Poor starting and miss fire

bigalcoles · Post by **bigalcoles** » Mon Sep 21, 2015 7:22 am

First of all Hi there.
I've got a 3.9 running the hot wire injection system out of a range rover classic K reg. befor removing and when trial fitted it started and ran fine. Now it's fitted fully it can take a lot to start and requires full throttle until it picks up when started it won't idle hi enough to stay running but will idle after about 10-12 seconds. This does not happen every time some times it starts right on the button. It also has a miss fire underload again not all the time. Fuel is supplied through 8mm lines to an inline disposable filter then the hp pump and then an inline hp filter to the fuel rail. It's had new plugs leads cap arm coil ignition model and air bypass valve. The manual gear box wire to the ecu has a 510ohm (I think that's the size) resister to ground. The speed transducer is fitted. It has a K&N cone filter fitted more for ease than performance. Also the air flow meter is bolted to the inner wing and is there for grounded I've heard this needs to be insulated from ground but also told it does not matter? Your thoughts on this? No cats or lamders were ever fitted. I have a rover gauge and all seems to be working. It would be handy to know what values I should expect to be getting from cold thow. Any help appreciated. Regards Alan

richardpope50 · Post by **richardpope50** » Mon Sep 21, 2015 4:22 pm

Have you enough pressure in the fuel rail? Press the bleed valve to check.

Is your pre-pump fuel filter stopping fuel getting in - assume it is gravity fed to there? I use a 12mm feed mesh pre-filter then an 8mm feed paper filter after the pump so that enough fuel gets to the pump. You are pumping quite a lot of fuel even though it returns back to the tank.

Worth cleaning your stepper motor to make sure it is working all OK. Somewhere a year or two back I posted how to clean it but eventually found this all on the net anyway. It's easy and can re-post if required.