Yep. Sensor plugged in.

 

So, so?? Since it's all runny now, how is it?

See if you can get injector opening time from the supplier, otherwise there's a little test you can do: Set injections per cycle to 4, or 1, and see if it gets leaner or richer. If at 4 (verses 2) inj/cyc, it gets richer, your open time is too long, make it a little shorter. When it's pretty flat, you've got it right.

 

I'm still cleaning up the install, but I can get the car to idle and rev so far.

However, I cannot get the fans to shut off. Going in to the output port settings and configuring the middle LED to trigger the fans does nothing. Disabling the LED does nothing. Reconfiguring the thermosistor figures has no effect as well.

 

I think on the menu, it's not the middle one. I think on the menu, it's the WarmUP LED. Otherwise, we'll have to trace some wires back, find out what controls it, but that's how I like to set them up.

 

Once again, Abe is man. It took more time for me to solder in a new transistor than it did for him to diagnose the problem, from 3,000 miles away, over IM.

My last issue preventing me from driving is the voltage regulator situation. I have the GM regulator grounded, and hooked up to the two wires leading from the MS harness. As the car is running the battery voltage steadily declines until the car stalls.

Well, there's one other issue. I screwed up the IAT sensor and have to wait for a new one from DIY. There isn't a GM dealer within 100 miles that had one in stock.

 

I'm worried about this IAT thing, so I really hope there's nothing in the MS cooking it. It's almost impossible to imagine that happening, but still. If it were me, when I put in the new one, I'd put an amp meter in there, if it read over 250 mA I'd shut it off and figure out why.

 

0 mA across the signal wire from the IAT.

Plugged in or unplugged Megatune shows 70 degrees regardless of actual temperature.

 

Er, across? You mean... "in series with"?

Is that with the new sensor? You should measure the resistance of the sensor, just for kicks. :-)

 

What, across isn't technical?

Yeah, in series, sorry.

The new IAT sensor read 4k ohm at 40 degrees. Resistance drops as temp rises. MS doesn't respond.

 

Ah, good, more troubleshooting!

Well, we want to know what the ground is. First, if there was enough current to melt the other one, perhaps you blew up something in the MS. First thing first: Measure the pin (you can look up the number on the jimstim), find the resistance from that pin on the DB-37 of your harness 'boomslang' to ground. It should be ~4k or whatever the sensor is.

If that's bad, the trouble is the wiring. If it's good, the problem should be in the MS. Does the AIT work on the jimstim?

 

Go figure. If you use a waetherpack to make a connection, you should probably make sure it is plugged in if you want it to work.

So now I can get the MS to recognize the IAT sensor, but the values on this page of the megamanual produce some less than believable numbers on the megatune dash.

Wiring and Sensors

What numbers should I be using for the GM open IAT?

 

I'm pretty sure it's a default setting, like, when you go to calibrate it, it's right. That might be another configurator issue.

Otherwise, I guess I'd try their chart:

GM Temperature Sensor Resistance
Degrees F
Degrees C
Ohms
-40º
-40
100,700
0º
-18
25,000
20º
-7
13,500
40º
4
7,500
70º
21
3,400
100º
38
1,800
160º
71
450
210º
99
185


I think that makes sense. But you shouldn't have to do this.

 

Swapped in a NA internally regulated alternator. New battery as well.

Battery voltage is 11.78v when running. When the fans come on it drops down to 11.10, but voltage goes back up to 11.78 as soon as they cut off. I've verified this with a multimeter.

I'm stumped. The voltage should be at least 12.5 at idle.

 

Huh, yeah - they are internally rectified, right? It would seem like you have something pulling the voltage down. I guess you should start reading currents? Your meter might not be good for this, you might want a sense resistor (put it in series, measure the voltage accross it and calculate).

It's hard to imagine how you could do that without blowing a fuse. Did you rev the motor up tp ~2-2.5k, just to make SURE that the alt is running at full steam? You could pull fuses one (start with the big ones in the engine bay) at a time till you find out what's doing it. perhaps the wideband is taking that much current? Can't be the MS cause it would burn up. :-P but worth checking, check the current out of hte battery and unplug the harness.

 

I just read all of this, twice. This thread needs A LOT MORE PICTURES. Like take clear, well focused pictures of everything imaginable. Shots of the MS board, zoomed in on pics of different areas of the board, both sides, pics of wiring harness, pics of how each sensor is wired, etc.

Is one side of the AIT sensor hooked to ground of +12V? Should be one side to ground, one side to MS.

Give us an update in one post that has:

Everything that's working:
Everything tha't's not working:

Cause I had to read this twice to try to figure out where you're at.

NA alternators are internally regulated and rectified IIRC.

Also posting some DATALOGS of the engine running would be very beneficia to you.

All of this would help....

 

Once thawed out I thought about this some more.

The NA alternator needs an exciter wire to start charging, correct? I don't think I have this, since the two wire plug at the alternator essentially goes nowhere as the 1-B and 1-O pins at the ECU aren't connected to anything.

I'm going to build the two 12v keyed connections the '97 wiring diagram shows and see if that'll kick the alternator on.


EDIT: It looks like the two pins at the ECU that control voltage are 1-O and 1-T, not 1-O and 1-B.

 

Uh oh, that might need some digging into. :-)

 

Good to go, 14.8v at idle.

On to tuning.

 

I kinda feel like a tool if that's on the wrong wire. Not that I remembered to check. :-)

 

Yep, wow, looks like you're right - on my car I did it all in the engine bay, so I didn't know I had the other wire - 1-T is the one you want to control, not 1-O, which is likely how I had it, since apparently that made it into my notes. It's clear as day from the wiring diagram, it controls the field coil.

This may lead to another via. :-P Thanks for catching this!