FMII is on Life Support

In my quest to solve a problem with voltages, I may have killed the FMII. Initially, the car would fire once and that was it.

I sent the computer back to FM and they resoddered several of the connections and put a new chip in and reloaded my settings.

Now the car will start if I flutter the gas. It will not hold idle. It seems to be running extremely lean (Based on wideband). The car drive, but misfires horribly and needless to say is not in a raceable condition.

I neeed HEEEELP!!!

Can anybody recommend somebody locally?

How difficult would it be to find another ECU to try in the car? I'm wondering if they didn't fix it properly.

It's either that or you have a problem with fuel metering or delivery. Do you have a fuel pressure/delivery test port installed?

It would be a strange coincidence to have a fuel system problem at the same time as the ECU dying.

What did you do to kill it in the first place?

RJ

I was trying to track down a voltage leak that was causing the WBo2 to ossilate. I removed some wiring that seemed to be connected to nothing. I removed the 2 low amp grounds (at position 2c and 2d on the ECU Harness) and ran a new ground. I moved the Wideband ground from terminating at the ECU to a direct wire to the Block.

The ECU powers up well, the Wideband powers up fine (although reads full lean). But the idle will not hold. I can boost the fuel to MASTER 140 and the car runs better, but still full lean. Misfires, pops are the norm when it is running. I changed the plugs too to try and help.

Unfortunately the guy that owned this car before me was an electrician that well lets just say didn't know how to make an electrical connection. So there is wiring running everywhere.

OK...

Well, if it reads full lean you need to check the power and ground connections for good connectivity. If you measure from the ground lead on the sensor to the chassis on the car you should get zero volts. If you get more you have a bad ground. What's the voltage reading from the O2 sensor? Is it correct? If it is then the ECU is bad and not interpreting the voltage correctly.

If that's the case then bitch at FM for not testing the ECU properly after "repairing" it.

Do you know what chip they replaced?

Also, are you sure it's really running lean? What do the spark plug tips look like?

I'm wondering if you miswired something. Are you off work today? Where are you located?

RJ

Off work and in Frisco.

I can be reached at (Subtract 1 from each of these digits)

570-075-3512

The O2 signal and ECU need to be on the same ground. Otherwise you risk introducing a voltage differential that will give you a false 02 reading in the ECU. So your guage may show an accurate lean condition but the ecu thinks its running just right.

Also are you running on the stock O2 or something like an LC-1?

Quote:

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Originally Posted by HudsonHawk

The O2 signal and ECU need to be on the same ground. Otherwise you risk introducing a voltage differential that will give you a false 02 reading in the ECU. So your guage may show an accurate lean condition but the ecu thinks its running just right.

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I agree. I have the 2 LINK grounds and the LC-1 ground come together within a foot of the ECU, with one single wire going from there to the block. I have heard others have problems when using configurations different from this.

Quote:

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Originally Posted by Screamin'Screw

Off work and in Frisco.

I can be reached at (Subtract 1 from each of these digits)

570-075-3512

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Let's see if I remember... 0-1=-1. Hmmm... where's that on the keypad? :D ;)


Just having fun...

Quote:

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Originally Posted by Treibenschnell

Let's see if I remember... 0-1=-1. Hmmm... where's that on the keypad? :D ;)


Just having fun...

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Damn'it! Where is my decoder ring when I need it?

ECU is Reading 9 which means start dumping fuel in even on master fuel set to 140.

Runnin AEM WB o2 with gauge