CIS problems

[spf40]

Does anyone know what the ohms should be on the air regulator valve??? trying to trouble shoot a cold start problem............. car starts but idles low and misses until its hot. The valve stays open always and no ohms is present on the connector.

1980 sc

[ossiblue]

Try this link:
http://members.rennlist.com/jimwms/CIS/CIShome.html

Click on CIS Components. If you're talking about the Auxilary Air Regulator, then the resistance is about 17 ohms, and your symptoms fit the situation of a non-functioning AAR. Be sure you are getting voltage to the connector also.

[spf40]

Thank you................ i have about 10.6 v to the AAR and the valve stays about 3/4 open all the time. Do you think this would cause low idle during start???

[ossiblue]

Actually, I misspoke in my original post--your symptoms do not necessarily fit a malfunctioning AAR.

Your AAR should be open fully when the engine is cold, and close as the heating element kicks in. If it stays open always, like yours does, that will lead to excessive air into the system causing a high idle. It does sound like your AAR needs looking into.

Let's go back to the start. I'll guess from your post number that you are new to the CIS. The system can be very touchy until all things are in balance--fuel pressure, air flow, ignition--the CIS relies on a system with accurate fuel pressures and no leaks of air and you'll pull out your hair trying to second guess your problems. Use the search function on this board and begin your education. Take your time and enjoy the input.

Directly to your symptoms, low idle and missing tends to mean a too lean mixture, typically caused by out of spec fuel system pressures, intake leaks, misadjusted valves, or combinations of all three.

Here's my opinion: Get the valves adjusted and ignition in order. Then, have the fuel system pressure tested--cold pressure unregulated, cold pressure regulated, and warm pressure regulated. That should be your starting point, IMO. These tests will determine, among other things, the condition of your Warm Up Regulator (aka Control Pressure Regulator). If that's out of whack, you need to take care of that first. Your symptoms do fit with too high cold pressures, so the WUR is a likely suspect.

Do some more diagnostics before you blame it all on the AAR. Yes, it is malfunctioning, but if all else in your system was good, the idle wouldn't be low with engine miss.

Oh yeah--Welcome aboard the forum, and get ready to get harassed until you post a picture of your car--it's tradition!

[spf40]

Thanks for the good advice................. will work in that order that you recommend.


G.

[T77911S]

if it is staying open something is wrong with it. PO may have adjusted idle down to compensate when it is hot.