Solved: 3.0SC with CIS bucking / surging, bad idle....

[javadog]

Have a look at the CIS training booklet that accompanied the addition of the O2 sensor in 1980. I don't have a copy, or I would send it to you. Someone here probably has one.

JR

[RarlyL8]

The -129 WUR was the Bosch replacement for the defunct -009.
Standard WUR for '73.5 was the -001, standard FD was -004. If you have these units and the small runners that go with that system it will never work properly on your 3.0L engine. I have seen entire 3.0L Euro CIS systems for a few hundred dollars here in the classifieds, that is what I would do if in your situation.
Here is some information on Porsche 911 CIS if interested: Porche Enthusiasts Page

[SkunkWorks]

Originally Posted by javadog

Have a look at the CIS training booklet that accompanied the addition of the O2 sensor in 1980. I don't have a copy, or I would send it to you. Someone here probably has one.

JR

Thanks JR. I've the manuals from timmy2 and co. on a CIS issue from two years back lol.

Just wondering if anyone had any thoughts on it. Will check the manuals.

[stevesc_us]

Another option to consider is to install a programable WUR from Unwired Tools: www.unwiredtools.com.

When I rebuilt my early 2.7 ltr CIS motor to 2.9 ltrs, but kept the original early 001 WUR that is not adjustable, the motor was running way too lean thru the entire power band. Installing this unit that was programmed to run much richer solved all my annoying hesitation on acceleration and detonation issues. Best $600 I ever spent!

[javadog]

Originally Posted by SkunkWorks

Thanks JR. I've the manuals from timmy2 and co. on a CIS issue from two years back lol.

Just wondering if anyone had any thoughts on it. Will check the manuals.

The 1980 CIS system was a one-year wonder. They changed the WUR from the vacuum adjustable unit (045) that was used starting in 1978 to a unit without vacuum (072) along with adding the control unit and other stuff related to the O2 sensor. In 1981, they changed it again (090) and added a bunch of things related to acceleration enrichment. The 1980 models also added a temp sensor and throttle switch that gave inputs to the control unit, so I'd probbaly start there. Of course, there's the school of thought that says you need to check the fuel pressures first, before heading down any diagnostic path.

JR

[SkunkWorks]

Originally Posted by javadog

The 1980 CIS system was a one-year wonder. They changed the WUR from the vacuum adjustable unit (045) that was used starting in 1978 to a unit without vacuum (072) along with adding the control unit and other stuff related to the O2 sensor. In 1981, they changed it again (090) and added a bunch of things related to acceleration enrichment. The 1980 models also added a temp sensor and throttle switch that gave inputs to the control unit, so I'd probbaly start there. Of course, there's the school of thought that says you need to check the fuel pressures first, before heading down any diagnostic path.

JR

Indeed. Currently sans gauges since my brand new Harbour Freight fuel pressure kit doesn't work!!! (even with schraeder valves already removed )

[MichiganMat]

A quick update:

Took the car to the track yesterday and observed a few things:
• When in stop-n-go traffic, the AFR numbers were on the lean side, mid 15s
• After a bit of cruising, the AFR numbers leveled out to the low 14s
• At the track, once the car was warmed up, WOT was well into the 13s

I was concerned a bit about those lean numbers when in stop-n-go traffic, but it seems like once the engine is hot (/warmed up/?) and at cruise that the numbers all come down into the 14s.

[javadog]

My suggestion is still to learn more about which components you have and, if much of the system is from a '73, swap it all in favor of a 78/79 US or any ROW system. The car will never run as well as it should with what you have now.

JR

[javadog]

There's a complete system off of a '80 ROW ar for sale in the classifieds right now. Been for sale for a while, you you might be able to make a good deal on it. The seller's user ID is charwood77.

JR