I put a stethoscope up to the bottom end of my motor near the oil pan in the position of all 6 cylinders, and my motor is very quiet.

I put it up against the flex plate inspection cover, and I heard what sounded like knocking on wood. I'm convinced that it must be a transmission noise. Although, I tightened my torque converter to hell already, so it must be the flex plate has a crack in it.

I will look into it soon.

 

Glad to hear it wasn't the motor though. Tranmissions are a bit cheaper than motors in the event of a catastrophic failure.

 

I hope it's the transmission, still not sure, I'll be checking it out on Saturday.

I bought a new flex plate from O-Reilly's just in case. That way, once it's apart, if it happens to be cracked, I can just swap it out.

 

Today, I ordered a set of Ford's version of the 784 injectors. Should be a good upgrade. I've heard nothing but good things about it.

http://www.ebay.com/itm/181358221420...84.m1439.l2649

They're currently on sale at a special price.

 

That is a steal

 

Those new injectors came today:




These are the Ford version of the 4-port 784 injector upgrade for the 4.0L.

 

The four-port injectors are plugged in now, and luckily, the motor didn't blow up. So now I'm waiting to see the results. I should see better MPG over time. I do notice better throttle response, insanely smoother idle, and also, a faster acceleration.

 

Wish those fit the 97 & down xj

 

Hey, THESE might not, but 703 injectors from some Chrysler vehicles will.

They're the same injector, but have the older style connector. Alternatively, they make adapters I think.

 

yup. 703s out of mid-90s 2.2L Neons

https://www.cherokeeforum.com/f51/in...ap-4-0l-92149/

 

I'm not so sure what to make of the upgrade so far.

My gas mileage doesn't seem to have "improved" at all. And perhaps the throttle response was an illusion – since resetting the PCM, throttle response actually feels weaker. I do seem to get better mileage at certain higher RPM speeds though. So it might be a "just broke even" kind of deal that is better for some applications, and worse for others.

I just refilled my tank with a full topped off tank from Chevron for the first time since the install, and I'm waiting until EMPTY to see how many miles I was able to travel. Will post results when the tank is empty.

I am noticing that the Jeep likes to start harder. I'll hear a loud "click" noise after the starter turns the motor over, and sometimes, the engine will even slug and feel like it's going to stall out before starting. That never happened before with the factory injectors. I don't really like the sound of the noise. I know the starter is good.

 

I replaced a broken lug bolt today that I snapped while doing a tire rotation (duh).



The aftermath after trying to extract the broken bolt from the lug:



I ended up just buying a replacement lug nut for $2.50 at Advance Auto Parts and I got the replacement stud from a buddy of mine.

 

New U-joints ready to go into the double-cardan front driveshaft.

 

Okay, new u-joints fixed my vibrations in the front driveshaft.

Now the only thing I need to look into is that knocking I'm getting. I still have a feeling it has something to do with the flex plate, but I won't know for sure until I tear into it.

On another note, the fuel injectors have given me about an extra 20 miles per tank. Not really that much, but over time, they'll pay for themselves.

 

Today, I picked up a brand new 1998 Jeep Grand Cherokee (ZJ) tie rod assembly for a V8 model.



The ZJ tie rod is a direct bolt-on mod for the XJ that replaces the pathetic rolled sheet metal tie rod. It's also a much beefier solid steel tie rod, which is great for over-sized tires: