Vacuum on 260E 1988 Help needed
 

Can somebody tell me how much vacuum should be with engine at nominal temperature manual transmission and without Airconditionning:

° at intake manifold when engine is at idle on a 260E 1988.

° at Electronic Ignition module

Normal idle vacuum in neutral, A/C off should be about 16" @700. Never checked vacuum at the EZL vacuum signal line. If it's a "ported" vacuum advance (signal port above the throttle blade) there would be no vacuum at idle. Even if there is vacuum, I don't think the EZL adds any advance until the engine is above idle. Idle timing is fixed at 9 BTC.

What are your readings?

Duke

Hi duke2.6

just had time this week end to make measurements engine idling

At intake manifold vacuum is 400 mm ( 16 psi) measured on vaccum line at electronic ignition module (after throttle butterfly).

At regeneration valve line ( before throttle butterfky ) between 0 and 50mm (2psi), difficult to measure.

Is this OK?

I am looking for the method to adjust the butterfly stop (I believe a vaccum method could work) unless some body can help with a better one.

Your idle speed is governed by the idle speed controller out in front of the intake manifold. If you set the butterfly stops so that they close farther, the idle speed controller will just open more to compensate.

What problem are you trying to fix?

Ditto what norm said. Adjusting the idle stop will do nothing unless your idle speed controller or control system is malfunctioning.

If your manifold vacuum gage reads 400 mm Hg. that would be 15.7 inches Hg. not "psi". The other signal you are measuring is not actual manifold vacuum.

The signal you are measuring at the line to the EZL sounds like actual manifold vacuum, but it doesn't affect timing at idle, which is fixed at 9 BTC.

My engine has a nipple on that manifold with a rubber cap that I remove to attach my vacuum gage. Very convenient.

If you have some kind of operational problem, why don't you just list the symptoms and someone can probably help out.

Duke

What I am looking for is the adjustment method for the butterfly stop because I modified it and would like to set it back correctly.

I posted the question some times ago and no solution so far.

Any thing would be sufficient, even a picture from a well adjusted butterfly stop.