engine shuts suddenly........

[jojo]

hello to all sifus....... i'm facing a problem where my 1984 e30 (320i,motronic) engine suddenly shuts. it normally shuts whenever the car continously running for about 30-40 mins (inclusive of several stop at traffic lights for few mins).... the engine shuts in a way that is similar when we plug-out the fuel pump relay...(which the engine slowly shuts as the fuel supply stop)...during this time the tempreture reading is in the middle...which is normal. whenever it happens, all i can do is just wait for the engine to cool off (say about 10-15 mins)...then only the engine will be ok to be turn on...(before it shuts again after few mins of running).. i've brought the car to the workshop and done this :- service the radiator fan clutch- flush the radiator tank and change the coolent- change a new electric fuel pump- change a new fuel filter- change a new fuel pump relay as a result, still the same! did anybody ever have the same problem as mine?...or maybe all the sifus can advice me on this..... .....so sad man! thanx!

 

[Alvin]

Checked the battery?

 

[c-square]

crank shaft sensor?

 

[lipisbimmer]

jojo,

me same problem with my m20b25 before...

changed the crankshaft position sensor a.k.a. pulse sensor... VOILA!!! everything back to normal...

U should try that since u have changed the fuel pump + it's relay.

rgds

 

[jojo]

alvin : what is w the battery?i had replaced a new wan last year when i fit in the new engine in my e30...any possibility of unsuitable battery being used?

c-square : checked!and still ok....

 

[jojo]

changed the crankshaft position sensor a.k.a. pulse sensor... VOILA!!! everything back to normal...

lipisbimmer : i dont get it....can u explain please!

tq bro..

 

[Alvin]

well these days the local batteries are sometimes cranky. When it gets hot, the electrical supply is affected from the alternator also. Better to check the altenator also if its charging alright. Had this problem before in my 5series.

 

[Alvin]

Crank position sensor is the same as crank sensor. From your post above, you checked it already.

 

[lipisbimmer]

jojo,

how do u check the sensor?

U have spent quite a lot 4 the fuel pump etc etc...

why not change the sensor as well... it's not that expensive compared to your fuel pump (about rm100++ i think) and u can even DIY it...

just my 2 bath la...

 

[Alvin]

lipisbimmer

Just for info. If the crank sensor is faulty, the GT1 or modic will be able to detect, right? Why when its hot, there is an effect on the sensor? Any idea?

Thanks

 

[lipisbimmer]

no idea whether GT1 or Modic can detect that or not.... not a sifu la...

just using traditional method of diagnosing + some phone calls here and there...

the temperature is not an issue... it will not effect the sensor

it's just one of the parts that sooner or later u HAVE to replace..

like the fuel pump la, some say it will lasts a lifetime... but why do shops still have supplies of them...

jojo's car is 22 years already... just change la... if it's not the culprit, just think of it as a cheap preventive maintenance...

coz that is one of the signs that the sensor is going to kaput for good....

just my humble 2 kupang only...

 

[Alvin]

lipisbimmer

Yup, it does kaput. Good idea to do preventive maintainence. I'm looking at changing my crank sensor for my S50 also but S50 everything cost double. Sigh!

 

[jojo]

alvin : i'll check the alternator after this...and will do something on the battery as well....he.he....tq!

lipisbimmer :

how do u check the sensor?

upon checking my problem above, the mechanic told me that the crank sensor faulty may also cause the problem..and he did ask me wether im facing any problem of starting the engine immedietely after turned the engine off (i think that's the method he's using to detect the sensor's faulty)....so he did tried it himself and told me later that it is not bcoz of the sensor...

 

[jojo]

Good idea to do preventive maintainence

i agree on that!i think i'll try to change that as well....

thanks sifus!

 

[ersalle]

"no idea whether GT1 or Modic can detect that or not.... not a sifu la..."

Yes using diagnostic cannot detect crank pulse sensor fault on motronic engine(M40 for my case), my mech ever did use to find the fault but nothing show up.

 

[pussy]

jojo... change your ignition coil lah.. kaput already, is it runing very hot ? if yes, then change it..only 1 piece..


regards.

 

[jojo]

yes pussy! very hot! 1 piece only?

 

[pussy]

yes, my friend.. buy or borrow one to test..

 

[teejay]

plug wires.......

heat is a resisting factor to metal

when hot resistance increases, when hot current need more power to travel due to higher resistance

better to check and isolate distributor, then coil wires
both can be checked using a multimeter and measure the specific resistance when cold

crank sensor could also be it as heat will expand metal, metal expands, contact cold be lost, thus shutdown

 

[jojo]

pussy : thanx.i'll try it.

teejay : good info!thanx.