Spark knocking really bad, someone to read my log?
03-02-2014, 06:40 PM
#1
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Spark knocking really bad, someone to read my log? I'm kinda stuck tuning this car of mine. its an 88 volvo 740 wagon with a 94 z28 lt1 in it. Its .020" over, KB120 pistons, CC304 cam, CC 1.6 roller rockers, lt-4 springs, ported heads, port matched intake, and stock exhaust manifolds. Trans has been built with a transgo kit and a few other internal parts, stock stall HD converter. rear end is a 3.73 ratio.
This thing spark knocks/pings to no end under med-heavy throttle inputs. Never heard it as bad as this, The spark tables have been reset to factory tables but it still pulls a ton of timing while pinging away. Can anyone take a look at this short log and give me some input? I'd really appreciate it. Ive attached the log and tune files.
This thing spark knocks/pings to no end under med-heavy throttle inputs. Never heard it as bad as this, The spark tables have been reset to factory tables but it still pulls a ton of timing while pinging away. Can anyone take a look at this short log and give me some input? I'd really appreciate it. Ive attached the log and tune files.
03-02-2014, 07:48 PM
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Oh, also this car only put down only 233 hp and 272 tq on a dynojet. That was after a 'pro' tune. I have since fixed that tune and brought the drivability back. There is no reason this car should not be putting 300+ down to the wheels.
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03-03-2014, 04:56 PM
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only things I can think of are does it have a msd opti with the timing adjustment? also are you running an ac-delco ICM? I have heard that aftermarket ones can throw the timing off by a few degrees.
03-03-2014, 05:10 PM
#11
So you can hear the pinging?
I don't have tuning software on this computer so I can't open your files. There is an offset that I believe can add timing everywhere any chance it is adding timing on top of the tables?
You understand the pcm adds timing beyond what is programmed at higher rpm?
The LT4 springs NEED to be swapped before you drop a valve. They are marginal with slow HOT cam lobes and the heavy LT1 valves, no chance they are up to even that super mild aftermarket cam. Given mistakes like that coupled with other bad ideas like port matching the intake and porting heads with exhaust manifolds, stock stall, it begs the question what else is wrong with the build is there some other mechanical mistake causing this?
Were the knock sensors properly torqued? Piston clearance right? A friend had some loose forged pistons and we basically had to shut off the knock retard because it always "heard" the piston rattle as knock.
I sincerely hope you find something simple and no damage is done but there are so many things wrong listed already I really fear what else is done wrong in addition.
I don't have tuning software on this computer so I can't open your files. There is an offset that I believe can add timing everywhere any chance it is adding timing on top of the tables?
You understand the pcm adds timing beyond what is programmed at higher rpm?
The LT4 springs NEED to be swapped before you drop a valve. They are marginal with slow HOT cam lobes and the heavy LT1 valves, no chance they are up to even that super mild aftermarket cam. Given mistakes like that coupled with other bad ideas like port matching the intake and porting heads with exhaust manifolds, stock stall, it begs the question what else is wrong with the build is there some other mechanical mistake causing this?
Were the knock sensors properly torqued? Piston clearance right? A friend had some loose forged pistons and we basically had to shut off the knock retard because it always "heard" the piston rattle as knock.
I sincerely hope you find something simple and no damage is done but there are so many things wrong listed already I really fear what else is done wrong in addition.
03-03-2014, 10:17 PM
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So you can hear the pinging?
I don't have tuning software on this computer so I can't open your files. There is an offset that I believe can add timing everywhere any chance it is adding timing on top of the tables?
You understand the pcm adds timing beyond what is programmed at higher rpm?
The LT4 springs NEED to be swapped before you drop a valve. They are marginal with slow HOT cam lobes and the heavy LT1 valves, no chance they are up to even that super mild aftermarket cam. Given mistakes like that coupled with other bad ideas like port matching the intake and porting heads with exhaust manifolds, stock stall, it begs the question what else is wrong with the build is there some other mechanical mistake causing this?
Were the knock sensors properly torqued? Piston clearance right? A friend had some loose forged pistons and we basically had to shut off the knock retard because it always "heard" the piston rattle as knock.
I sincerely hope you find something simple and no damage is done but there are so many things wrong listed already I really fear what else is done wrong in addition.
I don't have tuning software on this computer so I can't open your files. There is an offset that I believe can add timing everywhere any chance it is adding timing on top of the tables?
You understand the pcm adds timing beyond what is programmed at higher rpm?
The LT4 springs NEED to be swapped before you drop a valve. They are marginal with slow HOT cam lobes and the heavy LT1 valves, no chance they are up to even that super mild aftermarket cam. Given mistakes like that coupled with other bad ideas like port matching the intake and porting heads with exhaust manifolds, stock stall, it begs the question what else is wrong with the build is there some other mechanical mistake causing this?
Were the knock sensors properly torqued? Piston clearance right? A friend had some loose forged pistons and we basically had to shut off the knock retard because it always "heard" the piston rattle as knock.
I sincerely hope you find something simple and no damage is done but there are so many things wrong listed already I really fear what else is done wrong in addition.
The springs were recommended by comp for that cam and that's what they were put in. I did not build this car or engine, and im trying to fix what is needed. The piston to wall clearance is a little bit high as it has some slap at cold start but goes away pretty fast. Its seems very common with the kb hypers after some mileage has been put on them.
I would appreciate if you could look at the files and also tell me where this offset might be under. I did not know it can add timing beyond the tables. How can this be controlled? Like i said, the spark maps were returned to stock.
afr's are good across the board, would be leaning out and maxing out the injector duty cycles if the pressure was low.
