(Very) Hard to start up

[Lvd94]

Hello guys,

I am running a MS2 V3.0, self built, fully sequential (peak and hold board) management using a single Cam-trigger with a 24-2 tooth wheel.
The engine is a 1.6L turbo and is running great ónce started up..

The problem is the starting up process, it takes quite a while and since it is now pretty cold here for our standards (-5C, The Netherlands) I don't really trust it anymore.

This is what happens:

Ignition on -> wait for fuel pump to finish priming -> engine will crank and wants to start but then the relay clicks (or after the failed attempt?) and the 'cycle' will start over, a couple of cranks later the engine tries to start again but fails once more(+relay). The third time is usually successful.

Whether the engine is hot or cold doesn't seem to be an important factor, but it does start a little faster when it ran for a few minutes.

I included the MSQ and tooth logger data from two attempts. I can't even find the trigger in the mess it shows. I tried adjusting the R52 and R56 pots, but I found no definite results. Sometimes it would start better but the next attempt would be the same as before.

Thanks in advance for any help, I'm sure we can figure this out.

Lodi.

[Matt Cramer]

Can you also post a conventional data log of trying to start?

[Yves]

Hello guys,

I am running a MS2 V3.0, self built, fully sequential (peak and hold board) management using a single Cam-trigger with a 24-2 tooth wheel.
The engine is a 1.6L turbo and is running great ónce started up..

The problem is the starting up process, it takes quite a while and since it is now pretty cold here for our standards (-5C, The Netherlands) I don't really trust it anymore.

This is what happens:

Ignition on -> wait for fuel pump to finish priming -> engine will crank and wants to start but then the relay clicks (or after the failed attempt?) and the 'cycle' will start over, a couple of cranks later the engine tries to start again but fails once more(+relay). The third time is usually successful.

Whether the engine is hot or cold doesn't seem to be an important factor, but it does start a little faster when it ran for a few minutes.

I included the MSQ and tooth logger data from two attempts. I can't even find the trigger in the mess it shows. I tried adjusting the R52 and R56 pots, but I found no definite results. Sometimes it would start better but the next attempt would be the same as before.

Thanks in advance for any help, I'm sure we can figure this out.

Lodi.

Similar thing happens with my car but not only with low temps. The fuel pressure drops immediatly due to leaking through the FPR (Aeromotive) which is made that way apparently.

Going to program my expansion board to switch on the fuel pump and keep it running during the first 20 seconds or so.

[Lvd94]

Can you also post a conventional data log of trying to start?

Sure can:

The wideband takes a while to heat up, that's why the afr values are so low.

Similar thing happens with my car but not only with low temps. The fuel pressure drops immediatly due to leaking through the FPR (Aeromotive) which is made that way apparently.

Going to program my expansion board to switch on the fuel pump and keep it running during the first 20 seconds or so.

I am still using the stock FPR and the pump is always on when cranking, shouldn't be a problem for me.

[Matt Cramer]

Your battery voltage is dropping to 8 volts while cranking - this may be turning the engine slowly enough that it's having a hard time getting a good signal.

[billr]

Post a log (MSL) of when it is hard to start. In the one posted it took less than 6/10ths of a second... or is that not fast enough for you???

[Lvd94]

Your battery voltage is dropping to 8 volts while cranking - this may be turning the engine slowly enough that it's having a hard time getting a good signal.

I have tried it before to use a new or fully charged battery and it didn't seem to do much better. But I'll give it another shot this weekend.

Post a log (MSL) of when it is hard to start. In the one posted it took less than 6/10ths of a second... or is that not fast enough for you???

Sorry about that, that happened to be a lucky shot.. That sometimes happens when I've been cranking before, Stop, and try to crank again.

I've added a datalog which shows my problem.

[turbo conversion]

"I have tried it before to use a new or fully charged battery and it didn't seem to do much better. But I'll give it another shot this weekend."

If this is the case I would suspect a draging starter or bad connection or high resistance in the battery cables.

Turn your key on and let your o2 sensor warm up before starting attempt, this will help to see what happens the first 45 seconds or so.

Also a fully charged battery will show 12.6 volts, at 12 volts it is 50% discharged.

David

edit: word

[turbo conversion]

I just looked at your last log and battery voltage before cranking is 11.4 volts, your battery is very discharged.

Something else that sticks out is the Idle Cranking Duty/Steps is inverted, normally it should start high at low temps and lower at high temps.

David

[slow_hemi6]

I know 5 degrees is not much but you could also try dropping your cranking advance to 0 and see if it unloads the starter any more. I am glad I don't have to deal with very cold starts.

[Lvd94]

"I have tried it before to use a new or fully charged battery and it didn't seem to do much better. But I'll give it another shot this weekend."

If this is the case I would suspect a draging starter or bad connection or high resistance in the battery cables.

Turn your key on and let your o2 sensor warm up before starting attempt, this will help to see what happens the first 45 seconds or so.

Also a fully charged battery will show 12.6 volts, at 12 volts it is 50% discharged.

David

edit: word

That could very well be the case, but since the cold weather started the battery holds its charge very bad as well.
I've got another starter, alternator and battery that I'll try this weekend, along with new cables and terminals.

And waiting for the wideband to heat up won't work because of the large drop in voltage, the wideband resets when I try to start the car.

I just looked at your last log and battery voltage before cranking is 11.4 volts, your battery is very discharged.

Something else that sticks out is the Idle Cranking Duty/Steps is inverted, normally it should start high at low temps and lower at high temps.

David

Fixed this today, but no improvement so far. Probably because the amount of air/fuel is not right yet. When the wideband-resetting issue is resolved I can finally see what happens during cranking.

I know 5 degrees is not much but you could also try dropping your cranking advance to 0 and see if it unloads the starter any more. I am glad I don't have to deal with very cold starts.

I'll give this a try as well. Thanks

Yeah we've got it all in The Netherlands, mostly wet tho haha.

[Matt Cramer]

I like the suggestion on less cranking advance. Also consider increasing Skip Pulses slightly. This will delay firing a little, which may seem like it would make starting take longer. But in practice this sometimes gives the starter the ability to build up a bit more RPM before it tries to light off and can make for an easier start.

[Lvd94]

Well guys, a little update;

I played around with less cranking advance but that didn't really do much for me unfortunately. After that I first increased the 'Skip Pulses' from 3 to 5 and 5 to 7. At 7 it seemed to give the best result so I left it on that setting. Starting now took a little less time

This evening I replaced the starter motor and now it fires up at the first try.. The cranking rpm is also higher and the motor itself just sounds much better.

I guess a dragging starter was the main problem after all. I didn't datalog a start yet, so I might add that to close this thread.

Thank you for all the help !

Lodi.