I need help!! Tuning issues... Spark??
12-09-2008, 11:14 PM
#21
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Can you post up the complete specs of your cam/springs(brand)/install heights?
Also, have the tune file and data log yet? We're all eager to help you out!
Random thought, how long did the gas sit in the tank while you were working the car over? Check your fuel pressure? Replace fuel filter?
Also, have the tune file and data log yet? We're all eager to help you out!
Random thought, how long did the gas sit in the tank while you were working the car over? Check your fuel pressure? Replace fuel filter?
12-10-2008, 01:06 AM
#22
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Try checking crankshaft end-play. I had a similar problem before. Chased that bastard-of-a-problem for four days only to discover that the crank thrust bearing wasn't clearanced properly (newly built engine). Higher rpm (also around 4K rpm) and load would cause the car to literally die out and detonate heavily as the crank walked slightly causing the crank sensor to read the adjacent reluctor wheel and throw timing way off. In my 20 years of futzing with cars, I never would have guessed, and yet there it was. Crappy problem that caused someone a ton of money and me a ton of gray hair (I was beautiful once!)
also the timing is staying solid when it begins to break up...
im not the tuner, but i have been working on the car, and suspect it to be a grounding issue if not a bad pcm...
12-10-2008, 02:30 AM
#23
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Well I spoke with Charlies secretary today and she said he hasnt been able to get back to me, because he has been swamped and supposedly he will be out til dec 15th?! :-/
and I havent gotten an email from him yet, so Im sorry I dont have any records of the runs to show anyone right now...
But one more thing Id like to add is, during ide when it sometimes would die, the tach doesnt come back on(sometimes) and this lasts for a few seconds or so... sometimes it idles at 1500ish rpms, and sometimes it just dies and other times it surges....
and I havent gotten an email from him yet, so Im sorry I dont have any records of the runs to show anyone right now...
But one more thing Id like to add is, during ide when it sometimes would die, the tach doesnt come back on(sometimes) and this lasts for a few seconds or so... sometimes it idles at 1500ish rpms, and sometimes it just dies and other times it surges....
12-10-2008, 09:31 AM
#24
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you need to post a log and a tune before anyone can really jump on this one.
Your tach issue sounds like a ground, make sure you check the pcm and all motor grounds.
Danny
Your tach issue sounds like a ground, make sure you check the pcm and all motor grounds.
Danny
12-10-2008, 09:37 AM
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what do you mean the tach wont come back on?
but the thing i dont get...why are all the vital engine sensors reporting solid signals when the engine starts to break up...
its not showing any drop in fuel pressure, duty cycle, afr, timing,or voltage drop... im not sure if it was getting knock retard or not, but the tuner said timing was solid.... the block is an ls2 so we relocated the knock sensors....can i run a system check through hp tuners on the knock sensors in order to ensure their performance?
but the thing i dont get...why are all the vital engine sensors reporting solid signals when the engine starts to break up...
its not showing any drop in fuel pressure, duty cycle, afr, timing,or voltage drop... im not sure if it was getting knock retard or not, but the tuner said timing was solid.... the block is an ls2 so we relocated the knock sensors....can i run a system check through hp tuners on the knock sensors in order to ensure their performance?
12-10-2008, 01:48 PM
#26
How do you know the AFR is good? Do you have a WIDEBAND hooked up? How do you know about fuel pressure? Do you have a fuel pressure SENDER hooked up?
I would suggest getting under there and rechecking the connection to the knock sensors, as they will get burned if not protected from the header primaries as they stick out quite far, had that problem myself.
I would pull out the crank position sensor and check it for damage, sometimes clearance is too tight, and the reluctor wheel will skim the sensor and cause those problems as well.
Also, double check your connection to your cam position sensor, make sure it isn't loose or burned up in the back/getting pinched either.
Oh yea, and last but not least.....DID you do a crank position sensor relearn procedure? You should be able to do it with the tech2, and MUST be done when you install a new motor to allow the PCM to correctly read the reluctor timing. If you haven't done this yet, THIS WOULD BE THE FIRST THING YOU SHOULD DO.
I would suggest getting under there and rechecking the connection to the knock sensors, as they will get burned if not protected from the header primaries as they stick out quite far, had that problem myself.
I would pull out the crank position sensor and check it for damage, sometimes clearance is too tight, and the reluctor wheel will skim the sensor and cause those problems as well.
Also, double check your connection to your cam position sensor, make sure it isn't loose or burned up in the back/getting pinched either.
Oh yea, and last but not least.....DID you do a crank position sensor relearn procedure? You should be able to do it with the tech2, and MUST be done when you install a new motor to allow the PCM to correctly read the reluctor timing. If you haven't done this yet, THIS WOULD BE THE FIRST THING YOU SHOULD DO.
12-10-2008, 06:19 PM
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what do you mean the tach wont come back on?
but the thing i dont get...why are all the vital engine sensors reporting solid signals when the engine starts to break up...
its not showing any drop in fuel pressure, duty cycle, afr, timing,or voltage drop... im not sure if it was getting knock retard or not, but the tuner said timing was solid.... the block is an ls2 so we relocated the knock sensors....can i run a system check through hp tuners on the knock sensors in order to ensure their performance?
but the thing i dont get...why are all the vital engine sensors reporting solid signals when the engine starts to break up...
its not showing any drop in fuel pressure, duty cycle, afr, timing,or voltage drop... im not sure if it was getting knock retard or not, but the tuner said timing was solid.... the block is an ls2 so we relocated the knock sensors....can i run a system check through hp tuners on the knock sensors in order to ensure their performance?
Also today I had 2 codes again camshaft position sensor and MAP sensor, first time in a week that they came back on...
12-10-2008, 06:21 PM
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How do you know the AFR is good? Do you have a WIDEBAND hooked up? How do you know about fuel pressure? Do you have a fuel pressure SENDER hooked up?
I would suggest getting under there and rechecking the connection to the knock sensors, as they will get burned if not protected from the header primaries as they stick out quite far, had that problem myself.
I would pull out the crank position sensor and check it for damage, sometimes clearance is too tight, and the reluctor wheel will skim the sensor and cause those problems as well.
Also, double check your connection to your cam position sensor, make sure it isn't loose or burned up in the back/getting pinched either.
Oh yea, and last but not least.....DID you do a crank position sensor relearn procedure? You should be able to do it with the tech2, and MUST be done when you install a new motor to allow the PCM to correctly read the reluctor timing. If you haven't done this yet, THIS WOULD BE THE FIRST THING YOU SHOULD DO.
I would suggest getting under there and rechecking the connection to the knock sensors, as they will get burned if not protected from the header primaries as they stick out quite far, had that problem myself.
I would pull out the crank position sensor and check it for damage, sometimes clearance is too tight, and the reluctor wheel will skim the sensor and cause those problems as well.
Also, double check your connection to your cam position sensor, make sure it isn't loose or burned up in the back/getting pinched either.
Oh yea, and last but not least.....DID you do a crank position sensor relearn procedure? You should be able to do it with the tech2, and MUST be done when you install a new motor to allow the PCM to correctly read the reluctor timing. If you haven't done this yet, THIS WOULD BE THE FIRST THING YOU SHOULD DO.
All I can say is, when I blew my old LS1, my mechanic tried to "relearn the crank" before we knew the reluctor wheel was messed up..., I dunno if this has anything to do with what is happening now (since it as the same PCM as is being used now.)
12-10-2008, 09:38 PM
#29
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Ok, you remember how my engine kept dying at idle at random times? Well when Id restart it the tach wont come back on for like 20 seconds, maybe longer... So id have no tach, then in 20+ seconds It will come back on..
Also today I had 2 codes again camshaft position sensor and MAP sensor, first time in a week that they came back on...
Also today I had 2 codes again camshaft position sensor and MAP sensor, first time in a week that they came back on...
12-11-2008, 10:10 AM
#30
well cam and map are both on the back of the intake and sounds like a harness issue and ground issue with the tach. cam sensor is only used during startup so it wont effect your timing after it starts. but on your next post sounds like you might have answered your own question
Not quite, the Cam sensor will be on his front timing cover since he has a LS2 block.
Check your harness for your cam position sensor/MAP sensor, maybe too tight at the back of the motor/getting pinched, as why you're seeing cutout at 4K rpms.
Also, do the Crank Relearn Procedure again, as that must be done when you install a new motor. Doesn't matter if you have the same PCM, you have to allow the PCM to learn the new reluctor so it can match up the firing sequence properly, and also check the sensor and MAKE sure its not damaged.
12-11-2008, 01:59 PM
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Not quite, the Cam sensor will be on his front timing cover since he has a LS2 block.
Check your harness for your cam position sensor/MAP sensor, maybe too tight at the back of the motor/getting pinched, as why you're seeing cutout at 4K rpms.
Also, do the Crank Relearn Procedure again, as that must be done when you install a new motor. Doesn't matter if you have the same PCM, you have to allow the PCM to learn the new reluctor so it can match up the firing sequence properly, and also check the sensor and MAKE sure its not damaged.
Check your harness for your cam position sensor/MAP sensor, maybe too tight at the back of the motor/getting pinched, as why you're seeing cutout at 4K rpms.
Also, do the Crank Relearn Procedure again, as that must be done when you install a new motor. Doesn't matter if you have the same PCM, you have to allow the PCM to learn the new reluctor so it can match up the firing sequence properly, and also check the sensor and MAKE sure its not damaged.
12-11-2008, 02:34 PM
#32
If the engine has been fired up a couple of times, it already learned the new engine. Crank Relearn must be done on inital start up, not after it has been run as it will not do anything afterwards. I would inspect the Crank Sensor and associated connections.
12-11-2008, 03:10 PM
#33
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this is definitely a possibility, since he is reusing his old crank sensor from when the reluctor wheel was damaged in his old engine...
if the sensor has a couple nicks in it, would it really make a difference, being as it is only a magnetic pickup?
if the sensor has a couple nicks in it, would it really make a difference, being as it is only a magnetic pickup?
12-11-2008, 03:22 PM
#34
Lastly,
Please answer these questions...
1.) Are you sure you're getting proper fuel pressure? You MUST have a fuel pressure sender installed to check it properly, if not, then you could simply be having a fueling issue.
2.) Have you upgraded your fuel pump? If not, then i would highly recommend it. Get the racetronix kit and have it installed professionally. Works great.
3.) How long has the gas been in the tank? It if was sitting too long, your gas may have gone bad.
4.) What exactly are ALL the codes you've gotten since you installed the motor?
5.) Cam (duration/lifts)
lifters(brand and preload you have them set at)
springs (brand and install height they're set to)
pushrod length
Thanks.
12-11-2008, 03:23 PM
#35
Yes, if there are any nicks or scratches on the sensor, it could cause problems. Sucks you will have to pull the intake off to get to it though.... But make sure you check the harness once you get back there to make sure the wires aren't too tight or being pinched while you're checking the crank sensor.
12-11-2008, 03:24 PM
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Yes, if there are any nicks or scratches on the sensor, it could cause problems. Sucks you will have to pull the intake off to get to it though.... But make sure you check the harness once you get back there to make sure the wires aren't too tight or being pinched while you're checking the crank sensor.
12-11-2008, 03:38 PM
#37
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This is incorrect. The PCM will NOT relearn the reluctor unless its told to do so. It will usually just throw codes if its really bad (misfires/cam sensor/crank sensor etc...), or nothing at all if its not too bad. But it still has to be done regardless if the motor has been running or not.
Lastly,
Please answer these questions...
1.) Are you sure you're getting proper fuel pressure? You MUST have a fuel pressure sender installed to check it properly, if not, then you could simply be having a fueling issue.
2.) Have you upgraded your fuel pump? If not, then i would highly recommend it. Get the racetronix kit and have it installed professionally. Works great.
3.) How long has the gas been in the tank? It if was sitting too long, your gas may have gone bad.
4.) What exactly are ALL the codes you've gotten since you installed the motor?
5.) Cam (duration/lifts)
lifters(brand and preload you have them set at)
springs (brand and install height they're set to)
pushrod length
Thanks.
Lastly,
Please answer these questions...
1.) Are you sure you're getting proper fuel pressure? You MUST have a fuel pressure sender installed to check it properly, if not, then you could simply be having a fueling issue.
2.) Have you upgraded your fuel pump? If not, then i would highly recommend it. Get the racetronix kit and have it installed professionally. Works great.
3.) How long has the gas been in the tank? It if was sitting too long, your gas may have gone bad.
4.) What exactly are ALL the codes you've gotten since you installed the motor?
5.) Cam (duration/lifts)
lifters(brand and preload you have them set at)
springs (brand and install height they're set to)
pushrod length
Thanks.
1. afr stays consistent, as well as duty cycle for injectors...even though i dont think it is a fueling issue, it is not a bad idea to see if fuel pressure at the rail is dropping.
2. new stock pump.
3. new gas 91 OC is what we are limited to here.
4.i forget the cam specs exactly, but from what i can remember 236/242 .613 split 113+2 ...or 3 i dont remember...cam was put in straight up...
lifters are oem replacment ls7...
preload is right around .080
prc duals... rated to .650 lift at 1.80... installed at 1.80
7.400 pushrod...
i dont think the problem is mechanical or fuel related....it feels like an electrical issue...
i will take everything in this thread into consideration to try to weed out the problem...
the only codes it throws is for maf fail since it is a speed density tune,
occasionaly it would throw a map code...p0106 i believe, which i attributed to a vac line that popped off the back of the intake...
lsgun is saying the map code is back as well as the cam sensor code so i will have to figure out what is going on...
12-12-2008, 11:39 AM
#39
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what valve springs r in it???? check the grounds... check your wires to your crank sensor. need to post up the file. why would your tuner be doing full throttle pulls if the car doesn't even idle correctly yet. sounds a little backwards to me. normally a car needs to idle first and it should come to an idle from higher rpms with no problems before even thinkin about full throttle pulls.
12-16-2008, 07:24 PM
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I still cannot reach my tuner. spo Im very sorry that nothing has been posted yet..
But today we found a loose pcm ground and the car felt a Little better, instead of breaking up at 4000rpms or so, it goes 4500+ ish, but breaks up before 5000rpms
Also at idle my timing is anywhere from 13* to 30* fluctuating, could this be any sign??
But today we found a loose pcm ground and the car felt a Little better, instead of breaking up at 4000rpms or so, it goes 4500+ ish, but breaks up before 5000rpms
Also at idle my timing is anywhere from 13* to 30* fluctuating, could this be any sign??