So, I went through that thing about 50 times. Actually pulled the hose itself off, and vacuum tested it at 20” and it holds perfectly. I went ahead and bought and installed a new MAP sensor and found no change. As the truck “runs” I have my hands all over the rubber grommet at the throttle body, pushing and moving the vac line with no change. Not to mention the bottle of carb cleaner I’ve sprayed around that and the throttle body. Insanely frustrating.

Also, I put a tee in line with the map and vacuum is kind of low ( around 10in if I recall ) but so was the idle. Vacuum goes up to 17 when I bring the RPMs up.

 

ECU connector refreshing done?

 

No sir not yet. I am going to do that right now. 🤙

 

Pulled the ECU, Pulled the plugs, sprayed them out and pinched the female receptacles closed a little more. Plugged back in and no change. Even swapped in a spare ecu I have still no different.

 

I think we're in the same boat. Is your dash dimming as well when the revs drop?

 

I haven’t even noticed actually, don’t have the lights on or anything while I’ve been fooling around with this thing.

My plugs are so fouled now l, and they are those stupid plugs with the 4 leads or what ever they are. Gonna grab some more tomorrow and keep
digging. It’s really pissin me of now lol

 

Our XJ's don't like them fancy spark plugs, standard NGK spark plugs is all I use in mine. That could be your problem and they are cheaper. Good luck hope it helps.

 

Replaced the plugs and although I know it likely wasn’t the fix, I started it up with the vacuum Guage hooked up. It’s ran okay for about 20-30 seconds again. 15” of vacuum at idle. Then it just flat died again.

Guess I’ll go through the MAP and O2 sensor wiring again. Anyone wanna buy a Jeep!?

 

Well it was said prior and seen in many other posts. “What’s changed, what have I changed” since this started happening. Been recking my brain for a week almost and for the life of me couldn’t figure what I have done with the steering gear box that could have screwed this up. As I’m sitting under the hood thinking about a thermite grenade, Starring RIGHT at the battery I realized while I was doing the gear box I had wired up my winch to the battery with the circuit breaker.

NO idea how that could cause these issues, I feel like I had nothing to loose just unhooking it from the battery. Well, it’s not running perfect but it’s NOT doing what it was! It’ll idle indefinitely and it’s a steady(ish) idle. Like, it’s not dropping to near nothing or dying. Weird. Anyone have a clue why that could cause this?

Feel like it’s kind of missing still but I can start looking at the coil refresh and what not for this.

 

Just kidding. Just Did the same thing again.

Found no 12v power getting to the O2. Suspect.
Can anyone verify the 12v power source for the O2?
For some reason I thought I’ve read somewhere it comes off the larger relay by the battery. Looks to be the same size orange wire.

Edit: Found the post from Cruiser54. Seems I can hear a faint buzzing sound from around that area too. If I am on the correct orange wire on the forward most larger relay, I get NO power at that post!

Edit again!

Apparently it needs to be running not just ON to test voltage to the O2 heater. Gettin cold up I here lol

 

REM is a must if you are driving a Renix. Unfortunately for me, the REM shows everything as fine, but I still have this idle jerk/stall going on.

 

One thing I saw in your pictures was gasket sealant under your TB, is a gasket in there or just sealant. I am not a big fan of just sealant in places like that, could cause a leak. One other thing to check is any wire connections that you unplugged are plugged back in correctly. Awhile back I was doing some work in that area and I almost connected the radiator fan motor wire into another wire connection (I can't remember what that connection was maybe the radiator temp sensor or something in that area but it was the same size). One other thing is did you take the air filter box out because there are some hoses that go to the EGR valve in that area, if the EGR valve is open it will not idle..

 

I did not install the TB however that’s a great point.
i sprayed the entire TB looking for vac leaks I did not notice a change in the idle at all. I have since gotten it running a bit better ( replaced the fouled plugs), but still was hesitating and bucking a occasionally when I drive it. I moved on to the Cruiser dizzy indexing and now it won’t start ! ( But that’s a new thread now)


Edit: Got it started... unplugged the CPS again and retested. Subsequently I thought I would ohm out the harness side of the plug. Seemed one side was reading high and erratic. (5-30ohms) All I did was push in the pins a little on both sides and plugged the CPS back in. Fired right up.

Its missing and bucking worse now but I’m going to dig into the CPS wiring more. CrAppY video of the buckin and fussin’ below

 

And it doing the same thing now from the beginning 🤬😡

surging idle and running super fat. DaYumiT!

 

BUMP! I have since re torqued the intake manifold bolts and REchecked O2, and MaP readings from the sensors.

Any suggestions to verification of the wiring on all ends? Ground, signal and power other than just the ohms ? I really don’t want to scrap this buggy. I am pulling all the looms apart now from the front to the back.