Help me AEU86, you're my only hope

[Nakilad]

(03-30-2021 04:50 AM)jondee86 Wrote:  Also I was looking at the way the AFR gauge behaves with the crankcase
breather blocked or venting to atmosphere.

Because of the much higher sensitivity of the narrow band sensor near
stoich, the gauge needle will always be much more active when he AFR is
near stoich. Conversely, when the mixture is very rich or very lean the
sensor is at the extreme end of its range and insensitive to small changes in
the mixture. In your case the needle moves further into the rich zone and
becomes steady which is in line with the mixture becoming richer when you
block the breather.

From what I read you should expect a narrow band gauge to have the
needle "twitching" as shown in your video with the crankcase breather NOT
blocked. That means that it is actually reacting to the minor changes in AFR
due to low V.E. and exhaust gas reversion that commonly occur at idle. My
wide band gauge always jumped around between 14:1 and 15:1 at idle.

That is what causes the unevenness you can hear in my video below. Bear
in mind this engine had cams so that exaggerated the rough idle.
https://i.imgur.com/JsnZvRJ.mp4

Cheers... jondee86

That exhaust note sounds pretty sweet there Jondee, nice!

I think I understand what you mean regarding the jumping of the needle, its just that it goes from 'rich' to nothing and then back again. See below for my next planned steps.

Idle bypass was completely closed, that is one of my points of the video, to show the bypass closed. You can also block the input to the idle up and it does not affect the idle speed when hot (it does when cold).

The tube above the throttle body is attached to the idle up solenoid. It opens when the lights are on, or the blower fan, and you can hear the change in idle speed.

Apologies for not updating this in the last week or so, its been Easter (and my birthday) and we had some snow this week so I haven't been really tempted to go to the carport in the last days!

Small update, I swapped out the battery for a known good one, and switched to RWD throttle body number 2. Result, idle was higher than before, and didn't really stall as easily when blocking the intake. Note, the idle up was swapped from RWD throttle body 1 to 2.

So, plan for tomorrow / sunday. I have taken RWD throttle body no. 1, blocked the port from the idle up (where the water goes through) where it reenters the input behind the throttle plate, as well as blocking the inlet port to the idle up. This should mean no airflow whatsoever through the idle up, which will make it a bitch to start when it is cold but at least should eliminate any possibility of air getting past the plate that way. The only air bypassing the throttle plate should be then through the idle speed screw. Then, its throw a battery in it from another car and drive it somewhere. I will do my best to get a recording of the gauges as I drive around, and add that to the playlist.