Timing problems 2.8 TBI
 

Hello and thanks for this forum.

Working on a friends 86 Blazer with a 2.8 that was diagnosed that the distributor was bad. Picked up a reman and pulled the old distributor, compression stroke TDC #1, lined the rotor up and double checked where everything should be and popped the cap and wires back on with the proper firing order and unplugged the wire behind the carpet.

Hooked up timing light and tried to start.

The engine will fire for a few seconds and die.

As an old school mechanic, I've always been able to drop in a distributor and be within a few degrees of desired timing before even hooking up a timing light.

I've been searching this forum for a couple of hours now but have been unable to find a detailed procedure to set the timing on this critter. I figure I am missing something simple here and in need of some wisdom to set me straight.

Any help would be greatly appreciated.

Thanks !

You are probably out 180 degrees...

To set base timing, you bring number 1 to the top on a compression stroke. I stick a finger in hole #1 and rotate the engine manually with my other hand from the crank pulley, then when your finger pops out under pressure, you know you are on compression. Now there is marks on the crank pulley, you want to line those up with 0 degrees on the timing marker, you should already be close. Now drop distributor in pointing to #1 and you should be set to run proper.

Thanks, but already pulled #1 plug and bumped the compression stroke and lined up the harmonic balancer on zero. Then set the rotor to #1 on the cap.

Going to re-do the procedure again shorty, I know I'm missing something and will post what I find out.

Firing order is backwards on the 2.8L to most normal chevys. Front of engine closest to radiator passanger side is #1 on the cap. Do you got this as #1?

Yep, and clockwise rotation of the rotor.

1-2-3-4-5-6

Well we went through everything and re-did a static timing procedure, and it finally came to life.

Ran VERY rough at first but smoothed out as it started warming up. Finally settled into an idle, re-checked timing @ 10*BTDC, but NOW when you touch the throttle it wants to die (ECM wire reconnected).

Not sure where to start looking now, after running for 15 minutes or so, the CEL came on, will be getting an OBD1 tonight to see what pops up.

Frustrating little bugger !

ETA; is there a proper way to reset the ECM ?

There is a link in my signature for how to check the codes. Although I bet you the code your going to get is going to be because of the rough idle and not for the actual problem.

When setting the timing did you unplug the connector under the dash in the pass foot well?

YES......and plugged it back in after the timing was set.

Thanks !

And noted !

wheres the brown wire cause theres like 10 goin into my comp on the passenger side

I have a 2.8 when I set timing I pull the plug under the dash set timing turn off, re plug the under the dash thing and reset your ECM by removing the fuses to it under the dash for a minute and replacing them.

I think it is tan it is under the glove compartment under the carpet at the top of it. it will be right there