Ok so on my 2000 4.0 Disco I upgraded to Magnacor 8mm wires and while I was in there I replaced the valve cover gaskets and cleaned the IAC, as I did so the Iac would make a noise like something was moving freely. It didn't seem to do that before I cleaned it. For some reason the truck will not start (and yes I hooked the wires back up correctly). there were several threads on proper wire diagrams for the coil and firing order as well as consulting my RAVE book. There is now a buzzing, vibration coming from my IAC while the key is on, like a pump that is locked up. It does crank and will try to start for a few seconds while first cranking, but then just cranks. If I disconnect the IAC from the intake it sounds like a back fire through the intake, popping but not loud. Could someone please give me a hard time for doing something wrong. Thanks!!

 

The IAC will buzz like that. I don't know for sure but, don't think that's your problem.

When you were putting the new plug wires on are you sure you got those right?

The reason I am asking is the diagram is showing the coils as if you were looking at them from inside the cabin looking through the firewall at the coils.

If you wire it using the diagram as if you were looking at the coils from the front of the truck it will be wired incorrectly.

I'm not saying that is your problem but, It's easy to get turned around on that so can't hurt to double check.

 

Ive read about folks who have to ?reset? or get their IAC to 'learn?' the truck they are in.

How did you clean it.? Is there a chance that it's now monkeying with your ignition, now it feels like a new thing.?

Following those plug wires wiring diagrams is a bit of a mind meld, it would have to be very wrong to just crank and not attempt to fire, no?

 

I'd start with double/triple checking the wires and get a 2nd opinion. The IAC usually wouldn't keep it from running at all....I'd think you at least get it start and die or just run like crap. Anytime a vehicle won't start I always check the fuel cut off switch. I'm sure it's fine, but never hurts to just push the button. It's on the pas side firewall, under the hood.

 

I think I may have not realized that the coil diagrams I based my routing off of was supposed to be viewed from the inside of the cab. I will be rechecking my diagrams and plug wire placement in the morning. I can be such a dolt sometimes. Thanks RicketyTick for the correction to my method.

 

Easy mistake. If that's the problem...

and remember odd # cylinders 1,3,5,7 are on the drivers side #1 up front and #7 in the rear closest to the firewall. Even # cylinders 2,4,6,8 are on the passenger side #2 up front #8 in the rear.

Bad enough they hide the coils like someone's going to steal them but, then they give us a diagram that can only be used with our head in the cab while our *** is under the hood.

These things are really just rolling mensa puzzles, designed to keep our minds sharp.

 

I officially retract the following statement, (and yes I hooked the wires back up correctly). Will be tackling the repair as soon as I get a ride back to the Rover.

 

Had the coil wires hooked upside down. Truck is running now, thanks to everyone for their help!!