Cold natured 85
Thread Starter
Instructor
Joined: Sep 2002
Posts: 185
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From: Rocky Mount NC
Cold natured 85
Are there any likely easy fixes for a cold natured 85. Usually it runs just a little rough at crankup and then smoothes out quickly. Today, I went outside to crank it up, and I had to turn it over quite a bit to get it to fire. It is about 45 degrees out today. I didn't worry too much, but with winter coming, I would like to correct this.
Pro
Joined: Aug 2002
Posts: 715
Likes: 0
From: Warner Robins GA
Re: Cold natured 85 (dmorris)
When I bought my car, the guy who sold it to me reminded me that the car was "cold-natured" so to expect it early in the morning. The next day I started the car and it stumbled a lot at first then finally smoothed out.
I did two things to the car between then and when the problem went away. Number one was clean the throttle body. The next morning when I started it, it was still a little rough but definitely settled down some.
Next was having all my exhaust redone. This means a new catback system (I chose Power Effects), and I had both my precats and the main cat cut off. One precat was trashed, one was completely empty, and the main cat was full of precat guts.
Now when I start it on cold mornings, it starts strong and stays strong.
I did two things to the car between then and when the problem went away. Number one was clean the throttle body. The next morning when I started it, it was still a little rough but definitely settled down some.
Next was having all my exhaust redone. This means a new catback system (I chose Power Effects), and I had both my precats and the main cat cut off. One precat was trashed, one was completely empty, and the main cat was full of precat guts.
Now when I start it on cold mornings, it starts strong and stays strong.
Team Owner
Joined: Sep 2001
Posts: 62,154
Likes: 1,731
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Re: Cold natured 85 (dmorris)
I would clean the TB and the IAC first. Then do a general checkup of ignition systems. Its possible that the cats would be clogged, but it shouldnt affect starting, and they would likely show up as excess heat in the console area or your footwells.
Le Mans Master
Joined: Apr 2000
Posts: 6,341
Likes: 1
From: Shelton CT
Re: Cold natured 85 (dmorris)
Hmm Mine actualyl starts faster when cold than when she's warm (slight injector leakage I presume) nothing damaging though..
I have remove dmy 9nth injector 2 months ago , but it was the same before and after..
I have remove dmy 9nth injector 2 months ago , but it was the same before and after..
Burning Brakes
Joined: Feb 2000
Posts: 824
Likes: 2
From: Camden SC
Re: Cold natured 85 (MrNuke)
Well, I would first check things that measure temperature if the problem seems temperature related. Of course you can never go wrong cleaning throttle bodys and IAC.
The Coolant Temp Sensor (CTS) is essentially an electronic choke. Lower ambient temps require richer mixture. The computer uses CTS for part of the equation in determing injector on time.
A scanner will tell you what the CTS is telling the computer. The temperature should be within a few degrees of ambient readings and Manifold Air Temperature. You can also check this by measuring the resistance across the CTS and comparing the value with a table listed in the service manual.
dlmeyers 90 coupe zf6 3 speed shocks
The Coolant Temp Sensor (CTS) is essentially an electronic choke. Lower ambient temps require richer mixture. The computer uses CTS for part of the equation in determing injector on time.
A scanner will tell you what the CTS is telling the computer. The temperature should be within a few degrees of ambient readings and Manifold Air Temperature. You can also check this by measuring the resistance across the CTS and comparing the value with a table listed in the service manual.
dlmeyers 90 coupe zf6 3 speed shocks
Drifting
Joined: Aug 2000
Posts: 1,251
Likes: 0
Re: Cold natured 85 (dmorris)
My 84 did this. My coolant sensor had been changed before & the wires had been spliced about 5 inches from the sensor.The connection had corroded up & failed.
After repairing this there is no load up & I have a fast idle!Nice.
After repairing this there is no load up & I have a fast idle!Nice.
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