XJ Heep 3.0

[Callelle]

When I replaced mine, I bought the cheapest one rock auto had and it's been fine for 3 years *shrug*

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[TrailTamer]

36x13.5R15 IROK BIAS on cheapies 15x8 3.75BS black steel wheels.

Drove it up and down at Attica on Friday. Tires are awesome on traction. It just goes, even in 2wd.

Need to get rear fenders cut and add some bump stops front & rear.

Unsure if I have something going on with engine, very underpowered. It was tolerable on old 35s. 5th gear useless unless perfectly flat or downhill.

[mr.mindless]

As worn as those 35s are and as big as these iroks are, this is almost like going from 33s to 35s or 35 to 37.

Not sure how marginal power was before though. Sounded fine when you left here FWIW

[Callelle]

Do you have stock gears? When first went to 35s from 31s, I had no use of 4th gear unless on the throughway.

[TrailTamer]

I’m running 4.56 gears in axles. AX-15. Callelle, yours is auto?

Seem to be ok idle-moderate throttle at lower speed, up to around 45 mph and no hill. 3rd gear is mandatory to go up a steep hill when not going any faster than 40-45 mph.

Foot to the floor to accelerate (slowly) up a steep hill at any speed and any gears.

Loaded 18 wheelers go up hills faster than me lol. WOT in 4th gear and unable to hold 55-60 (2,300-2,500 rpm) uphill.

No check engine light or pending codes. Surprisingly still get reasonable fuel mileage despite it see WOT regularly. Approx 250 miles to a tank with mixed of highway and city driving (factory 20 gallon tank).

I was able to hold my cruising speed at or near WOT on old 35s.

I’m fine with lacking of power if that’s what it is, but will want to fix it if this isn’t normal.

[mr.mindless]

Can you check fuel pressure under load? Might be dumb and wrong but it’s my first though followed by dirty injectors.

Seeing fuel trim or monitoring a wide and o2 would be the real way to check.

[TrailTamer]

Can you check fuel pressure under load? Might be dumb and wrong but it’s my first though followed by dirty injectors.

Seeing fuel trim or monitoring a wide and o2 would be the real way to check.

I might should've mentioned that injectors was fine. I tried to 'fix' it with 4 hole injectors as an upgrade (original only have 1!) before figuring out that the ECM is bad. Marc found me an ECM from a 97 XJ and that fixed it. No power gain or loss that I can notice with old ECM (before it broke) and replacement ECM or injectors.

I will need a scan tool with ability to show fuel trim. Even though usually it'll throw a code if corrections are so large.

I will need to try find my fuel pressure tester, but doubtful it's the problem. A note, my XJ is 98 and it use returnless fuel system, if that mean anything.

[M4wdFab]

needs more R's and less brick though wind.  if no codes and fuel mileage is on par, drop a gear and adjust your expectations. 

[mr.mindless]

drop a gear and adjust your expectations. 

well put

[M4wdFab]

hmm power curve link didnt work.  but shows 4.0 like >2500

[TrailTamer]

drop a gear and adjust your expectations. 

well put

I am fine with that, as long as this is normal for Jeep's HO 4.0

Doesn't want to 'deal with it' if there's more to be had lol

[Callelle]

I would suggest going back to 1 hole injectors, especially if they're from Raffi (k suspension). His products are chinesium junk that have a stupid failure rate.

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[TrailTamer]

XJ have an ongoing shimmy on highway and impending DW between 40-50 mph, DW when slowing down on highway exit ramp.

I finally took the time to inspect its steering components. Nearly all of them are bad!!! All 4 TREs (GM 1 ton), loose track bar heim at axle side, rust seized on frame side, steering box sector shaft (side to side with a clunk). Ball joints are still fine. Approximately 15,000 miles since the build, most are road miles.

I think some of it may have to do with steering stops on knuckles not perfectly matched with box? I welded a little on inner Cs to stop axle shaft yokes from touching each others.

Either way, I’ll tighten the steering box, replace all of TREs & heims.

[mr.mindless]

if you're not horsing against the stops, that shouldn't cause issues. seems young, but definitely explains things. off-brand TREs?

[TrailTamer]

I do not hold it at stops. I make a habit to back off a little if i touched steering stops.

Heims - Ruff Stuff.

TREs - drag link TREs are MEVOTECH Supremes, which supposed to be decent and is metal to metal. Tie rod link TREs are from Ruff Stuff.

I will be replacing them with $5 TREs. MCQUAY-NORRIS brand, don't know if they're legit, but whatever. I got a few as that brand apparently is being wholesaler closeout'd on RockAuto. I bought all of "1 ton GM TREs" they had a while ago as a trail spares lol.