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Discussion Starter · #1 ·
driving 9 months ago and it died while driving as if it ran out of gas, but i had a half tank still. over the last nine months i have problem solved and tried almost everything i could think of; injectors, plugs, cleaned throttle body, new fuel shut off relay, fuel pump and sender working, new fuel filter. its getting spark, battery is new and its cranking fine and its getting air, but it still wouldnt start. i finally got it started yesterday after cleaning the ground straps of all things, and drove it all day, but then it died again last night when i tried to chirp the tires, and it wont start again. Please, any one with some ideas or inside info, help me out. im almost to the point of serving the thing a flamming bottle if ya know what i mean.
 

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Here's the advice I got to a similar question on another board. I'm not diligent enough to do it all, but did most of it and my car runs a whole lot better. Good Luck!

Anyone working on a 24 year old E30 fuel injection system needs the Robert Bentley E30 Repair manual and RB’s Bosch Fuel Injection manual from the same era – plus a digital multi-meter. The manuals and multi-meter as good as a BMW shop fault computer.

Have the engine compartment thoroughly cleaned with water/steam (wrap any electronics to prevent water contamination) to eliminate any dirt that might be interfering with things. Dirt/oil/grease will seal air leaks or interfere with electrical operations one day, allow them the next.

To ensure dependability on a 24 year old fuel injection system, replace ALL rubber hoses and ALL gaskets wherever unmetered air can leak into the motor on the motor side of the air flow meter, or independent of it. And not just for the air/fuel systems. Replace the brake booster hose, all the oil hoses. Remove and throw away those ANCO hose clamps that have accumulated over the years and put real BMW ones on – properly sized against the BMW parts manual – instead. A new ring seal on the oil filler cap and a new valve cover seal aren’t utterly necessary on the M10 motor, but you’ll feel better in the morning after you’ve done that. Don’t overlook the distributor shaft seal. With the motor at operating temperature, station 2 friends with fire extinguishers on each side of the engine compartment and you squirt a little starter fluid around the intake manifold gaskets. Any change to engine idle or running characteristics noted as the stuff evaporates signals an air leak there.

The rubber hose FROM the air flow meter to the throttle body cracks on the bottom and around the clamps over the years. If yours is 24 years old, throw it away and invest in a new one. You might not even see the crack that’s letting in air. Make sure the clamps are BMW-authentic, too.

Invest in new fuel line hoses as well. If you can smell gas in the engine compartment, one is cracked somewhere. Old BMW fuel hoses are a fire hazard.

Once you have an absolutely airtight motor, you have eliminated about 20-30% of your potential intermittent drivability problems on the E30 M10 EFI system. Move on to the electrical stuff.

24 year old BMW wiring harnesses have been hammered all those years by heat, vibration and corrosion.

Before doing any of the following electrical system work, disconnect the negative side of the battery.

Check every wire that has anything to do with the fuel injection system or drivability for continuity. Flex the wiring while putting the multi-meter on them. Frequently, an older BMW wiring harness wire will crack inside its insulation and continue to pass current part of the time, and not at other times. The wiring to the oxygen sensor is a frequent culprit. Any soldered connection is suspect on a 24 year old BMW E30. The solder cracks and you’ll never see the defect by eye. If you are good at it, re-solder all connections you can reach yourself, or ask a friend to do it. Pull the circuit board out of the instrument cluster and take it to a professional electronics repair shop. Have every soldered joint redone on the circuit board as well. They frequently cause problems with invisible cracks after all the years. (You can have the shop rig a snap in/snap out holder for the NICAD batteries while it is at it. Never have to fuss with re-soldering the batteries while replacing them again.)

Thoroughly clean every wiring connector with a brass brush and connector cleaning solvent. Dremel Tools are wonderful for the hard to get at places. Test the connectors on the multi-meter. Make sure the connection is tight and the plastic and metal components aren’t broken or missing. Eliminate any corrosion damage that you can see. Splice in new connectors if any appear defective. Wires fatigue at connectors quite often. Pull the fuse box and completely clean all the connectors in and around that, too. Chances are you’ll break some because they are corroded. Replace. Re-solder. Lots of older BMWs have cracked or crumbling rubber boots that no longer protect connectors. Replace them if that’s the case.

Using your RB Service Manual’s electrical wiring diagram, find every ground point on the motor’s wiring harness, including the main ground on the intake side of the motor. Clean all mating surfaces to bright metal with a brass brush and emery cloth, then re-connect and protect with suitable dielectric or other compound, if you live close to the ocean or in a really wet climate (you said Seattle??). Don’t forget to get into the computer compartment under the glove box and clean all connectors to the car’s brains. Be very careful to disconnect power to the battery and ground yourself before touching the computer, however.

Don’t forget to check your distributor. A worn distributor causes considerable erratic motor operation, including bad idle. Have it bench tested by someone not interested in selling you a new distributor.

The E30’s EFI sensors are pretty simple to check, though not prone to defects. With the RB and Bosch manuals, you can check sensor resistance against given values. Throw away the components that you don’t like.

Once you have addressed your air and electrical gremlins, you have eliminated at least 75% of the E30 M10 EFI system problems. If there are still problems, your RB Manual and Bosch Fuel Injection guide can help you work through them.

Good luck! Enjoy!
 

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Discussion Starter · #3 ·
thanks man, really appreciate the advice. Any advice along the lines of it possably being a sensor or relay problem, yet not interupting the fuel flow or ignition spark?
 

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cHECK YOUR AIR FLOW METER DOOR AS MINE WOULD SOMETIMES STICK AND STALL THE CAR WITH A NO START CONDITION. uSUALLY JAM WHEN WALKING ON THE THROTTLE!
 

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Discussion Starter · #8 ·
ya, no go, the was'nt stuck. but i pulled my spark plugs out and they where covered in oil, so i may be into more seriouse trouble than i had thought. i would love to do the m50 conversion to it, but i have to take it through the emissions testing one more time for my 09' tab before it is old enough to not test anymore, then i can do whatever swap i want:)
 

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Discussion Starter · #10 ·
hell ya, that would be an awesome power increase, specially with twin inline turbos:) ya, i pulled the valve cover off today and there is some coolant in the the pockets of oil on top of the head bellow the exhaust valves, so not lookin good; either head gasket or cylinder head. im kinda getting tired of having the thing sitting around for so long not running so im thinking i might just sell it off in favor of something older like a 2002 or something, thus eliminating any future possibility of computer or sensor issues. i am very mechanicly inclined, but when it comes to electronics, im skrewed, and i dont really have the financial means to take a car to a shop, specially a bimmer shop, so i may just get rid of it, despite how much i love the fuel economy and handeling capabilities of the thing.
 
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