**Need Help** flashing service engine soon light and running rough
05-27-2014, 06:34 PM
#21
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so i finally had time to take out my plug and i see nothing wrong with it,so do i do a compression test or just take off my valve cover and look for a bent or broken pushrod or anything else,really don't want to start my car cause i probably won't be as lucky as drflathead and by the way why did you have a hunch it was a pushrod,did you have any noise.thanks
Read my first and second post. It had a valvetrain tick that was louder and more violent than any (rocker, valvespring, retainer, lock, keeper, etc.) than I have ever heard. Judging by the sound and how bad it was missing it just made sense that the pushrod was slapping around and the valve wasn't opening. In hindsight it was almost like a rod knock, but definitely coming from the top end, and Im assuming that the intermittent "bang" sound was the broken piece of pushrod hitting something. Also these motors are known for breaking or bending pushrods.
One way you could try to determine if the problem is mechanical or from the ignition is to disconnect the coil packs (you just disconnect the central plug on both sides, no need to unplug each individual coil pack) and listen for mechanical sounds while someone turns the motor over. I wouldn't necessarily recommend this method if you have any loud catastrophic sounds, I would only suggest this if you are pretty sure that its an ignition misfire and not something broken. But your best bet is to pop off the valve cover and see whats going on. It's a little bit of a squeeze to get to the rear coil bracket bolts on the passenger side (especially if you have big hands) but its not that big of a deal.
Last edited by DrFlathead; 05-27-2014 at 06:46 PM.
05-27-2014, 07:09 PM
#22
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I would absolutely recommend replacing ALL factory pushrods. They're complete **** and the achilles' heel of the LS1. I didn't due to financial reasons, and the fact that I did pull every rocker and pushrod on the passenger side and inspected them. They were all fine. Check for excessive play in the rocker bearings. A good way to see if a pushrod is bent is to roll it on a perfectly flat surface to see if there is any gap between the pushrod and surface at any point in the roll. I used a machinist square. When reinstalling the rockers just make sure to turn the motor over (by hand) to make sure the rocker is off spring pressure, all surfaces and bolts are clean, center the rocker tip over the valve stem, make sure the pushrod ball is seated in the rocker and torque it down to 22lb/ft. Then I bolted the valve cover back on without the coil packs, disconnected the coils on the driver side and cranked the motor over to listen for anything out of the ordinary. everything sounded great so I removed the valve cover once again to check that everything was good and torqued to spec (which it was) so I buttoned everything back up and its running like a champ... Hope that helped.
05-27-2014, 11:23 PM
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when my car started running rough and i got the flashing light i just went home and checked for codes,i never really heard anything and a rod knock noise i would have heard.Not really willing to turn over motor as hopefully i haven't done any harm to the motor.I'm going to go through the wiring again and if i don't find anything i'll take off my valve cover and look if anything is wrong and i'll check the pushrods on my metal work table and if i have a bent 1 i'll change them on that side(birthday today,got a $200 gift certificate to local performance store).Thanks for your input i'll keep you posted
06-01-2014, 08:47 PM
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I would absolutely recommend replacing ALL factory pushrods. They're complete **** and the achilles' heel of the LS1. I didn't due to financial reasons, and the fact that I did pull every rocker and pushrod on the passenger side and inspected them. They were all fine. Check for excessive play in the rocker bearings. A good way to see if a pushrod is bent is to roll it on a perfectly flat surface to see if there is any gap between the pushrod and surface at any point in the roll. I used a machinist square. When reinstalling the rockers just make sure to turn the motor over (by hand) to make sure the rocker is off spring pressure, all surfaces and bolts are clean, center the rocker tip over the valve stem, make sure the pushrod ball is seated in the rocker and torque it down to 22lb/ft. Then I bolted the valve cover back on without the coil packs, disconnected the coils on the driver side and cranked the motor over to listen for anything out of the ordinary. everything sounded great so I removed the valve cover once again to check that everything was good and torqued to spec (which it was) so I buttoned everything back up and its running like a champ... Hope that helped.
have an iridium plug i just bought a platinum tip, well it turned out it was my plug that was bad and now no more code, thanks for all the help
