Timing problem

[chuck41]

1989 Bronco 2, 2.9, auto 4w/drive, p/s, p/b, a/c
Just put in a Jasper rebuilt engine and RonD has been a big help getting
it running, I have no experience reading codes and not sure I`m reading
them right When I was checking
the timing with engine at hot idle and IAC connected the timing mark was
advanceing and retarding 5 or 6 degrees and the sound of the engine
changes in time with the timing mark, this happens to fast to see a change
in RPM. What would cause the timing to go up and down like that? If you
need more info. let me know. THANKS FOR THE HELP CHUCK41

 

[GentleRF]

There's a plug on the passenger side wiring harness called the Spout connector. When checking the ignition timing, you pull the plug with the engine off after you get it warmed up. Then you check the timing. According to the manual, it should be set to 10 degrees before top dead center (TDC). After doing this put the plug back in, making sure it is fully seated. Any timing wander after this is a result of the ECM (engine control module or EFI computer) changing the timing. That timing change is a result of the computer trying to find the best spot for idling. Realistically it shouldn't wander at all from a point lower than 10 degrees. You may have other issues than just the timing. My youngest son's Ranger had head gaskets going on it.

 

[chuck41]

GentleRF This engine is a Jasper rebuilt engine it came with cylinder heads and
rocker arms installed. I set the timing at 10 degrees with engine warm,
and the IAC disconnected. Connected IAC and let engine settle down to idle
at 800 RPM. can not see the idle change on the tach. but the timing mark goes
from about 14 to about 6 degrees, back and forth very fast and the change
in the sound of the engine is in time with the timing mark. Where is the engine
control module and how do I test it? What is the EFI computer? where is it?
and how do I test it? THANK YOU FOR THE REPLY CHUCK41

 

[truckerdawg]

When I would disconnect my battery to my slightly built 2.9 1990 BII 5 spd it would take it a day or two of running before the computer would settle in again and then perfect smoothness.

 

[chuck41]

truckerdawg Thank you, today I took the Bronco out on the road, it was
dead, no power at all. I brought back home and put the timing light on it again,
disconnect the IAC, timing is still at 10 degrees, reset the timing to 16 degrees
engine sounds better hooked up the IAC and went to get gas, 10 miles one way.
It runs much better and has good power. Will having the timing at 16 damage
anything?
I`ll keep the timing at 16 and drive it 3 or 4 days. Is there something that's not
working that makes it runs so bad with the timing set at 10 degrees? The owner
is 75 years old so I want everything right when he picks it up,
THANK YOU CHUCK41

 

[chuck41]

I Thank everyone that helped me by taking the time to answer what most of you
must have thought were dumb questions. I know it is out dated technology but it
is new to me, I retired in 1984 and have not around to see what was happing in
the auto industry. I finally got the timing right, has a smooth idle at 800 RPM and
runs good on the road, and that's as good as it gets.......
AGAIN THANK YOU.....CHUCK41