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View Full Version : electrical problem need help please. Starter motor/interior lights/fuel pump.


Moore
08-02-2010, 03:29 PM
I know this is my first post on here. I have been a long time reader. I'm active on a canadian 240sx forum but I really need some help from some experience 240 owners.

Heres the story. Thanks to anyone in advance I really appreciate it.

Ok so I'm trying to track down what this problem is it has to be a short somewhere but I'm out of places to look and need help.

On friday after driving on the highway for about an hour with no problems I got off the highway and was cruising I put my lights on they were fine for a bit then they blew the fuse. (interior light and brake run light 15amp 3rd up on the right side drive side). After a little while longer the fuel pump start acting really bad like i was running out of gas. At the time i thought it was a bad pump and a short somewhere in my interior.

I think its fuel related i change fuel filter and top up on gas. Car seems to be running fine I drive it home on sunday carefully with no problems.

Today i go to get 15amp fuses. Car starts fine and pulls hard appears to be no fuel delivery problem. I stop at crap tire get fuses get back and start it up again still no problems car still pulls hard ( at this point i'm trying to find a problem with fuel so I'm really stepping on it when i can).

Now I drive a little further and i stop in a parking lot with the car idling and i put in the 15amp fuse for the interior lights. All of sudden car is dead. car stops even the clock is off full electronic short.

I have a 150A breaker in the back it did not pop but i manual reset it. Car now has electricity all accs work minus interior lights which the fuse has popped on again.

Car now will not even try to start!! I turn the key and hear what sounds like a popping short noise and all electrics are dead again. I have to reset my breaker every time even though it is not popping.

Now I pull the ground off the starter motor and I can turn on all accs. I even was able to put the 15amp fuse in and have interior lights. a new Fuse blew when trying to start it.

I get a bump and start and drive it home. Car works fine at first then start to suffer from fuel pump problems. It starts bogging and lurching and almost dies at lights. I believe this is related to ground being pulled off the starter. (key ground messing with engine electronics).

I'm going to take some pictures of a few of the problem areas I see. There is this unit I have no idea what its for but the box is cracked and theres dirt in it. Also a plug with a lot of cut wires.

I have owned the car for over a year with out problems. I haven't really done anything electrical to the car.

Most recent thing i did was change a busted oil pressure gauge from electrical to mechanical. I have disconnect the stereo and any wiring to the speakers/sub.

Thanks for any help I'm really stumped with this one.

Moore
08-02-2010, 05:21 PM
so get this, after cleaning a shit ton of contacts and checking for bad grounds everywhere with still no luck i ended up by passing my Hi-Amp buss. I believe this was installed for the stereo. I'm not great with car audio I've never cared to learn I really only use it when my gf is in the car (came with car has been untouched since purchase over a year and half ago).

Either way I just randomly tried it and the car started up and idled perfectly. I even was able to put the 15amp fuse in with out it blowing. Now interior lights are working and car will start.

http://img.photobucket.com/albums/v282/tamboman/parts%20for%20sale/grounds/DSC00125.jpg

Has anyone ever heard of these going bad? I'm about to go and pull it off the car maybe something melted through and it was grounding on the car chassis?

I also am still interested in figuring out what this box is.

http://img.photobucket.com/albums/v282/tamboman/parts%20for%20sale/grounds/DSC00123.jpg

Its on the passenger side tucked in the front fender. the case is cracked and its full of dirt. It must not have been the problem but still looks awful.

slider2828
08-02-2010, 05:35 PM
Your hi-amp box looks like ass right now.... just my guess, usually that stuff needs to be isolated from the chassis as it is a ground. From what that hi-amp box looks like, its a positive current circuit so any contact with the body is going to short your interior and possible alt or starter.

Either way you can check with a volt meter if that thing has some sort of voltage/current. But that box looks like it should be isolated from the chassis....

Just my guess and I am not a stereo guy either.

Moore
08-02-2010, 07:44 PM
Thing is it had been running fine since i got the car.

I have it completely out of the car now. I just connected the wires with a bolt for now. Stereo is completely out as well so I don't see why I would have a use for it.

My 15amp fuse blew on me again. I'm thinking I must have a loose wire on a contact somewhere thats blowing when it hits the side of the car. I'll have to check out more on that tomorrow.

The pump ran ok. I only did a 1st gear pull without break lights i didn't want to go to far from home. It pulled hard untill 5500-6000 when it then seemed to plateau.

Could this still possibly be a weak or dying fuel pump?