Hit a pothole, turned off

[lolcantturn]

E30 has been acting especially weird today. About 1 minute before I hit a pothole, my temp gauge was fluctuating between 1/2 and 3/4ths, and my gas gauge was fluctuating between empty and the 3/4ths mark (I had nearly no gas anyway, the light was on, but I definately didn't have 3/4ths of a tank). Then I hit a pothole and the car turned off! It turned back on again, but the check engine light came on.
It hasn't turned off again, but I want to know why this occured??? I know I had a similar incident about a month ago where my CPS wires were shot and the car turned off randomly, but I replaced it since then.

update on post 5

[nrubenstein]

Sounds like a loose connector or bad wiring. I'd start by checking your engine bay grounds and the main relays (by the left shock tower).

[lolcantturn]

Sounds like a loose connector or bad wiring. I'd start by checking your engine bay grounds and the main relays (by the left shock tower).

Main relays are new
Where's the engine bay ground?

[nrubenstein]

IIRC, it goes from the oil pan to the frame rail on an M20. It's been a while since I looked.

Also, you relays may be new, but that doesn't guarantee that they are securely installed.

[lolcantturn]

IIRC, it goes from the oil pan to the frame rail on an M20. It's been a while since I looked.

Also, you relays may be new, but that doesn't guarantee that they are securely installed.

Checked both today, everything's fine

OK, so get this
I turned my car on this afternoon and drove it around, the check engine light was still on. then I turned it off, and turned it back on. the speedometer, econometer, and tachnometer stopped working, but the check engine light went off! WTF happened? I can't diagnose it for the life of me, I checked the fuses and they're fine, nothing seemingly loose in the engine bay.
The check engine light still lights up when i put it on accessory mode, so i know that didnt turn off with the meters, but WTF? Any help?

[tjmonsen5]

Im surprised the check engine light turned on. I have never had mine turn on, even with a bad TPS, idle control valve, O2 sensor, and when the head gasket blew. I dont think E30s are very smart cars lol.

sorry thats of no help.

[lolcantturn]

Im surprised the check engine light turned on. I have never had mine turn on, even with a bad TPS, idle control valve, O2 sensor, and when the head gasket blew. I dont think E30s are very smart cars lol.

sorry thats of no help.

Check engine's helped me quite a lot actually..everytime a hose blew out or I had a coolant leak the light always came up before I could really notice. Also came up when you have a major vacuum leak.

[moatilliatta]

Check your grounds and the resistance of them. I would start there first. There are a couple more body grounds i believe also than just the ground to the oil pan.

[lolcantturn]

Check your grounds and the resistance of them. I would start there first. There are a couple more body grounds i believe also than just the ground to the oil pan.

The check engine came off and I didn't notice anything noticably loose...now my tach and speedometer don't work. And it's not the fuses either.. darn

[lolcantturn]

So I drove it around hard to see if anything would "fix itself."
Damn, these cars have an automatic fixing ability because the speedometer began working again.. the tachometer and the econometer don't work still..but that doesn't concern me too much.
What's facinating is that, my temp gauge doesn't flucuate between the halfway point to the 3/4ths mark like it used to before.. It used to go between 1/2 to 3/4ths in about a 2 seconds or so then back to the 1/2 mark..it doesn't do that anymore..it stays on the halfway mark. Which means the "overheating" problem I had was just the temp gauge acting up?
I hate these cars. They fix themselves and you don't know if you should be happy or mad haha. Still dunno what's up with the tach.

[r3d e30]

My tach goes out all the time and then suddenly fixes itself. My gas guage has never worked, and the car itself just has problems, but I love the car and its a toy car anyways so I dont get too upset besides mine is over 22 years old and its bound to have a few quirks.

[Higelac]

I just got my E30 and I am pretty unfamiliar with them, having come from the world of Datsuns. However, I just finished doing my timing belt and I noticed some things which may help you. On the front of your engine right above the water pump pulley should be routed two stiff, black cables (similar to bicycle brake cable). On the passenger side, one runs down to the crank position sensor and the other well crap I already forgot where that goes. There is a third, similar cable higher up that runs to what appears to be an inductive sensor attached to one of the spark plug wires. This cable, I would think, signals your tach but shouldn't be necessary for the car to run. Check all three of these cables since on my car, at least two of them were routed in a way where if the clips holding them were missing (mine were) they could easily be rubbed through by the water pump pulley. You might have a short here. On the drivers side of the car, I think all three join up at a large, round connector with a screw on lid. Perhaps this is a diagnostic connection? I didn't look at this area closely since I was not working on these components, but you might try disconnecting all of these cables, cleaning them out with electronics cleaner spray, then reassembling.

[gearheadE30]

For the gauges, I bet you have a bad connection behind the cluster, considering that that is about the only thing that could possibly cause the entire IP to die. Fluctuating gauge readings are typically caused by the ground nuts on the back fo the fuel and temp gauges coming loose. If that isn't it, then it is probably time for you to replace the SI board batteries, as they have a pretty big impact on the stability of the gauges.

As for the car just turning off, definitely a loose connection. Did all of the interior lights and everything else stop working as well, or was it just the engine? If everything went out, maybe the main battery straps are loose. Also check the battery power lead where it comes into the engine bay and mounts to the firewall on the passenger side of the engine bay.

If it was just the engine, make sure the ECU plug is latched (could also cause gauge error) and the aforementioned ground straps. Maybe check the coil wire and the leads to the injectors too if everything else checks out.

[kamotors]

these cars really do "fix" themselves, I went 6 months with no light on my tachometer and then one night it turned on and has stayed on since that day.

[evil_twin]

OP try this.

1st what do you have on your key ring? If your key is heavy and the ignition cylinder is worn, you may cause it to shut itself off when you hit a pot hole.

2nd, check your battery connections. Make sure they're good and clean.


LMK on what happens after that.