Voltage spikes!!!!

[Blindedlegacy]

Originally Posted by cre

The swap would be a bandaid, nothing more... You still wouldn't have fixed the real problem. Unless you've got the heater running on full and the headlights on you shouldn't see it dim significantly when you step on the brakes... a little isn't surprising. Start with the basics first (It's MUCH cheaper too). Regardless of the voltage you're seeing you should take the battery to a shop for a complete battery test (charge/discharge); It takes about an hour so you'll need to drop it off. There are home chargers which have testers built in, the method and accuracy with which they test varies significantly so I would read reviews and don't cheap out. IMPORTANT!!! If you have an AGM (Absorbed Glass Mat) battery do NOT connect it to any charger which does not specifically have a setting for AGM!

The only time I really recommend a larger alternator is if the electrical load has been significantly increased placing demands on the charging system well beyond the original specs; Huge amplifier, electrical fan conversion, electrical cabin heater or an old battery with a bad cell or two. The only other time I'd consider it is if it's a city car where it sees lots of short trips and the battery probably isn't charging enough.... My wife goes through about a battery a year if I don't keep on it with a charger every few weeks.

No, the MR-2 isn't a straight swap in but I think it was close... Something like swapping the pulleys, maybe the wiring pigtail and a washer.

I highly suggest you fix the real problem though. A larger alternator still may not remedy the symptoms.

i cleans up the grounds and everything and still the same thing. i replaced the sending unit for the gauge and it still slowly goes to running hot. i would also (very seldom) see my oil press gauge move, hasnt worked since i got the car. so do you think it might be a ecu problem or wiring harness issue because i found this

[cre]

Originally Posted by Blindedlegacy

i replaced the sending unit for the gauge and it still slowly goes to running hot.

I may have missed something because I have no idea what you're talking about here. Please elaborate.

Originally Posted by Blindedlegacy

I would also (very seldom) see my oil press gauge move, hasnt worked since i got the car.

The oil pressure gauge has only one wire running to the sender on the engine which is a variable ground of sorts. It gets it's power from the same circuit as the other dash components so if the dash lights light up and the tachometer works then the problem with the oil pressure gauge is most likely: a bad wire, a bad sender, unplugged or the engine is not well grounded.

Originally Posted by Blindedlegacy

so do you think it might be a ecu problem or wiring harness issue because i found this

No, the problem is inconsistent with a bad ECU. The two wires bolted together should be obvious... Look at the fusebox lid and the fusible link that's missing probably where they're supposed to go. Someone was being cheap or trying to bypass a fuse which kept blowing; replace it and see what happens. Replace the yellow wire fusible link while you've got it open just to be sure.

You have the rest of my suggestions for things to start with.

[cre]

I take that back. The bolted together wires should bolt to the 100A Fusible Link (the Yellow wire)! Replace the yellow wire with a new FL (either another wire one or a sealed unit) and bolt the wires back where they belong. I didn't realize that nothing was running to the 100A FL but I did notice the wire colors were wrong for the ABS circuit... that'd be Blue and Black I believe. I assume you don't have ABS then.

[Blindedlegacy]

Originally Posted by cre

I may have missed something because I have no idea what you're talking about here. Please elaborate.



The oil pressure gauge has only one wire running to the sender on the engine which is a variable ground of sorts. It gets it's power from the same circuit as the other dash components so if the dash lights light up and the tachometer works then the problem with the oil pressure gauge is most likely: a bad wire, a bad sender, unplugged or the engine is not well grounded.



No, the problem is inconsistent with a bad ECU. The two wires bolted together should be obvious... Look at the fusebox lid and the fusible link that's missing probably where they're supposed to go. Someone was being cheap or trying to bypass a fuse which kept blowing; replace it and see what happens. Replace the yellow wire fusible link while you've got it open just to be sure.

You have the rest of my suggestions for things to start with.

the coolant sending unit i just replaced it because it was always reading hot and the new one does the same thing.

and the oil pressure is connected to anything.

i saw a fusebox wiring harness for about 120 i think. you suggest i get that instead because who ever had that car before me is an idiot because there are custom jobs all over that place.