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So i finished up a 4.6 flanged liner bosch swap into my disco few weeks ago. just got the first 1k onto it. Most everything seems fine but had few lingering questions was hopeing somebody could help answer. im still runnin my stock 4.0 ecu. I have read multiple times over about internally switching you ecu from 4.0 to 4.6 but on at least one occasion i read a post saying that it only actually changes essentially the labeling not actual perameters, whats that truth. i dont want to pay a garage to switch it if it doesnt do anything in actuallity. It would make sense to me that it would be a labeling change not a parameter change. i know both ecu's have same part number but i have a hard time believeing that every ecu has tuning for both engines. Secondly my 4.6 long block came from a shipping auction. its got a 4.6 crank and after removing the head flanged liners, and its never been fired thats all i really know about it. I found one striking huge difference while bolting on my 4.0 gems parts (other than the crank senson and cam sensor bs). My block didnt have provisions milled for the oil pickup tube that was on my 4.0 and resulted in alot of costly bs. i had to swap to a d2 oil pan, pickup tube and oil pump/front cover. Other than the cost of the d2 parts i didnt have my only issue running about 9/16" spacers behind my water pump pulley to make it line up properly. so my question on this is why no oil pickup milled in my block? i assume since the front cover design changed to not utilize the pickup tube to the block they quit milling them? And does this mean d2 accessories pulleys sit 9/16" closer to the block. Sorry for my long rant and to all the people who have no clue what im talking about, but any thoughts on the ecu and water pump spacing would be apreciated.
 

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bottom of my 4.6
 

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im not surprised nobody responded about the water pump. but i figured as common as this engine swap is somebody would have an idea on the ecu switch thing. just wanted to know if anybody can confirm it actually changes perameters? :confused
 

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No difference in the A/F parameters. Unless you really want a variable reset I wouldn't bother unless there's an indy garage around that doesn't stick it to you for the reset.

Why didn't you go with the GEMS 4.6? Hope it wasn't an 03 4.6 you dumped in......boat load of TB's on those babies.
 

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Discussion Starter #5
it came from a shipping auction no idea what its out of. the block numbers are milled off. price was right for a remaned flanged liner. what do you mean TB's? i just wanted to know what everyone else out there did for there ecu. i wasnt sure if the 4.0 ecu would cause long term damage.
 

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No damage at all, it's the same parameters for both AFAIK. Tech Bulletins. 03's have a liner issue (which if yours has top hats isn't one) and oil pump issues.
 

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How does it run and drive with the 4.0 tune? I've had one on a stand for about a year waiting for the swap in my 97 5 speed, if it doesn't run well with the stock tune it would be good to know ahead of time.
 

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it seems to run fine but i think i need new injectors. i had no pressure in the rail after about 12 hrs of sitting. not sure how long it should hold pressure but i thought i would get a squirt at least. didnt use a guage just a quick screwdriver test but i felt it should have been still holding something. im going to start a fuel injector upgrade thread. i've scoured the internet high and low and havent found some of the injector answers i want.
 

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it seems to run fine but i think i need new injectors. i had no pressure in the rail after about 12 hrs of sitting. not sure how long it should hold pressure but i thought i would get a squirt at least. didnt use a guage just a quick screwdriver test but i felt it should have been still holding something. im going to start a fuel injector upgrade thread. i've scoured the internet high and low and havent found some of the injector answers i want.
19 lb at 2.5 bar is all it needs. I swapped mine out for ford injectors years ago without any trouble. It was maintenance and not an upgrade. There is no need for a bigger injector for any rover engine, an injector of the same size was used on 454 trucks in the late 90's (though the rail pressure was at 3 bar instead of 2.5)
 

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I am wondering about the samething about the ECU. From my researching on various forums it will work but not optimal.

Another 4.6 swap question? - Defender Source

The 4.0 ecu will work, but it's not correct. And using Rovacom or Autolodgic to change the 4.6 ROW setting does not work, either, and you'll get a transmission fault (1777). The truck will run rich up to op temp, and lean at throttle. The 4.6 setting also does not look for O2 sensors. A UK 4.6 ecu will eliminate only the rear O2 sensors.

Stock ign timing on a 4.0 advances to 50 degrees at 2000 rpm's.

Using a 4.0 GEMs ecu on a 4.6 you'll max out at 46 degrees @2000 rpm's. At 3800 rpm's you're retarding to 43.6 degrees.

Injector pulse rates are a concern, too. In other words, at full throttle you're starving the engine of fuel. An injector that flows a little more fuel would help, or maybe add a 9th injector on a relay. Both would be experimental unless you can find someone who has done this already.

By pulling the knock sensors you can retard timing 6.8 degrees at idle. Take that FWIW.
 

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Discussion Starter #11
Same thing I read. Ive put 4k miles on and running great!
 

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Same thing I read. Ive put 4k miles on and running great!
I have been running 4.6's on the 14CUX system for years. Around 200,000kms on the 2 cars. That is, I changed the 3.9 in my wife's Disco 1 to a 4.6 and I have run the other 4.6 in my 84 rangie, then my 93 rangie and now my 76 rangie ute. When it was in the 84 it had carbies, but the 93 and 76 is on EFI.

The engine will lean out with running stock tuning. You can send your ECU to the UK for retuning, but this was too costly and too much hassle for me.

The main thing you need to fit is an adjustable fuel pressure regulator. You only need to boost the pressure by around 2psi to get the motor right. The other thing you need to do is adjust the MAF unit.
 

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Discussion Starter #13
How do you adjust the maf ?
 

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How do you adjust the maf ?
Not sure on your model. Here and in the rest of the world on a 98 Disco we were still running the 14CUX Lucas EFI system. In the USA you moved to a later system in 96. But you might find that your ECU is programable or just a chip change.
 
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