280ZX (S130) Forums Dedicated to 79-83 ZCars

Runs Rich at Start up

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Old May 7, 2012 | 07:06 AM
  #1  
andrewsz's Avatar
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Runs Rich at Start up

I have been trying to fix a 82 turbo, almost done the last problem is a poor start up, When it starts runs it really rough. I have to work the throttle for about 5 minutes then it clears up and runs pretty good. i have searched for solution but have not had any success. I have FSM and have cleared AFM, and CHTS "both are new" could this be timing any help would be appreciated
Old May 7, 2012 | 07:37 AM
  #2  
iamericgee's Avatar
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maybe the fuel injectors
Old May 7, 2012 | 10:07 AM
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NismoPick's Avatar
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From: Wild Wild West, UTAH!
Welcome to ZDriver!

As always, check the basics first...

Reading the spark plug tips will tell you what's going on.
Also check the fuel pressure and air regulator.

You asked about timing... what is the timing set to?
Old May 7, 2012 | 12:04 PM
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andrewsz's Avatar
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I will check those things tuesday as I am working today, thought I would ask the question early so I have a place to start. Just thought id mention that after warms up it idles good and passed smog. I will get back with you
Old Jun 16, 2012 | 12:07 PM
  #5  
andrewsz's Avatar
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Fuel pressure is good needed a new air regulator it was stuck shut so iI replaced it runs a little better checked the spark plugs they look good too. also have checked and replaced afm and chts.
Old Jun 16, 2012 | 01:29 PM
  #6  
rogerz's Avatar
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From: Mill Creek WA
are you sure you replaced the chts and not the coolant temp gage sensor. people tend to get confused on that with zx. the chts is back around #5 plug and the temp gage is at the front of the engine. the chts has two wires going to it with a connector that is the same as the fuel injector connector. did you check the wiring from it back to the ecu? don't overtighten the chts it only needs to contact the head not be cranked down. usually cold run problems that clear up are related to chts funtioning incorrectly. have you put a timing light on it to determine what the ignition timing is? Get your battery load tested. Be sure you have clean, tight corrosion free terminals on both ends of your battery cables. Be sure the ground (negative) cable goes to a bolt into the frame before going to the starter. grounding through the starter is not a reliable connection. Z's don't like low voltage. causes the electronics to act funny. it is possible to have enough amps to crank but not enough voltage to run the electronics. If you have one size fit all cheapo clamp on terminals they are a problem waiting to happen.

Clean the connectors for the maf, ecu and tps. Deoxit by CAIG is probably the best connector cleaner on the market. spray with CorrosionX after cleaning and before putting together this will help prevent any further corrosion.

don't discount the battery system as a problem. the ZX is very finicky about the voltage it dines on.
Old Jun 21, 2012 | 05:38 PM
  #7  
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Mine suffers from the same rough idle when cold but I determined that mine was a result of the cold start sytem being inop. I did find someone had removed the thermostat and once I replaced that , the car warmed up quicker and thereby the idle smoothed out. Maybe you suffer from the same?
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