Leaderboard

I just ran through it again. at 3:17 it is closed loop and it is lean.

I don't believe there is any more that can be done for the peculiar information that comes up when viewing ECM data, as well as a single item in BCM data. The new Prom made no difference in the way data is displayed. The data does display the correct code for the ANCX Prom, so at least that worked. After a careful examination of the ECM and BCM data it was determined the data is in fact correct and displayed in the correct order but 2/3 of the labels or descriptions are incorrect. Essentially, if this was a 90 or 91 with only the data identifier number and the data itself, this wouldn't be a question. This case is closed for now. My son is pursuing the possibility of a slow leak in the a/c system but the system held vacuum overnight and using the R12 we had on hand at the time, which is a few oz. undercharged, the system is working for now.

Ok, I found a photocell. Not only does it work, it also cured the B119 error. BD44 shows values between 10 and 90. ...but still no background illumination. I'm starting to run out of ideas. The inverters?? Power supply module?? BCM?? Any suggestions? HAHA! My bad. Forgot to reconnect that 2A12-wire. Without that there is no power to the luminescent foil and the inverters. Gotta try that next.

Nice videos! I wondered the same as others when I watched the O2 in the rich zone, (above 450mv),and the fuel integrator locked at 128. That must have been at idle, and it is not unusual for the O2 to cool off and stop doing its job. When revved up a bit it started to go rich/lean and the integrator floated around 128. It will always read 128 unless in closed loop. That is pretty normal. Idle conditions, especially extended idling, will go rich. I am not certain why that is but it is one way to keep the catalyst in the converter hot. Your numbers, fuel pressure and engine sound are pretty good. Nothing jumps out to me. Even the FSM will tell you that the engine speed must be raised for a period of time to get everything online, even if the engine coolant is hot. Today, faster computers, heated O2 sensors and O2's before and after the cat are normal. Not so 30+ years ago.

I think that would be a good idea. When in open loop the ECM is operating on data tables stored in memory. When it goes into closed loop the ECM starts looking at the O2 sensor and probably other sensors as well to determine the proper fuel mixture. The readings you show in your video aren't the true readings you will see when the engine is in closed. loop. The ECM should be operating in closed loop by 170* under normal conditions. If not there is a problem keeping that from happening. See if you can get it to go into closed loop and post another video of your readings. By the way, you did a good job on the video. Very helpful. that looks like a really good scanner.

Did your O2 Sensor ever switch to LEAN? Have you done any checking of it? Jim

I posted to YouTube 2 videos. Fuel preassure test and diagnostics. Im not sure what to make of the B411 and E47h codes. Fuel preassure readings... Diagnostic readings...

Hey all, I got rid of the flickering, the problem persists though. Today was the day of Deconstruction. 😄 First of all (and unrelated to the flickering), I noticed that I have no background lightning on the switches and gearbox lever. That's when I remembered that I had a photocell code b119 in service mode. When I looked for the photocell I noticed someone hat crammed a 20amp fuse in the spot. There is no photo cell in my Buick. We then removed the ICP and noticed that a tab was broken and a plactic piece of one of the connectors was missing. Also, two pins in the back were bent (one on each connector). Somebody must have tampered with it before. So we straightened the pins and tested, no improvement. In the meantime I had bought another IPC from eBay, so we tested that one, still no improvement. We then checked the plugs on the BCM. Everything fine on that side. That was confusing. It's not the IPC, it's not the Photocell. The IPC must get weird signals, that's the only remaining options. So we tested a radical idea. We cut the 2A12 wire on the BCM plug (see red markings on the attached image). The 2A12 wire is a grey wire that controls incandescent dimming on the ICP. Cut the wire and attached a plug (so I can reconnect later). And -lo and behold- the flickering is gone and the cluster is dimmable (even w/o the photocell). So, workaround found. But what about the problem? Do I have a faulty BCM, because it sure feels like it? Thanks Pip Edit: Clarification: only the fluorescent bit of the cluster and the CRT dim. Not the bulbs.