2011 SOHC Ping/spark knock on 87

[PetroleumJunkie412]

So, my 2011 has been giving me a weird "power loss" issue since new (to me), and now it's progressed into a spark knock and pinging.

Power loss occurs after WUE has ended on a cold start. When the truck is stone cold and on warm up, runs great, no knock, "feels" like a 200hp engine. After WUE, it feels like a 2.3.

Truck knocks and pings when running 87, especially on gentle hills under 2200 rpm, and gets a steady 16-17mpg. Not sure where to chase the issue next.

Oddly, when I run 93, the power loss issue clears up, and it doesn't ping. Also gets a consistent 20+ mpg on 93.

No codes, tuner has been off for the last 3k miles or so.

Open to suggestions, fellas.

 

[RonD]

The difference in running 87 and 90+ octane means it not a fuel pressure or fuel mix issue

So Knock sensor or its wires most likely, but surprised there is not a code for it
Knock sensor is the only way a 9.7:1 compression ratio engine can run on 87 octane

Sensor itself is in the valley under the intake manifold, seen here: https://www.explorerforum.com/forums/attachments/knocksensor-jpg.69257/
Well the bolt holding it seen there, lol

The 2 wires for the sensor are on a 2 wire connector on passenger side valve cover top edge, towards front of the engine

Look here: https://www.explorerforum.com/forums/attachments/headsfrt-jpg.63497/
Lower left of picture, Yellow wire, that's the connector for Knock sensor and it was an issue

 

[Shran]

Excess carbon buildup? Pretty common on the OHV 4.0s as I understand

 

[PetroleumJunkie412]

The difference in running 87 and 90+ octane means it not a fuel pressure or fuel mix issue

So Knock sensor or its wires most likely, but surprised there is not a code for it
Knock sensor is the only way a 9.7:1 compression ratio engine can run on 87 octane

Sensor itself is in the valley under the intake manifold, seen here: https://www.explorerforum.com/forums/attachments/knocksensor-jpg.69257/
Well the bolt holding it seen there, lol

The 2 wires for the sensor are on a 2 wire connector on passenger side valve cover top edge, towards front of the engine

Look here: https://www.explorerforum.com/forums/attachments/headsfrt-jpg.63497/
Lower left of picture, Yellow wire, that's the connector for Knock sensor and it was an issue

So, put a knock sensor in it (Bosch) a while ago when I did the thermostat/housing. Didn't seem to help. Figured I'll chase wires next. Fun fact, you can get to the sensor with a 1/4 inch drive ratchet without removing the intake if you lay on the core support.

Didn't think it was a fuel pressure issue, have one of the Jap 240lph pumps in the tank, seemed to help more than anything else so far.

I've been curious about injectors, but wanted to pick your collective brains before throwing money at it.

I'll read through the links and do some tests and report back on the knock sensor.

Excess carbon buildup? Pretty common on the OHV 4.0s as I understand

165,000 mi, I've been afraid of that one.

It seems to run a helluva lot better with a can of Liqui Moly intake valve cleaner or jectron in the tank, then right back to crap when I refill.

 

[sgtsandman]

The knock sensor or the wiring is the first thing to come to mind.

Carbon build up is the second.

You could try some techron fuel system cleaner with a tank fill up and drive it like you stole it until the fuel light comes on. With it being as bad as you describe it, it might take more than one go to get things cleaned up. Generally not the best idea but a couple of tanks shouldn’t cause a problem.

 

[RonD]

Pull a couple of easy to get at spark plugs, check the tips for carbon build up
You can also check compression when spark plug is out, 165-175psi is expected on cold engine with good battery, higher would mean carbon build up issue

 

[PetroleumJunkie412]

So, it looks like I fixed this.

And would require humility to admit what the problem was.

So I shan't.

 

[RonD]

I'm with Stupid ^^^

Humility is nothing but truth, and pride is nothing but lying. -- St. Vincent de Paul

 

[Snoranger]

So, it looks like I fixed this.

And would require humility to admit what the problem was.

So I shan't.

What did you do wrong?

 

[PetroleumJunkie412]

What did you do wrong?

I do'n wanna.

 

[Uncle Gump]

C'mon...

You will feel better about it when it's all in the open.

 

[PetroleumJunkie412]

No. Y'all just gon make funna me.

 

[Roert42]

Yeah,

It'll be great.

Peer Pressure.
Peer Pressure.
Peer Pressure.

 

[dirtymike]

If you push the gas and brake all the way to the floor simultaneously while driving, your truck will take a screenshot.

 

[Snoranger]

No. Y'all just gon make funna me.

We’re going to make fun of you no matter what, admitting to your mistake will just make our job easier.