Trying to set ignition timing on my 85 Iroc 5.0 TPI
From what I have read and the manual it says to get engine up to operating temp.
Disconnect the EST plug connector.
Then I set the timing to 6 BTDC
reconnect the EST plug connector and the timing is way to far BTDC. It is off the indicator on the harmonic balancer and pings really bad when given some RPM.
Am I missing something?
If I set it with the EST connector plugged in it bounces a little when looking at it with the timing light. If I set it at 6 BTDC with the EST plugged in when unplugged it is ATDC about 6-8 degrees.
any help would be great.

Pete

 

Sounds like your "mark" system is inaccurate, like everybody else's. Everything else is also just like everybody else's when they decide to mess with that. Altogether completely normal in every way.

Unless the factory's priorities for that "spec" are particularly important to you - emissions, compatibility with 1984 fuel, emissions, compatibility with altitude anywhere from Death Valley to Pike's Peak, emissions, compatibility with weather anywhere from the desert to central Alaska to the Gulf Coast to everywhere else, emissions, and ... EXCUSE ME, I forgot to mention the single most important factor that the factory was legally required to be concerned with - EMISSIONS - then it doesn't matter anyway. Set it to where it runs the best, lock it down, and leave it alone, since it NEVER changes by itself, ONLY by somebody messing with it. Best thing about that is, YOU get to decide what's "best" to YOU. That could be any combination of most power, crisp throttle response, lowest fuel consumption, cool temps on the highway, freedom from pinging, no hard starting, compatibility with 2025 fuel, and so on. YOU get to decide all that according to what YOU want and what's important to YOU, on roads YOU drive on, in the climate YOU live in, with the fuel YOU can buy TODAY, for YOURSELF. You don't have to be a slave to the factory's legally mandated concerns for, ABOVE ALL ELSE, emissions.

 

Thanks.
The reason I was trying to dial it in was because I set the distributor and I had it close. Was trying to fine tune it.
As soon as my Antique plate comes in I’ll get it on the road to see how it runs !

Pete

 

I have never understood why the EST connector needs to be disconnected when adjusting ignition timing (my setup is non-computer)...

 

Well mine doesn’t like the timing set with the EST disconnected.

Pete

 

When you have a Computer Command Control system that controls the feedback carburetor and a computer controlled distributor you have to disconnect the computer from being able to adjust the timing.

You can't set base timing with the computer always trying to adjust the timing.

You car most likely has a harmonic dampener which has slipped on its hub. They are bonded together with vulcanized rubber and it wears out over time. Also probably has a timing chain & gear set and distributor gear or shaft bushing that is wore slick the f*ck out.

 

When I dropped the distributor in, I barred the engine over until it was at TDC on #1 cylinder and aligned the V 0 degrees with the line on the balancer. Then dropped distributor in pointed at #1. So it’s close.
I will run it and see. Engine has 71,000 on it. So not too high miles.

 

I got it fixed. Looks like it was the ignition control module. I replaced it and retimed it and its good. With the EST hooked up it is just above the timing bracket on the balancer. Which sounds right from what I have found online. I just need my plates to get it out on the road and see.

 

Can't f*ck**g be more expres-f*ck**g-sive than that!

 

Glad you got it running good again.

 

In the real World I make sailors blush. George Carlin would be embarrassed.