FIXED: Idle was HIGH, now too low, popping and missing VIDEO, Solution was CHT Options

[ctc911ctc]

I could not get the idle down below 1800, I took the advice from the excellent suggestions within 914world-garage and replaced EVERY gasket in the vacuum chain, including fixed a leaky plenum. """But mine looked so good - it can't be leaky! """ It was VERY leaky!

When I rebuilt the plenum (both sides of the support columns were leaky) and put it all back together, the resulting idle was way too low. I now have the reverse problem!

If I open up the ARR (remove hose) the idle is still low. If I take off the air cleaner and loosen the idle screw (all the way) still around 800-900. hhhhmmmmm.....

Throttle works, car will rev.
When driving the car it runs ok, however it does not have the power it used to have.

Engine is popping/missing, though the audio is not optimum, check out the video:

https://youtu.be/p5uM67DXJnk

Looking for next steps, what would you do next?????? (IMG:style_emoticons/default/WTF.gif) (IMG:style_emoticons/default/WTF.gif) (IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/confused24.gif)

Background; '74 2.0 all STOCK with 20K miles, I have rebuilt:

throttle sensor PCB
Throttle control - does not leak, very smooth control, set spec on the electrics.
MPS - tested and perfect
PCV - seems to work
Injectors - just back from Hurst injectors - all on spec
Distributor - clean and spiffy, advance works
plugs - new
AAR - tested and works
Computer Control Unit - I have 2, have swapped them and they both perform the same.
Flow Down - on spec
Dwell set
Timing set

Many thanks in advance

CTC911CTC

[ctc911ctc]

**************PROBLEM SOLVED************

Picked up this car in October 2018,

I have fixed 100+ problems, some are listed above. I believe it is NOW ready for the road, it has not been registered since 1984.

When I pulled the Plenum (chasing the too rich issue) I was able to remove the CHT. Could not get a wrench on it prior. I replaced it. As I wrote above; after I got the fixed plenum back into the car, the idle adjustment screw had no effect. This according to the all knowing Anders, is the result of a car running too lean. which also caused the popping....

So I went back to the old CHT (I had not tested it, just changed it because of it's age and it is on near everyone's list of things to replace) and I found that it was open - No Good. Ahhhh, so this could be why the car is now LEAN!!!!!



I then went to the MCU and turned the dial from the all left position (I used to be chasing too rich as the result of the CHT) to something in the middle and now the car is running at what seems to be the correct mixture. No More Popping.

Changing the CHT if there are any rich/lean issues seems like a good place to start!

Next getting an O2 sensor from Mark Henry to vernier the mix-dial/idle-screw!

THANK YOU ALL TEENERS FOR THE SUPPORT! (IMG:style_emoticons/default/beerchug.gif) (IMG:style_emoticons/default/piratenanner.gif) (IMG:style_emoticons/default/beerchug.gif)