Looking for LT1 help
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Teching In
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Looking for LT1 help I have a 1996 Lt1 engine that idles rough, bogs and sometimes backfires in the exhaust when you depress the accelerator. The fuel is fresh, fuel pressure is 43, fuel rail was cleaned, all injectors replaced and fuel pressure leak down is very slow. The optispark, spark plugs and spark plug wires were replaced. The MAF sensor was replaced and the throttle position sensor tested good. The EGR valve and air pump have been removed and blanked off. Compression was tested, all cylinders tested good. Temperature checks on the header pipes at idle indicate all cylinders are firing and temperatures are all very close. Has anyone experienced this problem and found a solution? Thanks.
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Teching In
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Plug wires are on the correct spark plugs. I'm going to send the unit I removed away to be reconditioned. The bearing will be replaced, the optical sensor replaced with a Mitsubishi is it's not already that make, internal fasteners assembled with locktite, a new MSD cap & rotor installed, unit sealed with a high temp. sealant and bench tested at 180 degrees using an oscilloscope and video proof that it's my opti and it works. The business is called Optispark Reconditioning Service in Ohio, the cost is $310, he's done 94 units and has a 5 star rating on eBay. If the engine still doesn't run properly it's unlikely an Optispark problem.
I have a 1996 Lt1 engine that idles rough, bogs and sometimes backfires in the exhaust when you depress the accelerator. The fuel is fresh, fuel pressure is 43, fuel rail was cleaned, all injectors replaced and fuel pressure leak down is very slow. The optispark, spark plugs and spark plug wires were replaced. The MAF sensor was replaced and the throttle position sensor tested good. The EGR valve and air pump have been removed and blanked off. Compression was tested, all cylinders tested good. Temperature checks on the header pipes at idle indicate all cylinders are firing and temperatures are all very close. Has anyone experienced this problem and found a solution? Thanks.
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Teching In
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+1 for a suspect Optispark. Never tried the AIP units, but corvetteforum guys have good things to say about Petris.
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Verdad Gallardo Teching In
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Got a link to the eBay guy? Wondering if he uses OEM style Mitsubishi sensors. I hear a lot of the issues with the cheap optisparks are the sensors, and some even have counterfeit Mitsubishi logos.
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From: Lansing, MI via Bowling Green, KY, Dalton GA, Nashville, TN & Atlanta, GA
I’m pretty sure he just refurbs OEM units and does not replace the optical sensor. It’s the first hit when I google eBay optispark rebuild.
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Teching In
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You were correct, the new opti was the problem. Took it apart and found a spot on the plastic cover below the rotor where spark was arcing through to the metal cover underneath. There was a burned spot the metal cover.
Really sucks that we cant find a decent opti for a decent price these days. Not the sole reason I'm going 24x but it is part of it. I'm mainly going for the tune aspect of the system and the fact that ill be able to finally use my HP Tuner on it is a bonus. I replaced mine around 4 years ago, it wasn't a cheap unit but it still wasn't a quality unit. Im starting to notice breakup around 5700+ RPMS. Once I get the TH system, im going to pull my cap and rotor off as im curious as to what she'll look like. Im sure there will be play in there as well.
