CIS rebuild threads?

[SCWDP911]

Originally Posted by JK-81SC

I'll throw in another thing to check on your high idle problem. My car had a high idle problem before my CIS rebuild. When the CIS was out of the car I also rebuilt the distributor. When I took the distributor apart, the mechanical weights were gunked up with sludge and dirt. I cleaned up everything and oiled the moving parts with 3 in 1 oil.

The high idle problem was gone, but I don't know if the CIS rebuild or the distributor rebuild fixed the problem. My high idle problem was intermittent, so I'm guessing the mechanical advance in the distributor was sticking sometimes, instead of moving freely.

This is very interesting, in that over the summer, I occasionally had the high idle, but like you it was intermittent. I need to dig up that recent distributor thread again... thanks

[Porsche_monkey]

^^^ A worthwhile suggestion there...

[Bobboloo]

If your car is staying at high idle to long it could be that the WUR and/or AAR are not getting current (likely) or that the coils have opened (unlikely). These two devices perform idle up while cold.

The WUR controls fuel pressure and the AAR regulates an auxilliary air source for idle up when cold. Both have bi-metal strips, that are sensitive to temperature, that perform the adjustment. Both have coils on the strips that are activated (12v) via the temperature sensor. They both will perform without electrical current but will take much longer to adjust to warm running condition because they will have to be heated by ambient engine heat.

First thing I would check would be that they are getting 12v when the motor is cold.

The rough running sounds like another problem so keep in mind that your problem(s) could have more than one source.

Troubleshooting is best done with the motor in the car. You need to be able to put a CIS pressure tester (must have!) on the motor to make a diagnoses of the systems condition. You may want to do a partial engine drop before you start to address replacing vacuum hoses. Your call.

Here's a some threads on the AAR and the WUR. Both these units tend to go out of adjustment over time due to the bi-metal strip getting a little "fatigued" an becoming "relaxed". They can fairly easily be re-adjusted to perform back to spec without needing to replace $$ them.

Both of my units had "relaxed" over time so I just bent the bi-metal strip inside back to perform at spec.

WUR malfunction repair?

making WUR adjustable?

AAR Revisited

I saw a thread where some guy rebuilt his CIS fuel distributor but from what I understand is sealing the unit back together can be a real problem. It's best to try and clean it with it assembled. I believe this may be done by feeding it Berrymans' B-12 Chemtool through the WUR port. I would think this is best done without injectors attached because you wouldn't want to just send the crud downstream to the injectors.

A lot of people replace the CIS with other systems to solve a problem but really CIS is quite simple, effective and reliable in design. If you take the time to understand it you can repair it so it will perform well for years.

[SCWDP911]

I am learning a LOT just from this thread, and the many others that I am coming across and that you guys have provided links to. Thanks again to all. Hopefully my tester will get here soon. The 12 volts on the WUR and AAR, it will come just with key on right?

[Fidalgo911S]

I've scanned this thread but saw no mention of Souk's thread regarding CIS.

Do a search for "Souk" in the member's list. In his signature he has a link for his "Bi-annual CIS mystery" thread. Good reading.

Nate

[SCWDP911]

Originally Posted by Fidalgo911S

I've scanned this thread but saw no mention of Souk's thread regarding CIS.

Do a search for "Souk" in the member's list. In his signature he has a link for his "Bi-annual CIS mystery" thread. Good reading.

Nate

Definitely a must read there.

Souk, email me sometime... I would still like to further our discussions from our pre-Hawaii days.

[Bobboloo]

Originally Posted by v8_ranch

I am learning a LOT just from this thread, and the many others that I am coming across and that you guys have provided links to. Thanks again to all. Hopefully my tester will get here soon. The 12 volts on the WUR and AAR, it will come just with key on right?

Probably depends on the year. The early CIS yes but on 83' the motor probably needs to be running. Pull the electrical connector off the WUR. Start the motor cold and then check for 12 volts.

[SCWDP911]

Just wanted to add to my CIS journal here. This morning, I start the car up (it's 39 degress out), car starts right up, steady idle for about 10-15 seconds, and then the hunt begins until I get to the end of my street, where it is now a steady 1600 rpm. I make the 45 minute drive to work and every where I came to a stop along the way, including final stop at work after 30 minutes of 70mph i-state driving, is still steady 1600 rpm idle. This morning it never kicked down at all.

[GothingNC]

Originally Posted by Fidalgo911S

I've scanned this thread but saw no mention of Souk's thread regarding CIS.

Do a search for "Souk" in the member's list. In his signature he has a link for his "Bi-annual CIS mystery" thread. Good reading.

Nate

You mean this thread?


It's that time of the year AGAIN! (CIS)

[boyt911sc]

Originally Posted by Bobboloo

Probably depends on the year. The early CIS yes but on 83' the motor probably needs to be running. Pull the electrical connector off the WUR. Start the motor cold and then check for 12 volts.

We all do learn from sharing knowledge and experience in this forum. You can check the electrical power for both WUR and AAR without running the motor. Simulate a test similar to running the FP (fuel pump) by lifting the sensor plate or using a jumper wire between 87a and 30 terminals. The FP. WUR, and AAR all get power from terminal #30 (fuel pump relay). I prefer the jumper method because it eliminates the injectors from unnecesary spraying fuel in the chamber. Did the above test before and then realized it was not necessary to start the motor. This is applicable to '76-'83' 911 motors (US models).

Tony

[SCWDP911]

Thanks Tony

[peon77]

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