I'm having problems with my 1990 325is

[DRUMandGUN]

I'm new here and a bit new to the e30 world and i need help figuring out what's wrong with my e30 and i thought now would be a great time to join this forum.

So any help you guys can give me would be much appreciated.

These are my known problems with my 1990 325is.

1. Bouncing idle. Sometimes can dip so low the car can stall. Would sometimes stall at stop signs because the RPM's dipped to low.
This problem would only happen maybe half the time we drove the car.
Also the warning lights on the dash would shudder/flicker sometimes when the RPMs would dip really low, also when almost to the point of stalling out the dash warning lights would shudder/flicker sometimes.

2. Choppy running at low RPMs, like the car isn't getting enough fuel but once you build to higher rpm's it acts normal. This problem would only happen about half the time we drove the car.

3. If the battery is disconnected the car will always have known problems number's 1 and 2 for about 30 to 45 minutes after reconnecting the battery and will slowly correct itself as time passes. Problems 1 and 2 still happen when the battery has been connected for a long time, about half the time we drove it.

4.Having to pop start the car whenever it stalls out or is shut off. The starter clicks but the starter motor doesn't engage. We just replaced the starter and it worked fine for about a month.
The old starter we replaced didn't click when the car was turned over and when we bunch tested it, it didn't work so we knew that starter was bad.
We don't think it's a problem with the new starter since it's new and we just replaced it.

5. Probable misfire of 1 or more of the cylinders. It started randomly while driving home.

6. Half the dash lights on the left side for the gas gauge and speedometer don't work half the time unless you give the dash a couple swift smacks.

7. Gas gauge doesn't work 75% of the time and smacking the dash can only sometimes get it to work again.

8. Whining tone sound coming from what sounds like the underneath left side, close to the passenger side someplace.

9. Left dome light doesn't work and the backlight for the OBC doesn't work but the OBC does. Probably just burnt out bulbs but i thought i would list them just in case.

10. Reverse lights don't work.

11. Battery seems to lose charge quite quickly.

12. Temp gauge sometimes fluctuates between anywhere from no reading to overheating and everywhere in between at random.


Again any help with this would be great, thanks.

[ELVA164]

Whew, ok.

1. and 2. sound like intake vacuum leaks. Have the car smoke tested for leaks at a shop and replace all offending boots/hoses. Having the car retested afterwards isn't a bad idea either, to ensure everything has sealed properly. These motors are very sensitive to this. The flickering lights are a result of the car almost stalling, nothing else.

3. This also sounds like the DME "learning" to compensate for the intake leaks, but it only has so much ability to. Hence it still happening half the time.

4. Sounds like you have power to the solenoid...I would recheck the wiring, clean any suspicious grounds, and see if anything changes. It might be worth trying the age-old trick of smacking the starter to see if it frees up...

5. Too little info to work with, at least for me.

6. The dash is lit by two bulbs in the rear of the gauge cluster. The cluster isn't hard to remove, there are a few DIYs posted around. Just search and ye shall find. It sounds like one of the solders to the offending bulb might be loose. You could take the bulb out and see if one of the two little "legs" that connect it to the circuit board has broken; otherwise you would have to look at the board itself.

7. The gas gauge (and the temp gauge, check both!) are grounded by small nuts on the rear of the gauge cluster. Make sure both of these are clean and tight, and still have washers.

8. Just to clarify, "left" and "right" are always described from the driver's perspective, so it's impossible for the sound to be on the left and the passenger side unless you have a right-hand drive car. When does whining occur? Does anything like turning, stopping, or accelerating affect it?

9. Bulbs in both cases most likely. Dome light pops right out, uses one of those tube-style bulbs. The OBC is a bit more involved but there is a handy shortcut to accessing it that you can search up.

10. Did you check the bulbs? Do the lights have voltage?

11. Sounds like a parasitic drain. Disconnect the battery at the negative side, then grab a test light or a multimeter. If there is more than a few tenths of a volt, you have a draw. Start pulling fuses until the voltage drops, then inspect everything associated with that fuse circuit. Start with fuses 12, 27, and 28.

12. See #7.

[jlevie]

1-5 are probably intake leaks, perhaps aggravated by aged ignition parts and an aged O2 sensor. A smoke test will find the intake leaks and the distributor, wires, plugs (with NGK ZGR5A's), and O2 sensor should be replaced. If the smoke test immediately reveals gross leaks, those must be fixed and the test repeated.

6 sounds like cracked solder joints on the main PCB in the cluster. They can be found and fixed.

7 sounds like a bad connection where the fuel gauge mounts to the PCB in the cluster. Re-flowing the solder on the pad where the stud and nut goes is the fix. Do the same for the temperature gauge (see #12).

8 sounds like a failing wheel bearing.

10 could be a bad reverse switch.

11 sounds like excessive parasitic draw, but it could be a weak alternator or aged battery.

[DRUMandGUN]

We put in a new battery from my 88 in the car and as soon as we turned the key we saw almost a 1 volt drop.
We decided to not go on because the battery cable in the truck was really corroded so we are splicing in a new cable to see if that fixes the starting issues.

We also checked the frame to oil pan ground cable and it looked brand new so that's not the problem.

The hood ground cable has been cut on my car.
I was wondering why someone would do that and what would not having a hood ground affect?

I'll start on the rest of the issues after the car starts. haha

[ELVA164]

Many of the hood grounds have been cut instead of just unbolting them if the hood needs to be removed. Their main purpose is to remove the static electricity from the hood vibrating slightly during normal driving, which can cause radio interference. You can buy new OEM ones or get them from Gregs///M on here for not too much.

Also: If the starter is still clicking and the battery is sufficiently charged, I would look there after the cable.

[Kristin Thompson]

I recently bought a 1989 BMW 325i with 138k miles from its original owner. It's in perfect running condition and cosmetically it's near perfect if not immaculate. I changed the transmission and made it a 5 speed just for preferance but the 4 Speed automatic transmission was flawless. I get about 23.5 combined mpg with either transmission with mostly hwy driving. I have put 5500 miles and I trully love this car that I picked up for cheap.

[noahsense]

To add to the good advice...

I had a very similar idle issue to what you describe which was solved with a new throttle position switch. The coolent temp switch is another source of idle issues.

It's also worth replacing the voltage regulator which is cheap and will often solve several seemingly unrelated electrical issues.

[DRUMandGUN]

We checked the starter and we determined that it was a bad starter so we pop started the car and it was running really rough.
My friend had to stay in the car to keep it from stalling out.

We checked for vacuum leaks with carb cleaner/wd40 and couldn't find any leaks so we let the car stall out and checked the cap and rotor and it turns out they were interfering and the points were all ground down.
We yanked the starter and bench tested it and it pops but the motor didn't engage so we replaced the starter and the cap and rotor and the new starter doesn't work either.
It's acting just like the last one did and the starter motor won't engage and we bench tested it before hand to make sure it worked before we put it in.

After that we were like well lets see if the new cap and rotor fixed anything so we tried to pop start it and nothing.
We attempted about 15 times at popping starting it and even had my buddy push the car with his truck to get it up speeds faster then the 5 of us could push it and still nothing and i even live on a bit of a hill so pop starting a car is normally a breeze.

What would cause it not to pop start?

We are feeling pretty darn defeated at the moment but we are going to be working on it most of the weekend to try and figure everything out so i hope something will go our way for once. :/

[jlevie]

A starter that bench tests okay, but doesn't work in the car, would be a problem with the solenoid control, power, or ground. Start at the battery and check all of the main power connections. Also check the battery ground and the engine to chassis ground (lower left front of the engine). Check for solenoid power with a test light when the key is turned to start.

You won't find any but the worst intake leaks that are close to the head with starter fluid. Only a smoke test will find any and all leaks.

Since you changed the distributor cap, the no start condition may be from misconnecting the ignition wires.