slow to idle after start up?

[RockyIII]

Just a quick one, if anyone has any thoughts on this.

What would cause the engine to rev quite high (1500-2000) after starting the engine, and then take about 5 seconds or so to drop down to my normal idle of 850.

I have stock filtration but 3-1 full custom made system, and 20050 ign_retard tune. I'm thinking it might be too much fuel as it takes a bit of cranking to get started because my battery is on it's way out and may cause a bit of flooding in the process.

Could I be on the right track here?

Thanks

 

[HansO]

Just a quick one, if anyone has any thoughts on this.

What would cause the engine to rev quite high (1500-2000) after starting the engine, and then take about 5 seconds or so to drop down to my normal idle of 850.

I have stock filtration but 3-1 full custom made system, and 20050 ign_retard tune. I'm thinking it might be too much fuel as it takes a bit of cranking to get started because my battery is on it's way out and may cause a bit of flooding in the process.

Could I be on the right track here?

Thanks

Possiblily so but I'd be getting a new battery if you think it is near done before changing anything else

 

[sams2100]

Just a quick one, if anyone has any thoughts on this.

What would cause the engine to rev quite high (1500-2000) after starting the engine, and then take about 5 seconds or so to drop down to my normal idle of 850.

Doesn't sound like its an intake leak as if it were, the rpm would be spiking randomly all the time, not just at start. What about when riding it around, when you come to stop lights does it spike at all or take a while to drop the rpm when you release the throttle?

 

[RockyIII]

Hi there, went out for a ride today, and the revs go high on start up and takes some seconds to drop back down. It seems to have this condition during warm up period. When it's at full temperature, it seems ok. There's no spiking at idle or when riding, that's ok.
I'm starting to think that after I adjusted the air flow to make all 3 cylinders equal and adjusted the stepper motor to read .72 and put in my current 20050ign_retard tune, that I should have done a full 12 min tune. If I'm correct, 12 min tune corrects the idle area and may need to be done in my case.

Also, why does it take lots of cranking to start the engine when cold? I checked my battery with ignition off and it reads 12.8V, meaning a good healthy battery. Could it be the crank angle sensor is dirty? or something else maybe.

Thanks for your time and input.

 

[sams2100]

Now that I think of it, I did have a car that had spiking rpm at start until it warned up and it turned out to be a worn out intake manifold gasket that I had to replace, but it would take 5 mins to warm up.

 

[RockyIII]

You could be right there, it doesn't seem to be a big problem, I'll be honest. I'll just let her warm up longer before I ride me thinks. Gonna check and clean the crank angle sensor in a mo to see if that helps with starting her up more easily. I won't hold my breath tho.
Thanks for your help.

 

[RockyIII]

Maybe this is the problem??

Regarding my high idle problem when initially starting the bike, I decided today to unplug the stepper motor connection in front of the throttle bodies and see what happened.

I then started the engine and it went straight to normal idle speed and the excessive high idle at 1600-1800rpm was gone imediately.

Does this mean that I can adjust my stepper motor one way or the other, to keep the ISCV connected up.

I noticed that when I start the bike the stepper doesn't fully return back and I can physically push the back plate further back another 1mm or so. Should I just remove the stepper or spray some WD40 over the spring part?

Can anybody advise, most grateful.

 

[captain jack]

You seem to have fixed your problems, but if you are still having cold cranking problems try leaving the ignition on for 30 sec. or so before starting. It's a lot easier if you have the headlight harnes with on/off switch.

 

[RockyIII]

Thanks Jack for your advice there, but can I adjust the stepper motor somehow so that it doesn't cause the high idle at start up. Because when I unplug the stepper motor, there is no such high hanging idle before returning to normal idle.

It appears to me that the sping/lever arm on the stepper motor is not fully returning are switching the key to on.

 

[captain jack]

I had the high idle problem (big time)all the usual things were checked but made no difference.However the mech. found that the clearance between the stepper motor shaft & the plate is critical also the voltage to the motor, had no problem since. Downside is that I cant remember the settings but I do remember reading a thread about this & giving detail of how to. Sorry I cant be much help, if I find the thread I'll let you know.