New to me CRD Back in Los Angeles, a few questions

SFHLibertyCRD · **Posted:** Wed Sep 04, 2013 8:44 pm

Could this under inflation be part of the puzzle in the low mpg numbers? Now I'm really interested in pumping them up around 60 and see how things go.

thermorex · **Posted:** Wed Sep 04, 2013 9:31 pm

Before Geordi answers, I can tell you that from 38psi to 45 psi I got an extra and some change mpg. So I bet you can have 2 mpg better if you do 50 psi.

racertracer · **Posted:** Thu Sep 05, 2013 3:02 am

At fifty psi I got better mileage and quickly wore out my new tires within 4 months time.

The increased air wore out the center part of the tread pattern sooner than I wanted.

geordi · **Posted:** Thu Sep 05, 2013 12:11 pm

racertracer wrote:

At fifty psi I got better mileage and quickly wore out my new tires within 4 months time.

The increased air wore out the center part of the tread pattern sooner than I wanted.

That is unusual - Which tires did you have for this?
I didn't have any problems with unequal wear between the center and the edges on either of the 2 sets of tires I had on my CRD. I used the BFG Commercial TA Highway tread first, those are a load range E tire and quite heavy and hard. The 'Traction' variant is the load range D, lower pressure (65 instead of 80) and physically appear wider, even though they were the same exact size rating.

The Traction variant also comes with 18/32 of tread depth, fully an extra 2/32" more than the highway tread, and a shocking 7/32 more than most other tires available (IIRC, such as the Long Trail tires!) Tread depth = miles = savings in not needing to buy tires as often... So they might not be a bad thing to purchase. I liked them a lot.

It is entirely possible that the LT tires that are specifically marked with a "Load range" rating instead of (or in addition to) the normal weight ratings... Might be manufactured to a tougher standard. They might not allow as much tread deformation just because of pressure. Radial tires shouldn't bulge in the middle the way the old bias ply tires could, and the way the graphic shows at most tire shops. Which tires did you have that did this?

racertracer · **Posted:** Thu Sep 05, 2013 12:36 pm

Goodyear Fortera Tripletred 245 70 16

thermorex · **Posted:** Thu Sep 05, 2013 12:59 pm

I also didn't have issues at all at 45psi, using bf Goodrich m/t. I think it depends on the tire and finding the "sweet spot". I wouldn't go too high though with Pressure even if the tire allows it, due to premature wear of bearings, bushings and ball joints.

papaindigo · **Posted:** Thu Sep 05, 2013 3:24 pm

I suspect the OEM KJ tires were selected for EPA mpg ratings which means they would generally be light weight and low rolling resistance. I don't know all the factors that go into low rolling resistance but clearly tire pressure, tread design, and tread compound would factor in. High mpg tires I suspect are weaker in the sense that they are less forgiving of impacts and excess tire pressure hence with OEM tires it's a really good idea to stick with the door sticker although I'll confess I tend to just put 35psi in everything, excluding the Dodge D250 Cummins trucks I used to own.

After market tires can be found that are relatively light weight, which is good as that's unsprung weight, but have much stronger tread and sidewalls than OEM, which is good for impact resistance but bit less good for mpg but that can be offset by running higher PSI. While there are rules of thumb, old ones at that, about how tire tread wears based on over or under inflation that's really caused by what tire psi does to the orientation of the tread to the road. I suspect stiffer after market tire can keep the tread parallel, side to side, to the road at a higher psi than an OEM or other high mpg tire. I know stoutdog is running Michelin Latitudes at 45 psi with no "typical" over psi wear in the center of the tread and he gets a bit better mpg than me with no obvious impact on ride.

However, I suspect if you go much higher than 45psi the ride could get pretty harsh even for a Jeep. I know on my Dodge's if I upped the psi to carry a load and forgot to reduce the psi once I got rid of the load the ride was exceedingly harsh.

DOC4444 · **Posted:** Thu Sep 05, 2013 11:42 pm

A tire pyrometer allows you to fine tune the tires you have on your specific vehicle so they wear evenly. I have found wide discrepancies from stock guidelines. If the temps are even, the wear is even. If the center is more than 10 degrees hotter, center wear will be much higher.

DOC

geordi · **Posted:** Fri Sep 06, 2013 12:18 am

racertracer wrote:

Goodyear Fortera Tripletred 245 70 16

Wow, okay, those were some WIDE shoes, and tall too. Over 1.25 inches wider at the tread than the 215s I was using. At 9.65 inches wide, I can easily see how those would allow some center bulge from extra pressure. Goodyear also isn't known for super-stiff sidewalls, which could allow the shoulders of the tire to creep closer together with such a tall sidewall.

I'll admit that Doc's temp gauge idea is something I've never heard about, but it sounds very interesting. Would an infrared temp gun work?

Sir Sam · **Posted:** Fri Sep 06, 2013 1:07 am

geordi wrote:

racertracer wrote:

Goodyear Fortera Tripletred 245 70 16

Wow, okay, those were some WIDE shoes, and tall too. Over 1.25 inches wider at the tread than the 215s I was using. At 9.65 inches wide, I can easily see how those would allow some center bulge from extra pressure. Goodyear also isn't known for super-stiff sidewalls, which could allow the shoulders of the tire to creep closer together with such a tall sidewall.

I'll admit that Doc's temp gauge idea is something I've never heard about, but it sounds very interesting. Would an infrared temp gun work?

Yup, cheapo IR temp gun from harbor frieght will work, this is sort of a poor mans alignment tool, or sometimes a get it good enough to get to the shop tool. Basically if its out of alignment it will heat up more on that part of the tire.

My last set of tires was 245/75/16, my current set is 245/70/16, the size has nothing to do with how much the center will bulge, its just how stiff the tire is, even within the same load rang tires tend to vary on stiffness.

SFHLibertyCRD · **Posted:** Fri Sep 06, 2013 1:39 am

This is turning into a tire thread! I got mine pumped up to the proper 60-65psi spec tonight, and will see how the last half of this tank goes. It didn't feel too much harsher on the few miles home. Hopefully I'll see an MPG increase.

As far as the radiator test . . . Engine was totally cold as the car has been sitting for 2 days. I ran it for 30 seconds, turned off, ran out to unscrew the radiator tank cap and listen. Nothing I could discern. I waited a minute and thought maybe I'll try again. Nothing the second time either. I'll continue monitoring the coolant level and look for leaks if it goes down much. I'm also going to try this test out again occasionally.

Tomorrow I'm going to undo the oil separator / EHM mod in order to get this thing smogged and registered in CA. I'll try to get around to some of the other suggestions above (MAP clean, etc.).

A few minor annoyances if anyone has quick suggestions:
1) Rattly rear hatch glass
2) Hood latch cable seems to not be returning to position in order to latch shut. I have to manually move it with a screw driver to get the hood to latch shut.
3) Want to get an EVIC eventually if anyone has one or knows a good source

geordi · **Posted:** Fri Sep 06, 2013 2:03 am

SFHLibertyCRD wrote:

As far as the radiator test . . . Engine was totally cold as the car has been sitting for 2 days. I ran it for 30 seconds, turned off, ran out to unscrew the radiator tank cap and listen. Nothing I could discern. I waited a minute and thought maybe I'll try again. Nothing the second time either. I'll continue monitoring the coolant level and look for leaks if it goes down much. I'm also going to try this test out again occasionally.

Tomorrow I'm going to undo the oil separator / EHM mod in order to get this thing smogged and registered in CA. I'll try to get around to some of the other suggestions above (MAP clean, etc.).

A few minor annoyances if anyone has quick suggestions:
1) Rattly rear hatch glass
2) Hood latch cable seems to not be returning to position in order to latch shut. I have to manually move it with a screw driver to get the hood to latch shut.
3) Want to get an EVIC eventually if anyone has one or knows a good source

No pressure / hiss from the radiator cap - GOOD! This is what you wanted as a result! IF there is coolant loss now, then you have two possible sources: A leaking hose (potentially hard to locate) or the water pump. Given the mileage and age, even money on which it is, but I'd lean toward the pump. That has the moving parts, and has been spinning for every one of those many miles. A weeping seal is certainly within the realm of possibility, and not something that you will be able to easily detect.

Rear door is also an easy one: Tighten the giant Torx screws in the end of the door, it is the latch that is loose, not the window. (most likely). The window latch itself IS partly adjustable, but you have to remove the interior plastic to do it, and then there are only 2 bolts that hold it to the door. Mine weren't loose, but the door latch was.

Hood cable... Maybe a really good silicone spray lube? If not, it is only stamped steel, maybe you can spread that apart a touch with the screwdriver, it could be binding in the housing. If it is actually the cable, maybe a strong return spring can be rigged up, but I don't know about that. Try the lube down the housing first, then into the cable sheath.

WolverineFW · **Posted:** Fri Sep 06, 2013 2:14 am

DOC4444 wrote:

A tire pyrometer allows you to fine tune the tires you have on your specific vehicle so they wear evenly. I have found wide discrepancies from stock guidelines. If the temps are even, the wear is even. If the center is more than 10 degrees hotter, center wear will be much higher.

DOC

Or if you are cheap you can get some chalk and see if all your tread is making contact at a specified air pressure.

papaindigo · **Posted:** Fri Sep 06, 2013 6:44 am

Good to hear on the coolant test. If you do use a bit of coolant I'd recommend adding some HOAT compatable UV dye to the coolant and then driving for several days after which you can use a UV light, cheap from like Amazon, (best to do in shade not bright sun) to look for leak points. Leaks can be tiny and leave no visible trace. Don't forget area of EGR cooler (driver side toward rear of block) and oil cooler (passenger side in front of turbo).

EVIC - good luck there are threads on this but finding one that will work is apparently a problem.

SFHLibertyCRD · **Posted:** Fri Sep 06, 2013 6:54 pm

I pulled apart the EHM in preparation for CA emissions. It turned out it wasn't a oil separator or other blow by device. It was just an aluminum box that collected oil and had a small drain hose (pics in another thread). I felt around in the turbo inlet and didn't find any perceptible movement. Also noticed that the air box hose connection point had been pinched in one spot, presumably from too tight a connection at an angle where the hose wasn't fully seated against the MAF this probably happened during purchase inspection. I took a heat gun too it and bent it back a little but I should probably purchase another cover. I'll post a picture soon.

SFHLibertyCRD · **Posted:** Fri Sep 06, 2013 6:57 pm

Air box hose connection pinched plastic:

SFHLibertyCRD · **Posted:** Mon Oct 14, 2013 1:11 am

Hi everyone, a few updates:

After I did the following, my MAF idle number now reads 17.5+ (I am about 165 feet above sea level) :BANANA:

, anyone know what might have done the trick? Perhaps my rockers are in decent health after all? Prior to this, I was getting a consistent 16.5 idle MAF. Here is what I did this weekend:
- Replaced my MAP sensor (old one was a bit gunked, but not too bad, but their were a few broken pieces of plastic on the little cage around the sensor)
- Replaced air filter (old one was pretty stiff and looked terrible)
- purchased a new top for the air filter box (previous one was kinked at the turbo hose outlet)
- Cleaned my MAF sensor with MAF cleaner

On the downside, TPMS: Previously, it was flashing at startup, then every 10 minutes, but not staying on constantly, which according to the service manual indicates a "system fault": "If the indicator lamp is flashing on/off three times, once every ten minutes, there is a system fault detected. Refer to the appropriate diagnostic information." I purchased new Dorman TPMS sensor for all 5 tires since I was getting that fault and figured they were nearing the end of their life.

After replacement last Thursday, I didn't have a chance to drive it enough over 20mph until today. It went from lighting up solid (presumably since the ECM/BCM hadn't been retrained for the new sensors), to going back to the old behavior of a chime on ignition key and then flashing light every 10 minutes again :roll:

. . . I'm not sure what troubleshooting to do next. Is it possible I got a bad sensor from Dorman? Is it possible one of my transmitters are bad? Where to start diagnosing this silliness. I already have $125 in the sensors (purchased myself on Amazon), and another $60 in for installation. Should I take it back to the tire shop that installed and see if they have any ideas? Contact Dorman? Or do I need to go to the dealer for "diagnostic information"?

EDIT: One additional note, my AT/S Geolander tires are currently at 50 (60 was too harsh, sidwall max is 65). Not sure if this has bearing on the TPMS system's ability to reset itself.

SFHLibertyCRD · **Posted:** Tue Oct 15, 2013 5:50 pm

Hi all, here is the first UOA if anyone wants to have a look and sees any warning signs of impending issues. I had the PO pull some oil at 68k when he changed the oil (I would guess 5-6k on the oil, but he wasn't certain). Shell Rotella T6 5W/40 I also don't know whether he sampled the oil properly, but it is better than nothing. Let me know what you think, especially about the aluminum number:

yakers · **Posted:** Wed Oct 16, 2013 11:20 am

I am not sure there is anything much to worry about in the aluminum, my recent oil analysis showed 10 for that element, my copper was 9 so I have to keep an eye on that. Seems like a good oil analysis, my first one indicated I had antifreeze in the oil which led to an engine replacement.

SFHLibertyCRD · **Posted:** Thu Oct 17, 2013 1:56 am

yakers wrote:

I am not sure there is anything much to worry about in the aluminum, my recent oil analysis showed 10 for that element, my copper was 9 so I have to keep an eye on that. Seems like a good oil analysis, my first one indicated I had antifreeze in the oil which led to an engine replacement.

My aluminum is 16 though. That seems significantly higher?

New to me CRD Back in Los Angeles, a few questions

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