Lt1 cuts out under load
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Teching In
Joined: Feb 2007
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Lt1 cuts out under load i have a 96 or 97 lt1/4l60e in a streed rod. i put around 100 miles on it with no motor problems. i took it on a 120 mile round trip friday, and on the way home the motor would cut out while under a load. as in, when i tried to pull a hill it coughed and bucked till we hit the top. then it was fine.
well i limped it home, all the while it was getting worse and worse. kinda felt like it wasnt getting fuel. changed the filter (even though i had only ran one tank through it, i guess i missed some crap in the tank) it had crap in it so i thought i had it whipped. well not-so-much. only now the more i drive it the worse it gets. i put a gauge on the shrader valve on the fuel rail and at idle i have plenty of psi, cant see the gauge when it cuts out tho...
put a test light on all injector plugs and they are all pulsing, put a timing light on all plug wires and all are firing. i noticed the passenger side exhaust would smoke alot while it cuts out, (black smoke) so i pulled those plugs. all were covered in soot. the entire right side appeared not to be firing under load. however the left plugs on the left side were clean. so i changed the plugs and it does the same. any ideas?!!? i'm at a loss here...
Thanks
well i limped it home, all the while it was getting worse and worse. kinda felt like it wasnt getting fuel. changed the filter (even though i had only ran one tank through it, i guess i missed some crap in the tank) it had crap in it so i thought i had it whipped. well not-so-much. only now the more i drive it the worse it gets. i put a gauge on the shrader valve on the fuel rail and at idle i have plenty of psi, cant see the gauge when it cuts out tho...
put a test light on all injector plugs and they are all pulsing, put a timing light on all plug wires and all are firing. i noticed the passenger side exhaust would smoke alot while it cuts out, (black smoke) so i pulled those plugs. all were covered in soot. the entire right side appeared not to be firing under load. however the left plugs on the left side were clean. so i changed the plugs and it does the same. any ideas?!!? i'm at a loss here...
Thanks
check all of your plug wires and make sure they dont have any burns in them, they could be grounding on something. Alsoit could be the opti getting ready to take a dump.
Ya.. it could be an O2... I had a plug wire with a slight crack in it and it would sputter really bad under a load.. I know they are "new" but one could have been cut during install and could have got worse during those 100 miles..
I cant tell you how many times the ol' LT1 would do something so simple and cause such a major problem..
I cant tell you how many times the ol' LT1 would do something so simple and cause such a major problem..
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Thread Starter
Teching In
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pulled the o2's out of the original manifolds. motor has ~20k miles on it. i switched the sensors from side to side and the problem followed the sensor the best i could tell. (its raining and only drove it ~5 miles) i have a new sensor and i'm going to stick it in there and cross my fingers...
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Teching In
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I didn't want to be one of those guys that don't follow up a tell if that fixes it or not. The new 02 sensor seems to have fixed it, I have around 50 miles on it and no problems, THANKS for all those that chimed in.
Yea don't rule out plug wires until you REALLY check them...cylinders 5,6,7 & 8 and all very close to the header and can be hard to spot a burned spot......I would pull the wires off one by one and check them or turn all the lights off in the garage and see if its arching anywhere....When we built my 355 it only had 100 miles on it with brand new Moroso wires and it would run great just idling but would miss under a load...wires looked good until I pulled them off and really inspected them......If they all look good check your plugs and see if you can tell what cylinder is missing...
Good Luck!!!
Matt
Good Luck!!!
Matt
