My lt1 is killing me!!!!!
Thread Starter
On The Tree
Joined: Jul 2008
Posts: 149
Likes: 0
From: Sulphur Springs ,tx
My lt1 is killing me!!!!! I have replaced the opti,02s,walbro fuel pump,injectors,msd coil,and when the car has been run for a while ,it cuts out bad above 5500 ,any of u guys been here before.I am thinking maybye the ignition module ,no codes or anything?????????????????
I am having the EXACT same prob...ugh
Runs great up to 5500 and then crap....shift to the next gear and runs great to 5500 again..
New coil, ICM, opti, Plugs, Wires....
No codes...Good fuel pressure, regulator and pump...Plugs look good!
Good valve springs and hardened push rods...
car ran great for a while then one day it started missing then cleared up then it came back and I haven't been able to figure it out....
If i figure mine out I will let you know!
There are TONS of threads about high Rpm misses but no one updates them when they figure it out
Runs great up to 5500 and then crap....shift to the next gear and runs great to 5500 again..
New coil, ICM, opti, Plugs, Wires....
No codes...Good fuel pressure, regulator and pump...Plugs look good!
Good valve springs and hardened push rods...
car ran great for a while then one day it started missing then cleared up then it came back and I haven't been able to figure it out....
If i figure mine out I will let you know!
There are TONS of threads about high Rpm misses but no one updates them when they figure it out
The times I had trouble with upper RPM break up in a SBC it was always ignition. Cap, Rotor, wires, plugs, plug gap, coil.
I have not had an LT1 have trouble without boost...and an MSD box akways fixed the bust up. I would recommend trying autolite plugs and tighten the gap .005 to .010" from recommended, that will probably clear the problem, then I would put an MSD box on te ca and return to recommended gapped plugs.
The other common problem I have seen in an LT1 is poor ground at the drivers head. Make sure none are broken and the ground is making good connection. I rough the conection point with sandpaper.
Good luck
I have not had an LT1 have trouble without boost...and an MSD box akways fixed the bust up. I would recommend trying autolite plugs and tighten the gap .005 to .010" from recommended, that will probably clear the problem, then I would put an MSD box on te ca and return to recommended gapped plugs.
The other common problem I have seen in an LT1 is poor ground at the drivers head. Make sure none are broken and the ground is making good connection. I rough the conection point with sandpaper.
Good luck
Thread Starter
On The Tree
Joined: Jul 2008
Posts: 149
Likes: 0
From: Sulphur Springs ,tx
Cutting out high rpms My car will pull to 6200rpm until it gets warm ,then cuts out above 5500 ,has not done it all winter,now the temps up the problem is back,it all started at the end of last summer,but seems to be getting worse.
My Car has an MSD digital 6 box too...on or off it still breaks up...
All grounds are good...
Tried 2 different sets of plugs and closed the gap....
If you car will run to 6200 and then after warm breaks up after 5500 it is def not mechanical....
I just pulled my opti off again and am going to send it in for warranty and see if that fixes it....fingers crossed!!
Matt
All grounds are good...
Tried 2 different sets of plugs and closed the gap....
If you car will run to 6200 and then after warm breaks up after 5500 it is def not mechanical....
I just pulled my opti off again and am going to send it in for warranty and see if that fixes it....fingers crossed!!
Matt
My Car has an MSD digital 6 box too...on or off it still breaks up...
If it's not that check under the hood at night and look for plug wire arcing.
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Verdad Gallardo Ive replaced the ICM too and checked the wires for arcing...also replaced the wires and plugs completely.....New coil as well....
Ive ran the car with and without the MSD and does the same either way..
I think it almost has to be a bad opti...
clwz28 - not trying to hijack your thread just figured we both have the same issue and maybe between the 2 of us we can figure something out...
Matt
Ive ran the car with and without the MSD and does the same either way..
I think it almost has to be a bad opti...
clwz28 - not trying to hijack your thread just figured we both have the same issue and maybe between the 2 of us we can figure something out...
Matt
Launching!
Joined: Feb 2010
Posts: 227
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I have seen this happen a couple of times never to me but have you checked the spark and also i have herd about a clogged cat being the issue or could be a bad tune or pcm just some things you can check ill keep trying to pull up some info for you guys
Good I hope that ICM did fix it for you!!!
Unfortunately for me it didn't fix my issue...I sent my optispark back for warranty hopefully when I put the new one on it things will be good again!
I don't have any cats on the car (No Emissions Florida
)
The tune has been in the car for a long time with no issues so I doubt that would be it...
Def thinking opti at this point.....
Unfortunately for me it didn't fix my issue...I sent my optispark back for warranty hopefully when I put the new one on it things will be good again!
I don't have any cats on the car (No Emissions Florida
)The tune has been in the car for a long time with no issues so I doubt that would be it...
Def thinking opti at this point.....
mines from All Ignition
My buddy runs the same one with NO problems but mine has been horrible...
I have another MAF I will change it out when I get the car back together...
Matt
My buddy runs the same one with NO problems but mine has been horrible...
I have another MAF I will change it out when I get the car back together...
Matt
