CIS Misture "Leaning" Out - Calling on the CIS Gurus
10-31-2006, 06:46 PM
#16
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hupp
I have this control valve on my 82 euro 5 speed the wire that comes from it joins the wire to the Ac compresser clutch i think it is used to up the idle when ac is switched on
DJB
I have this control valve on my 82 euro 5 speed the wire that comes from it joins the wire to the Ac compresser clutch i think it is used to up the idle when ac is switched on
DJB
10-31-2006, 07:32 PM
#17
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Hupp, my 79 has the same set up of a a small vacuum valve mounted on the outboard side of the decel valve. Never been able to figure out how it works.
I guess if you want to remove the decel valve you just block off the two ports it is connected to?
Sean
I guess if you want to remove the decel valve you just block off the two ports it is connected to?
Sean
10-31-2006, 10:25 PM
#18
Scott,
Believe you are talking about the EEC valve which shares a vacuum source with the decel valve. This valve controls the evacuation of fumes from the charcoal cannister.
Dennis
Believe you are talking about the EEC valve which shares a vacuum source with the decel valve. This valve controls the evacuation of fumes from the charcoal cannister.
Dennis
10-31-2006, 10:51 PM
#19
Burning Brakes
Thread Starter
DJB,
The valve you describe is most likely the idle solenoid for the AC. The solonoid open and allows air to bypass the throttle (mych like the aux air valve) to bump up the idle when the compressor is powered. This is different than what I was describing.
Dennis,
Definately not the EEC valve. But, just to make sure we're comparing apples to apples: The EEC valve(which is black plastic on my shark) does draw vacuum from the back of the throttle body via vacuum tubing. The valve is plumbed on one side through the fender wall to the canister. The other side is plumbed to the intake manifold between the #7 and #8 via the "suction/ejection nozzle". The smaller vacuum valve I was describing has a metal housing in is mounted on a bracket between the 1 and 2 intake runners. In some cases I've seen it labeled as the "barametric cell", so I assume this is for some sort of altitude adjustment. Definately not something I would need in Louisiana.
The valve you describe is most likely the idle solenoid for the AC. The solonoid open and allows air to bypass the throttle (mych like the aux air valve) to bump up the idle when the compressor is powered. This is different than what I was describing.
Dennis,
Definately not the EEC valve. But, just to make sure we're comparing apples to apples: The EEC valve(which is black plastic on my shark) does draw vacuum from the back of the throttle body via vacuum tubing. The valve is plumbed on one side through the fender wall to the canister. The other side is plumbed to the intake manifold between the #7 and #8 via the "suction/ejection nozzle". The smaller vacuum valve I was describing has a metal housing in is mounted on a bracket between the 1 and 2 intake runners. In some cases I've seen it labeled as the "barametric cell", so I assume this is for some sort of altitude adjustment. Definately not something I would need in Louisiana.
11-01-2006, 08:47 AM
#22
Burning Brakes
Thread Starter
Dennis,
Not the smog pump diverter. This "barametric cell" is located up by the front of the engine. My smog pump utilizes a dedicated vacuum port and is not "T'd" into the decel valve as shown on the CIS hose diagram. My ignition distributer has centrifugal advance and vacuum retard - only one vacuum line which is routed from the front of the throttle body. Unlike the diagram, which illustrates 2 vacuum lines to the distributor. Anyway, this free'd up a vacuum port at the rear of the throttle body and this is where my diverter valve vaccum is tied.
Dave,
I have no EGR - I believe EGR was for Cali only. Ports on the intake and exhaust manifolds have been blinded.
The barametrec cell can be found in the WSM on the exhaust diadram -- sorry don't have access to the WSM now so I cannot give the page. But, this diagram is another representation of the hose layout but it includes the EGR and smog system. The barametric cell is item 7 on the diagram and is mounted adjascent to the pressure transducer for EGR between intake runners 1 and 2.
Not the smog pump diverter. This "barametric cell" is located up by the front of the engine. My smog pump utilizes a dedicated vacuum port and is not "T'd" into the decel valve as shown on the CIS hose diagram. My ignition distributer has centrifugal advance and vacuum retard - only one vacuum line which is routed from the front of the throttle body. Unlike the diagram, which illustrates 2 vacuum lines to the distributor. Anyway, this free'd up a vacuum port at the rear of the throttle body and this is where my diverter valve vaccum is tied.
Dave,
I have no EGR - I believe EGR was for Cali only. Ports on the intake and exhaust manifolds have been blinded.
The barametrec cell can be found in the WSM on the exhaust diadram -- sorry don't have access to the WSM now so I cannot give the page. But, this diagram is another representation of the hose layout but it includes the EGR and smog system. The barametric cell is item 7 on the diagram and is mounted adjascent to the pressure transducer for EGR between intake runners 1 and 2.
Last edited by hupp; 11-01-2006 at 09:07 AM.
11-01-2006, 01:54 PM
#23
Rennlist Member
I believe EGR was for all US/Japan. Just removing the EGR can have unintended consequences if other components are not adjusted and/or removed to compensate for the change.
The device you're talking about -- is it item #7/11 in the diagram below?
The device you're talking about -- is it item #7/11 in the diagram below?
11-01-2006, 02:09 PM
#24
My 79' was originally bought in Vancouver Canada in 1979 it had the EGR, Baro cell, decel valve, vacuum activated carbon cannister valve,etc. All have been since removed and pluged. The only difference with it all out or all in was that the rpms will drop very quickly when throttle is closed with no decel valve helping to slow down rpms.
Before I removed the decel valve and after I accidently tore the diaphram in the decel valve I noticed that my idle rpm was @ aprox 2300 rpm, and was nonadjustable using the air bypass screw. Before the diaphram ruptured the rpm @ idle was at 800 and adjustable using the idle air bypass screw.
After much messing around with my mixture adjust screw I found it hard to get the happy medium between a steady idle and a non lean condition @ wot. I ended up getting the eng. as hot as possible and then adjusting the mixture screw until it was on the ragged edge of rich (idle fluctuating up and down by around 200 rpm).
Before I removed the decel valve and after I accidently tore the diaphram in the decel valve I noticed that my idle rpm was @ aprox 2300 rpm, and was nonadjustable using the air bypass screw. Before the diaphram ruptured the rpm @ idle was at 800 and adjustable using the idle air bypass screw.
After much messing around with my mixture adjust screw I found it hard to get the happy medium between a steady idle and a non lean condition @ wot. I ended up getting the eng. as hot as possible and then adjusting the mixture screw until it was on the ragged edge of rich (idle fluctuating up and down by around 200 rpm).
11-01-2006, 02:25 PM
#25
Rennlist Member
Robbie, EGR is supposed to reduce combustion temps and allow a more agressive timing curve. If you don't get pinging under load you're probably fine.
11-01-2006, 02:40 PM
#26
Now that's an intersting fact I did not know Dave, thanks for the info.
How does that thing work again?
Egr valve opens at wot and routes some exaust gas from the passenger side exaust manifold to the upper plenum?
How does that thing work again?
Egr valve opens at wot and routes some exaust gas from the passenger side exaust manifold to the upper plenum?
11-01-2006, 05:07 PM
#27
Rennlist Member
EGR should close at WOT. There is a lot of info in the 1978 service info doc(Tech docs CD) PDF pages 38-42(Paper doc pages 36a-36e) but here is a good summary:
11-01-2006, 05:40 PM
#29
Rennlist Member
Scott, it shouldn't affect your performance unless you have to back off the timing to reduce pinging. Otherwise, the biggest difference should be increased NOX emissions.
11-01-2006, 10:47 PM
#30
Burning Brakes
Thread Starter
I spent some time this evening dialing in the CIS. Much better at this point. Mixture gauge shows just right when up and running. No idle hunting issues either.
Dave,
Out of curiosity, how does your 928 feel at idle. I would say that mine idles with "character". Not a rough idle by any means, but you are reminded that a V8 is churning just inches from your feet. Reason I ask is I've read that the idle is often very smooth -- I guessing that this would be characteristic of a 32 valve not a 16 valve. Am I wrong?
Dave,
Out of curiosity, how does your 928 feel at idle. I would say that mine idles with "character". Not a rough idle by any means, but you are reminded that a V8 is churning just inches from your feet. Reason I ask is I've read that the idle is often very smooth -- I guessing that this would be characteristic of a 32 valve not a 16 valve. Am I wrong?