Hello everyone, I have a 2003 Disco 2 with the Bosch 4.6L V8 and Secondary air system. I recently replaced the head gaskets and all the gaskets along the way (Valley Pan, Intake manifolds, air intake) and it will crank and turn over but stall out before idle. I cleaned the Crank Position Sensor with CRC Electric cleaner and connected it with some dielectric grease in the connector. The Service Engine Soon light is on but not throwing any codes. I checked the vacuum hose on the back of the intake and it seems to be locked in and in good shape (no leaks). I checked the Idle Air Control valve and confirmed it is in the correct direction and plugged in. The vehicle will stay alive if I stay on the gas but will stall out once released.

I posted a quick YouTube video to show the issue. https://www.youtube.com/watch?v=WNiP...ature=youtu.be

 

Do you have the SAI & purge control valve plugs mixed up? Black = purge control valve & Grey = SAI Valve. How does it run with the MAF unplugged?

 

Well it seems you have some great advice! I did seem to have the SAI and Purge Valve connectors switched and I correct that with the photo shown (Wanted to verify). When I unplug the MAF the engine idles but it is extremely rough. It will hold idle better though than when the MAF is not connected. it sputters a lot still though and struggles to stay alive.

 

sounds like no MAF signal or large amount of un-metered air throwing off idle fuel /air ratio. How well did you get that lower intake sealed. Also did you drain the fuel rails they may be full of air if they were disconnected. I heard popping.

 

I did have the purge valve and SAI valve connectors switched (pic above to verify correct now)! After I switched it back it still had the same issue. I disconnected the mass air flow sensor and it will idle but is very rough. It has problem holding a steady idle and just sounds bad but at least tries. In terms of the lower being mounted on I followed the Atlantic British video to a T and Torqued all the bolts in a spiral pattern starting low and ending at 38ft/lbs.

 

I had a similar issue, my head gasket blew and and to replace a helicoil in the block. When I drove after it would struggle to idle at the light then die after I pulled away. Grabbed a can of MAF cleaner and cleaned both the sensor and wire harness. No more issues, hope this helps.