Tbi 4.3 Troubles

I advanced the timing 4° from yesterday... would not restart.
Got it running and set it 2° ahead and went on my way. It's Better but there is still a bit of choppy chop at highway speed (55mph with 5.38s)

I'm gonna order the aldl adapter, map sensor, and rework the exhaust in a month or so from rotten out 2" duals to a single and see how it goes.

 

I was rereading your post and I have some questions. In your first post, you said "Ever since I built my 4.3 it's been a pain to tune and has never been "right"." The way that was written, it makes me believe that included the time before the TBI system was installed. Did this ever get resolved before the TBI installation or was that the purpose of the fuel injection system upgrade? And if so, did it fix your problems and run properly? In post #13 you said, "The fella that did the tune was the seasoned pro so I'm confident it is something simple that is on me to fix I'm just not too keen on what the smells and tastes indicate." Did this fellow or anyone at Affordable Fuel Injection follow up after the installation with a request for a data log of the vehicle running and driving to confirm the system was operating as programed or correctly for that matter? You also said, "I'm gonna order the aldl adapter, map sensor, and rework the exhaust in a month or so from rotten out 2" duals to a single and see how it goes." Why buy the adapter cable unless you have a scanner that will read obd1 codes? If you do, it will not tell anything more than the fault code 33 as indicated by the check engine light. You can get a sense of the condition of your map sensor and circuitry with a vacuum gauge and a digital volt ohm meter before spending any money. Does the gauge show low or good vacuum? With the VOM, you can check map electrical circuitry for shorts or opens, measure the 5 volts to the sensor, ground on another lead and the third is the signal back to the ECM. Of course, a good sound exhaust system is very important for this EFI system to operate correctly.

Which ECM did Affordable provide for this project? There were two ECMs that GM used in this era for their TBI system with each using a different code to control the system. You should find the GM ECM number on the case. It will look like 1227747 or 1228062.

 

Sorry for the delay, busy day.
Soo the 4.3 was built to drop in place of a 3.3l that took a swim. Exhaust manifolds, waterpump, accessories. Every thing I could but looking back I should have kept the Rochester 2bbl carb and intake. Instead I put a used 4bbl Q-jet on it someone gave me. And the stock 4.3 distributor had to be converted from a 5pin to 4pin hei. I swapped out weights and springs and took it to my old college and we ran it on the distributor machine. However it kept hitting the firewall and throwing caps into the rotor. The q-jet was not easy to adjust and I'm not that great with carbs anyway so eventually my wife gave the green light to get the tbi.

... to be continued after bathtime.

 

I do have a cord for USB to obd2 so the adapter would simply make my existing cord pin out the same as a $70 aldl to usb cord.

The death of the 3.3l was a bit drawn out..
See I misjudged the depth of this puddle and managed to walk on foot between the full size truck ruts...

1122111417 by Joe the adapter guy, on Flickr

I had a open element air filter and the fan was throwing mud everywhere. The engine never hydrolocked but it was definitely taking on water.
Eventually I dragged the rig out backwards and the exhaust was full of mud. It fired right up and I made it an hour or so on the highway before running out of gas. I hosed out the exhaust several times now but there is the chance that that mud was mostly clay and is now pottery in my muffler. (It's all torn up and needs replaced anyway) that old engine was loosing oil out the exhaust.

1124111022 by Joe the adapter guy, on Flickr

This motor did pull good vac at idle with the carb even with the relatively big cam. But it had more flat spots than my bald head. One day I went to my inlaws with the pop-up in tow and the accelerator pump crapped out and I was done with carbs. the tbi starts every time and runs reliably but I just wish I could get all my ponys out of it.
20190905_072353 by Joe the adapter guy, on Flickr

 

Further detail to respond, no this has never had a data log done and I believe I would need the cord and software on my pc to do that. I don't see ECM number on the case, if it is on the back it is covered by velcro. Here's what the guts look like (just visually checking for shorts and bugs). I'll get the volt meter to it after work if I have time.

 

I thought I read that AFI only uses the 1227747 system.
But still... Reposition and test map sensor. Replace exhaust. Then check fuel pressure with speed and load.

 

I don't think that is a 7747 ECM, the Cal-Pak looks to be soldered in place. 7747 ECM's have removable Cal-Pak's just the the Prom Chip.
Do you have a functional check engine light? Any codes stored?

 

I'll stick a paperclip in it before I roll out from work, but I did just unplug the brick for the pictures. I want to swap the lines for the map and wipers and see if that makes a difference.

 

If you look at the AFI website, the picture shown of the ECM used in their Legacy kit has the GM number 1228062 stenciled in the lower right corner. What the GM number tells you is, the computer program used when the ECM was installed in the vehicle. The 1227747 number indicates an earlier program developed for TBI. The same ECM could have either program installed. At this point in time, it probably doesn't matter much unless you want to dive in deeper into the ECM programming or datalogging.

Is the engine still pulling the 21 inches of vacuum as shown on the gauge when the carburetor was installed?

 

How exactly do you have the map sensor installed. You said something about switching the wipers and map lines.