p { margin-bottom: 0.1in; line-height: 120%; } May 25, 2015


Current Theory and My Impressions on my 1988 ford E250 van's status:
I didn't realize that the ECU/ECM was so integrated into the van systems so well! I replaced the serpentine belt tensioner... It's a bit difficult managing all the hoses, applying tension and re-installing the fan belt! But after several tries... I got it done.


Now several observations, I heard a different noise, maybe from the air pump or that area. After a few minutes running it became quieter and a bit later the engine stalled. I restarted, allowing a few seconds of ignition time on to let the fuel pump achieve pressure, I do that every time. It started and ran so slowly for the first time since my purchase it about 13 months ago. WOW, I'm so pleased!


I got a feeling that there was a lot of slippage causing a fast idle issue as compensation. The ECU/ECM really is integrated to the accessory drive system too, I'm thinking power steering pump and maybe Air pump as well. I salute the FORD engineers!
Most of my fast idle issues came from a leaking vacuum modulator (green) on the transmission a C6.
I replace that and measure the rod length to maybe help someone else. It was 1.43 inches long, well rounded on both ends.


Regards, Billdarr of Tucson.

 

You are more correct than you realize.
If the charging system is not putting out enough to keep the vehicle running, the ECM will raise the RPM to compensate and attempt to raise the output.
Nice when the puzzle pieces come together isn't it ??