pgtr

Timing SEVERELY Retarded (40ATDC) in order to run?

1984 2.8L Auto F-Body E2SE Carb 180k mi, gets (got?) 25mpg, NO codes, smooth high vacuum, but timing @ 40ATDC:

As preventative maintenance I recently replaced the intake manifold gaskets and timing chain set as well as the balancer. I also replaced the EGR valve and installed a new set of plugs. The ignition wires are only a few years as is the cap and rotor.

Prior to all of this the car ran fine and got 25mpg. There was a little looseness to the old chain but not bad. There was some notable corrosion in the intake manifold water port gasket area so this was a well timed project in that regard at least. But unfortunately things are worse off overall.

Upon re-installing of everything I'm finding I can't get the timing mark ONTO the tab at all. In fact the mark is barely visible. I'd estimate it to be about 30 or 40 degrees ATDC (retarded). Let's say 40ATDC is what it is idling at. Timing mark is correct (has not shifted on balancer). This was true before and after the chain replacement.

When I try to slowly work the distributor rotation to where I even 'approach' TDC on the mark - the engine starts idling horribly and eventually will not run at all the closer to TDC I get.

Question: With the 4-wire EST connector disconnected - will the ECM go into a 'dumb' or default mode? Or can other subsystems still potentially affect things? Like the MAP Sensor? TPS? ECM Temperature Sensor? Mixture Control Solenoid? etc...?

project89

iTrader: (1)

the 4 wire connector on the dizzy is not the est wire its on the passenger side strut tower it pops out of the harness its a single wire

if u unhooke that 4 wire connector from the dizzy im not even sure the motor will run

make sure ur new balancer does not have 2 keyways or timming grooves cut into it

RBob

iTrader: (1)

I'd grab the old balancer and the new one and compare them side-by-side. See if the crank key-way and timing marks are in the same locations between the two. Make sure that the balancer crank key hasn't pushed out which would allow the damper to rotate.

There isn't much in the ECM that will affect the spark timing to the point this engine is being affected. With the 4-wire to the distributor disconnected the ECM has no control over the timing. It'll turn on the SES but not much else.

What you can also do is to use a pencil in #4 (center drivers side) and get it to TDC. Compression or exhaust, doesn't matter. With the piston at the top the timing mark should be lined up at zero (or close) on the timing tab.

That is a quick easy check of the timing marks. Just rotate the engine by hand while using the pencil to 'see' for having the piston at the top.

RBob.

Six_Shooter

iTrader: (2)

Without the 4 pin connector, the ECM will not fire the injectors, so the car won't run, it will still have spark, the module will still have output to the coil, without ECM control.

pgtr

Thanks.

Yeah I did compare the balancers and the new was identical (except for the darn pulley bolt threads - had to run back for bolts!). The outer ring had not slipped at all but as severely cracked as the rubber was - it was worth replacing anyway.

Checked initial timing using #4 as it was easier for me to verify the alignment of the crank/cam sprocket marks better when they were closer. #4 piston was at top and distributor rotor was pointed in direction of the #4 wire. So yeah - everything lines up nicely w/ the engine off...

My apologies for not being clear - this is a 1984 model, is carbureted and the emissions / tune-up label specifically states to disconnect the '4-wire' connector coming off the distributor which is identified as the EST by the FSM.

I'll review things tomorrow and if I run across any add'l info will share - thanks everyone.

pgtr

Just to follow-up (sort of)... I went out this afternoon and finished installing a few things after the recent timing chain swap. Fired it up and voila it was on 8 BTDC (factory is 10). So I set it at 10 and it seems fine. There is slight pinging at partial throttle (spark detonation) but other than that it seems fine. I'll probably back it off a few degrees and maybe run some SeaFoam thru. Bit annoying that I don't see what I did or didn't do that would cause such off readings...

Thanks everyone for the responses!

Time to move on to ball joints and steering linkage...

project89

iTrader: (1)

sound sliek u may have possibly had the timming light on the wrong plug wire
or u could have been picking up the signal to fire the light from the wire nexto the one u were clamped onto