Electrical issue.. Possibly Alternator?
Thread Starter
Intermediate
Joined: Apr 2013
Posts: 40
Likes: 0
From: Culver City CA
Electrical issue.. Possibly Alternator?
symptoms. at idle, interior dash and headlights flickers based on the idle(Ex: low idle(500+ which usually happens lights flicker. idle at say 700 no flicker), using power windows seems to drain.
I've researched this and I am pretty sure its the alternator but I just want to make 100% sure because I do not wish to start replacing parts that may not need replacing. power wise it seems fine. battery voltage doesn't seem to dip once started and idles but this is based on guage.
starting. it cranks no problem but cold start is definitely hard. although I am suspecting this is a separate issue here.
this is a lot more of a annoyance than a major problem but I have a lil extra cash and wish to fix this. any help is appreciated.
thanks
I've researched this and I am pretty sure its the alternator but I just want to make 100% sure because I do not wish to start replacing parts that may not need replacing. power wise it seems fine. battery voltage doesn't seem to dip once started and idles but this is based on guage.
starting. it cranks no problem but cold start is definitely hard. although I am suspecting this is a separate issue here.
this is a lot more of a annoyance than a major problem but I have a lil extra cash and wish to fix this. any help is appreciated.
thanks
Thread Starter
Intermediate
Joined: Apr 2013
Posts: 40
Likes: 0
From: Culver City CA
ive had this idle issue since ive owned it.. I am not sure if its a separate issue or bad alternator. I've read low idle is a symptom.
Instructor
Joined: Oct 2013
Posts: 162
Likes: 1
From: Lower Burrell Pa.
Honestly I do not know. I bought the vette from a vette dealer in april. I do know the engine was replaced with a gm goodwrench about 27k miles ago. based on the previous owners notes and logs I do not see underdrive pullies installed.
ive had this idle issue since ive owned it.. I am not sure if its a separate issue or bad alternator. I've read low idle is a symptom.
ive had this idle issue since ive owned it.. I am not sure if its a separate issue or bad alternator. I've read low idle is a symptom.
Thread Starter
Intermediate
Joined: Apr 2013
Posts: 40
Likes: 0
From: Culver City CA
Good news.. confirmed its not the battery or alternator
Crappy news... confirmed it is an electrical issue.
just my luck considering battery and alternator are simple fixes...
the manager then recommended I goto JD Corvettes which is the exact place I goto anyways. in which they told me if the car has good power and runs decent then save that electrical issue for last when restoring because chasing down an electrical issue can get pricey real fast.
good advise..
thanks guys for the help.. Have a safe holidays!!!
Thread Starter
Intermediate
Joined: Apr 2013
Posts: 40
Likes: 0
From: Culver City CA
but no I do not notice the lights dim under your proposed scenario..
Burning Brakes
Joined: Jul 2013
Posts: 1,027
Likes: 30
From: Granite City Illinois
I wouldnt think theres anything electrical to worry about. It sounds like the regulator is working ok so the alternator must be ok too I think.
Im just learning about these cars but why would the idle be so low?
Im just learning about these cars but why would the idle be so low?
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Racer
Joined: Aug 2013
Posts: 301
Likes: 0
Is this the 85 listed in your profile? Does the car maintain the same idle speed when turning on lots of electrical loads(headlights, blower motor, rear defroster, etc.), or when turning on a/c, or going from park to drive? The ecm controls idle speed with the IAC, and will aim for anywhere between 550 to 750 and sometimes higher depending on conditions. What is the idle speed at cold startup? Also, what does the idle speed do at warm startup? This kind of info will help the guys here help you narrow down any problems. It does sound kind of like fixing the idle issue will solve the other problems you explained.
Last edited by nobodycls; Dec 17, 2013 at 08:39 PM.
Thread Starter
Intermediate
Joined: Apr 2013
Posts: 40
Likes: 0
From: Culver City CA
Does the car maintain the same idle speed when turning on lots of electrical loads(headlights, blower motor, etc.), or when turning on a/c, or going from park to drive? The ecm controls idle speed with the IAC, and will aim for anywhere between 550 to 750 or so depending on conditions.
Racer
Joined: Aug 2013
Posts: 301
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Thread Starter
Intermediate
Joined: Apr 2013
Posts: 40
Likes: 0
From: Culver City CA
cold start 600-800 then once it hits 100 degrees on the gauge it jumps to 700-900.. then once warmed up it dips back to drive rpm mentioned.
yes 85 corvette..
thank you for your input btw
Racer
Joined: Aug 2013
Posts: 301
Likes: 0
I'll answer both questions. in drive it idles between 500-600 rpms... in park 600-700 rpms..
cold start 600-800 then once it hits 100 degrees on the gauge it jumps to 700-900.. then once warmed up it dips back to drive rpm mentioned.
yes 85 corvette..
thank you for your input btw
cold start 600-800 then once it hits 100 degrees on the gauge it jumps to 700-900.. then once warmed up it dips back to drive rpm mentioned.
yes 85 corvette..
thank you for your input btw
Last edited by nobodycls; Dec 17, 2013 at 10:33 PM.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
http://forums.corvetteforum.com/1570563689-post1.html
The ECM adjusts the RPM based on the startup coolant temperature. If the car is -40° then the ECM is programmed to idle at 1200 RPM. My car idles at about 900 RPM in Park when cold (that's Southern California cold -- it was in the 70s today).
[ EDIT ] On further thought, I think your CTS (Coolant Temperature Sensor) has a problem, either the sensor itself, the connector pins might be corroded or you might have a broken wire. This is the CTS on the front of the intake manifold. If the ECM thinks the engine is hot it will set the idle to a low RPM. [ /EDIT ]
Last edited by Cliff Harris; Dec 19, 2013 at 03:45 AM. Reason: Added a hint.