Mailorder tune , big problems after cam.
You had your hands on every single part that CAN cause a misfire during those mods. Which is why I suggested you DOUBLECHECK everything. It stands to reason the affected areas during the mods are the cause and source of the problem.
Thread Starter
Launching!
Joined: Jan 2010
Posts: 236
Likes: 0
From: Warrenton, VA
What errors during valve spring install could I have made to bring about missfire? I changed my plugs with the headers and duals over a month ago, before the cam. They've never had a problem.
On The Tree
Joined: Mar 2009
Posts: 175
Likes: 1
From: shrewsbury, ma
Any thing ignition related...plugs or the wires. could b Leaking or not firing injectors..bad compression..( mayb not your case but will do it) intake leak. Those pesky intake gasket if one pinched or rolled off could cause a large intake leak making a cylinder run lean...
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo In regards to the intial high idle... The PCM shipped with a sheet that explains how to setup the throttle body's blade screw. It tells you how to do it with a scanner (via IAC steps) and how to feel it out based on idle and small adjustments with no scanner.
The misfire is something real and physical to find. Your timing isn't too advanced; it's lower than stock at no-load up to around 21-2300 RPMs except for deep decel.
The fact that it's ok during first startup (no correction from O2's; open loop) and then, once it goes into closed loop it runs poorly just re-enforces a plain old misfiring cylinder. The misfiring cylinder passes off it's unused oxygen content to the front O2 on the side with the issue. The PCM is a little dumb and mistakes this misfiring cylinder for a lean condition and begins adding away at the fuel to try to 'fix' what it thinks is a lean condition. It can't, and it over fuels that side of the engine as a result. As this adding goes on, the car will run worse and worse.
To figure out which side of the engine the misfire is occurring on (if you have a scanner), look for the side that has very high positive long and short term trims. That's the problem side.
Alternately, unhook the O2s and the car will run open loop. Unhook the battery and it will reset previous learning. You can then run the car in open loop to search for the problem more safely because the PCM won't drown the offending side with closed loop operation.
There is a real physical problem here. We can certainly get it fixed for you if you'd like, and I'd be happy to answer any questions.
The misfire is something real and physical to find. Your timing isn't too advanced; it's lower than stock at no-load up to around 21-2300 RPMs except for deep decel.
The fact that it's ok during first startup (no correction from O2's; open loop) and then, once it goes into closed loop it runs poorly just re-enforces a plain old misfiring cylinder. The misfiring cylinder passes off it's unused oxygen content to the front O2 on the side with the issue. The PCM is a little dumb and mistakes this misfiring cylinder for a lean condition and begins adding away at the fuel to try to 'fix' what it thinks is a lean condition. It can't, and it over fuels that side of the engine as a result. As this adding goes on, the car will run worse and worse.
To figure out which side of the engine the misfire is occurring on (if you have a scanner), look for the side that has very high positive long and short term trims. That's the problem side.
Alternately, unhook the O2s and the car will run open loop. Unhook the battery and it will reset previous learning. You can then run the car in open loop to search for the problem more safely because the PCM won't drown the offending side with closed loop operation.
There is a real physical problem here. We can certainly get it fixed for you if you'd like, and I'd be happy to answer any questions.
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
Likes: 17
From: So.Cal.
Things happen and can happen at any time. Sometimes it is related to what has just been done, and it probably is, but do not focus off of any one thing until you verify that it is correct. Sometimes things happen and it is just a coincidence.
Point I am making is take a logical approach to diagnosing the problem starting with the basics first.
K.I.S.S.
Do the simple things first...they are usually the culprit. Did you try unhooking the MAF yet? If you over think this, you could end up with a bunch of little problems that take forever to get right. You paid Frost for his expertise. Use it. I've been around this a long time and everything he said is dead on the money.
Do the simple things first...they are usually the culprit. Did you try unhooking the MAF yet? If you over think this, you could end up with a bunch of little problems that take forever to get right. You paid Frost for his expertise. Use it. I've been around this a long time and everything he said is dead on the money.
Original poster emailed me but never updated this thread, so I will.
Whomever he had working on his car "installed the coil bracket backwards", and one side had total misfires. Since the implication is that the poor performance was somehow my fault (this IS posted in the tuning section), I thought I would let anyone reading know what happened.
Whomever he had working on his car "installed the coil bracket backwards", and one side had total misfires. Since the implication is that the poor performance was somehow my fault (this IS posted in the tuning section), I thought I would let anyone reading know what happened.
Maybe, I havnt been able to drive it due to not having the stall, it pops really ******* bad, maybe I can deal with it and drive it a little after the stall, see if it mellows out? New plugs, but wires are stock. Again only 50,000 miles, nothing major mechanically is wrong. I know camshaft is degreed well because i can crank it without the coil packs plugged in and its not smacking the pistons or anything, it cranks up with no noise, but plug the packs in and its missing like a bitch, anyway I could have wired the coil packs wrong? I was having some problems and its really messy.
Didn't think it was a FROST problem, but installing a coil bracket backwards??? Is that possible? Why would it cause his misfires? Now that is interesting.
Why would he take the packs off the brackets anyway?
Why would he take the packs off the brackets anyway?
Original poster emailed me but never updated this thread, so I will.
Whomever he had working on his car "installed the coil bracket backwards", and one side had total misfires. Since the implication is that the poor performance was somehow my fault (this IS posted in the tuning section), I thought I would let anyone reading know what happened.
Whomever he had working on his car "installed the coil bracket backwards", and one side had total misfires. Since the implication is that the poor performance was somehow my fault (this IS posted in the tuning section), I thought I would let anyone reading know what happened.