PLEASE HELP 325is keeps dying on me

[sailorjase]

Hey hows it goin guys, Im new to r3vlimited

My car is having problems and i have some experience working on cars so I can handle whatever is wrong with it but first I need to figure it out.

Heres the info

Its a 1988 325is with 17x,xxx miles on it (5spd), just traded for my old 89 automatic 325is a few days ago.
The guy that gave it to me said he had recently replaced the battery and fuel pump and that it ran fine for a day after he swapped the fuel pump.

I drove it for about 30 mins after making the trade and it died on the freeway. Gas just lost power, lights dimmed and then it died.
we pulled over and waited about 10 mins then jump started it and it worked and we drove another 30 miles to my house.

The next day I drove it for about 15 mins and it ran fine, started up and everything.
Yesterday i drove about 5 mins and then pulled over to wait for a friend and left the car idling. The idle started getting weak and acting like it wanted to die but then would come back up and down until it finally died. I tried to start it and it didnt crank (as if the battery was dead)

I was on a hill so i tried to jump start it and it worked, i reved it to make sure it was on then it died. Tried again and same thing. I got to the bottom of the hill and lights didnt work nothing electrical as if battery was dead.

Then a lady gave me a jump with her car and it started fine and ran fine until we unhooked the cables then it died automatically.
Tried a second time and same thing, it died when we unplugged cables.

I got the car towed home and explained this to the tow guy and he said he was sure it was a bad alternator.
My next step is to remove the alternator and test it at an autoparts store.
If the alternator is good then i will replace the battery cables and alternator ground cable.

The car has many electrical issues as well
RPM dosnt work. (when car starts it jumps a bit then drops to the bottom as car is in idle)
Temp gauge and fuel gauge dosnt work. (car does have gas)
Windows are electric but move very slowly.

After that i wont know what to do, please chip in with any tips or opinions, Thanks in advance guys
Anything is appreciated!

[SmokeE30]

Put a multi meter on the battery when it's running you should see 13.5-14 volts if the alternator is actually charging the battery

[Saascat1]

I'd check all your grounding/earth points on the block, chassis, alternator. You may have a break in an earthing wire, this would explain intermittent symptoms.
Another thing to check, and this may only be a tropics thing (it happens here in Darwin a lot and the symptoms are the same), is your relays. This is gonna sound weird but ants sometimes get inside and build a nest, as some are always live and so warm, eventually shorting out the relay.

Good luck. Electricity is the Devils work! And according to James May, "nobody really understands it"

[MF DOOM]

get a meter and ohm your alt. make sure its grounding. i had this issue with my m42 car. i dont know if m20 alternators ground through the block like m42s do but i added a ground from the alt to chassis and it fixed it.

[jlevie]

Put the battery on a charger over night. Then check the battery voltage 15-30 minutes after disconnecting the charger, it should read 12.7v. Start the engine and check system voltage which should be ~13.5 v at idle and ~14v at 2500rpm. Those readings should not appreciably change if you load the system by turning on the head lights and HVAC blower on high.

Make sure that the battery/alternator warning light in the cluster comes on when the ignition is switched on before starting the engine. That bulb is the exciter supply for the alternator. Without exciter power the alternator won't work properly.

[sailorjase]

Thanks for all the feed back everyone, greatly appreciated.

Heres the update on what it did today

I made sure gas was in it and took the battery out to get it charged at an auto parts store. then i went back to the car with the fresh battery, installed it and the car started after three attempts. it idled fine and lights worked and everything so i drove it to a gas station, filled the tank then drove it home about 2 miles.

On the drive, the stereo started shutting off and coming back on back to back like it was blinking. as i got closer to my house the dash lights started to dim and cars idle started to begin to bog out. battery light also came on. i managed to get to the front of my house and park the car right before it just completely died again.

i tried to crank it and again, battery was completely dead.

the car is parked now and awaiting a new alternator.

on top of this, i will check my ground cables, relays and fuses
also ill check if the battery light comes on before i crank it.

in the morning i'll remove the alternator and go exchange it for a new one. also ill have to get my battery recharged again. ill install them and keep you guys updated


thanks again for all the helpful feedback!

[sailorjase]

Quick update:
Things are looking good...
I removed the alternator and got it tested and it failed twice so i bought a new one for $70 at oreileys (with the pepboys price match)
I got my battery recharged and cleaned my ground wires.
Tomorrow i will instal the new alternator and put everything back together and that should solve the problem.
If the car still dies on me then im guessing it will be a wiring problem...

Thanks again for the feedback

[sailorjase]

New Update, still skeptical...


I installed the new alternator

I tired to start the car and it didn't want to, it just kept cranking
I tried about 10 times so then I figured id try to get another car to give me a jump to see what would happen
Once jumper cables were hooked up, I tried to start my car about 10 times and it didnt want to start.
Finally after a few mins and more attempts it fired up and i had to keep reving it to keep it alive.
*If i let go of the gas pedal it sounded like it was going to die so i kept my foot on the gas and kept the car around 2500-3000rpm.
After about 5 mins of keeping the car alive i let go of the gas and the car was idling
The problem is that my idle wasn't steady, it was fluctuating as if i had a fuel or oxygen problem
I let the car idle for about 20 mins then took it for a 10 mile test drive and everything felt fine, no funky smells or sounds but i am still nervous that my car will die on me again...

What do you guys think?

Any input would help!

[dnguyen1963]

There are a few things you can do to eliminate some potential problems. First thing is to have a smoke test done on the car to fix any vacuum leaks. Second, replace the O2 sensor if it has not been replaced recently. Third, check your coolant system including the temp sensor. And last, but not least, check your fuel pressure. Good luck. BTW, the DME takes a bit of time to adapt to the new environment since the battery was dead/removed. That might be the reason for why the car is running fine after some 30 min after rough idles.

[sweet6e30]

obviously it was the altenator as the car was driving off the battery and not being recharged. when ever your driving a car and the POWA dims and kills the car, its in most cases due to inadaquit charging ,

the hard start issue after replacing everything was because you fouled the spark plugs on trying to get it started multiple times with not enough ERECTRICITY to produce enough spark!!!. So the plugs were most likely soaked in GRASORINE!
After waiting a little bit you squeeked by as the gas on the plugs evaporated a litle bit and then with added cranking POWA .... starty starty,....Happy dance !

enjoy.

Give it a good thourogh tune up, and sensor refresh: o2, coolant temp senser. After some new Parts love, das bimmer is happy

[dnguyen1963]

Love your English!

[TG Goose]

ERECTRICITY

[Pocket Chant]

POWA .... starty starty,....Happy dance !

[sweet6e30]

lolz i thought ya'll like that ! ;)

[sailorjase]

Update:
The car seems to be running fine now and hasn't failed me in about a week.

I'll do a major tune-up and swap the sensors.
Ill check for vacuum leaks, my cooling system and fuel pressure.

Thanks again for all the help, much appreciated!