5-90

The input voltage is a reference voltage provided by the ECU. It is known to drift and decay over time - which is why there's a feedback loop in the ECU to keep track of it.

This is also why the procedure is to adjust the TPS output to either 17% or 83% of input voltage, and not to an absolute number. 83% of +4.8VDC is 3.984VDC, 17% of 4.8VDC is +0.816VDC. Use whichever value your procedure (transmission) requires, after you check my math!

blazer 2008

Thanks for the help,the problem was back probing the wires,not a very reliable way with paper clips but tryed again and made a good connection and got my 4.82 reading

cruiser54

How's it working?

blazer 2008

No more erratic shifting but I don,t have enough idle to keep it from stalling,I,m sure I have to change the IAC,it was getting a little erratic on cold start ups.I just have to keep my foor on the gas a little to feather it when I stop until I get my new IAC

5-90

Paper clips work - I just prefer quilting pins (I get the packet with various head colours in, get a couple of each, and round them off as needed. Store them in a piece of corrugated cardboard, which is made with "little tubes" running through it - the corrugations - that may as well be purpose-built for such a thing.)

The head colours get written on a note as they get inserted, so I can tell what colour probes which wire. Set it all up, then probe and test at will, having access to each circuit with ready visual ID.

cruiser54

Adjust your tPS using the "engine" side connector per my instructions and you'll probably be just fine.

Cjjcalhoun

Cruiser,
I followed your steps above and replaced my TPS with positive results. I was getting the engine rev (2500-3K) at start up. Now I don't. Problem is I have about 50 ohms, give or take five, on my ground. You said above that you had a procedure for fixing this? I have just replaced my engine and I know my grounds at the dipstick stud are clean, and my engine seems to be running great, little excessive cranking for electronic timing, but great. Any tips would be appreciated.

cruiser54

My latest write-up addresses your issues. Need a soldering gun and shrink tubing. See Post 27 in my tips below for photos and all. But, I'll post the text here. Should take less than an hour to do.



C101 connector elimination

Unbolt the 2 halves of the C101 using a ¼” socket. On each half there is a plastic cover where the wires enter. They are removable but you'll probably end up busting them off. Lightly bolt the C101 back together, away from the firewall. Peel back the split-loom covering from the body side of the C101 connector down to where the harness splits and goes toward the firewall, pretty much below the MAP sensor. On the engine side, remove the split loom about the same distance. See first photo.

Now you can see from one side of the C101 to the other. Beginning at the top row, closest to the motor, be absolutely sure you cut the matching wires on each side of the connector off to about 1/2 inch. This will allow you to verify the original position of each wire color in case of mistakes or confusion. CUT AND SOLDER ONE PAIR AT A TIME. The wires may be wound a bit in their looms. See the first photo. Get them unwound neatly and do the following, ONE AT A TIME.

Slide your shrink tube over one wire. In a well ventilated area, solder the wires together and then slide the shrink tubing over the solder joint. Heat the shrink tubing so it seals your completed solder joint. Keep going until you've done all 22 or so connections.

Both sides of the C101 connection have a wire that is brown with white tracer. Follow each of these wires back until you come to a point where three wires are crimped together. See the second photo.

What you want to do here is cut the crappy factory crimp out of each set of three and bring both sets of three wires together and solder them together, using shrink tubing as well. All 6 wires. These particular wires will not end up in your normal C101 elimination loom. See the third photo.

After all the soldering and shrink tubing is done, bundle the wires together in a new piece of 3/4" split loom. Tape it up and secure it to the C101 connector's original bolt hole or somewhere else along the firewall so it will be protected. See the third photo.

Revised 03-06-14