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I just partially trimmed an Audi A4 1.8T.
I have a problem starting the engine.
I have tried cranking fuel between 20ms and 2.5ms.
if I give it start gas the car can start right away.
once started the car runs perfectly but just has these startup issues.
this is for both cold and hot engine ..
How much fuel is being injected at Idle? Try 1.5 to 3 times that amount for starting.
i will try thanks
What size are your injectors? 20ms on 1000cc delivers a lot more fuel than 20ms 440cc injectors.
It does sound like it's getting too much as you've said that it'll fire when you open the throttle, introducing more air
the injectors is 337cc
I tried a few settings today,
nothing seems to be much better than before ...
the engine uses approximately 2 ms injector pw at warm idle
then it start at cold, the warmup table is perfekt.
i have atteched af picture off the current settings..
I suggest changing the cranking ignition angle to something more reasonable like 4-8 degrees. Also what does the Engine Start - Prime Pulse Table look like?
The prime pulse table is also at the picture, its from 11-5,
i will try the Ignition angle also? but why does it help to lower the ignition?
The engine is turning very slowly, but the air-fuel mixture burns at about the same rate. Your mixture may be correct, but completes combustion before the pressure increase can do any useful work. The EMU Black default is 10 deg, and I usually use 5-7 degrees and get good starts on most engines.
It makes sense,
i will try with low ignition degrees,
do you think i need any changes on the fuel mixture ?
Why don't you untick the "enable prime pulse" until you know that is needed.
You don't give much useful information.
Is it hesitating/kicking back when cranking, is there any back-firing from the exhaust or intake, when it starts is the engine running smoothly or does it misfire or hesitate, etc?
Is the engine turning over quite slowly and only starting when the engine is cranking quite quickly, having built up speed?
Do you have the ECU voltage available to you as it's coming up to speed?
Very hard to say, but if you're confident you've eliminated most other things, I would suspect the battery voltage drop during the initial cranking, with the drops throughout the rest of the management's wiring and returns, is such that the injectors and/or ignition isn't initially getting enough voltage to operate correctly until the engine speed increases to a point where the battery voltage drop isn't as severe.
On that, something that may make a significant difference to your base cranking speeds is to strip and service the starter motor, as this is so often over-looked until it totally fails.
With basic tools and mechanical ability it's a simple job to strip it, check the brush lengths, clean the commutator (copper segments the brushes run on) with some fine W&D and iso-prop', or electrical/plastic safe (just in case), spray cleaner. A little grease with a drop or two of oil on the busghes and pivot points and slides, and re-assemble it.
NOTE, some brushes can be fiddly to position/hold back to allow the commutator to slip in, but some thinking and bits of stiff wire (and maybe YT videos) should sort you out easily enough.
You should notice quite a difference, and I frequently this to starters when I have them out, if I have the time, even if there isn't currently an issue - at least I can check the brushes' condition if it's got a few miles on it as it's already out, and I may save pulling it in the near future when a brush set replacement may last the rest of the life of the vehicle.
The engine runs at about 250 rpm when cranking.
I have tried all these options with a 100amp charger on, which I also use for chiptuning, so it should not be a power problem ...
sometimes it backfires, while cranking for 20-30 seconds
if I then turn the ignition off and ignition on again, it starts perfectly right away (sometimes).
most times it almost does not start ...
i have now tried with 5-10 degree ignition and no change.
with and without prime pulse settings.
tried and raised and lowered cranking fuel.
I have measured ignition marks with ignition gun, it should be 100% on marks.
but I have tried changing the ignition points on the crankshaft inside the primary trigger settings, + - 4 degrees.
none of these different settings seem to change quite a lot either for the good or the bad side ...
If the engine doesn't start or try to start within 5 seconds, stop cranking.
Very surprising -- "if I turn ignition off and on again, it starts perfectly" -- that is HUGE!
I'm pretty much done guessing -- and asking endless questions. You need to post your config so we can understand if your crank trigger is VR or hall effect, if your coils have sufficient dwell at low voltages, and answer lots of other questions that could be behind your issue.
Do you have a log of the start attempts?
We need to see injector pulse widths, Engine Speed (RPM), Manifold Pressure, ECU voltage, Ignition Timing, Fuel Pressure, any ECU status / diagnostics related to crank / cam sensors.
i found the problem the cam did not sync,
i disabled cam sync, and made igition crank to wasted spark...
So, what was the root cause? -- your configuration of the trigger pattern required for synchronous injection wasn't correct? Because sometimes it did work. How did you have it configured? What do your crank and cam triggers look like?
yes the root cause it was because it not was running wasted spark, i did not have a Cam sensor to sync on.