CIS Troubleshooting for Dummies

[SkiVT]

[RarlyL8]

There is no need to collect the charts, just get a Porsche repair manual. All the charts are there plus factory troubleshooting and repair procedures.

[RarlyL8]

These charts are copyright protected by Porsche, rather surprised that Pelican allows them to be posted. May as well just post the entire repair manual and be done with it.

[pmax]

Drivability Issues '77 CIS
Need control pressure chart -- '76 911S

Another chart


WTB 930 Warm up regulator

[Michael1234]

Hi Tim,

thanks for your fantastic description.

Iīve a 911 SC 3,0l, 1982, Euro and had some trouble. If the engine was warm it stoped immediately - no idle. Iīve done the tests and think I find the problem.

My AAR looks closed, but if I pluged the lines of the AAR my idle is perfect.
This seems slightly against the characteristic symptome -what do you think?

Best regards

Michael

[Michael1234]

I removed the AAR and test it. The restistence was 33 Ohm and it was closed after 6 min.
It was total closed but if I blowed in it was not airtight.

After build into the car the same problem and if I pluged the lines the car runs fine.

What is the different? Must it be airtight?

[tirwin]

Michael,

Sorry I have been slow to respond. I've been traveling on business. My advice would be to start a new thread here with all the details. My gut reaction is that there is too little to go on from your initial description and we could guess at a lot of things, but we would just be guessing. The starting point is going to be fuel pressures and very thoroughly checking for vacuum leaks.

[Michael1234]

Hi Tom,

thanks for your Response.

Here the things Iīve done before:

Problem: begins after winter brake. In warm condition no idle. Engine stops immediately.

- CO / mixture was right before
- System pressure: 4,8 bar
- Cold control pressure: 21 °C, 1,0 bar
- Warm Control pressure: 3,6 bar

- Changing vacuum lines (because really old)
- air leaks (only sight test, if open oil tank - idle falls down)
- Thermo valve: cold closed, after power open
- WUR (-089): 33 Ohm, after opening clean filter, every thing fine

- AAR (0280140201): 33 Ohm, cold open - power after 6 min closed complete, but not airtight.

If I closed the lines to AAR the idle (warm condition) is perfect.
This could means there is a bad scource (circle of AAR) for additional air or the fuel mixture is so lean that minimal air disable the idle.

My question:
Why is the idle perfect after closing lines to AAR (AAR is closed, so only minimal air comes out. Is the idle for air so sensible)?
Could it be the AAV (not checked because ist nearly behind the engine)?
Which part affected the idle in terms of the fuel mixture?

Thanks in advance.

[Vereeken]

These numbers look good Michael. You do not say what the CO setting is.

If the AAR closes in about 6-10 minutes it is fine. I have tested a couple and none is 100% airtight after closing...

WUR is OK correct for your car and OHM is spot on.
Warm control is perfect.

You did not give us System pressure.

Aside from tracking air leaks please check the routing of the small diameter hoses.
99% of the information on the Web is incorrect for a 82 SC with a 089 WUR.

If I have to venture a guess maybe someone swapped the 2 small vac hoses to the WUR. You can install them in 4 different manners , one of them will cause the engine to stall when warm if the co was set with the vac line incorrectly attached.

[Michael1234]

Thanks.

The system pressure is 4,8 bar (see above).
I find your picture before in your thread and checked them. All lines are OK on my car.

[Vereeken]

Damn that sucks...

System pressure is a littel low but within spec.

So my best guess now is that the AAR does not fully close but that should give you high idle not "No idle."

The AAV can also play a role but the symptom is usually a high idle.

[brentrussell]

My Vacuum test pump... a aquatic tank pump, reckon its around 2-3 PSI, worked great and cost approx $15 USD.

[Vereeken]

Someone asked for a good graph of the notorius 089 ROW WUR.

[boyt911sc]

Michel,

Thanks for posting. My copy is same as yours except it is faded and not easy to read. Now, I have a good photo copy of the WUR-089 cold control fuel chart.

Tony

[angelny911]

Interesting page thanks to all.

[pmax]

Adjustable WUR

Made an Adjustable WUR- Step by step, got Pics!

How hard to hit the WUR cold pressure adjustment PIN?

[Michael1234]

Thatīs a very nice idea, but my WUR works well.

Next week-end I will check my AAV and tell you more.

[Michael1234]

I didnīt checked my AAV until now. After a short look I see there is nearly no way to remove it without removing the complete k-jetronic. So I switched it to the winter break.

[rwest]

Originally Posted by Michael1234

I didnīt checked my AAV until now. After a short look I see there is nearly no way to remove it without removing the complete k-jetronic. So I switched it to the winter break.

You can also remove and just plug the lines to see if there is any change in how the car runs.

[Charles Freeborn]

Apologies in advance if this has been covered already -
Can a vacuum test @ distributor be a quick and dirty check for vacuum leaks, or is that in the wrong part of the chain to be valid? Also, what is the target vacuum at idle for an early CIS system? Mine is a '74 with a xxx xxx 004 FD and a xxx xxx 008 WUR.
Thanks!