limp mode?:


No helmet required!
Driving to work Monday the GN starts to intermittantly cut out. Engine cold or hot doesn't matter. Yesterday I hook up the Direct Scan and as I pull away slowly from a stop it cuts out and I capture it on DS. No codes but the DS numbers for O2's and A/F are upside down. A/F starts out at 12.4 and goes up to 14.8 when the problem hits. O2's are running 750's and go to 0. This lasts 5 seconds. I'm thinking fuel so I hook up the pressure gauge and tape it to the windshield and go for a drive. Pressure is fine and the engine is still cutting out. I run the ignition module up to O'Reilly's and it checks good as I expected. Swap ecm, use the same chip and go for a test drive. I runs fine. Drive it to work today and it runs fine. Problem fixed. As I'm driving to work I'm thinking about the injector PW that showed a flat single line and it hits me. That sounds like limp mode.

Possibility one - removing and reinstalling the ignition module fixed a bad connection.

Possibility two - bad ecm

Possibility three - DS cable connection to ecm. I've read that if the cable is pushed in too far you will have problems but I don't recall the exact symptoms.

Possibility four - chip wasn't seated

I can tell you one thing. If that was limp mode, running 12.8 A/F ratio really sucks the gas.

What do you guys think?
Limp Home mode involves a Service engine light.

Fail Soft is when something goes out of limits and the ecm uses a default value. And not always is a SES light set. Nor always is a code stored.

Try the old ecm again, and see what happens.

Grounds good?.
It has a ground stretcher kit. No lights, no codes. I've never heard of Fail Soft. I'll do a search on it. Thanks.