3.2 Carrera Idle Redux. DIFFERENT this time!

[kdfoust]

Hi:

I have been mining around on the board looking for solutions to my cold idle problem on my '85 3.2 Carrera engine. From searching here I know that many people have been frustrated by 3.2 idle and cold start issues. Here's my story...

I just finished installing the 3.2 in my '72 914 (you can see the conversion thread HERE ). I did everything. The car started first attempt after the conversion but won't idle due to a kinked fuel line. I fixed that and found that everything seemed pretty good except when the throttle was blipped on a cold engine it would die every single time AND hot starts took a little more cranking than they should. Those issues aside it ran okay but did feel a little cammier than it should have as well. This morning I started troubleshooting in earnest, Bentley manual in one hand and a meter in the other. I went through the relavent DME stuff on the engine: idle speed control valve, idle switch, throttle position switch, CHT, and fuel pressure. The results from those tests are below but to save you the trouble I found nothing out of spec EXCEPT that the idle speed control valve wasn't getting power. At that point I accessed the ECU and started troubleshooting the DME connector once again according to the Bentley. My first check was pins 33 and 34 which should go to the idle speed control valve. I found no continuity across 33 and 34 but should have seen 40 ohms just like at the valve itself. I checked a few other functions at the connector level and they all checked fine. So I figured that I'd either boogered the DME cable which seemed unlikely because I'd been pretty darned careful handling and routing it or something even wierder was wrong here. I pulled the connector on the idle speed control valve (iscv) and skinned back the boot to look at the wires. One white, one brown with red tracer. The ECU connector pins 33 and 34, had one blue, one blue with red tracer. Holly smokes something was clearly goofed up here! I started looking around the engine compartment to find another three pin connector like the one on the iscv. I found it on the throttle position switch. Appartently I had placed the iscv and the throttle position switch connectors on the wrong places when I reassembled the wiring harness in the car. I switched the connectors to the correct locations. The 3.2 started and idled perfectly and blipping the throttle only produced a return to idle. The camminess also seems to be gone.

I would have never suspected that the engine would run with those two connectors switched but it did. It could be the peciliarities of my installation that made switching them possible. Hope this helps at least one more of the 3.2 Carrera idle problem people out...

Regards,
Kevin

[911Atlanta]

Great info, Kevin, thanks. I'm having starting problems with my 3.2 and am surfing for help. Takes 3 or 4 key turns and gas pedal pump to start it, but after it settles, it idles and runs smoothly.

On a 3.2, exactly where are the CHT and ISCV on the engine ? Any photos ?

Thanks, Dan

[fastteo]

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