1983 633csi No Start PROBLEMS !!!

[SHARKNOVA]

My son and I bought this project car 1983 633csi. It sat for about 3 years. Problem is it won't start. I have changed the speed and reference sensors, the coil and changed the ECU and still no spark. I have 12 volts to the coil, 12 volts to the main relay. I have tested the coil wire going to the sparkplug, that has the right ohms. We can plug the sparkplug directly to the coil wire and ground it to the engine and still no spark We are replacing the front radiator support and have the whole front end removed, therefore we want to get this at least to spark before we put the front nose clip on because it is so easy now to get to. My question is this. We have the alternator, injector rail, throttle body and fuel pump all disconnected and removed from the vehicle. Couldn't we at least get a spark to the plugs even if these items are removed or do they all need hooked up for the right signals to "sent out" before it will spark?

thank for your help

[Kit2kay]

All of those things need to be connected to get a good spark in your engine. The three things an engine needs to start are Air, fuel, and spark.

For Air check your mass air flow sensor and your throttle body because they control the air going in your intake manifold which goes in your engine

For fuel, check your fuel pump, filter, and fuel pressure regulator, fuel rail, and fuel injectors to see if they're working, And when your in the car turn the key to the on position, but don't turn on the engine and listen to the fuel pump prime, if you can hear a noise coming from the fuel pump then you know the fuel pump still able to send fuel into the fuel rail and into the engine.

For spark, check your battery, alternator, your starter, and your ignition switch which is usually located under to steering on the opposite side of where you insert in your key because they're what help your spark plugs ignite your engine

Make sure to check all the fuses in your car to make sure none of them are blown, and if they are they'll need to be replaced. Also it's always a good idea to have a obd scanner on you to scan your engine codes, because that always tell you if you have problems with your car, and also make sure to listen to the sounds that your car is making, that can also tell you what's wrong with your car.

I know it seems a like a lot, but that's how BMW's are they're great to drive but can be a pain in the ass when they don't work right.

[carsnplanes]

All of those things need to be connected to get a good spark in your engine. The three things an engine needs to start are Air, fuel, and spark.

For Air check your mass air flow sensor and your throttle body because they control the air going in your intake manifold which goes in your engine

For fuel, check your fuel pump, filter, and fuel pressure regulator, fuel rail, and fuel injectors to see if they're working, And when your in the car turn the key to the on position, but don't turn on the engine and listen to the fuel pump prime, if you can hear a noise coming from the fuel pump then you know the fuel pump still able to send fuel into the fuel rail and into the engine.

For spark, check your battery, alternator, your starter, and your ignition switch which is usually located under to steering on the opposite side of where you insert in your key because they're what help your spark plugs ignite your engine

Make sure to check all the fuses in your car to make sure none of them are blown, and if they are they'll need to be replaced. Also it's always a good idea to have a obd scanner on you to scan your engine codes, because that always tell you if you have problems with your car, and also make sure to listen to the sounds that your car is making, that can also tell you what's wrong with your car.

I know it seems a like a lot, but that's how BMW's are they're great to drive but can be a pain in the ass when they don't work right.

This car should have an AFM or Air Flow Meter(door operated potentiometer) instead of a MAF or Mass Air FLow sensor. Also It will not have a OBDB port as it is pre-OBDB so the use of a OBDB scanner does not apply.

You said you measured 12V on the coil when turning on your ign switch. That's good. The trigger comes from the ECU when good "Speed" and "reference" sensor information is given to the ECU during cranking. YOu also said your pump is working. That;s good, that means the FP relay and the Main relay are working. So if the ECU has everything it needs to think all input sensors are working during the crank cycle, it should output the grounds for the injectors and the ground to complete the circuit for the coil. The only other needs are actual fuel and actual air. Make sure the speed and Ref sensor connectors are good and connected correctly. Sensors are same P/N but located differently on the bell housing.

[1986series6]

I think you need the speed and reference sensor to inform the dme for spark.
Here is a pinout for a 5 series but should be very similar.

http://e28-535i.com/upload/Montronic1.0pinout.pdf

[RSheiman]

Why not the coil, all go to that point.

[1986series6]

Rob, I think you still need the ECU to initiate signal to collapse the coil.

[SHARKNOVA]

thanks to all that replied. I found the problem....bad ecm. A buddy of mine let me borrow his to plug in and then I got spark.

[DesktopDave]

Thanks for the update, it's always good to hear that a problem has been solved. Also good so others can figure it out.

Not to be nebby, but are you going to repair the old DME?

[SHARKNOVA]

yes, I want to get the old DME repaired. Know of any good places that do that and are honest?

[DesktopDave]

I was hoping you'd have a suggestion, LOL. I've only head of Programa. Google turns up a few likely candidates:
SIA Electronics, ECU Doctors, Module Experts, etc..

I have managed to swap out coil drivers in later DMEs myself with mixed results, but the early ones look a lot tougher.

[Bert Poliakoff]

Try Fuel Injection Corp of America. I was going to send him the ECU from my early Motronic to be checked out, he said save your money those don't go bad. Seems pretty honorable for a guy to do that. On top of that a bunch of E9 guys use him and those guys are fussy. May be a little more one on one rather than being tossed in line