Engine Health Check Via Parameters

[annihil8ted]

Hello All,

If possible, could I get a second pair of eyes on my engine parameters? It was running super sweet and smooth and then a little bit after swapping out my transmission mount (I'd estimate about 6 hours of driving time), I got a weird start and vibrations coming through the cabin. At idle, it feels much much rougher but RPMs are holding steady, no fluctuations and at speed, the vibrations dies down but overall, everything sounds "louder" for lack of a better phrase. This is in a 06 LJ with the 4.0 and no CEL. I know some of the suggestions are to clean my IAC which I plan to but was hoping to check everything else too.

I recorded a short 5 minute run to get a live log of my engine parameters and can do more as needed. I tried looking what would be normal range for the parameters but haven't found any and would love to understand what is considered normal. The scanner I'm using is one from Harbor Freight, the Zurich ZR11s.

PARAMETER	AVG	MIN	MAX
Fuel Sys 1	CL	CL	CL
Fuel Sys 2	CL	CL	CL
Calc Load	34%	0%	59%
ECT		0	185
STFT B1		-9.4	7.8
LTFT B1		-3.1	8.6
STFT B2		-8.6	6.3
LTFT B2		-2.3	10.9
MAP		0 inHg	17.423 inHg
Eng RPM		0	3276
Vehicle Speed	21 MPH	0 MPH	37 MPH
Spark Adv	27 degree	0 degree	44 degree

IAT	96 F	0 F	109 F
TPS	18%	0%	27%
O2SLoc	O2S11 O2S12 O2S21 O2S22
O2S B1 S1	1V	0V	1V
STFT B1 S1	0%	-8%	7%
O2S B1 S2	0V	0V	1V
STFT B1 S2	99%	0%	99%
O2S B2 S1	1V	0V	1V
STFT B2 S1	-1%	-9%	6%
O2S B2 S2	1V	0V	1V

STFT B2 S2	99%	0%	99%
OBDSup	OBD and OBD II

 

[annihil8ted]

In my search, I’ve found a few post suggesting that the exhaust could be a source of vibration and so I went to go inspect it. While it was not vibrating I did find it had become super lose and was swinging so I tighten that up and went for another drive

the good news is my exhaust leak sound is majorly reduced. I think I may be able to tighten the exhaust more to eliminate it or maybe somewhere else is leaking?

The bad is the vibration is still there. If almost feels resonant the more I drive it.

Is it possible that in changing my transmission mount, the new weak point in vibration isolation is now the engine mounts? I did a quick test and it wasn’t jumping out or anything

 

[DuckNut]

I am not going to be very useful, but I can make you think and that should give you some ideas.

If your old mount was shot and allowed the trans to sag by 2 inches and ran like that for 3 years before fixing...could it be possible that the entire drivetrain got wore in to the angles and now that you lifted it back up it caused everything to come out of that "groove"?

Like I said, I don't have an answer for you.

 

[annihil8ted]

I am not going to be very useful, but I can make you think and that should give you some ideas.

If your old mount was shot and allowed the trans to sag by 2 inches and ran like that for 3 years before fixing...could it be possible that the entire drivetrain got wore in to the angles and now that you lifted it back up it caused everything to come out of that "groove"?

Like I said, I don't have an answer for you.

I’ve considered that as well; that this new transmission mount positioning is a little too far off of what it got used to.

But the old one that came off wasn’t bad in neutral position, it’s just that half of it detached from the metal plate so under load, it would twist. This new one is just holding it in place better (no clunk on throttle input changes) and should be in the same place at neutral. Funny enough, things were so smooth initially after the transmission mount swap, I had considered doing poly the next time I had to change it

I’ve also driven it around a bit to let things settle and loosen and retighten the mount to see if it would move into a more neutral position. It didn’t move and still the vibration persists.

Thinking about it more too now, I’m more convinced that since replacing the weakest part, it’s moving to the next part. Motor mounts are likely to be original I feel consider everything else was too which means it’s due for a swap

Another thing I’m considering too if changing out the spark plugs. Since my ownership earlier this month, it’s always been on my to do list and I do wonder if a spark plug is struggling enough to mess with the idle but not enough to throw a code.

The only code I have so far is a P0153 which isn’t throwing a CEL and I doubt is related