P0301 coming on with light weight flywheel

I picked up my new to me LGT 5mt last night. The previous owner warned me about the exedy LWFW throwing a misfire code. I haven’t had a chance to verify that is is indeed the P0301 but will check tonight. I was wondering if there’s a way to stop this code coming up through a tune. For the time being, I think I’ll keep the scanner in the car at all times. Car is running and driving absolutely fine so I can’t imagine it would be anything else

If the flywheel is the culprit, the misfire will be on all cylinders randomly. If you have P0301 and not P0302-4, follow the standard procedure for diagnosing a single-cylinder misfire. Also inspect the car carefully for any and all modifications, including a LWCP.

The engine was pulled 1,000 miles ago by a Mercedes tech who rebuilt the top end. The previous owner before him blew it up and passed away before fixing it. His dad sold it to the Mercedes tech who documented every modification. This guy definitely knows his stuff and was not the type to screw me over so I’m confident it’s the LWFW causing the ECU to think there’s a single cylinder misfire. Mostly happens during hot restarts. The Exedy LWFW is 12.6 pounds which is well below the weight threshold where this commonly occurs. If it had a LWCP too I highly doubt it would even be drivable. I’ll confirm the CEL code after work. I just don’t know if this can be stopped by tuning

UPDATE: Sure enough P0301 single cylinder misfire came up. Cleared it out but I’m sure it will come back again. Still wondering if there is a way to increase the tolerance so it does not happen all the time. I’d prefer to not cancel out the code all together

previous owner blew it up...and your new to the Forum.

 

Can't tell you how many times we've heard this same story.

 

Describe "blew it up" ?

previous owner blew it up...and your new to the Forum.

 

Can't tell you how many times we've heard this same story.

 

Describe "blew it up" ?

 

Not entirely sure to be honest as I’m sure you can tell by how vague that statement is. All I know is I have receipts that the heads are fully machined. Good compression good everything. I’ve been running the crap out of it as the guy I bought it from told me to... he also said bring it back if anything were to go wrong. I picked it up from his house where it was parked next to a 600whp 383 stroker 67’ Chevy truck he fully restored himself. Can’t say I’m too worried about being screwed over

I admit I'm no tuning or turbo expert... but I wouldn't run the crap out of it too hard until you get the misfire figured out. I just worry what if you're running too lean or somethin..

I admit I'm no tuning or turbo expert... but I wouldn't run the crap out of it too hard until you get the misfire figured out. I just worry what if you're running too lean or somethin..

 

I really don’t think it’s actually misfiring. It idles and accerates smoothly as it should. Just drove an hour to my parents house from my apartment... ran flawlessly. I have shoulder surgery Thursday so I won’t be driving it for 4 weeks. I’m going to order an Accessport to monitor AFR amongst other things. My main question in this thread is: is there a way to reduce the sensitivity of a P0301 CEL without removing it altogether.

Make sure the coil pack wires are making good contact. Some have had to adjust the pins in the connector. Same with the fuel injector.

Agreed. Check coil packs and injectors.

 

I have an Exedy LWFW and a Perrin LWCP. I started to pick up a misfire on Cyl 1 after a year of running it, ended up being the injector.

 

And just because it was fine, doesn't mean it still is. Things break.

I really don’t think it’s actually misfiring. It idles and accerates smoothly as it should.

 

When does it misfire? During warm idle only? How about cold idle?

 

 

 

 

I’m going to order an Accessport to monitor AFR amongst other things.

 

Look into the BtSsm app and dongle too.

 

 

I have two Subarus, both with LWCP and both with LWFW (same as yours). They do not throw any misfire code. I have some doubt that the LWFW is the culprit.

 

 

My main question in this thread is: is there a way to reduce the sensitivity of a P0301 CEL without removing it altogether.

 

I don't know if it is possible. All I know is that with the AP or the BtSsm app, you can view the misfire count (or 'roughness' count) per cylinder. Usually, that count should stay at 0 at all times. Occasionally, you may see a count of 1 or 2 and I usually don't worry about it. But if you consistently see a higher count, then yeah something is up. A misfire CEL is usually thrown when the count reaches like 30 or 40+. Not sure if that threshold can be changed. That count maxes out at 99 btw and goes back to 0.

In my limited experience it’s under hot restarts. Hot or cold it fires up instantly with no roughness. I’m going to look into that app rn. My only concern is that it’s running lean so I’ve been easy on the car. Might buy a pyrometer before cruising to Lehigh valley cars and coffee this weekend. I won’t be driving as I had my surgery this morning but a trusted friend is driving me up in the car. Reasearching the BtSsm app now

Make sure the coil pack wires are making good contact. Some have had to adjust the pins in the connector. Same with the fuel injector.

 

I gave it a look and it looks fine. Light has yet to come back. If it comes on again I’ll look at the injectors

My car was basically the same, expect I had a cyl.3 misfire at times. The injector was the culprit. A LWFW shouldn't cause any issues with the engine running except make it easier to stall..

 

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Okay now this is strange. I had the CEL come on and within 15 mins of driving it turned itself off. Now I’m thoroughly confused

Did it flash when it came on or was it steady? I have never witnessed a steady CEL turning off while driving.

Did it flash when it came on or was it steady? I have never witnessed a steady CEL turning off while driving.

 

100% steady CEL. Cruise light was flashing as usual but I can confrirm the CEL was steady.

Okay now this is strange. I had the CEL come on and within 15 mins of driving it turned itself off. Now I’m thoroughly confused

The ECM will shut the light off when it see that the original fault has passed it self diag tests. I now have a P0420 code now.. no biggie. It turns itself off every few days or so..

 

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