CIS pressure test, question

[Vereeken]

Ok success. Now measure your FP engine both control and system on a cold engine.

I am sure they will be in spec again.

As timmy2 said. Way rich cause this symptom as well. The decelvalve also. If the latter is bust forget about it. Some year can be adjusted but it is usually the membrame inside that is torn, and a new one is big bucks for what it does.

[npresley]

Adjusted the mixture a little so the idle smoothed out (lean), and then adjusted the decel valve counter clock wise slightly. The rpm dive between shifts improved. We're on the up and up. I'll have to double check the pressures later, but if they are out of spec what can be adjusted? Thanks for all the help and advise!

[Vereeken]

Originally Posted by npresley

Adjusted the mixture a little so the idle smoothed out (lean), and then adjusted the decel valve counter clock wise slightly. The rpm dive between shifts improved. We're on the up and up. I'll have to double check the pressures later, but if they are out of spec what can be adjusted? Thanks for all the help and advise!

Every aspect of the pressure can be adjusted. The WUR can be made adjustable for both Warm and Cold control. look for Adjustable WUR. Not so difficult but time consuming.
There is a gentleman that goes by the name of RarlyL8 I think he can rebuild any WUR.
Also system pressure is adjustable look for Primary Pressure Valve.

[timmy2]

Adjust the mixture richness by setting your CO with a meter to the best settings for your car, I'll bet if you get the mixture right the car will drive just fine. I don't have specs for your engine but I'd bet your car would run right with lots of power set around 3.5% CO at warm idle. Mine sure does.

[npresley]

Valve closed pump running pressure is what? (system pressure) 4.5 bar

Valve open pump running pressure, wur unplugged pressure is?(cold control pressure) 1.5 bar

Valve open pump running wur plugged in pressure?(warm control pressure) 2.3 bar

Valve open after warm pressure check, turn off car and residual pressure reading immediately and after 30, 60, 120 seconds and then 15 and 30 minutes? 1.8 bar immediately, 1.5 bar @ 30 secs, 1.5 bar @ 60 secs, 1.4 bar 120 secs, 1.1 bar @ 15 min, & .9 bar @ 30 min

[timmy2]

Much better numbers, now you need to fine tune.
What is warm running pressure with car fully warmed up and running?
Mine is about 3.2, yours still seems low, but I'm assuming it's without the car actually at full operating temp.

[Vereeken]

Much better indeed. At what ambient temp was this CCP taken?

Does it start well at that pressure and does it do its high idle routine for a minute or 2?

@Timmy 2 how much pressure is added between the WUR heated only by internal bimetal and the WUR also heated by engine heat? I assume it could be 0.1 or 0.2 bar but not 0.5 bar right?

Michel

[npresley]

It was about 80°. I started the car and let it idle for about 5 minutes when I got the 2.3 bar reading. I'll drive it some today and see how it behaves. Before taking the most recent pressure readings, it was running much better.

[timmy2]

More of a curiosity to see the difference. Mine is about 0.5 bar. IIRC. Driven for 20 minutes.

[npresley]

When it starts, it idles about 1800rpm. As it warms, it settles to 1000rpm. I adjusted the mixture just lean enough that the idle doesn't oscillate. I then adjusted the idle speed to 1000rpm. Now when I shift, drops to 2000rpm and comes down to 1000rpm. I had to adjust the decel valve out and then the mixture and then the idle speed.

[timmy2]

Sounds like you are getting very close. It is a fine balance getting everything to syncronize correctly. Putting a CO meter on mine to set the richness just right is what helped me in the end when I was setting my car up.

[npresley]

I don't have access to a CO meter. I'm fine with it as long as the idle don't oscillate. I am a little concerned as others have mentioned that my control presssures are a bit low.

[timmy2]

If the car starts, runs and drives well, then why worry?
Specs are specs.. Averages, ideals. If it's working, why try to fix it...

[boyt911sc]

Originally Posted by npresley

I don't have access to a CO meter. I'm fine with it as long as the idle don't oscillate. I am a little concerned as others have mentioned that my control presssures are a bit low.

Nathan,

Both your WCP and system fuel pressures are on the low side. When the engine is fully warmed up, I like to see a 50-55 psi with system fuel pressures no less than 70 psi. Is your FP capable of producing 90+ psi? Another thing you have not demonstrated is the absence of a significant air/vacuum leak. Why do you keep adjusting the mixture setting? Keep us posted.

Tony

[npresley]

As I adjust the decel valve to settle the rpms between shifts, the idle will oscillate. I'll lean the mixture just enough to stop the oscillation. Then the idle speed will be off so I'll adjust it back to 1000rpm. I grabbed the air box and tried to rip it out (not really) as the motor was running, shifting it around. No change in idle. The intake boots are fairly new (5000miles, 3yrs).

[npresley]

same with the vacuum hoses. If I had a vacuum leak, would the mixture end up being lean?

[Paulporsche]

Yes, unless you do something to mask it, like richening the mixture .

[manbridge 74]

Checked your sensor plate height? Do it when there is no fuel pressure remaining.

It's often missed in these CIS diagnosis threads.

[Vereeken]

What is the correct sensor plate height on an SC. The bentley and haynes manual drawing are worthless.

Do you happen to have a picture of the sensor plate shot from in the air filter housing?

Michel

[npresley]

How and where do I measure the sensor plate height?

When I am adjusting the mixture, I am turning slightly counter-clock-wise, leaning it out.

When attaching a vacuum tester to any vacuum line, is there a best way to check for vacuum leaks?