85 wont idle when cold
Thread Starter
Instructor
Joined: Jan 2003
Posts: 233
Likes: 0
From: IL
85 wont idle when cold
When you first start it coolant is cold it wont stay running, you can raise the idle by pushing down the gas pedal a small amount to keep it running. when it gets to 175 degrees it will stay running but it is only at about 650 in drive, setting no codes. Im going to recheck the TPS setting. bot not sure what to do now?
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Although it should set a code, check the ECT sensor and wiring. If the ECM doesn't know the engine is cold, it won't command the IAC to retract the pintle to maintain a faster cold idle.
RACE ON!!!
RACE ON!!!
Thread Starter
Instructor
Joined: Jan 2003
Posts: 233
Likes: 0
From: IL
idle issue
Originally Posted by RRT vette
I think checking the TPS is a good idea. Have you set minimal idle lately? Sounds like it's starving for air until it hits closed loop and the A/F mixture is better.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
Go to the General section and read the post "SEA FOAM" don't know if the CSI (cold start injector) is the same on an 85 as it is on an 87, but the IAC and CSI both use the same body for passages to the TB, if either of the passages are carboned up..well you get the picture..and SeaFoam is very good about cleaning these type of problems.
Thread Starter
Instructor
Joined: Jan 2003
Posts: 233
Likes: 0
From: IL
idle issue
Originally Posted by rick lambert
Go to the General section and read the post "SEA FOAM" don't know if the CSI (cold start injector) is the same on an 85 as it is on an 87, but the IAC and CSI both use the same body for passages to the TB, if either of the passages are carboned up..well you get the picture..and SeaFoam is very good about cleaning these type of problems.
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Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
The CSV (9th injector) it there to help start the engine when the coolant temp is below 90*. I experienced having to troubleshoot the CSV here recently. There is a thermal time switch located at the front of the intake manifold next to the CTS. It is supplied voltage by the starter solenoid when attempting to crank and in no way is controled by the ECM. As the engine temp rises up and past 90* the thermal time switch decreases the amount of time to supply the CSV. After 90* the CSV is not functional anymore. There is a CSV fuse (5 amp) located behind the DIC on the dash where the SES light is. There are also a few other fuses there.
A blown fuse, faulty switch, or voltage supply will make the engine harder to start. Example: it took four attempts to crank the engine (first start of the morning) before my engine would start. I ended up tracing it to a blown fuse behind the DIC and now the engine starts on the first turn everytime. As far as I know by just looking, the CSV is attatched to the rear driverside fuel rail and this is where the fuel comes from. If you ohmed the CSV it will only ohm about 5 ohms and is different from the rest of the injectors which ohm around 16.
If this describes your problem, it's time to troubleshoot.
A blown fuse, faulty switch, or voltage supply will make the engine harder to start. Example: it took four attempts to crank the engine (first start of the morning) before my engine would start. I ended up tracing it to a blown fuse behind the DIC and now the engine starts on the first turn everytime. As far as I know by just looking, the CSV is attatched to the rear driverside fuel rail and this is where the fuel comes from. If you ohmed the CSV it will only ohm about 5 ohms and is different from the rest of the injectors which ohm around 16.
If this describes your problem, it's time to troubleshoot.
Thread Starter
Instructor
Joined: Jan 2003
Posts: 233
Likes: 0
From: IL
found it
I found the problem! I kept thinking about what I had changed, AND the only part that that it could possibly was the EGR valve! I must have been leaking a small amount. I changed it out and its fixed! 
