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-   -   Phantom Power Problem (http://www.318ti.org/forum/showthread.php?t=33324)

LeadFox 04-20-2011 03:18 AM

Phantom Power Problem
 
Got a 95 318ti, 160k, all stock, 4cyl, standard 5spd. Just replaced battery, alternator, O2 sensor, fuel filter and pump. Car starts up great, but after a few minutes it lobes bad and dies. Seems to be an electrical problem, possibly the coil? Any ideas?

cooljess76 04-20-2011 04:02 AM

With the engine running, check voltage across the battery terminals with a multimeter. You should see a steady 13.5-14v. If it's down around 10-11v and fluctuating, you probably have a bad ground somewhere. I know you just replaced the battery, but check the terminals anyway, especially where the negative cable connects to the chassis. Might be a good idea to remove the nut and scrub the end of the cable and the contact surface on the chassis with a wire brush. Also, this is probably your culprit but check the other things listed anyway. Look under the car, just inward of the front passenger side wheel well. You'll see a ground cable going from the passenger's side motor mount to the passenger side frame rail. Remove it and scrub both ends of the cable as well as the mating surfaces. Best of luck!

LeadFox 04-20-2011 04:36 AM

I already checked all the grounds because that was the first thing suggested to me. All of em were cleaned and checked out fine. I'm wondering if it's the ECU.

cooljess76 04-20-2011 03:05 PM

Did you check voltage across the battery terminals? When you say "ALL the grounds" what other ones besides the negative battery cable did you check?

LeadFox 04-20-2011 06:22 PM

I found a Bentley manual that helped me find the grounds. Like the main ground from the battery, another under the car that goes from the chassis to the arm, under the rear seat. I'm doing some electrical tests today/tomorrow to try and isolate the problem.

LeadFox 04-20-2011 06:38 PM

Gah this is so frustrating trying to find...I certainly don't know enough about electronics. Would you know the most common places for s ground problem? I'd rather not sit all day and do testing...but I will if I must. I love my car. I really appreciate the help btw.

xxxJohnBoyxxx 04-20-2011 07:06 PM

Jess can figure out all these issues:wink:

LeadFox 04-20-2011 07:31 PM

thanks man. I will have trust in her his advice. Other than a bad ground, I found someone with similar issues and it was the ICV/PCV valves. Any opinions? And I had a friend of mine tell me when he was having an error with his ECU that it was a loose wire on his starter so checking that too.

familytruckster 04-20-2011 08:56 PM

Intake boot maybe?

cooljess76 04-20-2011 10:03 PM

I had an electrical gremlin when I had an M44 in my car. Went through 3 alternators and 3 batteries before I finally found the lower engine ground was loose and arcing. First thing I'd do, which I've already mentioned twice, is check voltage between the battery terminals while the car is idling to determine IF IN FACT you even have an electrical problem. You should also check voltage coming out of the alternator. Just touch one lead to the big terminal on the back of the alternator and the other to something grounded to the chassis(one of the three upper strut bolts works well). You should see 13.5-14v. Anything less, start checking grounds again or pull the alternator and have it bench tested for free at your local auto parts store. While you're at the auto parts store, pick up a can of brake & parts cleaner for 3 bucks. After you reinstall the alternator(assuming it tested good), start the car and while it's idling spray brake cleaner on and around the intake boot. Soak the hell out of that sucker, try to get up underneath it as well. Spray it on any vacuum hoses and around the intake manifold, but focus on the rubber intake boot as these are known to crack and leak. If you hear and fluctuations in idle, you have a leak. Usually the engine will rev up to about 3k rpms as soon as brake cleaner gets sucked through a vacuum leak.

LeadFox 04-21-2011 12:17 AM

hmm very interesting...I know what I will be doing tomorrow now.
But today working on it I found a wear spot in my + battery cable where I see it must have touched something because it was black and corroded. I cleaned it up and healed it with rubber tape. I traced the wire through the harness to the starter to make sure I didn't see any more problems from/caused. All good. I took the ICV off and am cleaning it atm. It was preeetttyy dirty. But all the hoses have no cracks, including my boots (but I will still do that spray test thingy). So I will put that back on tomorrow and do another test start to see how it is working then.
Is there anyway I can have my ECU tested? I WILL be doing the electric test first tho, I'm just worried that the cable wear I found could have caused a short somewhere.

cooljess76 04-21-2011 12:54 AM

Quote:

Originally Posted by LeadFox (Post 298792)
Is there anyway I can have my ECU tested? I WILL be doing the electric test first tho, I'm just worried that the cable wear I found could have caused a short somewhere.

Everythings pretty much protected by fuses. The only thing I've heard of being damaged by shorted wires are the headlight switch and starter solenoid, but to short out the starter you'd have to do it directly to the starter itself while hooking up the wires upon installation. Pretty hard to do since the manual tells you to disconnect the battery first anyway.

LeadFox 04-21-2011 01:34 AM

ok cool that makes me feel better. Well I will update tomorrow after I put the ICV back on and do that testing. Thank you so much, you have no idea <3

LeadFox 04-23-2011 02:17 AM

Well I cleaned out my ICV with some carb cleaner, put everything back together. Check all the grounds from the battery and I followed the main + cable through the wire harness and made sure everything was tight. I touched every bolt and gave it a good turn to make sure everything is secure. Check the battery, just under 16v, ditto with the alternator. No lights, smooth idle. Took her out for a vigorous test and she is running fine now <3

cooljess76 04-23-2011 02:31 AM

Quote:

Originally Posted by LeadFox (Post 299056)
Well I cleaned out my ICV with some carb cleaner, put everything back together. Check all the grounds from the battery and I followed the main + cable through the wire harness and made sure everything was tight. I touched every bolt and gave it a good turn to make sure everything is secure. Check the battery, just under 16v, ditto with the alternator. No lights, smooth idle. Took her out for a vigorous test and she is running fine now <3

Wow 16v, that seems really high! Glad she's running good now, hope it stays that way. BTW FWIW, Carb cleaner is probably the worst thing you can use on rubber and plastic parts. It dries them out almost instantly, especially rubber o-rings. The only thing carb cleaner is good for is cleaning carbuerators while you're rebuilding them and only after all of the o-rings have been removed. Brake & Parts cleaner or SimpleGreen are much better choices for cleaning/degreasing:wink: Even engine degreasers such as Gunk and STP have really harsh detergents that can dry and damage stuff if you don't rinse it off thoroughly. Purple Power degreaser has alkalines that can harm aluminum parts if left to dry or soak for extended periods.


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