Intermittent P0336/ constant P0300
Thread Starter
Joined: Mar 2005
Posts: 1,678
Likes: 14
From: san antonio, tx
Intermittent P0336/ constant P0300 So...…. I recently missed the infamous 3-4shift and went 3-2 and hit limiter. I have a 383 with -3 dome pistons with valve reliefs cut into them, (PRC heads with larger valves installed). After the missed ****, it drove fine but then my SES light came on a few miles down the road. I have not been able to check the code yet and don't hear anything obvious in the valvetrain. I still have to change the oil and check for anything in there as well. Haven't have time to tear it apart to check the PRs yet but was wondering if it was a possibility. Thanks.....
**So, P0336 has popped up recently but not all the time. I have replaced crank sensor, pigtail, plugs and wires. I also replaced 3 coils that showed misfires but havent hooked it back up to check to see if those are gone. I ran well for a while after the coil swap. This is killing me! Worst case i think would be a bad/damaged reluctor wheel. Can a bad over rev cause reluctor wheel damage? Any help is appreicated.**
**UPDATE**
So I finally got a chance to do the compression test. Ran the test twice on each cylinder. Took the car for a drive and let it come up to operating temperature before testing. Just did the dry test. Here are the results. What should I do next??
CYL PSI
1 190-195
2 195-200
3 190
4 200
5 190
6 200
7 190-195
8 195-200
**So, P0336 has popped up recently but not all the time. I have replaced crank sensor, pigtail, plugs and wires. I also replaced 3 coils that showed misfires but havent hooked it back up to check to see if those are gone. I ran well for a while after the coil swap. This is killing me! Worst case i think would be a bad/damaged reluctor wheel. Can a bad over rev cause reluctor wheel damage? Any help is appreicated.**
**UPDATE**
So I finally got a chance to do the compression test. Ran the test twice on each cylinder. Took the car for a drive and let it come up to operating temperature before testing. Just did the dry test. Here are the results. What should I do next??
CYL PSI
1 190-195
2 195-200
3 190
4 200
5 190
6 200
7 190-195
8 195-200
Last edited by blkbird; Nov 2, 2019 at 12:55 PM. Reason: new issues
Thread Starter
Joined: Mar 2005
Posts: 1,678
Likes: 14
From: san antonio, tx
So I turned it on for a few minutes to listen for anything and let it warm up a bit. Didn't hear anything out of the ordinary. I checked to see if all the chambers were firing by making sure the primary was hot. They were. Still need to check code though.... It cold be unrelated. Oh, and still good oil pressure.
12 Second Club
Joined: Aug 2014
Posts: 205
Likes: 26
From: Houston, Texas
I had a mechanical over-rev on stock LS1 valves kissed the pistons car still drove fine no detectable loss of power..... didn't find the "custom valve reliefs" in my pistons until I swapped heads..... I just cleaned em up and sent it. I don't think rev-limiter protects against mechanical over-rev... but since your motor is not stock perhaps your valve train was able to handle it way better than the stock valve train. Aside from my custom valve reliefs I did notice that one exhaust valve seal was a little bit damaged. Hopefully you escaped the money shift!!
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The rev limiter won't protect against a money shift.
How far did you rev out 3rd before going into 2nd? If you red lined 3rd then hit 2nd there's a good chance a valve touched.
If you were cruising you're probably fine.
How far did you rev out 3rd before going into 2nd? If you red lined 3rd then hit 2nd there's a good chance a valve touched.
If you were cruising you're probably fine.
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Thread Starter
Joined: Mar 2005
Posts: 1,678
Likes: 14
From: san antonio, tx
So the codes turned out to be a generic misfire, and both 02 sensor codes. Cleared them and drove it around all day and they havent come back...... Still sounds a little off to me, but i could be wrong.....
after you clear codes.....
if you make it 25 miles you have a 75% chance of code coming on, basically make it over the 40 mile hump is my goal. after 40 miles id say 25% chance your code comes back. make it 75 miles you have 10% chance of a code, after 100 miles you are basically in the clear. no science behind it other than i believe most monitors are running by 20 miles and all should be running by 40.
so basically go put some miles on it and report back, what shifter you running
Last edited by Floorman279; May 27, 2019 at 08:09 PM. Reason: ......
Thread Starter
Joined: Mar 2005
Posts: 1,678
Likes: 14
From: san antonio, tx
Yeah, I drove it a little over 60 miles yesterday and no codes have popped up.
Shifter is Hurst Billet Plus.
Shifter is Hurst Billet Plus.
Last edited by blkbird; May 28, 2019 at 09:38 AM.
Thread Starter
Joined: Mar 2005
Posts: 1,678
Likes: 14
From: san antonio, tx
So..... Still keep getting the P0300, random misfire. I am going to pull the plugs, rockers, pushrods and do a compression test to see if any of the valves are bent/leaking. If i have to pull the heads, and are not damaged, i will probably sell them to get a better set. Any recommendations?
So..... Still keep getting the P0300, random misfire. I am going to pull the plugs, rockers, pushrods and do a compression test to see if any of the valves are bent/leaking. If i have to pull the heads, and are not damaged, i will probably sell them to get a better set. Any recommendations?
Thread Starter
Joined: Mar 2005
Posts: 1,678
Likes: 14
From: san antonio, tx
Most of the time this code is caused by a defective crank or cam sensor, bad wiring and or connections issues.I'd start by checking the wires to see if they're in good shape and make sure they are not touching the manifold causing arcing. Go out there when its dark and start the car and look around the wires to see if you can find any of them arcing off the exhaust manifold. If that checks out go ahead and pull the plugs and inspect them and run a compression check on the cylinders. Hopefully it's something simple and you don't need to tear into the engine. It could be a fuel related issue such as a low fuel pressure due to a pump going or clogged fuel filter. Is this a stocker?
LS1 block 3.903 bore
4.00" Callies Compstar crank
6.125" Callies forged rods
Weisco -3cc forged pistons
LS7 lifters
233/244 .629/.615 111+3 Pat G Cam
Comp Cams 7.4 pushrods
LS2 timing chain
Melling HP oil pump
TSP 2.5 799 Ported Heads 2.02/1.57 valves
.660 PAC dual valvespring, titanium retainers
LS6 Valley cover
Powerbond 25% underdrive crank pulley
FAST 92mm intake/throttle body
FIC 50# hr fuel injectors