454 TBI swap from refrigerated box truck, timing problems I can't figure out

**EagleMark** · 07-03-2014

What is the BCC (Chip four letter code) on the chip in ECM.

No it's not normal for that truck to have a 1227747... it should be a 1228747.

There is no extra spot in either of those ECMs for an extra O2 sensor. Not sure what your seeing?

Motor must be warmed up to set timing, even then they do not run well, barely idle.

Wonder what year motor that BB is? Could have been a swap from 94-95 which require higher fuel pressure? Can you get the number off the top of injectors?

**yellowsnow** · 07-03-2014

The four letter code is "ANVA" which doesn't show up in the search.

The truck was an 89 but with a gen V goodwrench crate motor. I don't know the history of it.

The injector number is "GM 52352 (8 or3) 1 * ? PD

**1project2many** · 07-03-2014

Maybe that is causing the problems. That is how I was able to connect 2 O2 sensors because the harness had 2 spots for them. I don't have the original emissions label.

Is it a single wire plug? What color wires are on the ECM side of the connector? If not purple (probably green or black w/ white stripe) it's not O2.

4 letter BCC means not an early calibration. There are some 7747 BBC calibrations.

We'll get this figured out. ;)

**yellowsnow** · 07-03-2014

Both O2 sensor wire are purple/violet one is by the relay on passenger side and the other on drivers side close to the brake booster. Both had the O2 sensor clip on the end, so I just bought some O2 sensors and hooked them up. But the harness was from the truck, not the engine but it also had a 1227747 ECM.

**EagleMark** · 07-03-2014

Someone has messed with it. That ECM can not run 2 O2 sensors. Check wiring and remove one!

No luck in my search of a ANVA But ANUA comes up as a 7.4L Manual 1227747

5235231 - Red / Blue - 80pph - 7.4L / 454 - 88-90 Got the big injectors!

**1project2many** · 07-04-2014

Both O2 sensor wire are purple/violet one is by the relay on passenger side and the other on drivers side close to the brake booster. Both had the O2 sensor clip on the end, so I just bought some O2 sensors and hooked them up. But the harness was from the truck, not the engine but it also had a 1227747 ECM.

The connector on the passenger side is not for O2. Disconnect it. I can't remember what it is... possibly TCC diagnostic wire. But as I remember, O2 should be on driver's side

**yellowsnow** · 07-04-2014

Alright, I fixed it some how. I replaced the riming chain which was stretched with a lot of slop, That was getting finished up when I started this post. I unplugged the passenger side O2 sensors, and I installed a knock sensor just for the hell of it.

So now I set the timing to 4, then hook the wire up and it goes up to about 16. It would never do that before. It was stuck in limp mode before. That was like the main thing that didn't make since.

So now it seems OK through out the throttle range. It seems kinda of week for a big block though. Makes me wonder if the ECM mapping is really tame.. My brother is a computer programer and programs microcontrollers for a living. Maybe I can get him to tweak the chip. But he has never messed with vehicle chips before. I probably need a better cam though. The stock cams are tiny.