Q:Cam and Crankshaft Sensors

[wan520i]

Can sifus tell me more about these 2 sensors: 1. Cam Position Sensor (Trigger Contact) 2. Crankhshaft Position Sensor (Pulse Generator) Reason is on & off I have starting my car problem recently, I can't start my car as the starter move half way and stop. And at one occasaion, I got back fire with loud exploded sound and seen lot of exhaust smoke in my engine compartment, then found out that the hose connect to idle control valve was kicked off. Questions:a. which sensor has direct effect or control movement of starter motor? b. why I have back fire? c. which sensor caused this problem? d. which sensor control spark firing? And for info, my fuel pump is new. Battery voltage is 12.63 v. I was thinking to change the above 2 sensors and fuel pressure regulator... Please help..THANKS!!!

 

[wan520i]

Calling sifus......sifu; sifu, where are you????

 

[Daniel]

to know which of those 3 sensors is faulty. get a GT-1 plugged in.

i had all 3 of those gone kaput. the symptons were lack in power, and misfires.

 

[wan520i]

Thanks Daniel for your input & advice, will do a modic scan if got chance..

But I think the above does not affect car's power, only problem during starting as described above.

Now another problem surfaced, heard "tak...tak..tak" ...sound underneath my car, wonder what is that..?? The sound follow engine speed, faster rpm faster the sound..., probably conrod bearing?

 

[pussy]

wan520i...

why never call me ? you always do...

 

[wan520i]

oh pussy, THANKS for offer, actually really scared to call you lah.., worry will disturb your job....and you know, to deal with this type of problems will give you haedache maa..hehe...,

Or can you tell me when is the best time to call you?? noon? after 5pm ? or after 10pm....or anytime?...hehe.

 

[absidian]

camshaft sensor - power loss, but will still start and run.

crankshaft sensor - can start cold, but will die off when hot, difficult to restart when hot.

starter motor - battery may be strong, but check your ground straps (earth cables) around the engine. Corrosion and age will reduce current flow.

"exhaust smoke in engine bay" - maybe your manifolds are cracked/leaking, this can cause major starting and idle problems and over-fuelling which leads to backfire (because oxygen will mix in the hot exhaust gas that still has unburnt fuel in it). Normally, they'll go out the rear at lower temps so won't ignite.

Hope that helps.

 

[wan520i]

absidian, Thanks for your reply and good info provided...

Found out that my cyclinder head (CH) got cracked, water invaded into one of the piston, probably that's the cause engine "explosion"...

Already changed whatever need to be changed, now still monitoring coolant temp...

But I wonder how the CH got cracked? my temp gauge never shoot up high..., will adding cold water into radiator while engine is hot cause CH cracked? or will speeding/rallying at highway/jalan kampong at average speed fo 160 km/h to 200 km/h cause it cracked?

 

[pussy]

aiya.. wan.. the engine wants to blow, it blows..

bmw engines is sometimes quite funny, some of it blows at 200K km milage, some till 400K km still very strong...
it all depends on your mechanic works.. good or fast job..