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- Joined
- Sep 22, 2007
- Messages
- 13,864
- City
- Michigan
- Vehicle Year
- 1987
- Engine
- 2.9 V6
- Transmission
- Manual
- My credo
- A legend to the old man, a hero to the child...
87 ranger xlt 2.9/5sp
About a month ago i got a weird surging idle when warm. Runs great cold. i pulled codes and seen a coolant sensor code, replaced that, good.
Same problem comes back...notice an O2 wire laying on the exhaust....changed that.
Still having the surging idle, i notice (by accident) the surge seems to go away or atleast get way better when i turn my headlights off. I also notice the head/dashlights dim when i turn blower fan on.
So i check the alternator output at the battery. No load im making 13.2v. Turn accesories on the meter slowly drops till its gets to 11.8 or so.
Ok, so bad alternator.
I pull the one off rusty #1 and put on...check voltage...making 13.8. Awesome. Turn headlights/blower on and it does the same thing, and same idle surge.
I ordered a new alternator, be here wed...but im not sure thats the issue. Im not 100% sure what could be causing this....even if i rev it up to cold idle RPM the volts dont come up...but the battery never dies either.
i would think a wireing issue would not just cause a slow drop to battery voltage?
Any ideas????
Oh i should also add that my gauges all read higher then they used to...sometimes...and that seems to happen with the headlights on to. I have checked the head to firewall ground and its intact and in good shape as is the battery negatives.
About a month ago i got a weird surging idle when warm. Runs great cold. i pulled codes and seen a coolant sensor code, replaced that, good.
Same problem comes back...notice an O2 wire laying on the exhaust....changed that.
Still having the surging idle, i notice (by accident) the surge seems to go away or atleast get way better when i turn my headlights off. I also notice the head/dashlights dim when i turn blower fan on.
So i check the alternator output at the battery. No load im making 13.2v. Turn accesories on the meter slowly drops till its gets to 11.8 or so.
Ok, so bad alternator.
I pull the one off rusty #1 and put on...check voltage...making 13.8. Awesome. Turn headlights/blower on and it does the same thing, and same idle surge.
I ordered a new alternator, be here wed...but im not sure thats the issue. Im not 100% sure what could be causing this....even if i rev it up to cold idle RPM the volts dont come up...but the battery never dies either.
i would think a wireing issue would not just cause a slow drop to battery voltage?
Any ideas????
Oh i should also add that my gauges all read higher then they used to...sometimes...and that seems to happen with the headlights on to. I have checked the head to firewall ground and its intact and in good shape as is the battery negatives.
