Cranking and Ignition problem - The car does not start at al

[minyus]

Hi everyone
Let me ask for some help. I have already read tons of forums about cranking issues, and tested everything on my car, but I am not able to find the solution.
I have a 85 M20B20 E30 L-Jetronic rebuilded to Motronic 1.3 engine. My car had ran fine, but suddenly it stopped working about a month ago and I am not able to start it at all from then.
Symptoms: Starter is working, engine is cranking, but do not start.
I have already bought new rotor arm, distributor cap, and ignition coil.
I have bought HT leads and spark plugs about a year ago, so they are new as well.
I had spark tested on the rocker cover.
Timing is good, the timing belt is in the right position. I have changed the timing belt a month ago, and the car started on the first try well. After I stopped it, it does not start from that time.
Replaced the fuel pump, tested with jumpering it, and it is working so fuel is present as well. Spark plugs are wet from fuel seems it doesn't caught fire.
Tested all the relays, but they are new as well, and work as well.
I have checked all the wires of the motronic ecu connector, they are good.
All the resistivity checks show correct values on CPS, Coil, and everywhere.
Some says I have to check the Fusible Link 50A connections, but I do not have that.
Tried the light bulb test on the coil. It is flickering a litle, and the light intense dropping down while cranking.
Some says I have to check the Over Voltage Protection Relay, but I do not have ABS system, so I do not have it either (or I could find it under the dash).
Any other ideas?
Previously I had some issue with engine, at high rpm on the move sometimes it stalls for a moment.
I have a raised compression ratio. Is it possible that the sparks are weak somehow and the pistons "blows away" the spark?
Please help someone is smarter than me.

[Grrrmachine]

Have you tested the blue temp sensor and its wiring to the ECU?

[minyus]

Have you tested the blue temp sensor and its wiring to the ECU?

Yes, of course I have the contact and the correct resistant on the pins of the ECU's loom. The temp sensor is brand new as well...

[Grrrmachine]

I'm less likely to trust brand new parts than parts that are years old, so you have to test EVERYTHING rather than just replace them.

Have you done a spark check for each plug?

Have you done a compression check on each cylinder?

[minyus]

All the tests I mentioned was taken on the old and new parts as well... Spark check on each plug was done. I found the spark a little weak but I have sparks at all the cylinders.
At the bulb test on the coil the light intense is much less while cranking. Maybe there is some voltage drop on the coil while cranking. But starter works very fine and fast so it doesn't make any sense...
Can some kind of grounding problems occur these symptoms?
I have not measure compression on each cylinder.

[Brianmoooore]

Quite normal for the bulb to dim and flicker to some degree when cranking. The large current drawn by the starter motor pulls the battery voltage down considerably, and the varying load caused by each compression stroke causes a flicker.
It takes a decent spark to ignite fuel mixture when its compressed, so what you say is a weak spark could be the problem. What sort of condition is the distributor cap and rotor in? Especially the spring loaded carbon button and the rotor arm?
Alternatively, wet plugs don't always mean that the fuel pump is working properly. As a result of the reduced battery voltage while cranking, a fuel pump that runs fine normally, can stall at the critical time. A £10 ebay fuel pressure gauge is the bet way to check on this.

[minyus]

I have the 2.5 Bar on the fuel line... The fuel pump is brand new as well... Distributor cap is brand new and a rotor arm is brand new. Everything is brand new
Can it be a problem with OBC Relay? All the E30s have this On-Board Computer Relay box with C2 connector connects on C104 to the junction of Motronic ECU pin 27 and Coil 15 Green wire? I cannot find this relay in my car. What if I bypass this relay connection on the C101 7pin plug? (Reffering to the ETM page 36 - Injection Electronics

[Brianmoooore]

OBC relay has already been tested by the bulb on the coil. It's mounted in the corner of a largish box mounted directly above the engine ECU.
The loom from the relay plugs into a two pin socket above the glove box area (two green wires in one side, a green and a green/red in the other), and this is the place to bypass it. On cars where the OBC was original fitment, there should be a plug fitted with a short loop of green wire tied up to the loom nearby for the purpose.
Have you checked the fuel pressure while the engine is being cranked?

[minyus]

Yes I have tried... and the pump is able to build up pressure between 2.5-3bar while cranking.
I have nothing above my ECU as it was an L-Jetronic and have converted to a motronic car.
At every first start on every day I try to start the engine the car puffs one or two times shows it wants to run, but thats all it can do. From the second try it does nothing except of the starter... Looks like it looses every power on the coil...
I hope you understand I'd like to explain... it is hard to express myself in english as I am a non-English person. Sorry for that

[Brianmoooore]

Take the AFM to throttle body hose off, and spray an aerosol of something like brake cleaner (or butane or propane from a gas cylinder) straight into the throttle body while cranking the engine with the throttle partly open, to see if it starts. This will establish whether its a fuel or spark problem.
It's possible to get the engine to actually run and move under its own power with a propane cylinder.
Does the OBC CODE immobiliser actually work? It may not be connected in at all. The 'relay' is in a black plastic box, almost the size of an engine ECU if it's present.

[minyus]

Hi and apologize for the late answer...
Tomorrow finally I will get the brake cleaner for the test.
My car is simple as a needle, it has no immobiliser and any anti-theft electronics such as central locking system or alarm system. That black plastic box is missing as well. I have only the check panel on the roof with some LEDs and with a button and a digital clock. I do not have OBC as factory default so I think there shouldn't be a relay for that.
Will inform the results of the brakecleaner test...

[minyus]

Didn't start with the brake cleaner test... Changed the CPS and makes nothing as well...

[k]

You said earlier it spins over fast, are you sure the cam belt is still intact?

Have you tried a compression test yet, or removed all the plugs and cranked it over to see if your getting any sort of compression? This will also clear the cylinders if you have disabled the fuel pump

Are you getting any sparks, get an old spare plug and see if it sparks when cranking the engine

If you have air, fuel plus the spark, you should get a bang, as you say the're very simple engines

[minyus]

fast... but fast for good battery, not as fast as the cambelt torn... I could say I am sure that the belt is good, I have changed it 3 months ago...
I could not have tried the compression test, I do not have the tool for that... But I am sorry to say I do not understand that removing all the plugs and crank it... How can I see any compression from that?
I have sparks as I mentioned...
I should un-assemble the engine to look for some mechanical errors... :S

[k]

If you have the plugs out and have someone crank the engine you can hear the air being blown out of the cylinders, and put your thumb over the plug hole and feel some pressure. That tells you the piston is moving up and down
I would then take the rocker cover off and check the top end is intact and camshaft is turning, rockers all ok, and a check that rocker clearances are there when both valves are shut on compression stroke

[minyus]

Hi all... New progress...
I do not have to check the compression test, because we managed to start the engine with my brother. Rocker arms are in good condition. I have already checked them with the clearance as well...
BUT I don't know how to express it in english: At the first try we couldn't start it with pushing the car running behind. It seemed that it has no ignition at all... We tried twice.
My brother had the idea to pull the car on to work towing with another vehicle and finally it started. We drove a few kms in the area and it can start and run by turning on the key by then. I hope you understand...
I did nothing with the car at all. What shall be wrong or malfunction? I am totally clueless

[daimlerman]

Reads like a low battery being unable to supply enough power for both cranking and ignition to me.

[minyus]

Hmm... interesting. Could it happen that a low voltage battery can produce enough power for cranking/starter engine and do not have enough power for the ignition/coil? Starter engines need more power than the coil, doesn't it?
In the cranking sequence should the alternator produce enough power for the battery and the coils? If yes, my alternator needs to be refurbished...
Could it be that my battery is weak for the ignition? I can read between 13-13.5V on the battery with the multimeter, and the starting current of the battery is about 430A (45Ah)

[daimlerman]

At rest(engine off)you should get 12.4 to 12.6v.
Engine running,you are looking for 14.4v.

A lower reading for the first figure indicates a buggered battery,lower reading for the second indicates a buggered alternator.

[minyus]

Thank you, I will have a look at the voltages... My alternator is about 30years old as the car itself and it hasn't been refurbished yet at all.
BTW a friend of mine agrees with You daimlerman; he says if I do not use my car very often (I don't) the battery can lose its ampere capacity and it might does not have the exact starting current causing weak sparks or low starting rpm for the DME...