I hate my LT1.
02-21-2010, 08:16 PM
#1
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I hate my LT1. Constant Issues. 
95 LT1. SES light flickers randomly (but no codes), it flickers most during acceleration and sometimes sputters/stalls when accelerating from a stop light. Check Gauges light also flickers almost constantly but never illuminates fully. Surges at idle, taking it out of D and putting it in neutral usually makes it settle down. Pops and sputters at WOT after about 5k RPM or so. Runs great at 10-90% throttle. shitty gas mileage (13mpg), exhaust smells kind of foul. I always run Chevron 93+ so it shouldn't be bad gas.
Replaced in last 6 months:
Opti
Opti cable, old one was crumbling
coil
wires (msd 8mm)
ICM
Timing chain and gears
alternator and battery
Checked:
tried swapping PCM for another, no change
tried stock tune, no change
loctited loose ground by coil (nut was loose). check other grounds
checked iac, TPS, and o2 readings with scantool, readings appeared to be normal
Cleaned IAC, throttle body, pcv valve, MAF
Spent hours and hours googling the forums, nearly every post with my symptoms has lots of talk but abandoned before a solution is posted.
I have never liked the LT1 and got a '99 LS1 (which runs perfect). At this point I am wanting to junk the '95 (I don't hate anyone enough to sell it to them) but the wife has an emotional attachment to the car so that options out.
Any ideas? I'm getting sick of throwing parts at it, and with no codes its hard to diagnose. And yes, I am too stubborn to take it to a mechanic (most seem borderline retarded anyway)
Thanks in advance..
95 LT1. SES light flickers randomly (but no codes), it flickers most during acceleration and sometimes sputters/stalls when accelerating from a stop light. Check Gauges light also flickers almost constantly but never illuminates fully. Surges at idle, taking it out of D and putting it in neutral usually makes it settle down. Pops and sputters at WOT after about 5k RPM or so. Runs great at 10-90% throttle. shitty gas mileage (13mpg), exhaust smells kind of foul. I always run Chevron 93+ so it shouldn't be bad gas.
Replaced in last 6 months:
Opti
Opti cable, old one was crumbling
coil
wires (msd 8mm)
ICM
Timing chain and gears
alternator and battery
Checked:
tried swapping PCM for another, no change
tried stock tune, no change
loctited loose ground by coil (nut was loose). check other grounds
checked iac, TPS, and o2 readings with scantool, readings appeared to be normal
Cleaned IAC, throttle body, pcv valve, MAF
Spent hours and hours googling the forums, nearly every post with my symptoms has lots of talk but abandoned before a solution is posted.
I have never liked the LT1 and got a '99 LS1 (which runs perfect). At this point I am wanting to junk the '95 (I don't hate anyone enough to sell it to them) but the wife has an emotional attachment to the car so that options out.
Any ideas? I'm getting sick of throwing parts at it, and with no codes its hard to diagnose. And yes, I am too stubborn to take it to a mechanic (most seem borderline retarded anyway)
Thanks in advance..
02-21-2010, 08:23 PM
#3
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i would say that the check guages light flickers because the engine is sputtering and the alternator slows down enough to start tripping it, so i wouldn't really worry about that...
did you ever change the plugs?
did you ever change the plugs?
02-21-2010, 09:12 PM
#4
Exhaust smells foul, how? How old are the Os sensors? Once they foul the PCM detects lean condition and dumps more fuel, making it worse if you're suffering a rich condition. Headers? If so, any plug wires close to the primaries, like #6 (pass. side, 3rd one back). Might get an arc. Wire arc and rich condition together = bad performance, bad mileage. Just a couple of things to check...
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02-21-2010, 09:25 PM
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I also just changed the fuel filter, forgot to add that one to the list..
I havent checked the FPR yet, i have read that I just need to pull the vacuum hose and if there is any fuel leaking its bad. for the injectors is there a way to check them without sending them off somewhere ?
I replaced the plugs a couple years ago with NGK Iridiums, supposedly 100k plugs but thats probably BS marketing. I should probably swap in some normal copper plugs.
not sure how old the o2s are (at least 5+ years), not getting any codes and the voltages are in spec. can they be bad and not throw a code?
I have bbk shorties, I have new MSD wires and I wrapped them with 'cool tape' and tied them off to keep them away from the headers. (I have burned up plug wires in the past, learned my lessons on that one)
I havent checked the FPR yet, i have read that I just need to pull the vacuum hose and if there is any fuel leaking its bad. for the injectors is there a way to check them without sending them off somewhere ?
I replaced the plugs a couple years ago with NGK Iridiums, supposedly 100k plugs but thats probably BS marketing. I should probably swap in some normal copper plugs.
not sure how old the o2s are (at least 5+ years), not getting any codes and the voltages are in spec. can they be bad and not throw a code?
I have bbk shorties, I have new MSD wires and I wrapped them with 'cool tape' and tied them off to keep them away from the headers. (I have burned up plug wires in the past, learned my lessons on that one)
02-21-2010, 10:42 PM
#11
The diapham inside the FPR could have taken a **** and one way to check it is to plug the vaccume line.. And for testing the injectors just pull the rail up and put some clear cups under them and have some one prime the system and just check to see if any are leaking..I've ran into both these problems and thats how i tested them..
Also even if the plugs say 100K i would still pull a couple from each side and see how they look..
Also even if the plugs say 100K i would still pull a couple from each side and see how they look..
02-21-2010, 10:48 PM
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95 LT1. SES light flickers randomly (but no codes), it flickers most during acceleration and sometimes sputters/stalls when accelerating from a stop light. Check Gauges light also flickers almost constantly but never illuminates fully.
but in all honesty, surges suck. Check grounds would be my guess. Maybe try seafoam.. wish i had more to offer man.. good luck
02-22-2010, 12:16 AM
#15
well if you have an exhaust smell with horrible gas mileage, something is messing with the fuel. I'd say possibly the injectors, but I'd start with the spark plugs-I'd bet this is the problem, also considering that's much more inexpensive and easy to do. Also, any shop should be able to test your fuel pressure for cheap and see if you have an issue there.
02-22-2010, 12:23 AM
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your sputtering uptop and problems at idle all sound like optispark. when you replaced the opti did you manage to get it in there the first few tries without damaging the o-ring? and are your seals on your timing chain cover not leaking oil on the distributer? and kind of trash is going to mess up the triggers on the lense of course but im sure you know that. you got air of course so fuel needs to be looked into more, and if not go back to spark
02-22-2010, 11:01 AM
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check fuel pressure... if that problem is not it then yeah possibly look into swapping some injectors in there (even a set of new stockers)..... Start it up in your garage at night with ZERO lights and let your eyes get adjusted under the hood. Make sure you aren't getting any arcing electricity anywhere OTHER than where it should be. The holes where your spark plugs are should be glowing but not shooting sparks out.....
also check coil and ignition system. You said you swapped opti, are you POSITIVE that you installed it correctly clocked and make sure all your plug wires are on the correct ends at the optispark. I did that once and my car ran like *** and has all those problems.... put the right plug to the right spot on the opti and all problems went away...
also check coil and ignition system. You said you swapped opti, are you POSITIVE that you installed it correctly clocked and make sure all your plug wires are on the correct ends at the optispark. I did that once and my car ran like *** and has all those problems.... put the right plug to the right spot on the opti and all problems went away...