97 silverado L31 cylinder 3 issues p0303

[RawbDidIt]

Hard to tell from the pics, but it looks like left side has some fouling on it other than the oil fouling on 3. They look lean to me, but I'm miles away. Best guess is that your head gasket is blown, dumping oil into the cylinder. This prevents that cylinder from igniting and you get your misfire and fuel smell. Symptom number 3 would be oil in your coolant, coolant in your oil, burning oil, or some combination thereof. You check your oil often? If so, do you notice the oil level going down between oil changes? If you don't check your oil, does your oil pressure drop when you hit the gas then rise again after a moment?

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[stutaeng]

Compression check is good. If that checks fine, I would check for injector pulse on that cylinder. They sell these noid lights for this, but I have just used an LED test light and it should be blinking.

Otherwise an injector balance test would reveal injector malfunction.More advanced scanners do this or there is a little gadget that Amazon sells for around $30 that's supposed to be good.

You don't have lean codes? P0171 or P0174?

Fuel trims will also tell you if it is running lean or rich. Probably do this first after compression test.

 

[Unssafe]

The truck does use alot of oil, I don't think the coolant and oil have mixed. I will check tomorrow.

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[Unssafe]

I don't recall ever getting a p0171 or p0174.

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[RawbDidIt]

I don't recall ever getting a p0171 or p0174.

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It's a weird conundrum, i would think that burned oil would make it read rich, but unburned fuel would make it read lean only thing I can think is that the oil is smoking, producing the same lack of oxygen that burning fuel would, without actually burning the fuel. It would be hard to strike this mix dead on, so it's probably running lean or rich one way or the other, perhaps not enough to trip the ECM to store the code.

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[Erik the Awful]

Without the data stream, hard to determine. With all the parts you've thrown at it, you could have gotten a legitimate scanner to diagnose the problem properly.

Yup. Less than $25, download Torque to your phone, and keep the reader in your glove box. I have one in the center console of my Mustang.
https://www.amazon.com/BAFX-Product...t=&hvlocphy=9026183&hvtargid=pla-405660976208

 

[RawbDidIt]

Yup. Less than $25, download Torque to your phone, and keep the reader in your glove box. I have one in the center console of my Mustang.
https://www.amazon.com/BAFX-Product...t=&hvlocphy=9026183&hvtargid=pla-405660976208

Will that do an injector balance test? Can't imagine it does, but that would be sweet.

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[Erik the Awful]

Maybe if you pay for Torque Pro, but I doubt it. For diagnosing any OBD-II vehicle, it's sweet, and the BAFX connects with more vehicles than the cheaper readers. It'll pull codes from my Mustang, my old Suburban, my wife's Chrysler 300, my daughter's VW Beetle TDI, my race team's BMW, my wife's old Scion xB, etc.

 

[RawbDidIt]

Maybe if you pay for Torque Pro, but I doubt it. For diagnosing any OBD-II vehicle, it's sweet, and the BAFX connects with more vehicles than the cheaper readers. It'll pull codes from my Mustang, my old Suburban, my wife's Chrysler 300, my daughter's VW Beetle TDI, my race team's BMW, my wife's old Scion xB, etc.

My Autel does all that, but not for $25 lol.

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[Erik the Awful]

Storytime hijack. At Houston we were having a misfire on our BMW the day before the race, during test and tune. I was physically looking over all the wiring on the motor, the electrical engineer on the team was reading the manual, the team captain was asking other BMW teams if they'd seen the same problem, another teammate was on a parts store run with the part shotgun in hand, and one of my teammates walked over and plugged his BAFX.

"It's got a cam sensor code."

We called the guy at the parts store and got a cam sensor. Fixed. That's when I bought one.