Hi, Hello, Greetings, and Salutations

[Jonald]

Hello - New member been lurking for awhile, thought it was time to get to know the crew. Hopefully some sage advice as well. Been troubleshooting my 89 c3500 for what seems like years trying to pinpoint emissions issues. I was able to sift through the forum, think I had the wrong PROM chip installed(?). Old chip was ANTY for 87 van. New chip is AKUN for 89 c3500. (Bought a programmer and some chips off eBay). However, I just started seeing a soft "code 42" (open or grounded EST circuit) when scanning with TunerPro. Diagnositic test shows bad ICM. I have new ICM waiting to be delivered. Hoping this solves my issues. If not, I got some back-up...Right?

[dave w]

The TunerPro RT .xdl file (data log) has very good information for others to look at if / when you need help.

[Jonald]

Thanks you for welcoming me here. Scan data is my nemesis so far (block learn values and such). Really just don't know how to interpret some of the data, but I am eager to learn. I am sure with help from this forum, I can get pointed in the right direction.

[dave w]

Most gearhead-efi members use TunerPro RT, myself included.

In a perfect world, all BLM's would be 128.

BLM's below 128 are rich.

BLM's above 128 are lean.

Nothing is perfect, so BLM's between 123 ~ 133 are acceptable.

BLM's above 138 will likely require tuning.

BLM's below 118 will likely require tuning.