F7R engine starting problem with itb's

[cliosportap]

my friends f7r megane with itbs doenst start properly or not start, we have two ecus and the problem is still the same(ms2 and aem ems 4)
the wiring is ok timing is ok , finaly we have fitted aem ems 4, after a few starts its again the same
thinking that the crank position sensors syncronisation is not ok with ecus
does anybody have an advice?
i saw there is a cps sensor like below from omex, is it usable with aem
can oem cps sensor is usable with aftermarket ecus, if we buy the omex one can it fix the problem
thanks

 

[Snake182]

Have you just fitted the itb's and now it wont start? Or did the car already have itb's and its started playing up?

 

[Chip-mk1]

In the tuner studio mapping software do your see "cranking" and "synced" when turning over and what does the rev counter read and how stable is it?

 

[Chip-mk1]

Ps

the standard sensor should work ok with MS if the input sensitivity is set appropriately and the sensor is in good order.

 

[cliosportap]

the car is ok when standart we tested also the cps on another megane f7r and it works
we see approx 250-300 revs but it is not stable, we couldnt start up the car properly so coulndt finish the mapping, the tuner said that oem cps is not usable with aem ems 4 and ms3 pro may fix it but we are confused this ecu can be used with this car and there is a mistake, the car gives timing error fault in every turn and increases and because of this the injectors are alos not opened by the ecu

if it can fix it we are thinking to buy the omex cps, our first aim is using aem ems 4

 

[Laine_16v]

Try adjusting the sensor height, or adding a 1k Ohm resistor accross the two sensor wires to pull up the signal.

 

[Chip-mk1]

The problem you may have with the omex one, is that it will work perfectly at cranking speeds and to start the car, but it will then end up with too much signal at higher rpm and will start misfiring as a result, as the teeth are very close together and very big, so when the flywheel is really spinning fast which induces a lot of current it can end up missing the gaps between the teeth. On the omex there is a software setting to drop sensitivity at a certain RPM point but on the MS you dont have this as far as im aware.

Does your MS3 have an adjustable potentiometer for crank input sensitivity? If so, adjust that and also try filing out the holes in the senor bracket to allow the sensor to sit slightly closer to the flywheel.

 

[cliosportap]

we dont have now ms3 it was the tuners advice but ms2 have that potentiometers to adjust it but not achieved to start it
if the omex cps will misfire at high rpms i am wondering how clio f4r's using them, the flywheel is same as i know
the car was working fine when the engine rebuilt new, after that he changed the gearbox with a shorter ratio one
as you said the distance is important for the cps i think there is also something else with the gearbox case

 

[Chip-mk1]

Ive just explained to you that omex has a switchover RPM where it goes from high to low sensitivity thats how it works so well on the clio with that sensor, the MS2 doesnt have that.
You just have one sensitivity and it takes a lot of playing about to get it in the right compromise between not enough signal at low rpm and too much at high rpm, IME the renault sensor works well for that though.

 

[cliosportap]

solved the problem with ms3, the car is working now
there is a little missfire problem at low rpms half throttle and hi rmps full throttle
which spark plugs should be used or can be the megane 225 coils a good upgrade over standart coilpack any advice?

specs: 12.5 cr pistons itb catcams and 315cc volvo injectors