View Full Version : Ignition timing not setting

sr vegas 240
08-20-2019, 11:38 PM
Trying to adjust timing on the old sr20 im doing this by the FSM stuck on the step where i unplug my TPS rev the engine to 3k 2-3 times (more like 25 times at this point) and rpms never drop to 800 or so it stay more at like 1800. I set the timing at 15* plug the TPS back in and timing drops to -5*. So i tried adjusting it with the TPS pluged in and as i turn the CAS the RPM's go up. My CAS was originally off but i redid it and its spot on now. Is it possible that my idle is adjusted wrong. I've read few other threads with same issue happening but no one ever resolved it or never posted back. Im thinking i need to unplug the TPS and adjust the IACV? Any one know of any other issues that it could be?

08-21-2019, 10:01 AM
RPM is airflow dependant. So you have an air leak to fix.
Fix the vacuum leak and use IACV to bring idle down if necessary (usually this is not required)
never use Throttle(blade/body) to adjust idle, unless absolutely necessary.

Once idle returns to below 800, try 650-750 ranges, the timing will steady with tps unplugged, If you have the correct type of timing light in the correct orientation.

With timing showing steady at the crank at normal "low" idle speeds,
Shoot for 15* btdc, and the CAS will be centered ALMOST (a little offset at the bolt holes).
Then, FLIP THE PICKUP on the spark plug wire or coil pack (turn the timing light's connector around 180* backwards)
And re-test the timing.

Many timing lights are not reversible, they read differently one way or the other (flipped pickup/clamp)
When you have the pickup correctly oriented the timing will put the CAS nearly centered.

Make sure it shows 15* btdc I forget which line that is but iirc they go, -5, 0, 5, 10, 15, 20
so you are looking for the 5th line I guess

If you plug in the tps and see timing bounce all over the place, that is good it should do that.

If it jumps around with the tps UNPLUGGED after a couple light revs, you have another issue, likely a timing light/pickup/clamp/coilpack related obfuscation and not the engine itself's fault, remember you are looking for a very steady consistent flashing of timing indicator, it should not be difficult to 'see', and when finished the CAS is set mostly centered (slight offset) when done properly.

sr vegas 240
08-28-2019, 10:23 AM
Wow so many thiny leaks which is mind blowing since most of my parts/gaskets are new or brand new. I got a small leak on radium fpr, newish greddy fv bov (from the piston) and my iacv is leaking from the idle adjust screw which is insane. I will delete the IACV all together so not worried about that. But I was able to set the timing to 15* the rpms did drop to about 750ish I will recheck once I have all the leaks sorted out.

sr vegas 240
09-04-2019, 08:28 AM
So radium's reply for their fpr leaking was oh we know just put some thread lock on it. Way to go

09-05-2019, 12:36 AM
Many fpr leak
brand new aeromotive out of the box leaks a little

pretty common. Little tiny leak is fine. As long as the plumbing basically holds 15psi for a good 20-30 seconds after removing the air pressure (pressure test)