*** URGENT *** Bosch Motronic MP 1.7

[Kurek, Larry]

Sounds like you might have a voltage drop problem. When you crank the
engine without the plugs in, it is under a light load and the starter
doesn't pull a lot of current, so your battery voltage stays high. Once
you slap the plugs in, the compression of the engine causes a greater
voltage drop, and you are probably losing enough power to fire the
plugs. Just a guess...but I have seen that before.

TTYL!

Larry

> -----Original Message-----
> From:	Joni [SMTP:joni.mikkola at dlc.fi]
> Sent:	Thursday, August 06, 1998 2:45 PM
> To:	DIY EFI
> Subject:	*** URGENT *** Bosch Motronic MP 1.7
> 
> Hello boys,
>  
> We have a BIG problem with our race car. We can't get it running. We
> don't get sparks. When we take four plugs (4 cyl Cosworth engine) out
> of the engine and put them on top of the camshaft cover and start the
> engine we can see sparks on all of the four plugs. But if put four
> replacement plugs into engine, and leave the four originals on top of
> the cam cover, and start the engine we can not see any sparks. ???????
> WHY ???????
>  
> The MP 1.7 uses two symmetrical sectors on the flywheel with inductive
> crank sensor. Plus a hall sensor in the distributor (with only one
> "window" on the rotating part). We have checked and double checked the
> sensor synchronization, wires, connectors and the sensors themselves.
> The sensor output looks OK on the oscilloscope. When we try to start
> the engine the fuel pumps and start running and injectors firing. 
>  
> We are out of the ideas. We have now tried to solve this problem for
> almost four days. Any ideas are more than welcome as we should be
> racing on Saturday.
>  
> Please visit our teams web pages at:
> <http://www.bookmark.fi/cosworth/index.html>
>  
> Appreciate your help,
>  
> Joni Mikkola