driving and car shuts off then turns back on electrically

[AbsorbantNut]

Hey guys, haven't posted a thread asking for help in a while since the car has been running normally. But I have this new issue that I can't quite seem to figure out. I'll be driving the car for about 20-30 minutes and then it will randomly cut out electrically. The radio will shut off along with some dash lights so I know its losing electrical power, the car hesitates, but then a second later it comes back to life and the power is back.

Any ideas on what it could be? Also, my AFRs begin to lean out during the "electrical cutout", I'm assuming because the fuel pump loses power for a second.

Please help me figure this out :(

[Bullet Ride]

Does your car have... or did it have an after market alarm system?

Only reason I ask was because I had an E30 that use to randomly die while I was driving and I'd have to fiddle with the key to get it to start back up. I thought it was a bad contact on the ignition switch. Then when I went to investigate I found that there were some "extra" wires under the dash connected with those snap together splice connectors. I removed that garbage and never had a problem after that.

[AbsorbantNut]

Does your car have... or did it have an after market alarm system?

Only reason I ask was because I had an E30 that use to randomly die while I was driving and I'd have to fiddle with the key to get it to start back up. I thought it was a bad contact on the ignition switch. Then when I went to investigate I found that there were some "extra" wires under the dash connected with those snap together splice connectors. I removed that garbage and never had a problem after that.

No, no aftermarket alarm has been in the car before. Ill check around my ignition switch to make sure though

[dnguyen1963]

Check your grounds.

[AbsorbantNut]

all grounds are tight, wiggles all the connectors in the engine bay, the battery terminals, nothing seems to trigger it, it just happens on its own. Mainly at idle sitting at a light

[dewme5]

Cutting out at idle really leans me towards a high resistance connection. Low power from the Alt, bad connection gets hotter, more resistance, shuts off. Bad connection could be loose, rusted, corroded, broken wires.

Methodically check battery to engine, engine ground to body, body to battery. disconnect the battery, and measure resistance from the + terminal to the Alt, and - battery terminal to the engine block. There should be very little resistance.

[Coupelx]

I recently found out a bad ignition switch in these cars does all kinda wierd things. I took mine apart and cleaned regreased it but you gotta glue the halves back together. If you do this open it carefully as there is some small parts and springs that get lost easily. Mine would randomly not start, or start and die or not crank at all or even die shortly after starting.

[ELVA164]

Like dewme mentioned, a bad ground can be due as much to corrosion as a loose connection. Even connections that have been tight for a long time can corrode; it would be worth loosening all the relevant grounds you can reach to see if they could use a wire brushing.

[AbsorbantNut]

Cutting out at idle really leans me towards a high resistance connection. Low power from the Alt, bad connection gets hotter, more resistance, shuts off. Bad connection could be loose, rusted, corroded, broken wires.

Methodically check battery to engine, engine ground to body, body to battery. disconnect the battery, and measure resistance from the + terminal to the Alt, and - battery terminal to the engine block. There should be very little resistance.

I recently found out a bad ignition switch in these cars does all kinda wierd things. I took mine apart and cleaned regreased it but you gotta glue the halves back together. If you do this open it carefully as there is some small parts and springs that get lost easily. Mine would randomly not start, or start and die or not crank at all or even die shortly after starting.

Like dewme mentioned, a bad ground can be due as much to corrosion as a loose connection. Even connections that have been tight for a long time can corrode; it would be worth loosening all the relevant grounds you can reach to see if they could use a wire brushing.

Thanks for all the tips guys. I'll give the grounds a good look and clean as many of them as I can. I'll also check the resistances that dewme mentioned.

Coupelx, I'll examine the ignition switch, but I believe mine is alright. I dont have starting issues, just issues while the car is already on.

[TurboJake]

This really, really screams of a momentary 12v to ground dead short to me.

[AbsorbantNut]

This really, really screams of a momentary 12v to ground dead short to me.

Okay, so I'll have to buy a multimeter to check resistance on my positive 12v wire coming from the battery to where? I know that the resistance along the wire should be close to zero, but if its grounding out somewhere it will show a high resistance.

I guess I'll just have to check along short sections, like trunk to c pillar. Then c pillar to a pillar, then a pillar to engine bay. My problem is that the issue isn't consistent. SO I don't know if this wire is grounding out all the time or what.

[ELVA164]

Okay, so I'll have to buy a multimeter to check resistance on my positive 12v wire coming from the battery to where? I know that the resistance along the wire should be close to zero, but if its grounding out somewhere it will show a high resistance.

I guess I'll just have to check along short sections, like trunk to c pillar. Then c pillar to a pillar, then a pillar to engine bay. My problem is that the issue isn't consistent. SO I don't know if this wire is grounding out all the time or what.

If you do it the way you describe, it may also have the benefit of revealing where the sheathing of a hot wire may have been rubbed through and is causing the intermittent short.