Lt1 misfire

**Aaron G** · 10-27-2015, 11:41 AM

I have a 94 Buick Roadmaster Lt1 that has developed a misfire/dead cylinder. I drove my wagon to get pizza ran fine, came out had what felt like a dead cylinder. I made it home the driver side bank was making a huffing sound at the exhaust tip. I have so far checked the compression 150 psi each cylinder and checked spark at plugs with a spark checker I have spark at plugs. I have discovered recently that moisture causes car not to fire at all motor spins over but no spark. I have not replaced anything yet all parts appear stock car has 220,00 miles. Thanks in advance for any help you guys can give.

**Injuneer** · 10-27-2015, 07:53 PM

You might want to repost this in the "LTx Engine Tech" forum, or ask a Moderator to move it there. This forum is for site problems, not car problems.
@popo8

***popo8*** · 10-28-2015, 04:42 AM

Moved. Thanku @Injuneer

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**Injuneer** · 10-28-2015, 10:04 AM

How old are the plugs and wires? Moisture can affect the wires, the coil and the Opti. Check for arcing wires in the dark, inspect the ends of the wires where they plug into the distributor and the distributor sockets for corrosion. Check the short Opti harness on both ends for corroded connectors, damaged pins, or missing lock clips. Check the plugs for fouling and excessive gap. If the Opti has 220K miles on it, it's probably on borrowed time.

Scan the PCM for codes. Check the fuel pressure.

**Aaron G** · 10-29-2015, 11:45 AM

Sorry to admin for posting in wrong spot noob mistake. Thanks Injuneer for information. The opti and wires are by no means new, haven't seen arcs in the dark from wire to ground. I also haven't touched the fuel system, gonna check that asap. If I was to replace wires and the opti unit what are some good replacement units, seen some mixed reviews on the msd/accel units not to mention ebay stuff. Thanks again for information given.

**Dan** · 10-29-2015, 01:12 PM

The only opti I would put on my car is an AC Delco. No eBay or auto parts opti. Spend the money the first time.

**SSlowBoat** · 10-29-2015, 01:47 PM

Stay away from msd/accell I have had both and they are absolute garbage. Spend the money on a delco with warranty

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**Ardent_Z28** · 11-03-2015, 12:58 AM

Originally Posted by SSlowBoat

Stay away from msd/accell I have had both and they are absolute garbage. Spend the money on a delco with warranty

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That means the vented MSD on my red Z28 is an exception to the rule? The previous owner rebuilt the engine in the dining room of his townhouse with the help of his buddy, a GM certified mechanic. I've had no spark trouble in the 4k to 5k miles I've put on it on both the street & 6 passes @ the track. All I've done is offset the coil from the head to prevent heat soak like so many members have advised should be done. Hhhmmm...I'm gonna put a few more passes on it in a couple of weeks too.

***popo8*** · 11-03-2015, 02:34 AM

Originally Posted by SSlowBoat

Stay away from msd/accell I have had both and they are absolute garbage. Spend the money on a delco with warranty

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Agreed with BOTH. 1st hand experience with many opti makes as well.

Originally Posted by Dan

The only opti I would put on my car is an AC Delco. No eBay or auto parts opti. Spend the money the first time.

LTXtech.com IS my drug...
OWNER/ADMIN

**SSlowBoat** · 11-03-2015, 06:52 AM

Originally Posted by Ardent_Z28

That means the vented MSD on my red Z28 is an exception to the rule? The previous owner rebuilt the engine in the dining room of his townhouse with the help of his buddy, a GM certified mechanic. I've had no spark trouble in the 4k to 5k miles I've put on it on both the street & 6 passes @ the track. All I've done is offset the coil from the head to prevent heat soak like so many members have advised should be done. Hhhmmm...I'm gonna put a few more passes on it in a couple of weeks too.

You are a lucky one. Older msd optis were semi ok, I had one for about 50k miles. When I removed it, the rotor had been eating into the separator plate, and their was play in the bearing. Figured ok, I can pay $100 and have msd redo the bearing, and they'll put a new cap and rotor on, awesome! Got it back, car wouldn't run. Sent it back again, recieved it back, car wouldn't run. Did it a THIRD time, car wouldn't run. Meanwhile got an opti full of coolant off a stock 180k mile motor, dried it out. Did home made vented conversion, put it on, and made dyno day. Car ran better than it EVER did. Once they went broke and got bought by some China company, they went to shit. Even their cap and rotor kits fit like crap too.

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