major problem
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Junior Member
Joined: Oct 2011
Posts: 13
Likes: 0
From: Dayton NJ
Car: 1988 iroc-z
Engine: 350
Transmission: t5
Axle/Gears: 355
major problem
hey im Dan i have an 88 iroc-z this past weekend i did a engine swap i went from tbi 305 to a tbi 350.. im having major issues... motor is in and running it will hold an idle but thats about as far as it goes... its got a cam intake full exahust. the problem i am having is that cyl. #5 and #7 are dead .. timing is right 4 degrees advanced.. firing order is correct... i checked numerous times... the motor was rebuilt and the heads were done.. im trying to narrow down possibilites but dont really know were to turn at this point... if anyone has any info regaurding this please feel free to let me know any info will help at this point 
Supreme Member
Joined: Jan 2003
Posts: 2,133
Likes: 4
From: Houston, Texas
Car: 88' IROCZ
Engine: 388 TPI Motown 350 Race block
Transmission: 700R4
Axle/Gears: 2.77
Re: major problem
Remove plug wires 5 & 7 completely.
Remove plug wires 6 & 8 completely and connect in place of 5 & 7.
Connect plug wire for 5 & 7 in place of 6 & 8 and start the engine if 5 & 7 are still not sparking then the problem is in the distributor system.
Have you changed the Distributor cap & rotor?
If 6 & 8 don't spark then the wires are faulty. Yes, even new they can be faulty.
FYI, Plug "Wire" is a misnomer there is no wire only a carbon core.
Web search snippet "... basic construction starts with a non conductive structural member (nylon or Kevlar™) over which carbon fibers are deposited. These carbon fibers are typically blended with latex or silicone to form a flexible coating. A layer of EPDM rubber is then deposited over the core as primary insulation. Next a nylon bonding weave is placed over the wire which is followed by a final coating of either EPDM or silicone rubber. When new, this wire performs as designed. Over time however, with heat and vibration the carbon fibers tend to loosen which degrades conduction and eventually requires replacement. For this reason some OEMs (original equipment manufacturers) recommend replacement every 3 years or 60,000 KM. Carbon core wire is quite economical for manufacturers to use while suppressing sufficient RFI. This wire typically has a resistance of 3,000 to 20,000 ohms /ft. depending on the manufacturer."
Bending, stretching, and twisting this type of conductor will cause internal damage which is not visually evident.
Remove plug wires 6 & 8 completely and connect in place of 5 & 7.
Connect plug wire for 5 & 7 in place of 6 & 8 and start the engine if 5 & 7 are still not sparking then the problem is in the distributor system.
Have you changed the Distributor cap & rotor?
If 6 & 8 don't spark then the wires are faulty. Yes, even new they can be faulty.
FYI, Plug "Wire" is a misnomer there is no wire only a carbon core.
Web search snippet "... basic construction starts with a non conductive structural member (nylon or Kevlar™) over which carbon fibers are deposited. These carbon fibers are typically blended with latex or silicone to form a flexible coating. A layer of EPDM rubber is then deposited over the core as primary insulation. Next a nylon bonding weave is placed over the wire which is followed by a final coating of either EPDM or silicone rubber. When new, this wire performs as designed. Over time however, with heat and vibration the carbon fibers tend to loosen which degrades conduction and eventually requires replacement. For this reason some OEMs (original equipment manufacturers) recommend replacement every 3 years or 60,000 KM. Carbon core wire is quite economical for manufacturers to use while suppressing sufficient RFI. This wire typically has a resistance of 3,000 to 20,000 ohms /ft. depending on the manufacturer."
Bending, stretching, and twisting this type of conductor will cause internal damage which is not visually evident.
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