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Very Strange Electrical Issue on '85 GT by codex653
Started on: 08-08-2014 04:58 PM
Replies: 8 (94 views)
Last post by: olejoedad on 08-08-2014 09:51 PM
codex653
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Report this Post08-08-2014 04:58 PM Click Here to See the Profile for codex653Click Here to Email codex653Send a Private Message to codex653Edit/Delete MessageReply w/QuoteDirect Link to This Post
So I've noticed something pretty strange in the last week or so on my Fiero. Whenever I turn left, my electrical system gets a boost of sorts. Reason how I know is that I discovered this interesting little phenomenon when I had my AC on and made a left turn. During the turn, my blower motor's RPM went up and more air came out of the vents. It sounded like the AC system was on overdrive or something compared to just normal driving. I also noticed that my oil gauge needle showed an increase in pressure during the left turn, and then it dropped back down when the turn was completed. None of the other needles changed position.

Normally this wouldn't be too concerning, however last night when I was driving back home from a movie, some really freaky stuff started happening. I was cruising down a road in 3rd gear when all of a sudden my oil pressure gauge dropped into the red (it was previously at 40), my AC air speed dropped drastically, my headlights became very dim, and my car began to slow down as if I was engine braking. So I pushed in the clutch and allowed the engine to recover from whatever the heck just happened, gave it a couple revs, and then continued on my way. However after that I could hear the AC blower motor RPM fluctuating which was indicated by the constantly changing vent air speed. It wasn't much, but it sounded like there wasn't consistent power getting to the motor...almost like the voltage levels were going up and down slightly.

My first thought was that something happened to my oil (I have a leak somewhere), which would explain the rapid oil pressure drop. I changed out the oil and oil filter, however the issue still persists. My next thought was that the alternator was going bad. I checked the connections and found them to be clean, shiny, and the bolts well tightened down for a solid connection. I measured the voltage while the car was running and found it to be 14.40 V, so it doesn't appear to be that the alternator is the issue. My last idea that I have is that perhaps the battery's fluid levels are down? That could POSSIBLY explain why my electrical system seems to get a boost on the left turn...acid could cover more surface area of a cell during the turn (the fluid shifts to the side and would move up the cell wall) causing a momentary increase in voltage, which would lead to the higher AC air speed I was experiencing.

What do you all think? Got any input?
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olejoedad
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Report this Post08-08-2014 05:09 PM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
Not the battery....there are six individual compartments.

Could be a grounding issue.
Check the grounds on the bell housing on the front side by the starter.
Add a couple of block to space frame grounds.
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evil_motors
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Report this Post08-08-2014 05:14 PM Click Here to See the Profile for evil_motorsClick Here to Email evil_motorsSend a Private Message to evil_motorsEdit/Delete MessageReply w/QuoteDirect Link to This Post
you dont have power steering do you?
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codex653
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Report this Post08-08-2014 05:26 PM Click Here to See the Profile for codex653Click Here to Email codex653Send a Private Message to codex653Edit/Delete MessageReply w/QuoteDirect Link to This Post
evil_motors: Nah no power steering for me. Does that make a difference??

olejoe: Despite having six compartments/cells, it would still slosh up the side walls if it were low...it would just do it on all 6 or whichever ones were too low. Yeah it perhaps could be a grounding issue, I'll double check on that. It's still quite strange that it only seems to do it on a left turn...
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evil_motors
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Report this Post08-08-2014 05:38 PM Click Here to See the Profile for evil_motorsClick Here to Email evil_motorsSend a Private Message to evil_motorsEdit/Delete MessageReply w/QuoteDirect Link to This Post
with power steering if you were low on fluid it would cause the engine to work harder so you can turn which would boost the rpms etc etc etc.
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85 SE VIN 9
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Report this Post08-08-2014 06:29 PM Click Here to See the Profile for 85 SE VIN 9Click Here to Email 85 SE VIN 9Send a Private Message to 85 SE VIN 9Edit/Delete MessageReply w/QuoteDirect Link to This Post
Look for your oil leak at the oil pressure sender. That might also be the root of the electrical problem. There is a circuit in the old style sender that runs the fuel pump if the relay fails. BTW is your fuel pump relay clicking off after priming? Turn the ignition on, then wait for a click behind your head, that's the fuel pump relay cycling off after reaching pressure. If not the power for the fuel pump is going through the oil pressure sender. From what I hear this won't go on for long. The relay is pretty cheap, ten bucks or maybe less.

You can replace the old style oil pressure sender with the 88 sender for about the same money, including the connector pigtail. See Ogre's site.

Both my '85's suffer from rust around the battery. Is the little black fuse box on the fender loose? The metal in that area should probably be cleaned up and patched, so while you're doing that look at the various grounds. They probably need cleaning and tightening.

The service manual has diagrams showing the location of all the grounds. If you don't have the manual you can download it (never worked for me) or get it from TFS on a CD.

Working A/C - I envy you!
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Jason88Notchie
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Report this Post08-08-2014 06:36 PM Click Here to See the Profile for Jason88NotchieClick Here to Email Jason88NotchieSend a Private Message to Jason88NotchieEdit/Delete MessageReply w/QuoteDirect Link to This Post
85's had absolutely no power steering. Can't make a blanket statement about the 88's though. I think 5 rolled off the line and were recalled.
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85 SE VIN 9
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Report this Post08-08-2014 07:21 PM Click Here to See the Profile for 85 SE VIN 9Click Here to Email 85 SE VIN 9Send a Private Message to 85 SE VIN 9Edit/Delete MessageReply w/QuoteDirect Link to This Post
I think that's right. I read somewhere it was supposed to be an electrical system like those now common, but then unusual to say the least. It's hard to imagine power steering in a Fiero, IMHO. My '85 GT is easy to steer, even parking. In fact it's too light at highway speeds.

Do you always get problems when turning left? What if you park with one side high, or jack up one side? Rock the car side to side? Wiggle some wires by the the battery? Left turn signal on? Got any loose wires under dash? A/C off? Do rpms drop at the same time? Do you have a volt meter? What does it do when this happens?
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olejoedad
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Report this Post08-08-2014 09:51 PM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by codex653:

olejoe: Despite having six compartments/cells, it would still slosh up the side walls if it were low...it would just do it on all 6 or whichever ones were too low.



Yeah, that's a good one.....

[This message has been edited by olejoedad (edited 08-08-2014).]

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