Engine sputters

1987 CHEVROLET CELEBRITY
142,000 MILES
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SNYDER69
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The car put out a code of 43. I had replaced the ECm and knock sensor. I was able to zero the code and the engine runs a little smoother but it still has the sputter to it. Did not notice any vacuum leaks and I have new plugs and wires. What else could it be??
Jan 17, 2011 at 12:16 PM
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JDL
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Your saying you no longer have the code? Use a gage and check fuel pressure.
Jan 17, 2011 at 6:45 PM
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SNYDER69
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That's correct I no longer have a code. What should the pressure be around 42?
Jan 17, 2011 at 6:51 PM
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JDL
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28--36 psi for mfi.
Jan 17, 2011 at 6:58 PM
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SNYDER69
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If the pressure is below spec would it be the fuel pump would need replacing? Also could it be dirty injectors?
Jan 17, 2011 at 7:14 PM
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JDL
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How about the fuel filter? Don't take any lines loose without being sure there is no pressure on the system. Check the pressure spec first, before worrying about the pump.

You could do a cylinder balance test, engine running, kill cylinders, one at a time, pay attention to the rpm drop when cylinder is killed. If no rpm drop with cylinder that you killed, that cylinder is dead. Could be fuel--spark--compression. For testing, if you kill spark at the cylinder, be quick, so you don't flood anything.
Jan 17, 2011 at 7:28 PM
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SNYDER69
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I did the cylinder balance test and found 3 and 6 were not working. I checked the spark on both and it wasn't a nice blue like it should be. I am thinking it is a weak coil pack, it happens to run both of those cylinders. I will purchase a new and try that. Thank you very much for your help! Hopefully this is the problem.
Jan 18, 2011 at 11:54 AM
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JDL
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Good job, hope that fixes it.
Jan 18, 2011 at 5:07 PM
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SNYDER69
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I installed the coil pack and it runs like a race car. Now I have another problem. My cooling fan is not turning on. I check my fuses there ok. Is there maybe a resistor that may need replacing? What else do I check?
Jan 19, 2011 at 12:08 PM
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JDL
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Use jumper wires from fan to battery, voltage and ground. See if fan will run? You should use an inline fuse on the jumper. If fan still won't run, replace fan motor.

The fan relay location is in the picture. With relay packs, those relays may be all the same? if you think the fan relay might be an issue, swap it out with ac relay, for testing.
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Jan 19, 2011 at 4:34 PM
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SNYDER69
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Great I will that out and let you know. Thanks!
Jan 19, 2011 at 5:01 PM
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SNYDER69
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Run jumper to fan, it works. switched out the relay fan still does not turn on.
Jan 20, 2011 at 5:09 PM
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JDL
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On some models if you turn on the ac, the fan will turn on. If you unplug the coolant temp sensor, the fan may run. If you use a jumper wire on the A & B terminals at the data link connector, like your going to check codes, key on, no crank, the fan may run. Anything?

I have seen faulty fans that would run intermittently. Can you check for voltage and ground at the fan connector, when you think it should be running?
Jan 20, 2011 at 5:55 PM