two electrical issue symptoms

[fastasleep]

I've got two different electrical symptoms going on:

1) Recently when I've gone to start my car it won't start turning over at first. I hear the fuel pump and relays clicking and everything sounds right, but it won't start. If I take the keys out and try it again a few times and pray, then it'll turn over and start right up. Starter on it's way out?

2) It's also becoming more frequent that when I hit the brake pedal I will watch my voltage gauge and it will spike down from 14 to 12 or 12.5 for half a second, just long enough to cause my head unit to die and restart; lights dim for a sec, etc.

My alt and battery are good. Where should I start troubleshooting? Starter? Relays? Bad gauge wiring? turbo timer wiring? batt relocation wiring? fp rewire wiring? The draw from the brake lights is what really triggers it.

 

[rgeier11]

I would say something with your grounds. It could be the one at the alternator or the ones at your battery. That would be my first and most obvious guess.

 

[Dialcaliper]

It also couldn't hurt to pop open your ECU and double check your caps for puking, as well as check around the rest of the board for any sign of damage. It started out pretty mild as a bad idle droop. The worst was a complete electrical failure with absolutely no warning on the freeway at rush hour doing 70 in the left lane!

Eventually it ended up started chattering and clicking, sometimes it would start just fine depending on the temperature outside, and then quit once the FIAV settled down, other times the relays and vacuum valves would go into outright seizures.

New caps, some cleaning and circuit repair plus a replaced ISC driver (on of those little 5-pin chips had a burn mark in the corner - look for signs of "magic smoke" trying to get out /ubbthreads/images/graemlins/rofl.gif ) and it ran and idled like a charm.

Pay attention to if it's happening when you come off the throttle and the ECU tries to "catch" the revs and return to idle, rather than actually being linked to use of the brake pedal.

Even if caps were replaced, they might have left permanent damage nearby, or elsewhere on the board due to arcing or overloading some of the chips.

 

[iceman69510]

I second the ground suggestion as well. I had a car did something similar when it had a ground issues. The brake lights bulbs actually take an amazing amount of current, enough that it made my dash lights go out when I hit the brakes until I fixed the ground connection.

 

[fastasleep]

Would it profit me to run the ground back up to the engine bay as opposed to the rear strut mount?

 

[EMX5636]

Well I have my battery relocation ground wire to the rear strut too, and exhibit a little bit of the same voltage drop with the brakes applied. I am going to add another ground or two in the trunk, and maybe a couple more up front from the block to the frame.

Good luck, if you happen to find anything out, let me know. I'll do the same.

 

[fastasleep]

Well, theres good news and bad news.

Good news: I discovered that the nut and bolt securing the (+) wire that runs from my batt in the trunk to the fusebox in the bay had been extremely lose. It was underneath electrical tape so I didn't see that the bolt had loosened over time causing a poor connection. This was responsible for the intermittant starting problem that I had been experiencing. After I tightened that up, she fired right up quickly, everything was brighter, and I didn't have any more idle surge! Now I know that when people say, "check your connections," to really check them!

Bad news: I finally ended up checking this as a result of my alternator biting the dust (or so it seems). I was sitting in a Starbucks parking lot the other night with my lights and heat on while my foot was on the break, and my voltage just tanked. I watching my gauge just drop to 9.5-10v as all my accesories dimmed. Drove to Advance where I discovered the aformentioned loose connection, but also tested the alternator which read: zero output.

So, hopefully, I can find parts and labor on the alternator for a good deal. I don't quite trust myself with it, nor do I have a garage where I currently live. I just hope that my optima red top is salvagable.

 

[rgeier11]

Woah woah woah. An alternator is an EXTREMELY easy job to do on your own. I bought a crummy set of tools from a gas station and replaced mine on the side of the road once.

Refer to this thread for how to squeeze the alternator out from the top.

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