Elect A4 to non-elec, LS
Elect A4 to non-elec, LS Putting a 99 5.3 into an old car. I’d like to keep the TH350 in the car, but am wondering how much of the 5.3’s A4 electronic transmission stuff I need to route to the PCM (and wire to “something” on the car) for the engine to start and run. I’d like to remove wires that I don’t need. I’ve read the LT1swap site and see what he shows can be removed for a non-elect trans, but wanted to ask those with experience.
For example, I know pin 34 gets a ground when in park/neutral, but I’m not sure that is required. The car already has a safety switch to inhibit the starter. Does pin 34 need a signal at all? I understand that’s how the computer knows it’s in gear or not, and thus may affect idle, but will the PCM allow starting if this isn’t grounded?
Is there anything in the programming I need to adjust so the engine/computer work well with the TH350 as obviously it won’t be getting all the signals back from the transmission that it expects. Will the computer get confused if all the settings in the PCM are for a elect A4 and it’s not getting anything back? Are there check engine things I must turn off too?
For example, I know pin 34 gets a ground when in park/neutral, but I’m not sure that is required. The car already has a safety switch to inhibit the starter. Does pin 34 need a signal at all? I understand that’s how the computer knows it’s in gear or not, and thus may affect idle, but will the PCM allow starting if this isn’t grounded?
Is there anything in the programming I need to adjust so the engine/computer work well with the TH350 as obviously it won’t be getting all the signals back from the transmission that it expects. Will the computer get confused if all the settings in the PCM are for a elect A4 and it’s not getting anything back? Are there check engine things I must turn off too?
Teching In
Joined: Oct 2019
Posts: 44
Likes: 9
From: Phantombullet
For example, I know pin 34 gets a ground when in park/neutral, but I’m not sure that is required. The car already has a safety switch to inhibit the starter. Does pin 34 need a signal at all? I understand that’s how the computer knows it’s in gear or not, and thus may affect idle, but will the PCM allow starting if this isn’t grounded?
That said, its not a bad idea for the PCM to know its in P/N or a gear, it does help with tuning (especially with cams and tight converters), so if you already have a working safety switch it wouldnt be too difficult to give pin 34 an earth should you need to, and can do this later on. With large cams the airflow requirements are quite different in P/N vs gear at idle, so when you pull it into gear it helps when the PCM knows whats going on and can apply the different settings, which can be tuned.
Is there anything in the programming I need to adjust so the engine/computer work well with the TH350 as obviously it won’t be getting all the signals back from the transmission that it expects. Will the computer get confused if all the settings in the PCM are for a elect A4 and it’s not getting anything back? Are there check engine things I must turn off too?
