Ohk so I set my timing with the est connected, then when I plug it back in I watch with the timing light and the timing just bounces around, not too much a few degrees, then if I rev it up it advances like a degree, even if I rev it to like 4000. I have been told it was my ecu not properly controlling timing, and It feels like I have about 50 horsepower. Give or take 5hp

 

Need to set the base timing with the EST/BYPASS connector open. This will be at 6* BTDC. Then key-off, engine-off, reconnect the EST/BYPASS connector and restart engine. Note that the key-off has to be for at least 10 seconds.

Now the timing mark on the damper should have moved toward the passenger side of the car. This is more advanced then the base and is typically in the 20* - 22* area.

RBob.

 

Thanks, now everything is good, my car feels better and runs smooth but it's still kind of weak, you think it's just the 305? Lol

 

Hey Guys,

This is my first post but I have been hovering around for a while...

I have a very similar issue and I'm hoping someone can help.

I followed the instructions for setting the timing, i.e. disconnecting the brown wire with black stripe, set to 6-7 degrees with a timing light and all is well.

But when I hook the wire back up and check the timing with the light, the timing goes WAY OFF!! It has to be off like 40 degrees and causes the engine to backfire badly.

My question is, what does this wire hook up to and is it bad to run the engine with it disconnected?

Thanks for your help!!!

 

If you run it disconnected you'll have no timing advance, go and test your icm at your local parts store, they'll do it for free, it's the little module inside the dist. Mine ended up being bad along with other things. What year is your car? Was it sitting? Is it throwing any codes? Check your codes it's easy just use a paperclip and jump the first two terminals together on the empty connector by your right knee while your in the drivers seat, read the flashes.

 

That wire/connector is the EST/BYPASS. When open the spark advance is under control of the distributor, the ICM in particular. Otherwise the ECM is controlling the spark advance (except during cranking).

Important question, which way does the timing mark on the damper move once the EST/BYPASS is reconnected and the engine restarted? Toward passenger side or the drivers side?

RBob.

 

Thanks for the replies guys!

FWIW, I have an '85 WS6 305 TPI (fully loaded) with a new long block (1650 miles) 70,xxx original miles, new EGR, Fuel Pressure Valve, new Lucas 19lbs injectors, ditributor cap, rotor, ignition coil, plugs, wires, battery....

When I plug the EST wire in, the timing goes off towards the passenger side... it starts off buy inches away from the timing bracket and settles to around 12 degees... its undrivable because it backfires through the exhaust when the rpms are above 2100..

I am contiplating replacing the ICM but the distributor is brand new.?.?

I'm confused...

Thank you for your help!!!

Chris

 

The damper mark moving toward the passenger side is correct. Is the correct ECM and PROM being used? Because with the EST/BYPASS connected the timing is under ECM control.

It may be that the ICM is bad, if you have a spare try it and see.

RBob.

 

Well, as far as I know, I have stock ECM and PROM.. From what I'm reading, if the ECM is going bad, it could effect my timing.. Is there a way to test the ECM or the PROM?

Thank you so much for your help!

 

Update,

I put the old (3000 miles) stock Cap/rotor/coil on and reconnected the EST wire and it drives fine... I know I put the new MSD on correctly... 100% positive... so it must have been a defective cap!! How annoying!!

I've seen people with similar issues, so don't forget to check the Cap!

I'll drive it for a spell and give another update...

 

That's good news keep us posted .

 

if you bought the MSD street fire, throw it in the trash. as they come from china.land of junk

 

Update,

After further research, I have a good hypothesis as to what was causing the timing problem and exhaust backfiring...

My Bird just received a 3" CAT-Back Y Magnaflo and a Cold Air intake.. when adding the MSD 84023 cap/rotor with a new MSD HEI coil and 8.8mm Accell wires, it was to much for the stock PROM and ECM. It is unable to compensate the timing and air flow well enough and so ran like ****.

I will be ordering a chip from Summit today.. not sure which one though if someone has an opinion..

Thanks!

 

Update:

I have solved the issues.. the MSD cap had spring loaded "L" shaped screws that hold down the cap to the distributor. Because I have a stock distributor, the cap did not line up properly due to the tabs where the stock bolts are held, causing bad timing and backfiring. On top of that, the ICM was not advancing the timing properly.

The solution was to remove the spring loaded screws and use standard screws to hold down the cap. I installed a Hypertech chip, and replaced the ICM.

The car runs beautifully now.

Good luck everyone!