Hey guys I got a hold of a 93 z28 and it has a misfire somewhere and in struggling to figure it out. So I tired a method that I thought worked but I'm starting to wonder.... I pulled off the injector connectors while the engine was running to try to listen to the engine to find the mis. All injectors except for 3 and 7 made the engine tone change. So I thought it was those two but everything checks out with them. Injectors are clicking using a scope, compression is good. Brand new msd plugs and plug wires.

I'm starting to wonder if my method is not legit or if they injector wires are crossed or something.

Ideas?

 

Well I've had brand new wires get burned on #7,it's a tight fit.
I had a '93 for 7 years,hopefully it's not the Opti going south.
The ignition is the weak point on the LT1 motors.

 

Well it looks like the entire ignition system has been replaced with msd parts. There is an msd coil in the front of the engine and also another coil pack that all the plug wires go into. I'm wondering if the wires may be plugged into the wrong cylinders.

Does anyone know about these systems?

 

Well my suspicion was correct it seems... In that picture above you can see one plug wire is new and the others are old. I replaced just the plug and wires on cylinder I thought was missing then I took the pic. That was cylinder 3. Well I just found this video and I took a screenshot. Looks like they are swapped.

imma use this and verify each are connected correctly when I get a chance later today

 

Oh good luck,hope it's that simple.

 

Well I decided to change the plugs and wires too. The new wires are slightly larger than the old ones so I'm having trouble with the clips that hold rh wires back. The one behind the power steering pump that round the passanger side was broken. It broke on the pin that goes into the alternator support. So I need to find a replacement for that or maybe someway to secure the plug wires. They are so close to the power steering pump pulley I wanna make sure they don't move. So I'm stuck here for now.

 

maybe try zip tie. also that may just be a msd cap with old opti can't see base so can not tell in photo. fyi I have had best results using ngk iridium plugs.

 

Yea... I know some people might cringe at this but what I did is drill a small hole in the alternator support and attach it with a zip tie and then used a couple more to secure it. I also had to modify all the wire clips. I used a Dremel and just adjusted them to fit the larger diameter wires. Worked great. I attached a couple pics.

It's an msd opti and coil. And now msd wires and plugs. I also have a 6a but I honestly don't know how to use it lmao! The previous owner bought all this stuff. I have all the receipts.

Btw.... It's running like a champ now.

 

looks great to me