79 SC starts good then almost dies

[Pats79SC]

My car had been sitting in a garage for about 4-5 years, after much work it does run now and runs pretty good, before replacing the FA hot starts were pretty bad but cold starts were great, after replacing the FA it starts on a click, revs to about 1800 for a few seconds, then it bogs down to you 400 missing and sputtering then gradually picks up and idles at about 1100 for several minutes then slows down to about 500 and the idle is rough.
I have replaced the FA and the injectors, tested the WUR and based on feedback here it is OK, just pulled the AAR and when cold it is about 75% open and with 12 volts applied it closes completely.
While the AAR was on the car I pulled the outlet line off and looked into it to see the 75% open valve, I then turned my key to on /aux and nothing happened for several minutes, does the car have to be running for the valve to close?
Thanks for any help.
Pat

[PeteKz]

The CIS electrical parts get 12V as soon as you turn the key to ON (except the TTS and CSV, which get voltage when you turn the key to START).

Test for 12v at the AAR with the key ON. If no voltage, test at the WUR. Then work your way upstream. Could be loose connection, broken wire, or bad CIS relay (on the rear relay panel). Check the rear fuses too.

[boyt911sc]

Originally Posted by PeteKz

The CIS electrical parts get 12V as soon as you turn the key to ON (except the TTS and CSV, which get voltage when you turn the key to START).

Test for 12v at the AAR with the key ON. If no voltage, test at the WUR. Then work your way upstream. Could be loose connection, broken wire, or bad CIS relay (on the rear relay panel). Check the rear fuses too.

Peter,

The FP, AAR, & WUR, etc. don’t get power with the ignition switch @ ON position unless the AFS (air flow switch) is defective or removed. When you turned the ignition switch to ON POSITION, the normally closed terminals #30 & #87A will switch to #30 & #87 (normally opened terminals). There is NO power supplied to FP, AAR, & WUR unless terminal #30 is energized. Test and verify.

Tony

[PeteKz]

Tony, thanks for the correction. I know the FP will not run until the air flow switch activates. I will test my other CIS components, and re-read the wiring diagram.

[AFB24911S]

This sounds an awful lot like my car before I had a bunch of vacuum leaks repaired; if you are unsure of whether you might have vacuum leaks or not, that could be another diagnostic to think about. Spraying something aerosol and flammable like brake cleaner or starting fluid around the throttle body, intake runners, injector sleeves, and vacuum lines would be a starting point.

[PeteKz]

Pat, Tony is correct that 12V will not be applied to the CIS parts until the fuel pump runs. To test for 12V at your AAR and WUR, lift the air metering plate slightly to get the FP to run. Then you should get 12V at the CIS components.

[Schulisco]

Pat,

I recommend to follow the instructions given in the troubleshooting manual from https://cis911primer.com/home.html
(Left menu "Testing" => "Troubleshooting" => "Troubleshooting Guide Booklet")

Here the behaviour is described in the following pages:
https://cis911primer.com/Troubleshooting%20Guide/pages/pages28-29.html



It mentions too what I always recommend on issues like this and often getting blamed that this wouldn't matter: Check the sensor plate height and the timepoint the fuel pump security switch switches on electrical power to the whole CIS system...

Thomas