96 5.7 ECSB - Still Misfiring - Which cap is best?

[8716valver]

Well its a little better after installing the delphi parts but i still have a multiple misfire happening. I'm convinced its the distributor so decided to buy a billet jobby off of ebay.

 

[big_mike]

Make sure you follow the replacement closely. From everything I have read you can't get the timing right on these OBDII Vortecs without getting it scanned but you can get it damn close. There is a thread about distributor replacement & details.

 

[8716valver]

Make sure you follow the replacement closely. From everything I have read you can't get the timing right on these OBDII Vortecs without getting it scanned but you can get it damn close. There is a thread about distributor replacement & details.

Thanks. When I did my intake mani gasket I had to get the dizzy re-timed at a garage. Only cost a little $ but it was the right thing to do. I'll probably do the same when I install the new dizzy.

 

[8716valver]

Installed the new dizzy and no change!

So that's it I've basically replaced the entire ignition system besides plugs and wires, which are relatively new. Meanwhile I've been noticing a good sized fuel tank leak developing so I've decided to replace the fuel tank, straps, pump (Delphi), strainer and inline filter. Finishing up the install tonight-ish. Hope to have zero drivability issues after that.

In the near future I MAY swap out my plug wires and redo all my grounds and battery connections for the hell of it.

 

[Blind]

Well its a little better after installing the delphi parts but i still have a multiple misfire happening. I'm convinced its the distributor so decided to buy a billet jobby off of ebay.

multiple misfire is typically a vacuum leak. Have you done a smoke test with it idling to look for a leak?

 

[8716valver]

multiple misfire is typically a vacuum leak. Have you done a smoke test with it idling to look for a leak?

I have not. What's the procedure?

 

[big_mike]

Installed the new dizzy and no change!

So that's it I've basically replaced the entire ignition system besides plugs and wires, which are relatively new. Meanwhile I've been noticing a good sized fuel tank leak developing so I've decided to replace the fuel tank, straps, pump (Delphi), strainer and inline filter. Finishing up the install tonight-ish. Hope to have zero drivability issues after that.

In the near future I MAY swap out my plug wires and redo all my grounds and battery connections for the hell of it.

If it doesn't fix the issue by replacing the fuel parts I'd definitely pull the plugs & wires next. I have seen plugs go bad extremely fast before just from bad manufacturing tolerances. Hell it could have already melted the tip off & just isn't getting clean spark for some reason. It's free to pull & check them anyway so that would be on my list. At least then you can say you checked everything out 100%.

 

[great white]

meter your wires....as a rule of thumb, should be in the range of about 5,000-10,000 ohms per foot.

Much higher than that and you're got a bad conductor or end connection.

Lots of times guys will pull on the boot wrong and stress the connection at the plug or cap (or pull the wire directly, bad,bad bad), flex them excessively when installing them (carbon core conductors on radio suppression wires don't like that at all) or not support them properly (oe wire supports) when the engine is running (flex, flex, flex - crack goes the carbon conductor).

They will still run with a bad connection, but spark will break down (ie: miss) as load comes up.

You can also check your cap to wire connection by removing the cap and metering from the cap terminal to the spark plug end. If you have good continuity at the cap/wire connection, it will not add resistance of any significance to your measurement.

 

[Blind]

I have not. What's the procedure?

there's many ways.

https://www.google.com/search?q=smo...7j5j0.1473j0&sourceid=chrome&ie=UTF-8&qscrl=1

 

[CrustyJunker]

Listen to everyone else...I have to chime in on this one...USE ONLY CAPS AND COILS FROM GM

I bought a Jeg's distributor cap with bronze terminals once. Looked like okay quality, at first. After a couple months, it started crossfiring so bad that it tore up a bunch of stuff just cranking on it. It busted the nose off of a starter and broke several teeth off the flexplate while cranking on it. Changing a flexplate is not a fun job. Nor is it fun when the wheel of fortune lands on a couple broken teeth, and you just hear your starter freewheel. I had to carry around a long 3/8" ratchet with an extension and a deep well 5/8", grab the crank bolt and crank the engine forward a little so it would have some teeth to grab. Not fun in the winter or in a bad neighborhood either...Which been at both at the same time, multiple times.

Oh yeah...
AutoZone coil - shorted out (blew a good mini-fireball out the exhaust at a steady cruise of 40 MPH of course with a proceeding well-lit gauge cluster coast. -1.5 years old.
MSD coil - opened up (seemed to be a vibration failure) -2 years old.