Hi i have a e30 320 1990.
It has been fine up untill two weeks ago. when the car has been left overnight it won't start in the morning. Just turns over and wont fire and smells of fuel. If i remove number 11 fuse (fuel pump)and turn engine over untill it startes to fire put fuse back in and away it goes startes straight away. I can't work out how it's fooding. I thought maybe MAF sensor but that only controles fueling when engine is running doesent it?
any help would be great.
flooding.
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Grrrmachine
- E30 Zone Wiki / Team Member
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There's no quick answer, but there's a series of tests you can do. You'll need some basic tools, including a cheap multimeter.
1) Look at the big rubber hose from the AFM (not MAF, E30's don't have MAF) to the Throttle Body, and all the side hoses. Look for cracks around the jubilee clips, splits near the creases, that sort of stuff. Tighten up anything that's loose, replace any rubber that's looking tired. You can wrap rubber pipes in electrical or gaffer tape if you find a split, as a quick fix to see if that's your problem.
2) Look for the blue temp sensor, which is on the top of the engine at the front, near the radiator (just next to Injector 1). Unplug the connector, and get the multimeter onto the sensor; it should read a resistance of about 3000 ohms. Blue Temp sensor is a common problem with these cars, and you can SEARCH for more info about it. It can also help to disconnect the ECU and measure this resistance across the relevant pins, to make sure the wire to the Blue Temp Sensor hasn't gone wrong.
3) Make sure there are no leaks around the rocker cover, or the breather hose that goes from the rocker cover to the throttle body. Sometimes an air leak here is enough to cause problems.
4) Operating the throttle arm manually, get your air near the throttle body and listen for a small "click" just as the throttle is moved away from its resting position. Hearing a click doesn't mean it's ok, but no click is not usually a good sign.
5) Run a wire directly from the battery positive terminal to the coil positive terminal (it should have a green wire running from it.) This should make all the electrics in the car come on, including the Idle Control Valve, which will buzz. Now try and start the car. If it starts, you have a spark problem, or a problem with that green wire, usually from an immobiliser.
6) Take out a spark plug and look at its condition. It should be a nice tan brown. If it's wet, they'll all need to be wiped and dried before trying to start the car again. If the tip is too black or too white, you have other engine problems.
7) Use your screwdrivers to take off the big rubber hose, then look for the Throttle Position Switch (the clicking thing) underneath the throttle body. This can get gummed up with oil over the years, meaning it no longer sends an Idle signal to the ECU. Unscrew it from the throttle body and clean it out with Carb Cleaner. Get your multimeter onto the middle pin and one of the side pins (there's three) and make sure you get a change from infinite resistance to continuity as the switch is rotated, or vice versa.
8 ) While the TB is off, look for a little rubber blanking plug on the bottom of it. This often degrades and becomes a significant air leak.
9) Check the C192 plug, which is underneath the intake manifold and throttle body. On M20 engines, this is prone to corrosion leading to breaks and cracks in various wires.
10) Check the condition of all rubber fuel pipes from the bulkhead (passenger side, under the brake servo) to the injector manifold, including the thin rubber hose from the top on the intake manifold to the fuel pressure regulator. Replace only with BMW genuine rubber pipe (8x13mm) if cracked.
That should keep you busy for a while. If you're getting fuel, I don't think it's your Crank Position Sensor or your DME relay.
1) Look at the big rubber hose from the AFM (not MAF, E30's don't have MAF) to the Throttle Body, and all the side hoses. Look for cracks around the jubilee clips, splits near the creases, that sort of stuff. Tighten up anything that's loose, replace any rubber that's looking tired. You can wrap rubber pipes in electrical or gaffer tape if you find a split, as a quick fix to see if that's your problem.
2) Look for the blue temp sensor, which is on the top of the engine at the front, near the radiator (just next to Injector 1). Unplug the connector, and get the multimeter onto the sensor; it should read a resistance of about 3000 ohms. Blue Temp sensor is a common problem with these cars, and you can SEARCH for more info about it. It can also help to disconnect the ECU and measure this resistance across the relevant pins, to make sure the wire to the Blue Temp Sensor hasn't gone wrong.
3) Make sure there are no leaks around the rocker cover, or the breather hose that goes from the rocker cover to the throttle body. Sometimes an air leak here is enough to cause problems.
4) Operating the throttle arm manually, get your air near the throttle body and listen for a small "click" just as the throttle is moved away from its resting position. Hearing a click doesn't mean it's ok, but no click is not usually a good sign.
5) Run a wire directly from the battery positive terminal to the coil positive terminal (it should have a green wire running from it.) This should make all the electrics in the car come on, including the Idle Control Valve, which will buzz. Now try and start the car. If it starts, you have a spark problem, or a problem with that green wire, usually from an immobiliser.
6) Take out a spark plug and look at its condition. It should be a nice tan brown. If it's wet, they'll all need to be wiped and dried before trying to start the car again. If the tip is too black or too white, you have other engine problems.
7) Use your screwdrivers to take off the big rubber hose, then look for the Throttle Position Switch (the clicking thing) underneath the throttle body. This can get gummed up with oil over the years, meaning it no longer sends an Idle signal to the ECU. Unscrew it from the throttle body and clean it out with Carb Cleaner. Get your multimeter onto the middle pin and one of the side pins (there's three) and make sure you get a change from infinite resistance to continuity as the switch is rotated, or vice versa.
8 ) While the TB is off, look for a little rubber blanking plug on the bottom of it. This often degrades and becomes a significant air leak.
9) Check the C192 plug, which is underneath the intake manifold and throttle body. On M20 engines, this is prone to corrosion leading to breaks and cracks in various wires.
10) Check the condition of all rubber fuel pipes from the bulkhead (passenger side, under the brake servo) to the injector manifold, including the thin rubber hose from the top on the intake manifold to the fuel pressure regulator. Replace only with BMW genuine rubber pipe (8x13mm) if cracked.
That should keep you busy for a while. If you're getting fuel, I don't think it's your Crank Position Sensor or your DME relay.
Hi thanks i have pretty much done all of this all ready. This would not explain why it floods when left over night. With most of these i think i would get the problem when it's hot to or if i stopped it for a couple of hours. This only happens when it has been left over night. I have replaced some of the rubbers that looked worn. The only thing i have not cheacked is the blue temp sensor.
thanks for your response.
thanks for your response.
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Brianmoooore
- E30 Zone Team Member
- Posts: 49358
- Joined: Mon Jan 10, 2005 11:00 pm
Another check: When you park the car in the evening, stop the engine by pulling out fuse #11 (fuel pump). When the engine dies after a couple of seconds, switch off the ignition and replace the fuse.
In the morning, it should take a couple of turns of the engine to build up fuel pressure, but then should start.
In the morning, it should take a couple of turns of the engine to build up fuel pressure, but then should start.