Black how works priming, cranking, ASE and WUE. Cranking RPM spike and hold

Single prime pulse, maded when Crank trigger first recognized, but engine phase- not.
Which cylinder will be filled into?
Does it prime to all cylinders?
Does crnaking values, in first engine revolution (after cam recognized) - added to prime?

example: 4 cyl engine, 1-3-4-2 fire seq
first 2 crank revolution:

  1. crank recognized, priming somewere (everywhere?)
    1.1. if priming everywhere - need fire in waste spark mode. Otherwise do not use priming at all.
    1.1.1. if waste spark occured - does it means “spark” for batch injection mode? does first revolution cranking table using?
  2. cam recognized - add fuel from crank table
  3. fire in seqential order
    I tried: set the entire cranking table to 0, tune prime pulse so that the engine starts only on it.
    And anyway, this ecu doesn’t start with 1-2 turns :rage:
    So you can stop dreaming about starting from the first revolution?!
    I turned off prime pulse, returned the cranking table to calculated values, checked the startup (with pre-heating of the lambda, waited until the residual fuel in the manifold had evaporated - the mixture shows 25.5) - the startup was normal.
    Plus or minus the same as on prime pulse alone.
    Turned on priming, try some times, engine starting same, may be a little bit worse.
    Turn on waste spark mode, and left what happened.
    It won’t be better?
    What am I doing wrong?

Many questions, not enough information to answer them yourself :slight_smile: .
ASE and WUE - this adders works together? or ASE - only when ecu state AFTERSTART, and WUE - when ecu in RUNNING?

AFTERSTART = ASE OR AFTERSTART = ASE+WUE simplifying the question in math terms.


It primes all injectors as soon as trigger signal appears. It is just one pulse.

If you work in full sequential mode, the first spark can appear after 2 engine revolution, as the engine need to sync with the cam sync. If you have trigger like 60-2, 36-1 it is possible to start in wasted spark so the spark starts to appear on cylinders as soon as a gap will be detected.

ASE is applied only when the engine change state from cranking to afterstart.
Warmup enrichment works all the time after the engine leave the cranking state.

thank you!

@Jadzwin_ECUMASTER , can you tell me what to do with this suddenly RPM spike when cranking.

this happens, when i try to set trigger configuration for “decode crank before cam sync” (change first trigger tooth 51-36=15, and outputs offset 2-2=0)

Of course I checked the base angle first with timing light.

Even geted oscillogram of cranking.
Ecu power off, CKP sensor disconnected

Connected sensor, ECU powered, injectors disconnected (only cranking spped some about 280 RPM):

Look closer (red rectangle - for visualize size of 2 missing tooth)

and move it

Looks normal ?

Сan you comment something, based on the shape of the oscillogram?

Engine trigger Toyota 36-2 whith “half cut long tooth= missing tooth”.

Engine working OK (and tuned on dyno) when primary trigger configured for “second revolution recognition”

anyway there is a one-time “Unexpected missing tooth”, but rpms not spike:

It is very interesting to understand the reason.

may be need to follow "When a Variable Reluctance sensor is used for Primary Trigger, and unexpected missing tooth error occurs, resistor 4K7-10K could be conected in series between sensor output and primary trigger input. In some cases increased sensor distance to trigger wheel can be beneficial. " ?

trigger drawing:

  • CKP wiring = shielded F/utp8 with termination near ECU on one side. Connection maked so: use all 4 pairs of twiste dpair, untwisted, solid color whires all used for sig+ , white&stripe whires - for sig-

  • sensor resistance 1.4 kOm

  • All P.GND and ECU Ground, and termination whire connected in single point, and from this point - whired to BATT ground terminal (no ground loops i think)

read info from innet, and added 10k resistor in series.
if something helped, but it couldn’t remove RPM spike:

somtime works well

LOG (rew near the end of the file): 20240130_1912_58.emublog - Google Drive

c= 01:10:46
c= 01:13:11

20240201_2219_51.emub (145.8 KB)