P0336/Spark Issues
Thread Starter
Teching In
Joined: Mar 2023
Posts: 1
Likes: 0
P0336/Spark Issues Hey guys,
First time post . I have searched this forum and many other for answers and have not been able to find a situation like mine or answers for the troubles I am having. Any info or help is greatly appreciated.
I recently picked up an 03 Silverado with a 6.0 ls completely stock (ECM, harness and engine) The harness had some wiring issues that I have fixed. I pulled the harness apart and tested all connections to verify it is in working order.
The problem I am having is regardless of the what I do or change I cant not get spark on cylinders 2 and 3. The engine runs, poorly but it runs on 6 cylinders. I have zero spark to those two cylinders only the others are fine. I have swapped coils and harness from side to side tried new spark plugs and wires, ohm and tested all the the wires from the coil connector back to the ECM with no smoking gun found. I am getting no codes other than a P0336.
I have swapped the crank sensor out with 2 other ones with the same result tried shimming it and cleaning the block/bore where the crank sensor is seated. With the same results. I see RPM while both cranking with my scan tool and while running the engine and it never drops out. My questions are, am I only getting the P0336 because of the extended cranking I am doing while trouble shooting? I have the fuel pump relay removed so I don't wash the cylinders with fuel. But I have noticed that if I clear the code and hook the battery back up the code returns as soon as the key is powered up. Is the p0336 causing the no spark on just those two cylinders? From what I have gathered it should not cause a no spark on individual cylinders and that if it was a Crank sensor issue it would be a crank no start with no rpm and no spark on all cylinders. I have also looked at the Reluctor wheel and it looks fine by eye while rolling the engine over by hand.
Could the cam sensor cause a no spark on just 2 cylinders? I have also checked all powers and cleaned all ground on the engine and chassis with no success and re seated the ECM connectors multiple times. Does anyone have any ideas for me? I do not have a scope to get the wave form of the crank but I may try and purchase a cheap one. I have also started the engine and tried wiggling the crank wires to see if there is a bad connection with no luck.
What would cause no spark on only 2 cylinders? I know this is a long shot but could it be a bad ECM coil Driver? But the likely of two of them is slim. I know ECMs are often changed out prematurely and i would like to trouble shoot everything before going down that path.
Does any one have a reliable way to check the coil drivers at the PCM? i have tried capturing it with a 3v led test light and a multiple meter and can not catch the trigger signal (On a known working coil).
I am open to try anything. Thanks again for any advice. Sorry for the long post.
First time post . I have searched this forum and many other for answers and have not been able to find a situation like mine or answers for the troubles I am having. Any info or help is greatly appreciated.
I recently picked up an 03 Silverado with a 6.0 ls completely stock (ECM, harness and engine) The harness had some wiring issues that I have fixed. I pulled the harness apart and tested all connections to verify it is in working order.
The problem I am having is regardless of the what I do or change I cant not get spark on cylinders 2 and 3. The engine runs, poorly but it runs on 6 cylinders. I have zero spark to those two cylinders only the others are fine. I have swapped coils and harness from side to side tried new spark plugs and wires, ohm and tested all the the wires from the coil connector back to the ECM with no smoking gun found. I am getting no codes other than a P0336.
I have swapped the crank sensor out with 2 other ones with the same result tried shimming it and cleaning the block/bore where the crank sensor is seated. With the same results. I see RPM while both cranking with my scan tool and while running the engine and it never drops out. My questions are, am I only getting the P0336 because of the extended cranking I am doing while trouble shooting? I have the fuel pump relay removed so I don't wash the cylinders with fuel. But I have noticed that if I clear the code and hook the battery back up the code returns as soon as the key is powered up. Is the p0336 causing the no spark on just those two cylinders? From what I have gathered it should not cause a no spark on individual cylinders and that if it was a Crank sensor issue it would be a crank no start with no rpm and no spark on all cylinders. I have also looked at the Reluctor wheel and it looks fine by eye while rolling the engine over by hand.
Could the cam sensor cause a no spark on just 2 cylinders? I have also checked all powers and cleaned all ground on the engine and chassis with no success and re seated the ECM connectors multiple times. Does anyone have any ideas for me? I do not have a scope to get the wave form of the crank but I may try and purchase a cheap one. I have also started the engine and tried wiggling the crank wires to see if there is a bad connection with no luck.
What would cause no spark on only 2 cylinders? I know this is a long shot but could it be a bad ECM coil Driver? But the likely of two of them is slim. I know ECMs are often changed out prematurely and i would like to trouble shoot everything before going down that path.
Does any one have a reliable way to check the coil drivers at the PCM? i have tried capturing it with a 3v led test light and a multiple meter and can not catch the trigger signal (On a known working coil).
I am open to try anything. Thanks again for any advice. Sorry for the long post.
