CIS troubles - two problems, related?

[mikesarge]

Originally Posted by AndrewCologne

As of your signature :-) I guess you dont need the deacc. valve and the cruise control, right?
If not already done just unplug the hose leading to the T-Part from the port of the throttle body and use a new hose leading to the WUR.
Cause by this as a needed side effect the vac. connection to the deacc. valve is removed an when deaccelerating from high revs the deacc. valve wont open and so the vac wont fall that low that the WUR will enrichen the mixture :-)

This is also very important for you mikesarge if your engine comes with a deacc. valve

I want to make sure I understand:

I have a deaccel valve- should I take the hose off of that, and decomission that valve when I install the new WUR? or are you saying that the deaccel valve is a necessary component to keep with the vac-controlled WUR?

Thanks!
mike

[Paulporsche]

mike,

Andrew's diagram shows a 1980-83 setup with lambda. Notice no lower chamber on the WUR because the lambda control performs that function.

Compare it with the link I posted for you. You will see the vac connections for a 045 and similar WUR, which need that lower chamber vacuum.

You can use the decel valve or not. It is up to you. Its fn was to keep revs up slightly between shifts and when slowing. Some drivers like it, many don't.

[mikesarge]

Originally Posted by Paulporsche

mike,

Andrew's diagram shows a 1980-83 setup with lambda. Notice no lower chamber on the WUR because the lambda control performs that function.

Compare it with the link I posted for you. You will see the vac connections for a 045 and similar WUR, which need that lower chamber vacuum.

You can use the decel valve or not. It is up to you. Its fn was to keep revs up slightly between shifts and when slowing. Some drivers like it, many don't.

Got it, I think I understand that- I'm going to tap in to the cruise control line with a T, as it's the closest place to the WUR with manifold vacuum. that I know of.

What I'm wondering about is specific to Andrew's comment regarding the Decel valve- I'm not sure if he's saying I need to decomission my decel valve, or if he was saying the decel valve needs to be preserved. it was unclear because of what I'm assuming is a translation issue.

[boyt911sc]

Originally Posted by mikesarge

Got it, I think I understand that- I'm going to tap in to the cruise control line with a T, as it's the closest place to the WUR with manifold vacuum. that I know of.

What I'm wondering about is specific to Andrew's comment regarding the Decel valve- I'm not sure if he's saying I need to decomission my decel valve, or if he was saying the decel valve needs to be preserved. it was unclear because of what I'm assuming is a translation issue.

Mike,

This is your car and nobody could stop you from deciding which direction to go. People eliminate the decel valve primarily due to lack of understanding. Same with the thermotime valve. A good decel valve will not cause the WUR to malfunction as claimed by someone.

Unfortunately, I re-read Andrew’s comment several times and could not understand what he was trying to say about the WUR’s unwanted enrichment. If you eliminate the thermotime valve, you will have a higher cold control pressure at START. Good luck.

Tony

[SkiVT]

A video of the TTV at work during cold start. See the pressure jump when it opens toward the end of the video. Allows a richer AFR at start as stated by others.

https://youtube.com/shorts/x3HXhqlwFMM?feature=share

[mikesarge]

Originally Posted by boyt911sc

Mike,

This is your car and nobody could stop you from deciding which direction to go. People eliminate the decel valve primarily due to lack of understanding. Same with the thermotime valve. A good decel valve will not cause the WUR to malfunction as claimed by someone.

Unfortunately, I re-read Andrew’s comment several times and could not understand what he was trying to say about the WUR’s unwanted enrichment. If you eliminate the thermotime valve, you will have a higher cold control pressure at START. Good luck.

Tony

Got it.

If I come across a TTV for not a ton of money, I’ll be right on it. I know the injection system isn’t going to be *perfect* on this car, but I’d like to make it as close to right as possible.

Thanks again

[AndrewCologne]

@ Paul
His Engine came with a removed ECU system and just changed to a non frequency vaklve driven Fuel Dizzy, means before 1980.

@Mike
Unplug the vacuum hose at the back of the throttle body, the hose which leads to the T-connector.
By this the vacuum for the cruise control and the deaccel. valve will be disconnect, but no problem if no cruise control is needed.

To that port (green hose in the pic above) you connect the vacuum hose to the WUR.
This port provides the permanent "throttle angle position independant" available manifold vacuum.
All other vacuum ports provide ported vacuums, means at idle only (dizzy retard vacuum) or just at cruising (dizzy advance vacuum) etc.

But this is only senseful in your specific case with removed Lambda-ECU where actually a vacuum driven WUR is needed for mixture enrichment while accelerating.

With a lambda CIS in a OEM factory state all parts work perfectly and NO power loss will be given if all parts have been set up/adjusted as they should.

There's a myth about the retard vacuum hose at the dizzy where many people do recommend to just unplug that one which is ... nonsense. Because: Beside less HC emissions for making passing the emission control/test it also makes the combustion at idle resulting hotter which on the other hand makes the OX-Sensor much hotter and by this making teh sensor working/reacting optimal at idle!
When hitting the throttle and leaving idle state the retard vacuum -->"directly"<-- will be superseded by the advance vacuum which makes driving/crusing at low load more efficient due to more ignition advance and therefore more torque. Means ... keeping the retard vacuum hose being connected at the dizzy will not result in any power loss.

Regarding the deaccel. valve.: If you use the retard vacuum at the dizzy but let the deaccel. valve vacuum hose disconnected then when deaccelerating from higher revs you will suffer from hughe pops and bubblering at the exhaust. Because when closing the throttle at high revs the combustion directly will lean out due to a huge vacuum rise in the manifold system, now in addition with a retarded ignition (as the throttle at idle now provides the retard vacuum to the dizzy) the party in the exhaust system with arbitary self ignited remaining fuel begins – !BANG!.
If you let the vacuum hose connected at the deacc. valve, then at a sudden throttle closing at high rpms this prevents a hughe vacuum rise in the manifold system as it bypasses metered air to the system (air sensor plate, throttle biody, manifold), which by this aviods .... pops and bubble sounds at the exhaust.

Cheers

[AndrewCologne]

Originally Posted by boyt911sc

Unfortunately, I re-read Andrew’s comment several times and could not understand what he was trying to say about the WUR’s unwanted enrichment.
Tony

What didn't you understand specifically? As Im not a native english speaker :-)


- On a lambda based CIS engine, as you know the orig WUR doesnt come with a vacuum driven control pressure, means enrichment at acceleration.
- If the ECU gets amputated from a lambda based CIS gengine then beside other problems like cold start, there will be no enrichment at acceleration/WOT anymore with beside power loss the risk of overheating
- So ... you need an older no frequency valve driven Fuel Distributor (mike in this case has one)
- and ... a WUR which comes with a vacuum connection for control pressure based enrichment at acceleration/WOT
- This vacuum provided to the WUR needs to be a permanent present, throttle angle independand manifold vacuum, not a ported vacuum like for the dizzy
- This needed manifold vacuum at originally lambda based engines is present at the lower vacuum port at the back of the throttle body (green hose in the pics), not at the front or the upper back vaccuum port.
- This means from this port you disconnect the hose which leads to the T-connector (crusie control and deacc. valve) and instead of that you connect the hose which leads to the WURs vacuum port (not the vent port!)
- So ... by this the cruise control and the deacc. valve won't get any manifold vaccuum anymore. And in mikes case this would mean he also must unplug the vacuum to the dizzys retard port ... to avoid popping sounds when deaccelerating. (As dizzy with retard vacuum connetced always must be used in combination with a working vacuum driven deaccel. valve – see explanation further above).

I hope I could clearfiy, if not just ask.

Originally Posted by boyt911sc

A good decel valve will not cause the WUR to malfunction as claimed by someone.

If all parts are origianl in factory state – yes.

But in case of mike as he uses an older WUR this one needs manifold vacuum.
An older engine model WUR in combination with a newer (lambda based) engine model deaccel. valve is a tricky solution as ... when deaccelerating the deaccel. valve opens, therefore the manfold vacuum drops and the risk is ... that then the vacum results that low in the manifold that the WUR -thinks- "oh, Mikes accelerating" and ... drops the control pressure and by this ... enrichens the mixture .... but here actually when deaccelerating. Uops.
This is theory ... and practically depends on actually how much the deacc. valve lowers the manifold vacuumto a point which lets the WUR enrichen.

[mikesarge]

My plan is to *not* disconnect deaccel valve, cruise control, dizzy, or anything else. I’m just going to add a T in the cruise vac line and run it to the port on the WUR.

I am trying to figure out if this is the optimal setup, or if some other combination of CIS gadgets should be added or removed.

I understand the TTV will optimize ~30 seconds on the first start, on the coldest days only, so because I do not already have one, and they look to cost over $100 used, I am willing to compromise there and go without.

If I will further do better by removing some other component, I am trying to figure that out.

[boyt911sc]

Andrew,

There is nothing wrong with your English. English is my second language too. I was referring to the bold and highlighted section in post #21.

Tony

[AndrewCologne]

Originally Posted by boyt911sc

Andrew,

There is nothing wrong with your English. English is my second language too. I was referring to the bold and highlighted section in post #21.

Tony

ah ok .... this was explained in my answer above ...

Originally Posted by AndrewCologne

But in case of mike as he uses an older WUR this one needs manifold vacuum.
An older engine model WUR in combination with a newer (lambda based) engine model deaccel. valve is a tricky solution as ... when deaccelerating the deaccel. valve opens, therefore the manfold vacuum drops and the risk is ... that then the vacum results that low in the manifold that the WUR -thinks- "oh, Mikes accelerating" and ... drops the control pressure and by this ... enrichens the mixture .... but here actually when deaccelerating.

[boyt911sc]

Originally Posted by AndrewCologne

If all parts are origianl in factory state – yes.

But in case of mike as he uses an older WUR this one needs manifold vacuum.
An older engine model WUR in combination with a newer (lambda based) engine model deaccel. valve is a tricky solution as ... when deaccelerating the deaccel. valve opens, therefore the manfold vacuum drops and the risk is ... that then the vacum results that low in the manifold that the WUR -thinks- "oh, Mikes accelerating" and ... drops the control pressure and by this ... enrichens the mixture .... but here actually when deaccelerating. Uops.
This is theory ... and practically depends on actually how much the deacc. valve lowers the manifold vacuum to a point which lets the WUR enrichen.

Andrew,

You are very knowledgeable and very impressed with your CIS information. Unfortunately, your understanding with the deceleration valve/s is flawed. If the deceleration valve is defective (out-of-spec or leaking), it should not be used. So we are discussing a DV in good working condition.

The opening and closing of the DV will not affect the operation of the WUR unless you have a defective DV. I agree with your theory if you have a defective or out of spec deceleration valve.

The key to this discussion is how to identify a good or bad a decel valve. I spent a great deal of time learning, testing, evaluating, and understanding between a good working unit from a defective one using multiple samples.



Tony

[AndrewCologne]

As we know both engines models, means pre 1980 and from 1980 leave the factory with deacc. valves. The one with the valve behin the throttle body and the newer models with the deacc. valve on the rear right of the negine
But ... here it depends at what vacuum state the deaccel. valve from 1980-83 opens and how much the vacuum loss in the manifold will be. As a significant manfold vacuum loss does affect the WUR enrichment, thats how it works.
As told its theory but at least mikesarge should check the AFR when deacceleating as Im only refering to/talking here about an engine model which has been modified in a significant way with parts out of specs as it is the particular case here :-) I do not refer to engine models where all parts are in spec. and no part mixing was done.


BTW a nice test would be ... on a vacuum driven WUR engine put a manometer between the WUR and its vacuum hose. And then when from idle rising to 5.000 rpm and then suddenly closing the throttle this should open the deaccel. valve for a short moment cause of the huge rise of vacuum in the manifold. And at this moment watch the manometer at the WUR.

[mikesarge]

Originally Posted by AndrewCologne

Im only refering to/talking here about an engine model which has been modified in a significant way with parts out of specs as it is the particular case here :-) I do not refer to engine models where all parts are in spec. and no part mixing was done.

Yeah, this does complicate things! I’ll run a bunch of tests when I get back up and running, hopefully soon (though pelican says they may not ship my accumulator for like 2 weeks?)

And hopefully with a co-pilot and AFR/wideband I can triangulate the ideal setup for running this thing. Just the vac-assisted WUR should make a huge difference though I suspect!

[mikesarge]

Bought a new (used) 045 WUR, fuel filter, and accumulator

new test results here seem to point to a rectified residual fuel pressure, and a dead WUR fairly conclusively:

1. Year of engine: 1980
2. US or RoW (Rest of World): US, but 3.1 9.5:1 w/964 cams, supertech kit and backdated FD, no FV/Lambda (FD no. 010)
3. WUR model number: 045
4. Ambient temperature at time of test (in degrees C): ~11
5. WUR Resistance (in Ohms): 27
6. System Pressure (in bars): 4.7
7. Cold Control Pressure (in bars): 4.7
8. Warm Control Pressure (in bars): 4.7
9. Time delta for Cold -> Warm Control Pressure (in minutes & seconds): never moved @ 5 mins
10. Residual Pressure @ 5 min (in bars): 1.9
11. Residual Pressure @ 15 min (in bars): 1.6
12. Residual Pressure @ 30 min (in bars): 1.4
13. Residual Pressure @ 60 min (in bars): .3

So, given that, what's the move? how does one rebuild a WUR? I'm happy to support a forum member like boyt911SC, i'm also a fairly intrepid wrench, so I could face this down myself as long as it doesn't require any tools too far out of the ordinary.

thanks all for your help on this one!

[AndrewCologne]

Originally Posted by mikesarge

6. System Pressure (in bars): 4.7
7. Cold Control Pressure (in bars): 4.7
8. Warm Control Pressure (in bars): 4.7

Sems the valve area/plate of the WUR is flawed.
You can try and buy a repair KIT and do the rebuild on your own, or ask someone like ... Tony:-)

[mikesarge]

Alright, we are back in business. Consider this one “solved” with two fixes:
1) the new accumulator, as noted above; and,

2) a newly refurbished WUR from boyt911sc

Just installed the WUR this afternoon, and while I’m still figuring out the final mixture setting, it runs better than it ever has as long as I’ve owned it. I always wondered why the throttle pedal did not change the AFR as much as I thought it should on decel, and having a WUR with a vac. port designed for this system took care of that.

The car is much more well behaved off idle and in low-load low-rpm situations.

It’s also a great deal quicker on the top end.

Not scientific by any means, but here’s the afr breakdown:
Idle: 11.8 or so
Low-load acceleration: 14-16
Decel: 16-17
WOT: 15 at the stab, then down to 14 pretty quick, then 12 or so by redline.

Anyone have any thoughts on where I might do well to set my mixture from here? Don’t want to burn a valve, but it seems a little rich at idle and at redline. Likewise it seems a bit lean on decel, so I think I might be in the sweet spot.

Thanks to everyone who helped me with this so far!
Mike

[Walt Fricke]

Assuming your cold control pressures are within spec, you might consider using your AFR meter to set the AFR at idle with the adjustment screw, then adjust the idle speed with the big idle air bypass screw, iterating as needed. Then see what your on the road AFRs are.

You can always go back (easy adjustments) if you don't like what you see.

Maybe the lag from lean to rich (mid-12s to low 13s seem to be what racers aim for, since WOT is the only thing they tune much for) is why Bosch/Porsche introduced an acceleration enrichment loop as part of its FV/processor?

[mikesarge]

This was pretty much my strategy, idle is pretty much perfect at 950 rpm so now I’m just trying to figure out the best spot for me to set the mix given my FD (010) and engine (3.1, 9.5:1, 964 cams)

I think I’ll keep leaning it out a bit at a time until WOT approaches 13 at red line, as long as part-throttle behavior stays good. I’ll report back with results as I get them .

[AndrewCologne]

Originally Posted by mikesarge

Not scientific by any means, but here’s the afr breakdown:
Idle: 11.8 or so
Low-load acceleration: 14-16
Decel: 16-17
WOT: 15 at the stab, then down to 14 pretty quick, then 12 or so by redline.

Seems your sensor plate setting needs to be checked and maybe needs a re adjust.