A question that I may be stupid but don't understand!

acs · Post by **acs** » Mon May 21, 2007 9:07 am

Right I now have my efi engine up and running and running well.

The only connection between the old and new loom is the cable from by the air flow meter to the negative on the coil.

My question or lack of understanding of the injection system is.

Do the injectors run constantly filling the inlet manifold or do they pulse? (which is what I always believed as the cylinder needs the fuel)

If they do pulse as the cylinders are fired what tells the injection system to fire which injector?

If there was a crank sensor or something similiar I could understand how the injection system knows which injector to fire at which point.

Am I just looking far to deep into these or am I missing some simple and being special?

Cheers
Adi

jrv8 · Post by **jrv8** » Mon May 21, 2007 11:16 am

Hi Adi,
If it's a standard Rover system , they just fire 4 at a time.
Jim

acs · Post by **acs** » Mon May 21, 2007 11:22 am

Ahhhhhhhh.

Is that the same side at a time 1 3 5 7 and 2 4 6 8?

I'm curious cause I had a number 7 cylinder not firing because I had the injectors connected the wrong way from 5 and 7. 5 was running fine and 7 wasn't firing at all and I was confused how if all the injectors ran all the time what difference that would make unless the it fired them individually.

Cheers
Adi

ramon alban · Post by **ramon alban** » Mon May 21, 2007 9:13 pm

acs wrote:Ahhhhhhhh.

Is that the same side at a time 1 3 5 7 and 2 4 6 8?

I'm curious cause I had a number 7 cylinder not firing because I had the injectors connected the wrong way from 5 and 7. 5 was running fine and 7 wasn't firing at all and I was confused how if all the injectors ran all the time what difference that would make unless the it fired them individually.

Cheers
Adi

I dont think that would make any difference, all four injectors on one side go off together and that is followed one cycle later by the other four. The fuel just hangs around until the inlet valve opens and the air rushes in to make it go bang at the next spark.

You probably had a bad injector connection to 7 so it was not firing fuel into the intake before you relocated the connectors.

The wire you mentioned in your original post tells the ECU that the engine is running (on a 3.5 Efi Flapper system) usually via a trigger resistor, so please send me some fuel. see here:

http://www.vintagemodelairplane.com/pag ... ger01.html

Ramon
http://www.vintagemodelairplane.com

acs · Post by **acs** » Mon May 21, 2007 9:32 pm

That was the bit I couldn't understand but as you say if the injector wasn't seated properly that would have the same affect and how for the same reason was was no 5 working.

That is why I was confused if pulsed the injectors individually or not.

Cheers for that.

Thanks for the site as well. I have read a lot of the documents on your site getting my motor to work. I had a lot of unknowns and mismatched parts.

Cheers
Adi