Georgia Fiero Club Forum

All Things Fiero => Tech Tips, Tech Questions => Topic started by: GTRS Fiero on July 27, 2019, 07:46:35 pm

Title: Rich on start
Post by: GTRS Fiero on July 27, 2019, 07:46:35 pm

My Fiero runs rich when starting--even after running for 300 miles, which should be sufficient to warm it up.  Basically, if I start it when cold, it runs rich.  If I run 300 miles, shut it off, then start it, it runs rich.  Is the CTS the likely culprit?

Title: Re: Rich on start
Post by: Fierofool on July 27, 2019, 08:16:19 pm

That would be my first thought.  What injectors are you using?  Do you still have the cold start injector in place?

Title: Re: Rich on start
Post by: GTRS Fiero on July 27, 2019, 08:19:18 pm

Stock 3.4 injectors.  No CSI.

Title: Re: Rich on start
Post by: Fierofool on July 27, 2019, 08:57:03 pm

The injectors could be the cause.  I don't know how they react with the 7730.

Title: Re: Rich on start
Post by: GTRS Fiero on July 27, 2019, 09:18:10 pm

Hmmm.  I have thought they were leaking.  It was the same with the TFS injectors.

Title: Re: Rich on start
Post by: GTRS Fiero on July 29, 2019, 10:07:56 pm

Have been discussing this with Ryan.  He seems to think the O2 sensor is the problem, because the CTS tests OK.  I thought that the O2 sensor didn't kick in until the system went into closed loop.  Since this happens irrespective of cold start or warm start, I had ruled out the O2 sensor.

I have a spare O2 sensor, so we'll see.  It is possible that the engine running rich could have fouled the O2 sensor, anyway.

Title: Re: Rich on start
Post by: GTRS Fiero on August 07, 2020, 08:48:39 am

It seems to be better with the new programming.