New motor.....miss issues

[ringman]

Just got motor back together, short block was untouched except for roller 206 cam, gn1 heads, new converter, fmic. Car also had cpt62 ball bearing turbo, alcohol, 3.5 inch dp and external wastegate. Anyways, car had terrible miss, as if running on 3 cylinders. Found out I had bad ground, which fixed problem 50pct of the way.


Set TPS, and the other numbers on scanmaster seem right. Car stumbles badly and won't build boost for say...3 seconds. Then it slowly builds through the stumble, and at 7 psi of boost it hits a sweet spot and runs great. I only went up to 13 psi or so half throttling it. Any ideas, throwing a 100 person cruise Friday, so need this thing to run decent.

 

[PSID6]

Did you check for proper clearance on the crank sensor?,unplug cam sensor after starting to see if it runs any better.

 

[ringman]

Seemed to run about the same unplugged....I had bad clearance, then replaced crank sensor...and I "think" it's clear, was basically told if it's not hitting it's good?

 

[PSID6]

So did you put the ground back on the passenger side cylinder head?

 

[whitehot1]

How old is the coil and ignition module?

Have you done an ohm meter test on the coil towers?

Coil Tower Resistance
(measure front to back, on top)11K - 13K ohms
(for each of the 3 towers)

Auto parts stores like autozone can test the ignition module for you but you will have to separate it from the coil pack for them to do the test,it doesn't cost anything for the test.

 

[ringman]

I did add the ground to firewall, also checked ohms, got 13 on all. The part that confuses me most is how smooth it is under boost

 

[dank GN]

Cam sensors set properly?

 

[ringman]

Pretty confident it is

 

[1fastcobra]

Make sure the puck is sealing and is free in movement with actuator off !
Reset the cam sensor to spec

 

[dank GN]

I would double check . As I just had the same issue with my new motor last week .

http://www.vortexbuicks-etc.com/cam_sensor.htm