SOLVED - Cylinder 7 misfire

InterceptorF · Nov 28, 2022

New spark plugs, wires, lifters odd bank pushrods odd bank, injectors, oil pressure switch, egr seal on the intake… So I had a collapsed lifter in the odd bank and pulled the odd bank head. Replaced all eight lifters and pushrods. I had hoped the collapsed lifter was the cause of my misfire on cylinder 7 P307 but nope . The tick went away so good on that but I am still seeing a P307 after the engine idles for more than 5 minutes. I am looking at the injector as my next attempt.

InterceptorF · Nov 28, 2022

InterceptorF said:
New spark plugs, wires, lifters odd bank pushrods odd bank, injectors, oil pressure switch, egr seal on the intake… So I had a collapsed lifter in the odd bank and pulled the odd bank head. Replaced all eight lifters and pushrods. I had hoped the collapsed lifter was the cause of my misfire on cylinder 7 P307 but nope . The tick went away so good on that but I am still seeing a P307 after the engine idles for more than 5 minutes. I am looking at the injector as my next attempt.

Also swapped coil 7 with coil 3

rockola1971 · Nov 29, 2022

Swap spark plug wire and spark plug. Either could have a fault. Possible ignition coil wiring harness damage to #7 Ignition coil.
Quick and dirty check on spark plug wires is fire engine up at night and pop the hood. KEEP HANDS IN POCKETS! Look for lightning flashes coming of spark plug wires to engine ground and any other metal surfaces near the plug wires. Listen for the distinct snapping noise the spark makes when its jumping an air gap.

Tonyv__ · Nov 29, 2022

InterceptorF said:
New spark plugs, wires, lifters odd bank pushrods odd bank, injectors, oil pressure switch, egr seal on the intake… So I had a collapsed lifter in the odd bank and pulled the odd bank head. Replaced all eight lifters and pushrods. I had hoped the collapsed lifter was the cause of my misfire on cylinder 7 P307 but nope . The tick went away so good on that but I am still seeing a P307 after the engine idles for more than 5 minutes. I am looking at the injector as my next attempt.

Did you make sure the lifter didn’t wipe out the cam? My bad lifter did this to my cylinder 7 lobe.

MassHoe04 · Nov 29, 2022

Tonyv__ said:
Did you make sure the lifter didn’t wipe out the cam? My bad lifter did this to my cylinder 7 lobe. View attachment 386207

Wow! Looks more like a pulley than a cam lobe...

Tonyv__ · Nov 29, 2022

MassHoe04 said:
Wow! Looks more like a pulley than a cam lobe...

Yeah I had a misfire at idle for like 6 months I was chasing. I finally caved one day after trying everything I was capable of trying to diagnose and pulled the heads. Found a bad lifter than the cam. The misfire also ended up killing my catalytic converter shortly after. It’s all straightened out now though

wjburken · Nov 29, 2022

Tonyv__ said:
Did you make sure the lifter didn’t wipe out the cam? My bad lifter did this to my cylinder 7 lobe. View attachment 386207

Definitely chewed through the hard candy shell and into the soft nougatty center on that one.

wjburken · Nov 29, 2022

Tonyv__ said:
Did you make sure the lifter didn’t wipe out the cam? My bad lifter did this to my cylinder 7 lobe. View attachment 386207

Definitely chewed through the hard Candy shell and into the soft nougatty center on that one.

nonickatall · Nov 30, 2022

I would first make a test of the engine compression.

That tells you if the system of pistons, valves, camshaft and so on, do what it should do.
That is the Fundament.

When after that, the ignition and Injektion is correct, the engine will run proper ..

InterceptorF · Dec 4, 2022

Tonyv__ said:
Did you make sure the lifter didn’t wipe out the cam? My bad lifter did this to my cylinder 7 lobe. View attachment 386207

Holy Crap! Yes, I did check my cam through the lifter bore - it was fine but I did replace the injector and the engine smoothed right out.

SOLVED - Cylinder 7 misfire

InterceptorF

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Tonyv__

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