I have had this topic on the Cadero List for a while, but thought I would give a different crowd a wack at it.

The car gets 30+ MPG on the highway, but about 8 mpg in town. The joke is that I can measure fuel in Gallons per hour. As it seems to get the same fuel economy sitting in traffic as it does flying down the highway at 90mph.

The only error code I am getting is low voltage to the fuel pump but watts, who did the harness for me says it is probably just a misplaced wire.

The ECM says Rich Condition, I can see and smell raw fuel, but the ECM does not seem to want to do anything about it.

My air fuel gauge on the dash will show it going to stoich and lean when under deceleration but as soon as I touch the gas, even crack it 1/16 throttle everything pins full rich.
It is so rich it is burning your eyes to be behind it and you can see raw fuel being spat out the tail pipe.
We cant figure it out. I could see if the ECM thought it was lean and was trying to make it rich. But this is just plain wacky.

Map Sensor New reads 1.00 v at idle, .50 at decel and 4.5 at WOT
MAT Sensor is from my 2.8 checked with scan tool reads correct.
O2 sensors are the Caddy ones. However read 600-900 mV Cross Counts between 0 and 6. Both O2 Sensors are reading the same
Coolant Temp sensor is correct and reads accurately
TPS reads around .59 closed and 4.55 WOT
Idle Fuel Pressure, car running with vacuum applied is 38psi. Is that correct. It seems high to me.
Inject pulse decel is 1.5ms, cruise is 3ms wot I think is about 5. (With the bad clutch I can’t stand on it long enough to get a proper loaded reading)

There is a sensor in the block driver’s side trunk side down low, it appears to be in the place were the V6 would have its coolant sensor. It is not plugged into anything. Should it be?
I am using the stock Caddy water temp sensor for the ECM and the Fiero one for the Fiero Gauge
I am using the stock Caddy Oil Pressure Switch for the Caddy and the Fiero one for the Fiero Gauge

What should the ignition timing be set at using the chip I have in here.

I really wish I could find a way to run this into a laptop and do some data logging and then send you or someone else on this list the file. Hell maybe with a data log sheet I could figure out what the problem is.

One thing I did note as strange.

When I had my Autometer O2 gauge on the Fiero sensor it moved around rather quickly, on the Caddy front bank O2 it is slow to move around. Is the Caddy Sensor slow compared to the single wire Fiero sensors.

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85GT 5spd MSD Everything,4.9 With Nitrous. www.captfiero.com

Had the same problem with mine. You need to give 12v power to the wire for the fuel pump refrence to the PCM. You also need to give 12v power to the pin for the power steering pressure switch at the pcm. I pm'ed PBJ about a similar problem with my car. He told me to do both and once I did all my problems went away. My o2 switches at idle and on the road and it gets good gas mileage all the time now.

The power steering input wire is pin C9 on the PCM. Give that power at pin F of the C203 connector (by pcm under console).
The fuel pump input wire is pin C13 (green connector) at PCM. Give that power at pin B of the C203 connector.

That should solve your problem.

Is the power steering switch input connected to +12v?

I am going to call Watts right now and see if he remembers it or not.

If he can't would someone like to give me an idiots guide to which wires I need to put 12v to.

IE Middle Plug 12th hole down from the top middle row.

If that is all the problem is, it could save me 100 bucks on new sensors.

Any other suggestions while I am in there.

quote Originally posted by Capt Fiero: I am going to call Watts right now and see if he remembers it or not. If he can't would someone like to give me an idiots guide to which wires I need to put 12v to. IE Middle Plug 12th hole down from the top middle row. If that is all the problem is, it could save me 100 bucks on new sensors. Any other suggestions while I am in there.

ohh **** .. im an idiot! haha, i forgot to mention that to you david, sorry about that.. unless there is 12+ to the PS input on the ecm, it will disable the fuel trim..from the way you describe the behavior, it sounds liek that is it.

quote Originally posted by FieroMaster88: Had the same problem with mine. You need to give 12v power to the wire for the fuel pump refrence to the PCM. You also need to give 12v power to the pin for the power steering pressure switch at the pcm. I pm'ed PBJ about a similar problem with my car. He told me to do both and once I did all my problems went away. My o2 switches at idle and on the road and it gets good gas mileage all the time now. The power steering input wire is pin C9 on the PCM. Give that power at pin F of the C203 connector (by pcm under console). The fuel pump input wire is pin C13 (green connector) at PCM. Give that power at pin B of the C203 connector. That should solve your problem.

The power steering input wire is pin C9 on the PCM. Give that power at pin F of the C203 connector (by pcm under console).
The fuel pump input wire is pin C13 (green connector) at PCM. Give that power at pin B of the C203 connector.

Thats the idiot's guide. The C9 pin is on the larger black connector at the PCM. The connectors are all labeled. It's easy.

quote Originally posted by FieroMaster88: The power steering input wire is pin C9 on the PCM. Give that power at pin F of the C203 connector (by PCM under console). The fuel pump input wire is pin C13 (green connector) at PCM. Give that power at pin B of the C203 connector. Thats the idiot's guide. The C9 pin is on the larger black connector at the PCM. The connectors are all labelled. It's easy.

Ok so let me get this straight.

If I shove(apply) 12v into Pin F on the C203 connector it will send power to C13 in the computer. Which will fix the Power Steering Pump Problem

If I cram (apply) 12v into pin B on the C203 connector it will send power to C9 in the computer and make the fuel pump error code go away.

Or just

put 12v to Pin C9 on the larger black plug going into the ECM
and
put 12v to Pin C13 on the large green plug going into the ECM

Thank you for your patience. I can rebuild and overclock the computer in your house tweak the bios, and clean any viruses from your system. But Wiring into the ECM (PCM) has got me so confused it is just nuts.

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85GT 5spd MSD Everything,4.9 With Nitrous. www.captfiero.com

quote Originally posted by Capt Fiero: Ok so let me get this straight. If I shove(apply) 12v into Pin F on the C203 connector it will send power to C13 in the computer. Which will fix the Power Steering Pump Problem If I cram (apply) 12v into pin B on the C203 connector it will send power to C9 in the computer and make the fuel pump error code go away. Or just put 12v to Pin C9 on the larger black plug going into the ECM and put 12v to Pin C13 on the large green plug going into the ECM Thank you for your patience. I can rebuild and overclock the computer in your house tweak the bios, and clean any viruses from your system. But Wiring into the ECM (PCM) has got me so confused it is just nuts.

You connect a wire from pin C13 on the green plug at the ECM to pin F on the C203 connector.
You connect a wire from pin C9 on the large black plug at the ecm to pin B of the C203 Connector.

Easy enough?

Ok that clears it up.

Well I bought 2 new NTK O2 sensors for 86 bucks. Installed them and the car seemed to come to life.

Part throttle and Throttle "Tip In" went way up. I am really happy now.

I drove it around for a bit last night and am very pleased. I only used about a 1/4 tank with all my running around yesterday. This is very good considering at fuel is up to nearly $4 USD per gallon for premium it was getting expensive driving a car that was getting 6-8mpg in traffic.

I will try to update this in a few days to say how much I get out of a full tank.

So Thank You to all that helped me out. FieroMaster88, Rockcrawl and Aaron

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85GT 5spd MSD Everything,4.9 With Nitrous. www.captfiero.com