All,

I posted this solution in another related post - wanted to close this one out.

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

Picked up this car in October 2018,

I have fixed 100+ problems, some are listed below. 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!!!!!

Click to view attachment

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!











Hi,

'74 2.0 with 20K miles.

Issues:
- high throttle, cannot get it to 800/900 - 1400/1600 is where it stays
- When de-accelerating the throttle is slow to get back to around 1400

Symptoms
- Idle adjustment screw does not get the throttle to a lower speed
- ECU adjustment has no effect


So far I have:
- Injectors are rebuilt with new gaskets, seem to be installed tight and correctly
- Rebuilt THrottle body
- Cannot detect any Throttle body leaks around the shaft
- New Plenum to Throttle Body gasket
- Valve adjustment
- All new hoses
- MPS holds 15in for 30 seconds +, induction is proper
- dwell is 47deg

Next Steps

Double Check timing
Remove plenum and the 4 connecting tubes
Replace gaskets and connector fabric/rubber things that are between the tubes and Plenum.

I have read and near memorized the Anders post on Rennlist, looking for any advise as to my chosen path to get this nailed.


Many thanks in advance.

CTC911CTC

Ignition timing is a suspect. How freely does the advance move in your distributor?

Vacuum leaks are the other suspect. The posts through the plenum can cause cracks were they connect to the top and bottom of the plenum; those are hard to see. Other leaks can be inside the various bits, like the Decel Valve and the AAR. As well as leaks at hose connections or through old brittle cracked hoses. And let's not forget the PCV system...

--DD

I agree with the idea of a problem with the ignition timing - Of note, My idle was acting the same... until I fixed the advance in the distributor.

De-accl valve installed the wrong way.

Wow - did not think about that - would it now be an Accel-valve?

Will check the plumbing of that one!

I need this part but the web site only mentions 1.7 and 1.8, will this fit a 2.0?

https://900designs-container.zoeysite.com/i...nifold-gasket-1

On other sites it looks JUST like this one.......hhhmmmm

Funny, looking at these two diagrams I can see why people may get this wrong - Seems there are either 2 different types of De-accel valves or perhaps one of these diagrams is incorrect?

Click to view attachment

Help!

914 2.0L had 3 intake studs. 1.7/1.8 had 4. The gasket you referenced is incorrect for your 2.0L.

READY-FIRE-AIM

Of course this is a topic that has been covered in great detail.....never mind!

Thanks - will keep hunting for new gaskets.

Look closely at the stacked elbow.

Classic symptom of an aar that is stuck open . Pinch off the hose with a pair of needle nose. If the idle goes down, it's stuck!

******UPDATE******

I found that when the engine is cold that I am able to get 800-900 RPM when I pinch close the ARR hose. When the engine is warm the ARR closes and then the RPM is around 1200-1400. If I pinch the hose close then there NO change in RPM.

****THEORY********
THere is a small leak (vacuum) that opens up as the car gets warmer........thoughts?

Sounds like the the AAR is working correctly. Another item to check is the decel valve. The one on my 2L was adjusted too low so the it would never close when decelerating. You can test this by pinching off the hose going to the air cleaner.

I'm going through something similar but haven't put all the pieces back on my car yet to see if I've got the issue solved.

Some other thoughts:

Triple check hoses are connected correctly.
TPS adjusted correctly
Check your distributer to make sure the advance plate moves freely when vacuum is applied.
Make sure your MPS and ECU are a match for each other. There apparently are certain versions that don't play well together. Details here: https://members.rennlist.com/pbanders/djetparts.htm (guessing this isn't the issue because you have a low mileage car).

Check the plenum itself for leaks.

Good luck!

@ctc911ctc
No if you have three bolt 2.0 heads. Look at the pattern.

Did you replace your intake manifold gaskets. Oil fill tower gasket? I replaced those and my idle finally went down.

I have purchased everything that is in the vacuum chain.

Waiting on intake gaskets and the pipe hose things that connect the 4 pipes to the engine from the plenum.

My latest find is about 500 RPM leak in the PCV valve (which I will need to remove and rebuild - there is not one available anywhere!)

FYI there’s a guy on the samba that seems to know a lot about D-Jet, he suggests that removing the PVC valve and replacing it with a specific size orifice will smooth out idle issues. I don’t remember the size he determined.

Makes sense - that will be the fall-back plan - I will rebuild(try) this one first.

************UPDATE***********

I have rebuilt the plenum (both sides of the support columns were leaky) and as a result the idle was VERY low. I now have the reverse problem, If I open up the ARR the idle is still low. If I take off the aircleaner and loosen the idle screw (all the way) still around 800-900.

Throttle works, car will rev
When driving the car runs ok, however 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.

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

BUMPED: for all following this thread.

**************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!!!!!

Click to view attachment

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!