Why don't flappers usually work?

[Chassis 33]

Hi folks, wondering if I could draw on your experience. I've just converted my SD1 to the flapper EFi setup, and I can only get it to "run" briefly while on the starter, it seems to want to fire but never quite gets there. Any suggestions as to what I might want to check?

I know the injectors are pulsing, and the cold start injector fires, I know the fuel pump runs when I open the flap on the AFM by hand, and the engine has a spark at approximately the right time (and its not 180 out).

Any thoughts, before I get fed up and stick the hotwire setup of the Chimmy on it, or a Megasquirt?

Regards
Iain

[gsx600]

Thats the same symptoms I get on a cold start. but with perservience it then starts.

So anyone got any ideas

[Mr Jenks]

Chassis 33 said:

Hi folks, wondering if I could draw on your experience. I've just converted my SD1 to the flapper EFi setup, and I can only get it to "run" briefly while on the starter, it seems to want to fire but never quite gets there. Any suggestions as to what I might want to check?

I know the injectors are pulsing, and the cold start injector fires, I know the fuel pump runs when I open the flap on the AFM by hand, and the engine has a spark at approximately the right time (and its not 180 out).

Any thoughts, before I get fed up and stick the hotwire setup of the Chimmy on it, or a Megasquirt?

Regards
Iain

Could be that the wiring to the coil/ballast resistor is wrong and only sparking while the starter is engaged because the coil is supplied directly from the starter solenoid, and not getting its normal running supply.
Crap description but I know what I mean.

gsx600 said:

Thats the same symptoms I get on a cold start. but with perservience it then starts.

So anyone got any ideas

Sounds like a different problem if it evetually starts, sounds like trying to start a carb engine with no choke. check the coolant temp sensor, cold start injector and auxillary air valve first.

[Chassis 33]

The coil has a good 12v supply, both on cranking and under normal conditions. when I say runs on the starter, it sort of splutters on the first couple of revolutions then sounds like your typical car not wanting to start.

Regards
Iain

[dwgriffith]

Check the inlet around the butterfly after cranking, is it wet with fuel?

[TVRleigh_BBWR]

best try without the cold start injector. can cause more problems than it fixes. and you may be flooding it.

Also is the throttle pot and AFM working ok.

and as said check the ECU temp sensor.

There's lots of SD1's and Landrovers running flapper systems.
they can have idle problems but so can hotwire, due the the idle valve.
you normally getting a better sound from a flapper system.

[honestjohntoo]

Iain,
Providing you have fat sparks occuring at the plugs with the correct timing you can pretty much assume the problem is due to mixture control and/or fuelling.

Because the engine ONLY attempts to run when cranking you may want to review the AFM fuel pump contacts function:

http://www.vintagemodelairplane.com/pages/Rover_Te...

and the Steering Module (plus Relays) that controls the fuel pump sequence during cranking and running.

http://www.vintagemodelairplane.com/pages/Rover_Te...

Failing that the two most common problems occuring on the Rover SD1 Flapper Efi system are rogue air leaks into the plenum and electrical connection failures.

The former can be easily addressed by following a methodical air leak test program. The latter will depend upon visually and electrically checking for broken connections/earths.

Test for air leaks can be found here:

http://www.vintagemodelairplane.com/pages/Rover_Te...

and the same site has many other test processes for all the Rover SD1 Efi system components including how to track down electrical connection probs too.

The only significant interaction between the ign system and the efi system is the trigger connection between the coil negative and Pin 1 of the ECU - also needs to be checked out.