Chasing an issue a possible crank hub/opti problem - LS1LT1 Forum : LT1, LS1, Camaro, Firebird, Trans Am, Engine Tech Forums
 
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post #1 of 6 (permalink) Old 05-16-2019, 11:00 PM Thread Starter
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Chasing an issue a possible crank hub/opti problem

97 lt1. What are the symptoms of the crank hub spinning vs a bad opti? Car idles fine, low/mid throttle pulls are ok. When I put it to the floor it develops a horrible misfire, engine sputters.

MSD opti on next day air, but retorqued the crank hub bolt and got almost a full turn before the torque wrench clicked. Kinda nervous about possible damage could have occured. Thanks!

97 Trans Am - being modified for DD/Track Car use
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post #2 of 6 (permalink) Old 05-17-2019, 07:31 AM
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If your unshure about opti performance of low & high resolution pulses, your only 100% way of testing them is with an oscilloscope. Luckily, you can buy a pc based scope for around $70 on ebay, amazon, etc.

Use the scope to check low & high res signals of opti for proper square wave. See if signal changes shape, degrades, or completly stops when engine acts up.

Crank pulley & damper do not affect opti performance as opti runs off of timing gears.

Msd opti has not been on recommendation list for a while. They were having reliability problems with them and I don't know if Msd has overcome this problem. Only optis to use are GM, Delco, or Delphi.

There's also the possibility that all that is needed to cure problem is cap, rotor, plugs, & wires. People forget these are regular maintenance items.

Last edited by cocobolo95; 05-17-2019 at 07:35 AM.
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post #3 of 6 (permalink) Old 05-17-2019, 10:27 AM Thread Starter
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Well crap. My over night MSD came in a 96-97 box but is obviously for 94-95. Getting it returned. Not going to make track day today unless I put my malfunctioning one back in. =( kind of upset as I just spent a full week ignoring the family and working on the car.

One week ago I took it apart to do the water pump, crank, distributor seal. Noticed that the Opti had a big Groove in it from the harmonic balancer starting to fall apart. The shop that rebuilt the engine 3 years ago warrantied the part for me even though it was working just fine. A bunch of oil came out when I uninstalled it and even with the big groove in it, it seemed to work just fine. Was probably just a matter of time before it bit the dust anyways though.

With the new Opti from the shop it is throwing a code p1371 which never happened with the old one. Really bummed now and I'll never be able to get the old Opti back (I checked).

97 Trans Am - being modified for DD/Track Car use
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post #4 of 6 (permalink) Old 05-18-2019, 07:17 AM
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You have the dreaded low resolution pulse missing code. Bet your new opti is a cheap China made parts store opti. Only decent one's are GM, Delco, or Delphi.

Msd opti used to be good. But as you found out, they can't even put the correct opti type in it's correct box. Quality control is out the door.

Better buy that pc based oscilloscope. I've got a feeling that your going to need it.

Last edited by cocobolo95; 05-18-2019 at 07:20 AM.
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post #5 of 6 (permalink) Old 05-23-2019, 07:48 PM Thread Starter
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100% the opti was defective. Got my new opti from MSD (the right one in the box this time) and was a little worried after the first start. Reving it up sounded like it was missing a little so I let it sit over night. I can only work on the car so much everyday and really needed some sleep. Next morning took it out for some city driving and everything seemed fine, had a few coolant leaks from not getting hoses tight enough so took care of those real quick. Then out to the highway to piss a few people off, GET OUT OF THE LEFT LANE TURD! Happy to say that it seems my ride is back to 100% badassery. 0-60 is WHEW and 60-*** is there and everything is just like butter. *FIXED*

Next up is a billet power steering pulley and maybe longtube headers before a dyno at TPIS.

97 Trans Am - being modified for DD/Track Car use

Last edited by Familiar_Enemy; 05-23-2019 at 07:51 PM.
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post #6 of 6 (permalink) Old 05-24-2019, 07:16 AM
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Glad to hear problem is solved. Keep us updated on MSD opti. They used to be good, then went downhill. Hoping they solved the quality problem.
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