Running rough

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12-11-2003, 06:45 AM

chrisc0623

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Running rough

Yesterday I had the head pipe on my 83 280zx n/a replaced. Now it's nice and quiet but the idle is rough and the car feels like it's missing. It ran perfect before the exhaust was repaired. I disconnected the battery for a few mins. thinking the ecu might need to be reset, but that didn't help at all. I've had the car for about 8 months so I don't know too much about it's history.
I have:
changed plugs and wires
oil
air filter
all the basics
the car has 264,000 so it may have had the timing set with the exhaust leak. Any sugestions would be greatly appreciated.

Thanks,
Chris

12-11-2003, 07:50 AM

Bleach

The Evil Twin

Join Date: Mar 2001

Location: Seattle, WA

Posts: 9,294

Did your oxygen sensor get replaced? ...or maybe disconnected? Its close to the head pipe.

Even if something was clogging the exhaust like a bad catalytic converter, your idle should be fine. Its the midrange and high rpms that are affected there.

Try adjusting the ignition timing by hand slightly. Don't worry about if its set to factory specs. Retard it a little then try it, then advance it. Usually advancing it smooths out an idle and bring the idle speed up slightly. If you smooth it out, you can bring the idle speed back down with the adjustment near the throttle body.

The ignition timing I'm talking about is just losening that little bolt at the base of the distributor and turning the distributor by hand. Once its at a good spot, tighten that bolt up some. (not too much)

12-11-2003, 08:03 AM

chrisc0623

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The oxygen sensor did not get replaced but is still connected. I checked that first. Should I replace the sensor?. I will try the timing tonight when I get home from work. Thanks for the advise. hopefully I can get this problem solved.
Thanks again,
Chris

12-11-2003, 09:01 AM

chrisc0623

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I forgot to add that as I accelerate from a stop it feels like it's missing across the power band. Almost sounds like it's running under water.
Chris

12-14-2003, 09:06 AM

yomammaZ

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Why don't you use one of those in-line spark plug/wire testers? That way you can see if you actually have an ignition problem and to which cyllinder is being affected.

A monster exhaust leak may be your culprit. Is everything sealed up correctly?

12-14-2003, 09:20 PM

chrisc0623

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Thanks for the help. I got it figured out. The Cat is plugged. After they fixed the head pipe the Cat built up pressure and has been causing the car to run poorly.
Again thanks for the help.
Chris