2 flapper efi questions

Ralphh85 · Post by **Ralphh85** » Mon Aug 10, 2009 7:35 pm

should the ecu start firing the injectors as soon as it detects cranking?

or does it need to detect a signal from the coil and cranking signal??

my ecu clearly has everything its supposed to have, the only thing i cant check is if its getting a proper signal from the coil. theres continuity between the relay and the ecu plug, and the relay works, but i dont know if the ecu is seeing what it should.

Ralph

plank22 · Post by **plank22** » Mon Aug 10, 2009 8:16 pm

both, i think!

the ecu only knows the engine is cranking from the coil neg, thats when it knows to fire the injectors. I dont think there is any otherway the ecu would know the engine was turning.

Ralphh85 · Post by **Ralphh85** » Mon Aug 10, 2009 8:24 pm

true, ok then is there any way to fool the ecu on this trigger?

i suspect for some reason the ecu is not getting this trigger, even tho its all in order.

this is pretty much the only thing which can be stopping it.

Ralph

plank22 · Post by **plank22** » Mon Aug 10, 2009 8:49 pm

are you sure the injectors are firing? i.e take one out and see if you get a squirt!

Ralphh85 · Post by **Ralphh85** » Mon Aug 10, 2009 8:57 pm

they are not firing, no smell of petrol and no voltage across the injectors, they have 12v but ecu aint earthing them.

in what circumstance would the ecu not pick up a signal from the coil???

Ralph

plank22 · Post by **plank22** » Mon Aug 10, 2009 9:31 pm

hummmm. I would check physicly for a spark and fuel. If your getting a spark then then the ecu should get the signal so trying to give the ecu a fake signal may not help as it could be another problem i.e give the ecu as many signals as you want but something like a bad earth or bust ecu could be stopping it. does the high pressure pump kick in for about 3 seconds on the second ignition click then stop? if it does then you know the ecu if recieving a power signal and sending it in return to the pump relay? sorry but im no hotwire expert but would love to know the answer as much as you!!!

bodger · Post by **bodger** » Tue Aug 11, 2009 12:17 am

Ralphh85 wrote:they are not firing, no smell of petrol and no voltage across the injectors, they have 12v but ecu aint earthing them.

in what circumstance would the ecu not pick up a signal from the coil???

Ralph

have you got an over run valve , as that shuts off the wire from the coil to the ECU ...?
if so fing the black/white wire on the over run relay and connect to the neg side of the coil

Ralphh85 · Post by **Ralphh85** » Tue Aug 11, 2009 9:04 am

bodger wrote:
Ralphh85 wrote:they are not firing, no smell of petrol and no voltage across the injectors, they have 12v but ecu aint earthing them.

in what circumstance would the ecu not pick up a signal from the coil???

Ralph
have you got an over run valve , as that shuts off the wire from the coil to the ECU ...?
if so fing the black/white wire on the over run relay and connect to the neg side of the coil

im not sure, where is it and what does it look like?