350tbi sluggish and fuel guzzler

[EagleMark]

With the key off the data is just what it changes to when off, it's not data from ECM. Just worry about what data is doing when key on and running is even better.

What chip do you have? Is this the thread I read that may have a TH400 Chip and now you have a 700 R4? Besides the chips being different so is the wiring...

[alkatyler]

The donor had a 700r4 also, but I will check the chip and see what it is.

I tried to keep everything the same from donor to mine. I am going to check the tcc solenoid today. I should be able to see if it is hooked up and operable.

[Fast355]

The donor had a 700r4 also, but I will check the chip and see what it is.

I tried to keep everything the same from donor to mine. I am going to check the tcc solenoid today. I should be able to see if it is hooked up and operable.

Sounds like seperate issues. When I converted my 1983 G20 to TBI, I used the reverse switch that had the built in Park/Neutral switch from the donor 1992 G20. The Park/Neutral switch gets the Park/Drive working correctly. The ECM needs this knowledge to anticipate shifts into gear to help control the idle speed. As for the TCC in the tranmsission. If your truck was non computer feed back and you used the old 85 700r4 and the stock 85 wiring, it is way wrong for the 87+ TBI. The older setups had multiple pressure switches and a vacuum switch. If you simply hook the TBI harness to the older unit it will lock anytime the transmission is in 2nd gear or above and could be very noticeably sluggish. I had to rewire my 83 unit and change a pressure switch. At the time (2005-2006) I picked up the parts I needed from GM using the 1992 G20 parts van VIN, however they are likely discontinued now.

My first TBI setup was on an 83 305 with a 204/214 cam in it. The second was the same 601' 305 heads and a 204/214 cam on a TBI 350 long block with an edelbrock performer RPM intake and headers. The next was the same short block, with a production LT4 203/210 roller cam, ported 193' TBI heads, and an edelbrock 3704 intake. All 3 setups performed very well.

[alkatyler]

the chip is a ARJT
The 700 R4 has a 3 wire plug going into it. I am going to pull the pan tonight and follow up on the wiring and replace an overdue filter change. I pulled down the ECM at the same time so I can check the wires out.

I will give an update when I get everything put together.

[alkatyler]

So...I found a problem with the wiring. The transmission wire was not seeing the signal from the computer. Fixed this along with the park sensor and it seems to shift better. At least I notice the torque locking up and it unlocks if I touch the brake slightly.

When I ran the new log on a longer trip down the interstate, I noticed it would now go into high gear and out.

One thing I don't see is the timing advancing or retarding? it just stays at zero?
I can upload the new log and hopefully you can see the changes.
The truck seems to have more zip when it is cold and in open loop just after being started, than it does in closed loop and warm? just feels kinda doggy and sluggish. I do still have the timing set at base of 0. There is a 180 thermostat in the engine, is this too cold?

[alkatyler]

Here is my latest log driving down the interstate

[EagleMark]

Unless you have added the Spark and BPW patch to the chip there is no Spark Advance in the data of a 12277747 $42 ECM. That is an option I added in...

IIRC these motors came with a 195 thermastat.