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98xj 5.3 swap (the poverty method).

Edit: You're right. Doesn't work in full sunlight. I may try to hack around it, but I did buy a 7" tablet specifically because it's exactly the right height for the cluster.

First drag test today on the way home from the border.
Street start, no stall:
0-30 - 2.9s
0-60 - 6.6s

This is with a full size 35" spare, bumpers, winch, full size roof basket, full tank of gas, all my recovery gear (at least an extra 200lbs), and a 50lbs tool bag.
Bone stock 5.3L/4l65e. Still using the injectors/plugs/wires that have sat dry on the motor for who knows how long, and my front brakes are dragging.

So pretty much the worst number I'll get unless I ever make friends to ride along. Nothing to write home about, but a massive improvement over my old beaten 4.0L's 16 or so seconds, and even over my fastest previous Jeep's 9.2 (loads of upgrades, stripped for weight reduction, 29" shoes).
Can't complain with that at all.

I'm going send my puter to scan every possible mode22 code tonight to see what all I'm missing. I started the scan this morning, but at 25 updates/second, it was only about 80% complete when I had to go for a drive, and I stupidly wasn't logging. Did find at least 50 or so unknown PIDs though.
 
Still trying to wrap my head around how the fuel level sensor works. Potentiometer sure. That makes sense to me. I also understand that measuring resistance is unreliable, and besides which, connecting one wire from the sensor to the ECM and the other to ECM ground doesn't produce any reading. I'm assuming you're supposed to push a 5V reference voltage through the sensor, and the ECM reads reference ground, but this seems like an explosion waiting to happen.
Is this correct? Should the sensor be getting power?
 
I'm too tired to mess with it right now but if I think of it later, I'll dig up the wiring diagram for your donor rig's fuel sensor.
I am fairly sure the sender is supposed to get 12V from somewhere and the return goes to the gauge (or ECM) but, y'know, it's way past time I should get off the interwebs and get some sleep.

EDIT: ok, click here. It's for an F-body but should be the same.
 
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Diagram shows just c1 23 (low reference) and c2 54 (fuel level sensor) going to the sensor.
C2 54 is 5V+, C1 23 is 0V.
Connected C2 54 to one end of the sensor, and C1 23 to the other end, but no data showing up.
Can anyone else confirm that the fuel level is even presented over OBD on the 03+? I assume it must as the gauge gets it's data directly from the ECM, but I'm just not seeing any data.
 
you have it right that there is 5v and a low reference. The GM ecm expects a different signal from what the jeep sensor will send. For some reason even though at a half tank the resistance should be in the range of both the GM and the jeep computers, mine doesn't satisfy the GM computer. Is it possible that the gauge and computer are both wired to the sensor? On my 96 the jeep system is wired that way, the reference splits off to the gauge and computer.

FWIW I can see the fuel sensor input on hptuners and set up a gauge using that pid
 
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Hoooper said:
you have it right that there is 5v and a low reference. The GM ecm expects a different signal from what the jeep sensor will send. For some reason even though at a half tank the resistance should be in the range of both the GM and the jeep computers, mine doesn't satisfy the GM computer. Is it possible that the gauge and computer are both wired to the sensor? On my 96 the jeep system is wired that way, the reference splits off to the gauge and computer.

FWIW I can see the fuel sensor input on hptuners and set up a gauge using that pid
Click to expand...

Do you happen to know the PID and formula you used?
98 XJ definitely doesn't split the signal from the sensor to gauge and ECM. Everything is handled by the ECM directly.

So, possibly need a GM compatible sender, but shouldn't I still be able to see that the PID is active either way, or does the ECM not see the correct signal, and just give up on reporting anything at all over the bus?

What have other people done to get the GM ECM reporting fuel level via OBD?
 
Pretty sure my TCC lockup isn't happening. Trans is getting way too hot on the highway. Seems fine around town, but once I've been cruising at 100km/h for about 15 minutes, it creeps up on 100C and I shut it down. Also, fuel economy goes way down on the highway. Can get 22-24mpg in the city, but on the highway I'm averaging around 17-18mpg and RPM's always seem a bit high.

I did wire a relay from the brake switch (normally on, brake switch open = relay open) and to the ECM. Is there any definitive way to know if TCC is locking up correctly? From what I understand, it should lockup when load is under a certain percentage and speed is above 50mph. Lots of guys say you can pretty clearly feel the TCC lockup as it feels like an extra gear shift. I don't feel anything beyond the actual gear shifts.

Fluid level is good, not throwing any codes, seems to shift fine. Thoughts?
 
John D said:
I don't know about feel, but you should be able to hear it and also see the RPMs drop when it locks. Musing something like HPTuners you can command it on/off also.
Click to expand...

Yea, I don't notice the RPMs drop at any point after hitting OD either. For such a light Jeep, I feel like I should expect the lockup to happen even under light-moderate acceleration as well.

I'm thinking I should be able to wire up an LED to the lockup wire to at least see if the ECM is sending the signal. If yes, then I still have no idea if it's locking up. If no, then I know where to start looking. I figure though, the ECM should've thrown a code if there was any reason the TCC lockup shouldn't have occurred.

What really kills me though, is that taking the trans apart for inspection will cost me more (just in fluids) than picking up another good 08 4l60e :) I'll do a bit of troubleshooting on this, but I get the feeling I'll just throw another trans on.
 
you might not feel the lockup kick in, it's pwm control and set up so that it isn't noticeable like a shift. Easiest way to tell would be to cruise on a flat freeway, then increase throttle a little bit and see if the rpm increases without the vehicle speed changing. Did you tune the pcm for your tires/gearing or is it stock? If lockup is enabled but not working you should get a code, I think p0741, for tcc stuck/off
 
Hoooper said:
you might not feel the lockup kick in, it's pwm control and set up so that it isn't noticeable like a shift. Easiest way to tell would be to cruise on a flat freeway, then increase throttle a little bit and see if the rpm increases without the vehicle speed changing. Did you tune the pcm for your tires/gearing or is it stock? If lockup is enabled but not working you should get a code, I think p0741, for tcc stuck/off
Click to expand...

Hrm. Did some more testing last night.
Put the Jeep back up on stands, threw in gear and hit 100km/h. Like always the TCC slip came down to 0, but doesn't LOCK on 0. It hovers between -5 and +5 or so. Perhaps I was just expecting too much lockup? I had my buddy disconnect the TCC lockup relay while I was at a 100km/h cruise, and sure enough, the TCC slip did increase to 20-30RPM instantly, and then I start seeing the RPM's rise/fall a bit before speed changes. So looks like the TCC lockup may be working after all, but perhaps it's slipping?
How much slip is enough to set a code? The poor highway fuel economy and transmission temp together, strongly suggest a slip somewhere in the trans.
I really don't know how much cooling this motor/trans should need to push my little XJ, but I figured the built in tranny cooler in my griffin should be sufficient. Perhaps I was wrong?
Like, I'm basing all of my tranny problems on the heat being generated and the poor fuel economy (at highway speed). Should a built in cooler be able to keep that trans cool for light duty? (sent griffin an email about this already).

I'd just throw an external cooler at it, but I want to hold off on that until I know for sure if the built in cooler should be able to deal with it. An external cooler may solve the overheating, but may just be masking a slip problem somewhere. Hell, I could also just pick up another tranny for $250 (08 4l65e), but again, I'd like to KNOW if I have a transmission problem, or just a cooling problem.
I know the truck my engine/trans came out of had a WAY higher GVWR than my XJ ever will, and had a separate cooler, but I've heard that most of the cars just used a built in cooler, and realistically, I can't be putting any more load on that tranny than a car does.
 
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Also, I worked out the final drive manually just to make sure my Engine RPM's seem about right at 100km/h, assuming a TCC lockup.

[ (Axle Ratio x Vehicle Speed x Transmission Ratio x 336.13) / Tire Diameter ] = RPM
(4.56 x 60 x 0.696 x 336.13) / 35 = 1828

1828 is about what I'm getting at 100km/h on axle stands. I guess I should go try that again on the pavement with some load to verify, but that sounds like the same number I was getting on the highway.

I should also correct myself from earlier. My Brake switch is normally open, so the TCC relay is normally closed. When the Brake switch closes, the TCC relay opens.

Also, on the stand, at 100km/h, with the brake switch disconnected (so the TCC power stays on when I hammer on the brake), I hammer on the brake but do not stall. No perceptible change from having the brake switch connected or not.
 
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Just talked to Griffin Rad. They say the rad I installed should be WAY more than adequate to cool my rig and I shouldn't have to even consider an external trans cooler unless I'm planning on hauling a 5000lbs trailer up a mountain, in a desert, on a ridiculously hot day. The guy says in his thousands of support calls, he's talked to heaps of guys with the same swap, using the same or smaller rads, who use the internal cooler all by itself with absolutely no issue. So, I figure he's probably telling the truth as he has an incentive to try to sell me a stand alone cooler.

Assuming my cooler is sufficient, what should I be looking at, at this point? Trans filter plugged maybe and getting poor flow?
 
I believe the slip code will set if you have consistent 50 RPM slip or more. If you were actually under load on the freeway they 20-30 you got when you disconnected the TCC circuit would go up. You wont see it stick on exactly 0 for very long, this is because the slip is a calculated value based off of a couple of other values and as a result has a lot of built in inaccuracy. I would assume its locking up as long as the values you see are bouncing around 0.

What kind of cooler do you have? Is its a separate row in the radiator or is it a coolant to trans fluid cooler? If its a coolant to trans fluid cooler, its not going to be staying much below 100C since the coolant itself should be near 100C. My personal thought on trans coolers built into the rad is that they work ok, but you cant expect to keep low trans temps like I prefer to keep. If you are hoping to keep the trans around 160-180 I think you will need an external cooler. If 200-220 is acceptable then a built in cooler is probably ok.

If you had a plugged filter your shifts would be awful. Really if you have low flow through the cooler for any reason the shifts would be terrible. You might also get some trans codes since the transmission expects things to happen on a specific schedule and low pressure would slow everything down.
 
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Hoooper said:
I believe the slip code will set if you have consistent 50 RPM slip or more. If you were actually under load on the freeway they 20-30 you got when you disconnected the TCC circuit would go up. You wont see it stick on exactly 0 for very long, this is because the slip is a calculated value based off of a couple of other values and as a result has a lot of built in inaccuracy. I would assume its locking up as long as the values you see are bouncing around 0.

What kind of cooler do you have? Is its a separate row in the radiator or is it a coolant to trans fluid cooler? If its a coolant to trans fluid cooler, its not going to be staying much below 100C since the coolant itself should be near 100C. My personal thought on trans coolers built into the rad is that they work ok, but you cant expect to keep low trans temps like I prefer to keep. If you are hoping to keep the trans around 160-180 I think you will need an external cooler. If 200-220 is acceptable then a built in cooler is probably ok.

If you had a plugged filter your shifts would be awful. Really if you have low flow through the cooler for any reason the shifts would be terrible. You might also get some trans codes since the transmission expects things to happen on a specific schedule and low pressure would slow everything down.
Click to expand...


That was sorta my thought as well with regard to the trans temp not being LOWER than the engine temp. I can't see any reason (while still observing the laws of thermodynamics) for the trans to be colder than the engine. I figure the trans should always heat up to about the same temp as the engine coolant at the very least.
That said, how do stock cars get away with this? I'm sure they run their motors at around 92C, which means their transmissions would always be above that temp, which is detrimental to the longevity of the fluid. Most stock cars don't have a stand alone cooler, so what do they do? Just not set a trans code until the trans is near blowing up?

Right now I'm just using the built in cooler on my Griffin rad. I was told it should be more than sufficient, and Griffin hasn't tried to sell me a trans cooler. That said though, perhaps they figure 100C is acceptable? Seems silly to me to run it that hot.

Shifts are pretty smooth, but I haven't driven an auto in 10 years or so, so I could be way out to lunch. I still feel like the motor has way more power than I'm laying down at the wheels, but it's still moving pretty good. Certainly much better than any Jeep I've ever been in.
Trans pan is leaking a tiny bit (bad gasket and/or bolts were loose) but my level is bang on. I just want to make sure I've ruled out a transmission issue before adding the stand alone cooler. I'd hate to mask a symptom.
 
Imma go confirm that again as soon as it cools down. Was out picking up a set of shafts for my roomies d60 rear, and they happened to have a stacked plate cooler about the right size, so snagged it for $30 as well. Will install once cool, and will verify flow direction.
 
blistovmhz said:
I can't see any reason (while still observing the laws of thermodynamics) for the trans to be colder than the engine.
Click to expand...

What you are missing is that the engine coolant is measured on it's way *to* the radiator. In the radiator, you expect to see a 30+ degree temperature drop from the inlet to the outlet. It's a loose number, that "30+", but it's a rule of thumb.

So where in the radiator do they stick the trans cooler (actually a liquid to liquid heat exchanger...) - in the 210* upper / inlet tank, or the 170-180* lower / outlet tank? In the lower-temp tank, of course - pulling the the trans temp toward the cold-side coolant temperature.

The factory does a pretty good job keeping the transmission at it's designed operating temp - usually 170-185, in there.
 
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