3.4 V6 advice

[ezrollin]

The tb off of 4.3 astro/safari was the only one that had the bracket on the proper side that I could find and the inj 0 rings take care to keep in place when rebuilding.

[geoffinbc]

All TBI units with the new style TPS have the throttle cable bracket holes.

[stimey]

The salvage had this TB tagged Astro, but it didn't have the drilling for the brkts. Your correct there isnt very much meat there for drilling, but if you are carfull it can be drilled out fine. I had to use some spacers on the top two holes because the bosses were not at the same height as the bottom single hole. This all went really good, I had no idea how to adjust the TPI so I just paid close attention to the position when I took it off the 2.8 TB. I still don't know how to adjust it. As far as the throttle lever I forgot all about the until I had everything bolted down and hooked up, so I had to get inventive. I just drilled out my throttle cable end a bit and went with an e-clip, and the kick down cable was fine after a little shaving down the thickness of the stud sticking off the throttle lever.

[jwvess00]

Hi there!

Newer TBI units don't have adjustable TPS arrangements. Unless the sensor you're using has slotted mounting holes, it's not adjustable.

[stimey]

Thats mine, it is slotted on each bolt attachment, I could swing it several degrees both directions.

[jwvess00]

Hi there!

The TPS should be adjusted to 0.50V +/- 0.05V with the throttle closed. You can measure across the TPS sensor signal and ground wires (do not use part of the vehicle for ground, use the sensor's ground wire to avoid potential issues with ground shifting) with the key on, engine off. I use some thin solid-core wire slipped between the TPS connector and the TPS itself, though it's possible to back-probe the connector iwth the right meter leads. I don't remember which two wires are the right ones, but there are only three TPS wires (5V, ground, signal) so a bit of probing around will find the right pair.

The other adjustment is "minimum air" and is also simple:
1) Jumper pins A&B on the ALDL connector.
2) Key on, engine not running. You should hear the IAC trying to extend forever (clicking sound). After ~30 seconds, with the key on, unplug the square 4-pin IAC. This forces the IAC completely closed and prevents the ECM from trying to move it later.
3) Start the engine and let it settle into an idle.
4) Adjust the throttle stop screw (which when stock is hidden behind a small metal plug in the TBI casting) to get to the minimum idle speed (500-600 RPM usually). The ECM cannot command a slower idle than what you set here, so it needs to be a bit slower than it ever needs to be.
5) Stop the engine, reconnect the IAC. After doing this, you will need to adjust the TPS.

[stimey]

Thanks jwvess00 that is what I needed, that is perfect, I like having things right. I just put the 4.3 TBI on and was expecting to have a rich idle. I think it is quite opposite, I am afraid that I might be running lean. I plan on hooking up a meter in the next week and just see where I really am, but would like to get all the other things set at the same time so i have a true picture of things. I don't even drive the S-15 at the moment, but shortly will be my daily ride and don't want to burn an exhaust valve. Thanks again

[stimey]

Just an update, 3.4 is running really nice, still cant get the idle down quite as low as i would like, still have some tuning to do. Posted pics on the S-15 in my avatar and the garage.