1990 mercedes 300ce will not start, battery is good, fuel pump is good, crank sensor is new, can you help?

Codes help. But you need to check what you don't have. Fuel pressure or spark at the coils/plugs. I know you replaced them, but it could be a bad wire, plug, or fuse. Could be a bad ECU.

First start with the basics check fuses relating to fuel and or injectors make sure there is voltage next look into your crank sensor usually if it fails the computer doesn't know you are trying to start the vehicle because the signal the sensor is supposed to give out to the computer is not there due to a faulty sensor once the computer senses the signal from the crank sensor then the computer will send a command to the injectors to start pulsating gas let me know how this turns out for you.
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The fuel pump pressure shoud be 55-61 psi . Check for spark by removing a ignition wire at a spark plug and put a spark plug in wire and hold to engine ground and crank engine , if no spark then remove coil wire at cap and repeat.If still no spark then coil , module,,crank sensor or pickup may be the problem.
Check fuel pump pressure first and if available check for codes for possible crank sensor.

Yes it is very much possible.But there are many other possibilities too,including starter and spark plugs issue.

If your engine cranks normally but will not start because it has no spark, or it stalls and won't restart because it has no spark.

You can also do a test to confirm the problem .The procedure to do the test is as follows:---

If your engine has spark plug wires, disconnect one of the plug wires from a spark plug and place the end of the wire near a metal surface on the engine. Then insert a small Phillips screwdriver into the end of the wire (the plug boot), or a small bolt or nail to provide a conductive path. Then crank the engine and look for a spark to jump from the screwdriver, bolt or nail in the end of the plug wire to the engine. If you do not see a spark, there is an ignition problem.

OR-----------

If your engine has a coil-on-plug ignition system with no plug wires, In that case remove one of the coils from the spark plug and insert an old spark plug, a spark plug tester or a screwdriver into the end of the coil. Ground the spark plug or plug tester to the engine, then crank the engine and look for a spark. No spark indicates an ignition problem.If the engine has no spark, check for voltage at the coil positive terminal when the ignition key is on. If NO voltage, then problem is on the trigger side of the coil (pickup, crank sensor, ignition module or primary wiring circuit).

But If there is NO voltage at the coil itself, then in that case the problem is on the supply side (the ignition switch or ignition wiring circuit).-----------------

Jeep cranks but no start:----------------

A jeep that cranks over but doesn't start, in many cases will be due to a bad fuel pump, a broken timing belt, an inoperative cam sensor or crank sensor. Also these problems are related to faulty spark plug. Check the spark at spark plugs when you start the jeep. Do you notice any spark. Actually you should see. If in case there is no spark then it's a spark plug problem. Also the coil pack gives power to spark plug. So check the voltage at coil pack. It will show 12 volt. If there is no voltage noticed at coil pack then its faulty coil pack that has to be replaced. If all the possible options checked out ok then check the car starter. The starter gets power from battery to start the jeep. If the starter is faulty then it will not let the car to start. Also check and confirm that there is fuel in the jeep. If its very low fuel then in some cases this causes the problem. Also check and confirm that fuel pump is functioning properly and the fuel filter is not clogged. One of the easiest ways to check for a fuel pump related problem is to spray a little starting fluid into the air intake while trying to start the jeep. If the car starts momentarily, then there's a good chance the fuel pump is not working or the jeep is out of gas. You can also listen for the fuel pump's humming sound when the key is first turned on. Also if a inoperative fuel pump is suspected, a good technician will always check to verify there is power and ground being supplied to the pump, to eliminate the possibility of a bad relay or electrical issue. Fuel pressure can be checked with a pressure gauge and if there is pressure, pulse can be checked at the fuel injectors in several ways including the most common, with the use of noid lights. If the injectors don't have pulse the engine won't start. ---------- This troubleshooting tips will help you to solve the problem. Thanks. Helpmech.

is the your car engine cranking when you try to start, first check spark plugs ignition coils, remove one ignition coil and spark plug fix the spark plug in to the ignition coil then connect ignition coil to wiring and keep spark plug body touching on ground of engine head mettle parts, ask some one to crank engine then you can see is the plug sparking or not, do the same way to all the coils and plug otherwise you have to buy a ignition spark tester, is the all the coils and spark plugs are OK then check the fuel pump, it's sitting in under rear seat, before that do one thing disconnect oxygen (O2) sensor wiring and crank engine, the thing is if your oxygen sensor completely dead fuel pump will stop working, if engine start after disconnect O2 sensor, replace new O2 sensor, otherwise need to check fuel pump relay fuse and fuel pump. is this information helped you? please vote me and give a comment.

Fuel filter is by the fuel pumps under rear passenger side of car. There is a plastic cover there. Also Look into your coil being bad, also wires, plugs cap and rotor. Ignition issues also can be caused by the OVP relay, the box with a fuse in it by the battery.

Is it not getting spark or gas? It needs both to run. Both main source. If no spark in any cylinder, then ignition module or crank sensor is likely faulty. If no gas, then fuel pressure regulator or fuel pump or fuel pump relay is bad.

could very well be a faulty sensor, leaky vaccum hose, bad coil packs, needing of new fuel filter, spark plugs, wires.

Have you checked your fuel pressure to make sure it is good. You can do this with fuel pressure tester on the fuel rail.

Also check every cylinder for spark
If you don't have any spark, or very weak spark, you could have bad coil pack, module, or crank sensor.

You can remove one plug at a time, and place it back on plug wire, place it on top of engine block, have someone else turn motor over well you observe to see if there is spark.

Do you have a service or check engine light on? If so, I would have the engine codes read to pinpoint exact problem area.

Let me know if you have any questions or need further help

if youve replaced all that. your getting a spark, BUT are u getting fuel?. could be your in tank fuel pump has gone out. If your not getting fuel or fuel/air into the fuel injector. you wont start.

I had the same problem, took to a benz dealer, it was the fuel pump relay, cost for repair $200.