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In need of an LT1 guru (new style 1996)

4X4HIGH

4X4HIGH

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Anyone know about the later LT1 engines? I'm having a problem after changing plugs, wires, cap/rotor, coil and waterpump. The LT1 in a 1996 Impala uses a coolant reservoir with the radiator cap on it instead of on the radiator and because of this there is an air bleed on the waterneck that you have to bleed any air from the cooling system. I fired the engine up after I was done and it fired right up and ran perfectly as it did before I changed these parts BUT as I was waiting for the engine to warm up enough so I could bleed the cooling system of air the engine stumbled then died on me and would not restart. I let it sit for about 3 minutes while I was cleaning up and then tried it again and it fired right up but this time when I tried giving it some throttle it bogged on me then died and hasn't started up again. I just gave up for now so I haven't checked for spark or anything like that yet but I guess that's my next move. I'm just curious if this car has some kind of sensor (maybe the CTS is incoporated in this) that would shut the car off if it gets too hot to help prevent engine damage.
 
Scott, I've heard of timing problems from the optispark sensor getting wet ...perhaps an issue?
Its under the water pump, and I had a buddy have problems with his 96 as well, expensive to replace he said.
 
76zimmer said:
Scott, I've heard of timing problems from the optispark sensor getting wet ...perhaps an issue?
Its under the water pump, and I had a buddy have problems with his 96 as well, expensive to replace he said.
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I made 300% sure the opti didn't get wet, like I said it started and ran perfect for about 5 minutes or so then just quit. I cleaned up for the day and went out for dinner for several hours and when I returned I tried starting it and it fired right up like nothing was ever wrong. :dunno:
 
I know next to nothing about the LT1. But my TPI motor started doing similar, although I don't recall the bogging beforehand.

I'd drive (or idle) it for 5 minutes or an hour, would shut it off, and even up to an hour later would not start. Let it sit long enough, it would fire right up, and run fine unless I shut it down. But the engine would have to be ice cold, as in first thing in the morning would get you one start for the day.

Turned out I had 3 or more "bad" injectors. I sold them off (disclosing there were at least a couple that were bad) and the guy had them checked, finding the 3 bad ones. No idea if the LT1 used similar/same injectors or if they had already transitioned to something different.
 
Got the car running again tonight. Turns out the NEW MSD cap and rotor I bought somehow went bad after about 3-4 minutes of running. I threw the old cap and rotor back on and she fired right up so I went down to the local auto parts store and bought a new AC Delco cap and rotor kit and now it's back together and running sweet.

I discovered this after I checked for spark at the plug wires rather than just at the coil, coil had tons of spark but NONE from the plug wires. :confused: It only took about 4 hours to tear it apart and put it back together (didn't make me happy that's for sure).
 
Are the cap/rotor fairly similar in operation to the standard HEI? Seems odd a cap and rotor (especially MSD) would go bad quickly if they are anything alike!
 
dyeager535 said:
Are the cap/rotor fairly similar in operation to the standard HEI? Seems odd a cap and rotor (especially MSD) would go bad quickly if they are anything alike!
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The distributor on the LT1 is camshaft driven off the front of the engine and is partially tucked up under the waterpump and behind the harmonic balancer. It is a crap style cap. The cap operation is the same as any distributor cap.
 
Did the rotor hit the terminals in the cap? I just can't figure out how MSD could mess that setup up if its just like any other cap/rotor setup.
 
dyeager535 said:
Did the rotor hit the terminals in the cap? I just can't figure out how MSD could mess that setup up if its just like any other cap/rotor setup.
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No contact was made between the rotor and the plug terminals, only the rotor to the center pin of the cap as should be.
 
82355 said:
MSD's LT1 parts are notorious for not working.

Martin
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This is the first MSD product that has let me down. Wish I had known ahead of time that there are issues with their LT1 stuff (where did you get that info from?)
 
Can't speak of the msd stuff, but have had issues with the opti spark cut out and cause misfires randomly, even with new delco cap and rotor
 
82355 said:
MSD's LT1 parts are notorious for not working.

Martin
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This^

Don't waste your money on any other opti or opti related parts on anything but GM or you will more than likely have problems and waste money.
 
i know a guy who converted his to coil packs and only used optispark for crank trigger inside to run the coil packs.

used gm waste spark coil packs. was a kit he got some place years ago.
 
sweetk30 said:
send a pm to philly87 our msd guy here. might be able to help or give some credit who knows. :dunno:

http://coloradok5.com/forums/member.php?u=974
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I did better than that and just called Phil on his cell last night when I discovered the problem, he told me to call him at work on monday to get an RMA and when he gets it he/they will check it out to find out where the problem is (hopefully MSD refunds my money on that kit).
 
4X4HIGH said:
This is the first MSD product that has let me down. Wish I had known ahead of time that there are issues with their LT1 stuff (where did you get that info from?)
Click to expand...

A lot of people use to mod those LT1's. With the readily available LS1's around for cheap, not many do anymore, but it was common knowledge that the MSD optispark stuff was failure prone.

Martin
 
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