Long story short- i've been battling vac issues far too long. I had the car working and driving a few months ago but I had to take it apart to fix some stuff. I've put it back together this week and it idles great with the spout out and I can lock in the timing at 10 degrees but with the spout in, it surges and dies. I took EXTRA EXTRA EXTRA care to set the lower manifold with a giant ton of sealer (around ends and coolant ports) so it is tight as a vault. A vac gauge (plugged into the canister line shown below) is showing low vac so somethings wrong. However- when I depress the brake pedal on idle, it seems to flatten out and surging goes away, but still very low vac, like 10lbs of pressure.
Troubleshooting steps done:
1) Compression test on all cylinders (newly rebuilt engine, all pass)
2) Reset throttle body - set arm 0.010" + 1 turn preload from body, set bypass to be 2 turns out from closed.
3) Pulled MAF and cleaned it with MAF cleaner
4) Cleaned ISC/IAC and verfied connections solid
5) Fuel pressure at 38-39psi, AFR 14.2-14.8 on wideband
6) Set timing at 13* at balancer, advanced dizzy to who knows and it idles but its still surging
7) Reset KAMs between steps above.
To Do:
Measure TPS voltage
This is my vac setup, am I doing something stupid here? Why would depressing the brake pedal stop the surging?
View attachment 158831
These are the mods:
Holley Systemax II intake
BBK 70mm TB
BBK cold air
stock MAF
stock injectors
AFR 165 heads
EGR delete
Anderson AF-N41 cam
Moates Quarterhorse tuner with Binary Editor - running base CABZA strategy with only EGR disabled and idle upped to 800rpm. I've driven the car near perfectly on this same tune before.
Troubleshooting steps done:
1) Compression test on all cylinders (newly rebuilt engine, all pass)
2) Reset throttle body - set arm 0.010" + 1 turn preload from body, set bypass to be 2 turns out from closed.
3) Pulled MAF and cleaned it with MAF cleaner
4) Cleaned ISC/IAC and verfied connections solid
5) Fuel pressure at 38-39psi, AFR 14.2-14.8 on wideband
6) Set timing at 13* at balancer, advanced dizzy to who knows and it idles but its still surging
7) Reset KAMs between steps above.
To Do:
Measure TPS voltage
This is my vac setup, am I doing something stupid here? Why would depressing the brake pedal stop the surging?
View attachment 158831
These are the mods:
Holley Systemax II intake
BBK 70mm TB
BBK cold air
stock MAF
stock injectors
AFR 165 heads
EGR delete
Anderson AF-N41 cam
Moates Quarterhorse tuner with Binary Editor - running base CABZA strategy with only EGR disabled and idle upped to 800rpm. I've driven the car near perfectly on this same tune before.