'87 350 TBI, custom application, looking to go bare-bones

[Mrgto68]

Your IAC will rise up too. Eventually O2 and closed loop will change too. If you don`t want idle setting over programming, why don`t you mount a manual choke to the gas pedal?

I looked to your xdl and imported it to excel. I fear if you want to reach your goal, you have to programm the memcal.At the moment the border line for switching to closed loop seems to be at 800 rpm.You may detect that if you hold your idle speed at constantly 825, your desired rpm) for a while.Have a look to column BD (closed loop) and column BR (rpm).
Engine was not fully warmed up when you stopped your logging.No fault codes at the moment.But have a look to excel yourself. Rename xuza.txt XUZA.xls.

Thanks for looking this over for me. I'll run a log again, I must have somehow stopped the logging sooner then I thought.

[mecanicus]

You have the wiring diagramm from SOOB, there you can see pin B8 is coming from A/C pressure switch. Try to give it a minus signal alternatively a plus signal, if you are lucky, rpm will rise a bit!

[Mrgto68]

[QUOTE=1project2many;74246]I'm sorry, but I seem to be having trouble seeing the relay or any of the wires attached to it. Maybe you have a wiring diagram and can match up wire colors?

Sorry about that, On the firewall there are two relays, the one on the left is the Fuel Pump Relay. It was already removed so that photo only showed what I believe could be the TH400 relay. Here are two photos, one showing the Fuel pump relay on the left which was removed and the relay in question.

I cleaned up the wires, the colors are a little faded, but it looks like orange, tan/blk, red/blk, brwn/blk?

relay2.jpg
relay1.jpg

[Fast355]

[QUOTE=Mrgto68;74258]

I'm sorry, but I seem to be having trouble seeing the relay or any of the wires attached to it. Maybe you have a wiring diagram and can match up wire colors?

Sorry about that, On the firewall there are two relays, the one on the left is the Fuel Pump Relay. It was already removed so that photo only showed what I believe could be the TH400 relay. Here are two photos, one showing the Fuel pump relay on the left which was removed and the relay in question.

I cleaned up the wires, the colors are a little faded, but it looks like orange, tan/blk, red/blk, brwn/blk?

relay2.jpg
relay1.jpg

The 87 G20 305/3spd auto Van I put a 6.0L into had the same part number relay as the fuel pump for the kickdown for the 3L80 aka late model TH400 with a 350 output shaft that was in it.

[Fast355]

The A/C on signal is +12VDC off the cycling switch.

[Mrgto68]

The A/C on signal is +12VDC off the cycling switch.

Ok, so If I connected 12v to the AC wire from the ECM, this in theory should then increase the idle?
If it does, then I could Mcgyver up a "fast idle" switch by running that AC wire to a switch.

This could solve one of the problems.. Thanks for the info!

[mecanicus]

Ok, so If I connected 12v to the AC wire from the ECM, this in theory should then increase the idle?
If it does, then I could Mcgyver up a "fast idle" switch by running that AC wire to a switch.

This could solve one of the problems.. Thanks for the info!

Hello, i fear you have to set rpm manualy by a choke.
I opened AHWZ.bin ( you can find it here on the forum) with the $42.xdf
Wenn looking to scalars I found that there is no acceleration for A/C.
Off course can you give the eprom to s.b. here on the forum to change this setting!

[Mrgto68]

The 87 G20 305/3spd auto Van I put a 6.0L into had the same part number relay as the fuel pump for the kickdown for the 3L80 aka late model TH400 with a 350 output shaft that was in it.

Ok, so you're saying that the Relay I have in those photos are in fact the correct wires and relay for the TH400 trans?

[Mrgto68]

You have the wiring diagramm from SOOB, there you can see pin B8 is coming from A/C pressure switch. Try to give it a minus signal alternatively a plus signal, if you are lucky, rpm will rise a bit!

On the new wiring harness there's a wire labeled AC Pressure which I haven't connected to anything.
Please forgive me, what do you mean when you say give it a plus signal or minus signal?

[mecanicus]

On the new wiring harness there's a wire labeled AC Pressure which I haven't connected to anything.
Please forgive me, what do you mean when you say give it a plus signal or minus signal?

I do not have a complete wiring diagram of such a car, but normaly ecm is controlled by minus signal (earth, ground). If the A/C pressure switch will ground that wire, you may do that manualy (by a switch) thus rpm could rise up these rpm`s you need even when engine is idling. Somebody mentioned this earlier in that thread.
"AHWZ",is that your memcal? what is XUZA?

[Mrgto68]

I do not have a complete wiring diagram of such a car, but normaly ecm is controlled by minus signal (earth, ground). If the A/C pressure switch will ground that wire, you may do that manualy (by a switch) thus rpm could rise up these rpm`s you need even when engine is idling. Somebody mentioned this earlier in that thread.
"AHWZ",is that your memcal? what is XUZA?

Thank you! I'll do some more research on the AC Signal, I don't want to guess and fry my ecm. ;-)


AHWZ=
20190217_114932.jpg


XUZA is the name of the rig. :-)