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| Running Rich (Page 1/2) |
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Mylek
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JAN 20, 12:12 AM
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I have an ‘84 2M4. It running rich. I’ve replaced the Coolant Temp Sensor to the ECM. It seemed to have an effect. But, still runs rich. I’m thinking the Idle Air Control Valve or maybe the Fuel Injector itself. I’ll be checking those out on my next few days offf. In the meantime, if anyone has any ideas, you’ll have my undevided attention.
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ed55fl
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JAN 20, 01:34 AM
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Mylek
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JAN 20, 06:15 AM
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No codes now. Not since I changed out the Coolant Temp Sensor.
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ZCR1
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JAN 20, 08:41 AM
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Did the '84s have O2 sensors?
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Mylek
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JAN 20, 08:46 AM
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I believe so. Good call. I’ll check that this weekend as well. Thanks
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Mylek
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FEB 02, 12:11 AM
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Well, I dun gone and broke it. While replacing the IAC valve, I over torqued it. Snapped the threads off of the unit. I spent over an hour removing and cleaning that thing.
The IAC valve seems to be a difficult part to come by. Does anyone know of interchange options? Other vehicles that used the same IAC?
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JMTUT
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FEB 02, 01:16 PM
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JMTUT
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FEB 02, 01:18 PM
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Let me know if you get it to run better. Mine still runs rich and I've replaced IAC, map, rebuilt the throttle body, changed o2 sensor, and replaced egr valve...
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AsaBergman
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FEB 02, 05:45 PM
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I have an 84 Fiero which ran absolutely terrible when I got it, it now runs 100% and gets something like 28 mpg even with all the hills here and doing 3000 rpm.
The IAC valves are common, as JMTUT said get them on rockauto, they're even on sale right now.
Make sure you didn't break the threads in the throttle body. I have a disassembled throttle body I could send your way if you ruined the threads although you'd need to rebuild it.
The first thing is the ECM temperature sensor, this is practically a must if you can't test the current one. Unless the car sat for a very long time I wouldn't worry about the injector right now as they're very durable.
I'd say both of you should change your spark plugs, wires, distributor cap and rotor, and ignition coil. Weak igniton = incomplete combustion, gives similar signs of running rich. If it's the original coil you'll need to grind off the rivets. If you're unfamiliar with it the cap and rotor is safe to do, you can't mess up the timing. Mark the wires by their position, they must go on the new cap in the same order. Also when you change the spark plugs blow compressed air at them before removal to clear out any gunk and rust. DONT skip this.
You may also have incorrect timing on the distributor although if this were the case you'd likely have difficulty driving it at all especially up a hill.
Here's a list of what I've done on my engine to get it up to 100%:
spark plugs, wires, distributor cap and rotor
ignition coil(still had the original)
thermostat and ECM temperature sensor(in the filler neck)
fuel filter
throttle body rebuild
replaced all vacuum lines
PCV valve, breather filter(circular thing on top of valve cover)
valve cover gasket
disconnect vacuum lines from cruise control(I never reconnected it)
disconnect vacuum lines from charcoal canister(this you should reconnect when its running properly)
MAP sensor, IAC valve
intake manifold gasket
engine computer(ECM): these can degrade/fail but my problem was that the previous owner put the wrong one in! they put in the ecm from an 85 automatic into my 84 manual.... it really didn't like that. moral of the story, make sure you have the correct ecm. 
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Mylek
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FEB 02, 06:16 PM
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| quote | Originally posted by AsaBergman:
distributor cap and rotor, and ignition coil. Weak igniton = incomplete combustion, gives similar signs of running rich.
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I knew this. But, to showcase my inferior mechanical prowess, I didn't even think about it
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