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3.0 sc engine without Frequency valve

is it possible to run 3.0 SC engine without frequency valve ? my problem is that i have an engine without the lambda box.

the engine runs perfect when i tried to power the frequency valve with 12V directly, i have tried to change with a new fuel line without the FV and the engine runs rough and wont take throttle, so when reading topics in here, i can understand that there is a difference between engine (CIS) with or without Lambda box.

So if i want the engine to run, there are 2 options:

1. buy the Lambda box and connect the FV so that can control the pulse freq ?
2. buy a used CIS from an older without FV ?

BTW. the FV burned of after i have driven for 1/2 hour with 12V directly connected ( lesson learned)

Michael
Old 07-14-2017, 01:59 AM
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check fuse 18

the FV gets a pulsed signal to it opening and closing it at different rates to change the mixture,.
with 12v on it all the time you held it open. that made it richer. the engine may be able to tolerate richer due to air leaks and perhaps the mixture was set lean to begin with.

with no power the FV is closed making it very lean.

the FV is pretty expensive.
an older FD would require another WUR because the older FD used vacuum control to the WUR to richen the mixture up.
buying a used FD is risky, you don't know what you are getting.

larry at flowcontrol can rebuild the FD and modify it to run without the FV. I know he does this with the 930 fd but not sure about the 911 FD. I would also get the WUR modified so you can adjust the CP to tune the engine better. price would be about the same as going the other route except you would have a rebuilt FD.
negative is larry is very backed up from what I hear and it could take a few months to get it done.

what all is missing from under the seat and how did it run with this stuff missing?
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Old 07-14-2017, 04:09 AM
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Fuel distributor........

Michael,

Could you check what is the Bosch ID number on your FD? Is it a -31 or -077? Keep us posted.

Tony
Old 07-14-2017, 04:40 AM
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Hi Tony

the ID of the FD, see picture.0 438 100 077.



isn't there are work around this FV... is it possible to use a universal mangetic valve or is there some kind of flow pressure in the return line that needs to be there for the engine to run ?

i was thinking if it was possible to fix the FV valve, so it was in NO all the time (right inner diameter) to the fuel flow and put a 12V magnetic valve (NC) in the end, so there will be pressure when ignition if of and possible to start the engine in warm condition.

To T77911S:
everything is missing, only the parts on the engine is there, like i explained, the car was running perfect, when i had 12V directly to FV, the mixture was set to 3.5 CO and the engine started perfect cold, the fuel pressure went from 2.5 bar to 3.6 bar when warm, when i took the egnition off, the pressure drop to around 2 bar and keps the pressure so it was easy to start when it was warm.

Michael
Old 07-14-2017, 08:51 AM
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12v opens the FV adding more fuel thus making it richer.
closed makes it leaner.
check fuse 18. make sure that is good.

i don't understand how the engine ran without any controls. did the FV use to vibrate before you had any issues? has it ever vibrated or did you ever check it.

the FV does not change the CP. it varies the pressure in the lower chambers of the FD. less pressure=more fuel.

I don't know enough about the lambda system to know for sure but I do know that in open loop mode the FV defaults to a set frequency. I don't know if when you accelerate in open loop if the frequency changes(makes it richer). but if you have no control then that does not matter.


I don't think anyone has fitted a pressure regulator in place of the FV but if you liked the way it ran with an open FV, then that may be an option for you.

i suspect your mixture adjustment has been adjusted CCW considerably to get 3.5% with the FV open. with the FV closed that would be extremely lean.
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86 930 42kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ [__] RUNNING: [__] NOT RUNNING:
05 BMW 330CI 130K:: [__] RUNNING: [__] NOT RUNNING:
08 VOLVO V70 190K:: [__] RUNNING: [__] NOT RUNNING:
90 B2200[] RUNNING:[_] NOT RUNNING:__2000 MER E320 WAGON [_] WRECKED:[]RUNNING:
Old 07-14-2017, 09:40 AM
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Your engine is a 1980 model.
That year was the ONLY year with that specific lambda system. You will need to buy a 1980 lambda box and the 1980 wiring harness for your system to work (and, obviously, a new frequency valve...).

The 1980 specific year equipment is quite a bit rarer and more expensive than the 1981-1983 equipment.

All said and done, it might not be much difference in price to convert to the non-lambda CIS equipment. Tony knows more than I do, but it might only require the new WUR and fuel distributor.
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Old 07-14-2017, 10:34 AM
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Quote:
Originally Posted by T77911S View Post
the FV does not change the CP. it varies the pressure in the lower chambers of the FD. less pressure=more fuel.
Freq valve tweaks control pressure. You mean system pressure, I think.
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Old 07-14-2017, 11:37 AM
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After reading the Bentley service manual and the very good Bosch fuel injection book by Charles Probst it appears that the frequency valve's duty cycle does not impact either control pressure or system pressure but rather the fuel dist.lower chamber pressure.
On page 23 He states " When the lambda valve's duty cycle increases so that it is open longer and returning more fuel to the tank, lower chamber pressure is reduced. The differential pressure-pressure valve diaphragms deflect further , reducing upper-chamber pressure. This increases the pressure at each metering slit and more fuel flows through the slits for any given plunger lift. In short , the greater the duty cycle, the richer the mixture".
The bottom line is that the frequency valve in concert with the Lambda box plays a very important role in the correct functionality of the CIS system.
Old 07-14-2017, 12:09 PM
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This is a very interesting discussion. I bought an 82 car project. The original 82 engine had been replaced by a 79 engine, but the 82 intake, complete with FV had been retained. The lambda box and harness were gone. PO said it ran fine like that?????
I did a top end rebuild on the engine and set it up on my test stand with the 82 intake, and it ran poorly, and would not idle. So I sourced a 79 intake, and the engine ran fine.
My guess is that you will need the correct intake, FV and lambda box with harness to get your engine to run well. Keep us posted!
Old 07-14-2017, 12:26 PM
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Wur....

Quote:
Originally Posted by mirat View Post
Hi Tony

the ID of the FD, see picture.0 438 100 077.

Michael



Michael,

Look again at your engine and find out what's the Bosch ID number for the warm up regulator (WUR). It should look like this 0 438 140 ???. The ID number is on top of the WUR closer to intake runner #2 if is properly installed. Keep us posted.

Tony
Old 07-14-2017, 12:31 PM
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Quote:
Originally Posted by dhanl82 View Post
After reading the Bentley service manual and the very good Bosch fuel injection book by Charles Probst it appears that the frequency valve's duty cycle does not impact either control pressure or system pressure but rather the fuel dist.lower chamber pressure.
On page 23 He states " When the lambda valve's duty cycle increases so that it is open longer and returning more fuel to the tank, lower chamber pressure is reduced. The differential pressure-pressure valve diaphragms deflect further , reducing upper-chamber pressure. This increases the pressure at each metering slit and more fuel flows through the slits for any given plunger lift. In short , the greater the duty cycle, the richer the mixture".
The bottom line is that the frequency valve in concert with the Lambda box plays a very important role in the correct functionality of the CIS system.
++
It is a SYSTEM that needs to work together. Can you make a system that has been pieced together run? Yes. Will it run great? No Will you have issues like cold start, missing firing, lean running. Yes

You may be better off starting from scratch and piecing together matching components rather that tweeking mismatched parts.

I don't think it matters what year CIS system you build as long as ALL the components match.

Good Luck
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Old 07-14-2017, 04:28 PM
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Get a CIS for a 3.0 of course
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Old 07-14-2017, 05:18 PM
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Quote:
Originally Posted by dhanl82 View Post
it appears that the frequency valve's duty cycle does not impact either control pressure or system pressure but rather the fuel dist.lower chamber pressure.
There is upper and lower chamber pressure.

There are two pressures. System and Control.

From CIS primer.

The Lambda system does its job by adjusting the duty cycle of the frequency valve, which is plumbed into the lower portion of the fuel distributor control pressure circuit.

What do we call the frequency valve pressure? How is it distinct from control pressure? There is only one lower chamber.

Lambda/frequency valve is just another very good band-aid on the original system.

Love the Probst book, BTW.
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Old 07-14-2017, 05:29 PM
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I found a good article on how the Bosch Lambda System works. It is very generic and easy to read. I don't believe its been posted on Pelican forum.

If anyone wants a copy send me a PM.
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Old 07-14-2017, 06:53 PM
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Hi Tony

the WUR nr. is: 0 438 140 072.

Thanks for all the respons to this thread, i am a bit more wiser how the system works, i can understand that there is/should be some kind of pressure (in the lower chamber) that is suppose to be controlled between the Lambda probes/box and the FV(up to 10 times per sec) to control the mixture.

If i am going for earlier CIS version, what more do i need (WUR, CIS intake ?) and the next question, where is it possible buy this used ?

Michael
Old 07-16-2017, 02:22 PM
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CIS components........

Michael,

Where are you located? I could provide you all the CIS components you will need but it would be cheaper to buy them at the classified section of the PP forum. If I remember correctly, you will need the following:

6-pin connector wire harness for the enrichment unit
Frequency valve and fuel line
ECU (?) and wire harness
Correct ignition distributor
Etc.

Make a list of the parts you need and I will help you locate these components. Thanks.

Tony
Old 07-16-2017, 03:49 PM
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Quote:
Originally Posted by Bob Kontak View Post
There is upper and lower chamber pressure.

There are two pressures. System and Control.

From CIS primer.

The Lambda system does its job by adjusting the duty cycle of the frequency valve, which is plumbed into the lower portion of the fuel distributor control pressure circuit.

What do we call the frequency valve pressure? How is it distinct from control pressure? There is only one lower chamber.

Lambda/frequency valve is just another very good band-aid on the original system.

Love the Probst book, BTW.
I have not done testing on a lambda system so I am only going by what I have read a deduced.
that's not "control pressure" as we know it and is probably a bad term to use.
the lower chamber has system pressure on it pushing up or closing the metering valve to the injectors. op top is the fuel pressure let I by the plunger. it about .1bar higher than the lower chamber pressure. this is the differential pressure mentioned above. this differential pressure is set by the spring in the upper chamber. early fd's were not adjustable but later ones you could adjust the spring pressure.
I suggest not messing with them.
so if you lower the pressure in the lower chamber with the FV then that differential pressure goes up thus opening the valve more for the same amount of air coming in.
so in a sense you COULD call it a control pressure but I would not due to the confusion it can create.

a good question would be if you lower the SP with the FV in the chambers why doesn't the pressure reg try to raise the pressure. since I have never thought about that until now I would assume the port to the lower chambers is small enough, perhaps much like the decoupling port for the CP, that the pressure reg does not sense the drop in pressure in the lower chambers. just a guess at this point.
I would also suspect it does not take very much of a change in pressure to change the AFR and I am certain you will never find that info anywhere, although I do know the person to goto for that info.

all 6 lower (and upper) chambers are separate but tied together. the upper are not tied together.
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86 930 42kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ [__] RUNNING: [__] NOT RUNNING:
05 BMW 330CI 130K:: [__] RUNNING: [__] NOT RUNNING:
08 VOLVO V70 190K:: [__] RUNNING: [__] NOT RUNNING:
90 B2200[] RUNNING:[_] NOT RUNNING:__2000 MER E320 WAGON [_] WRECKED:[]RUNNING:
Old 07-17-2017, 04:25 AM
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I think there are quite a few here that are baffled at how the car ever ran.

systems pop on the classifieds here.


as I said earlier,
I would price out the parts to either go earlier CIS, get yours going or just have the FD modified to run without the FV. bonus is you get a rebuilt FD. but you may need the vacuum controlled WUR to go with it.
personally this would be my first choice.
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86 930 42kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ [__] RUNNING: [__] NOT RUNNING:
05 BMW 330CI 130K:: [__] RUNNING: [__] NOT RUNNING:
08 VOLVO V70 190K:: [__] RUNNING: [__] NOT RUNNING:
90 B2200[] RUNNING:[_] NOT RUNNING:__2000 MER E320 WAGON [_] WRECKED:[]RUNNING:
Old 07-17-2017, 04:33 AM
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hi Tony

i am located in Copenhagen, Denmark

as i understand, i need FD and WUR with vacuum from an older model, i think that will be the solution to go for in my situation.

is it possible to get these parts used from here ? and what will be the name/numbers if i am going to seek the net for the parts...used.

thanks for all the help and understanding how the system works.

just so all understand my situation, i have bough and 911 from 1968 with 3.0 sc engine in it, the were only wire/connectors on the the engine nothing else (no Lambda box or wire to the box)

Br
MIchael
Old 07-22-2017, 08:34 AM
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