break it, and keep rebuilding it until it doesn't break anymore. Now, very little I build breaks...)

 

my renix also has a hesitation when first accelerating. more pronounced when engine is cold. my rig has a new fuel pump and filter, injectors have been checked, crank sensor changed(but it is an oreilly or autozone part, so i am gonna check the voltage when turning engine over as posted above).

i did try to adjust my tps, (i have an analog meter! and that may be my issue) but i set it as stated, and when i started it it revved to like 3000 rpm, so i adjusted it back to where it shouldnt be, and it idled normal, (well 800 to 1000). i also have an issue with the idle bein 1200 rpm sometimes, and 800 rpm others. could this all be related to the tps?

i live close to bolivar missouri if anyone is close and wants to take a crack at it! lol i got it on jack stands replacing the bearings in the dana 35 now, just have to put cover on and refill.

i love the xj, but they are a learning experience, and very much in need of attention all the time! and dont get me started on the crappy fuse box under the dash! thats another can of worms i dont ever wanna deal with again!

so for highjackin the thread to the o.p., but any help would be great.

 

Absolutely could be a faulty or misadjusted TPS. Get a digital meter and check it on the "engine" side per the following instructions. My experience has been when they start idling randomly either high or low, the TPS has usuallly failed.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.
Revised 11-28-2011


Be sure to do the sensor ground test under IMPORTANT NOTE.