Still fighting fuel trims

I purchased 4 new (and not cheap) injectors for the jeep today. Mainly because I’m grasping at straws here now. I was hoping possibly a leaking fuel injector was throwing too much fuel to a cylinder and causing the ECU to pull fuel. I admit I’m guilty and bought some cheap Amazon injectors. So I rectified that today with a $200 set. It did pull my fuel trims from -22 to -14ish so some headway was made. But there’s still SOMETHING causing this condition. I didn’t notice it when I first took ownership of the rig cause it had 33-12.5’s on the 4 banger so drivability was shit. I went to a 32-10.5 tire and re-geared to 4:56 gears from the stock 3:73’s. That should have woke the tiny beast inside the 2.5. But it really didn’t. It runs about 57ish on the highway in 3rd with the converter locked up turning about 3000 rpm. You can floor it and it just bogs. It should be right in the sweet spot for its power band, but it’s just blah. I see so many people talking about 65mph with my same set up easily down the highway and 14 mpg. I’m down around 9-10 mpg and have to keep it on the floor to maintain 57-58 mph. This causes the tranny to jump back and forth from 2nd to 3rd and the engine to begin to overheat in 6-7 miles. I’m not sure what else to do. I’m too far in to say to hell with it plus the fact that I love the jeep. Does anyone have any ideas from here ? I know you guys are prolly tired of my posts ….and I do apologize and appreciate every reply.

macleanflood said:

Did you reset the PCM after changing the injectors?

-Mac

Click to expand...

I THINK I did. It’s hard to recall at this point I’ll make sure I do it tomorrow.

TJ Jim said:

Sometimes I slip up and look at Reddit cause they’ve got Jeep stuff on there too. Read one where a fellow was having similar problems with his four banger, and he went on to tell one of the elbows on the intake manifold reduces from a 3/8” to 1/4” ? If incorrect it would turn his exhaust cherry red. Just throwing this out there. Not familiar at all with a four banger.
Maybe look at your tubing route ?

Click to expand...

I’ll give it a look today. Any info is good info my friend

AndyG said:

I’m grinning- you seen my 42 RLE adventures lately? Lordy.

Click to expand...

I’ve got the 30 RH. It seems like they put tinker toy drive trains in what was meant to be a fun play rig. Makes no sense. Like the H3 I had. GM said let’s build a mini tank. Put the lowest gear ratio we can. Mine had 5:11’s I believe. And power it with an in line 5

hear said:

Nah, you're actually following up on your troubles. The stuff I hate is the 5 year old bump for a dude's first post, and then never even comes back to the forum.

I feel like its been slow here lately, you're the flavor of the month.

Click to expand...

Oh I like resolution. And it seems like that doesn’t happen on some threads a lot. I don’t mind being the ho for the time being. As long as I get it fixed

97JadeTJ said:

I’m not much help on the injector issue but I’m well aware of 2.5 issue… my last TJ (wrecked) was a 97 2.5L 30rh and had 3.73’s when I got it… I put 33 x12.50’s on it and regeared to 4.88’s to make up for the tires… my gas mileage was never better than 10-11 mpg and as far as driving speed, I learned to be happy at 45 - 55 mph in these Arkansas hills… in 4low there was no place I couldn’t go but the highway was a different story… I didn’t realize how anemic the 2.5L was until I got my current 4.0L!… Trust me when I say you’ll be so much happier when you realize what you’ve got and nothing you can do will make it go any faster, except a 6 cyl…

Click to expand...

Fellow Arkie !! I’m south of Pine Bluff. I get the hills. And totally feel you on the vastly underpowered 4. I just ain’t getting the same results as others on the same set up. I know it’s a fuel issue. Down here in flatland country I should be able to run 65 and it’s frustrating as hell.

Oberst Oswald said:

... what is this? How do you reset a PCM? Disconnect the battery?

Click to expand...

Unless you have a scan tool you can unhook the positive and negative battery leads and hold them together off battery for about 10 minutes. Turn the headlights on to make sure you get a good drain. That’ll clear any codes and computer memory

AndyG said:

You are very right- the 32rh is actually a champ overall

Lee Iococca was rebuilding Chrysler and bought jeep and had to deal with keeping it viable with little ramp up time-

The CJ was archaic at that point, the YJ proved fast not to mess with the looks, and the TJ was a move into more comfort and modern manners that ultimately paid off.

They didn’t know what not to do except dont do square headlights again and dont chunk the I6.

The 42 makes me so mad I want to just circumcise myself with an angle grinder- it’s a smart transmission that has 400-600 more rpm gap in 0/D than the i6 can pull, drops it right out of its peak power. It would be amazing if it were not for that.

It will actually tell a computer when the torque converter is broken in.

Also at this point owners need to give the harnesses real attention- heat kills ‘em.

My rebuilt one with a billet t/c, billet pistons, cooler and transgo kit feels so good, shifts smooth and crisp, and pulls great at very low rpm. Hopefully it goes the distance.

Click to expand...

May I suggest a Metabo instead ? Much cleaner cut and it’ll leave a nice straight scar so far the 30rh hasn’t given me any fits. This damn fuel trim is killin me tho.

AndyG said:

K I’ll try that, has it got a magnifying glass attachment.

Click to expand...

Like changing a fuel pump it’s really a two man operation. You might wanna get someone you trust.

Ok. So little did I know the PO had done a timing kit and got the timing 1 tooth off on the set up. It cause all of my issues.