Still working on my 3800sc harness. ( wired as a 1998)When I stopped awhile back, I was looking for a pigtail for a 88 fiero OIL PRESSURE SENDER, now where do the wires get "Pinned to "? can't find oil pressure in the GM tuner Charts. Thanks
also, for the ac, I've got the wires run to the compressor, is the "Line Pressure wires" for a pressure sender like the one at the drier up front? ( that is in a front wheel drive cars compressor line) thanks

anyone ? A Link ??

The oil pressure switch (fuel punp) and pressure sender, wire into the connector in the console by the computer. Larry

The oil pressure signal wire goes to C203 pin E. It should be a tan wire. C203 is the medium sized clear colored connector under the armrest.

For the A/C, I can't help with a specific solution unless the compressor is from a Fiero, but generally yes, there should be an A/C cut-out switch on the compressor that opens above a certain pressure (425 psi on the Fiero) and, depending on the model, there may also be another switch as well.

quote Originally posted by Lou6t4gto: Still working on my 3800sc harness. ( wired as a 1998)When I stopped awhile back, I was looking for a pigtail for a 88 fiero OIL PRESSURE SENDER, now where do the wires get "Pinned to "? can't find oil pressure in the GM tuner Charts. Thanks

Oil Sender A -> C203-E = Oil Pressure
Oil Sender C -> Ground = Oil Pressure Ground
Oil Sender D -> C2-19 = Oil Pressure Signal

quote Originally posted by Lou6t4gto: also, for the ac, I've got the wires run to the compressor, is the "Line Pressure wires" for a pressure sender like the one at the drier up front? ( that is in a front wheel drive cars compressor line) thanks

1. Did you use a relay for the compressor wires?
2. Are you talking about the A/C Pressure Sensor? That is a round plug that hooks into the A/C line between the compressor and the firewall line.

A/C pressure Sensor A -> C2-35 = sensor ground (A/C press, term M of Trans Temp)
A/C pressure Sensor B -> C2-34 = 5 volt reference B (A/C pressure sensor)
A/C pressure Sensor C -> C2-27 = A/C refrigerant pressure sensor signal


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-Brian

My 87 GT Poly Suspension Upgrade (all pics) thread
Removing the roof panel
My HUD install thread
Modified stock air canister and base to 3.5 inch for 3800na

Isn't it strange that after a bombing, everyone blames the bomber, his upbringing, his environment, his culture, his mental state but … after a shooting, the problem is the gun?

[This message has been edited by MulletproofMonk (edited 10-08-2013).]

I AM using a 4 cyl Fiero Compressor on the 3800SC. I am also using the Stock Fiero AC Lines.( fiero lines have no pressure switch by the engine), that's why I'm thinking to just use the one by the Drier up front ( or will the pressure sensor work off of a Switch on the back of the fiero Compressor. ( I know, no one else uses a Fiero Compressor), but I changed the pulley/clutch over from the 3800 buick and it bolted right up. Thanks

Ugh. Good luck with breaking some new ground! That is how we learn... For better or worse. LOL

I don't think MulletproofMonk's oil pressure wire description is accurate. The FSM shows it this way:

Oil pressure sender pin A -> Fuel pump relay pin D -> Fuel Pump Fuse (all orn/blk wire)
Oil pressure sender pin C -> splice S509 which branches off in 3 directions: fuel pump relay pin B, ALDL pin G, and C203 pin L onwards to the fuel pump (all tan/wht wire)
Oil pressure sender pin D -> C203 pin E -> Oil pressure gauge (signal)

For the A/C, if the compressor is originally from a 4 cylinder car as you say, then forget about what I posted earlier. Here is what you need to know: there are two pressure switches located on the back side of the compressor. Each has a pair of wires going to it. The low pressure cut-off switch has a light green wire and a grey/red wire going to it, and the high pressure cut-off switch has two grey/red wires. They are wired in series meaning that if either one opens, the circuit is broken.

In the stock Fiero configuration, the power runs like this:

HTR/A/C Fuse -> A/C control Head -> Low Pres Sw -> Hi Pres Sw -> Splice S512 going to two locations ->A/C compressor control relay (coil, pin A) then from coil ground (pin C) to ECM which switches the relay coil to ground when commanded;
AND, Splice S512 also goes to a separate ECM pin to alert it to ramp up the RPM to compensate for the extra power needed to turn the compressor.

How you need to hook these up to your new ECM is what you'll need to figure out.

[This message has been edited by Bloozberry (edited 10-08-2013).]

For the past 4 years, I Have had NO pressure switches hook up at the back of the compressor of my 4 cyl car. ( the pressure switch at the front by the drier should shut down the compressor if the pressure drops) ( haven't had any problems in over 4 years). Now I'm going to use a "Like" compressor on the 3800 ( already installed on the engine, lines up, belt on, ac hoses will bolt right on) Once I've got the green wire from the comp Clutch run to the relay, (here's what I'm thinking,) if I just "Jump" the 2 wires at the ac "pressure LINE Switch" (Used on the 3800,) the compressor "should" work like it is now in the 4 cyl car. What do you think ??