L-Jet idle woes. (please help)

[dave blackburn]

OK. My car used to run flawlessly. It would start perfect every time and idle all day @ 850 rpm.
I dropped the engine to paint the tin, check the heads and do a valve job.
Replaced the engine and it would not start. Found out I hooked up the pertronix ignitor backwards and fried it. Replaced the ignitor with a similar ignition module and the car started right up, but it won't idle right (dies @ anything less than 1200 rpm). Sometimes it seems like the car is only running on one bank of injectors if the idle gets low. If I rev it up the problem goes away. If the rpms get below 1100 rpm it will suddenly die.
So........
I checked the compression, all good @ 110 psi.
Checked leakage from cylinders, all good @ less than 5%.
Checked all FI components, head sensor, AAV, throttle switch etc. all good.
Checked injectors and the flow and pattern seems ok.
Removed the entire intake to check for vacuum leaks, pressure tested intake runners and there was no leakage from the injectors, heads or gaskets.
Checked intake plenum, no leaks.
Checked everything I can think of that would leak three or four times and its OK.
Ignition is great (msd, new coil, plugs/wires new).

Could I have fried somehing in the brian when I hooked the ignitor backwards?
It really seems to be idling lean. Any suggestions?
I have been dealing with this problem for a while and can't find the solution. I am 99% sure its not a vaccume leak (it seems like it though!!).
Any thoughts?

Thanks, Dave

[Dave at Pelican Parts]

How's the timing? That will change, potentially drastically, when you replace the trigger.

--DD

[kellzey]

Check your timing, your gap in the Petronix, and your plug wires for connection.

[dave blackburn]

Sorry, I forgot to mention the timing. I just got a new digital light and the timing is set as close as I can get it. Won't idle @ 850 rpm for an exact timing set.

I am sure the electronic ignition module is good. I will get a spark just from rotating the dizzy by hand.

Anything else I can check. I really need some different opinions.

Regards, Dave

[sean_V8_914]

vac leak?

[Tidybuoy]

I don't have an answer as I have the same problem.

I just thought I would say something to get this post back up to the top of the list. Hopefully, someone out there can help.

[Clay Perrine]

Check the boot between the AFM and the throttle body. If it is split it will allow air to bypass the AFM (technical term is "false air").

It will run fine in the upper RPM ranges, but the idle will be erratic due to a lean mixture.

[sean_V8_914]

what would make L jet run rich?

[Clay Perrine]

Misadjusted fuel pressure, or an AFM that someone has altered.