gokussx4

iTrader: (3)

I recently upgraded to a GM Gen III hot cam, edelbrock DR headers, and double roller Timing chain. During the process i reringed the pistons as they were burning oil. Hone and rering seem to be fine since I am not losing oil anymore like I used to.
Also removed the EGR system because of the new headers (and who likes recycled gas anyway ).

Misfires are anywhere from 20-50 across all cylinders in the lower rpm's within a 20 second period. The misfires become much less in higher RPM's. I do understand the higher rpm misfires could be less because of the previous fire lights the second combustion.

I have a new alternator now as well. I had a bad alt because it wasn't getting the power over 13. Now its at 14.5 (roughly) when at idle.

The idle is really nasty random surging and can't idle at less than 800 rpm's. I figure the reason is due to the misfires and could explain why my hot cam install is completely different than everyone else's results.

What suggestions would anyone have? Thanks!

2000 Camaro z28 LS1

GM GEN III HOT CAM
3.73 rear gears
Edelbrock Victor Drag Race Headers
Dynomax bullet mufflers (direct connect to header collectors)
Double Roller Timing Chain
Disabled EGR

brad8266

iTrader: (23)

Hairline cracks in a spark plug, slight manifold leak, bad plug wires. A faily small vacuum leak can cause low end and idle misfiring but will dissapear once the rpm's get up a bit.

bczee

iTrader: (12)

Check for vacumn leaks, bad or broken wires, other related shorts in there system, .. and did you get your PCM reTuned for the new CAM ?

gokussx4

iTrader: (3)

I have brand new msd wires and brand new plugs, all installed after the headers. Checked the plugs and used known good working plugs as test and still same thing.

What would be the best way to test for vaccum leaks?

brad8266

iTrader: (23)

Listen for the hissing sound of air entering the manifold area and fell around for a leak with your hand.

gokussx4

iTrader: (3)

I have been trying to tune it myself but i think the misfires are causing too much trouble to finish the job.

Supposedly the GM GEN III hot cam doesn't need any tuning??? That's the word on the street.

gokussx4

iTrader: (3)

I have heard to spray brake cleaner around the engine top to see if it revs up suddenly, what do you think?

brad8266

iTrader: (23)

Yeah if fluid hit the leak and gets sucked in you will know it by the rpms.

gokussx4

iTrader: (3)

Sweet. I will try that out tonight. I guess vacuum would make sense since misfires are on all cylinders at lower rpms because the system is expecting much less air then a WOT situation.

bczee

iTrader: (12)

Yes.. use carb cleaner spray.. start by hitting vacumn lines connections one at a time with a little bit of spray.. then try the edges of the intake/heads. And any other area.

Did you take off the Intake ?.. maybe check for a gasket out of place or a crack in the manifold ?

785T/A

iTrader: (5)

Make sure your egr codes are deleted along with you rear O2 sensors if you have them.

Irocss85

iTrader: (1)

when your using brake cleaner or carb cleaner to check for vac. leaks, be very careful. if you DO have any ign. wires arcing or anything, it will IGNITE the cleaner very fast, and burn a long time. and the rpm will more then likely drop. know anyone with a tech2? that will show you current misfire's and that would tell you what cyl. is misfiring. check for vac. leaks around the inj.s too.