Thread: D2 4.6 conversion owners. 4.6 ECU swap & EOI.

As far as I know, my 03 disco with a TRS 4.6 has the standard air box, MAF and intake setup and I have never heard it ping in the 2 years I've had the motor. I have never tried running it on 91 octane fuel however - I always use at least 95 octane - when running on petrol (it mainly runs on injected LPG). It is a the high compression motor with a custom TRS cam shaft grind.

It performs much better than the 4.0 - How it should have been from the factory!

I have seen the Secondary Air Injection plumbing on the DII in the USA.

My impression of SAI is that it's an emissions device only - when the engine is cold, the SAI pumps in extra air into the engine to speed up the warm up process. When the engine has reached normal operating temps, the SAI stops working and remains off.

I too have a 4.6 conversion on my DII, and I do agree with the sentiments that only the initial surge is there with the engine and when the revs climb, the output is rather meagre. Just lots of extra noise and not much urge.

I'd be interested to know if there has been any further developments.

Originally Posted by clubagreenie

I have performed the swap that make the D2 what it should be but still have issues with pinging under load and also on bad/low octane (non 98 or 100) fuel.

Just thought you may like to know that I had a Range Rover P38 for diagnostics with nasty pinging (detonation) under load. This should never happen with the Bosch or GEMS systems unless something is wrong.

The vehicle in question turned out to have a defective air flow meter (AFM), which was under-reporting the actual load that the engine was running. At part load, the mapping will produce a great deal of ignition advance which drops away rapidly as the load goes up. Just to compound the problem it will be operating with a very lean mixture too, which is another cause of pinking.

This is actually quite a common failure mode for the Bosch AFM. Instead of just failing outright, they report a lower and lower load over time. Ultimately the vehicle has such a lean mixture and so much advance that it just bogs as you open the throttle, and will then record random misfires on random cylinders.

In this case, a new GENUINE Bosch AFM restored normal operation. Beware - there are loads of pattern copy Chinese cr*p versions out there.

I treat the AFM as a service consumable, and automatically fit a new one at around 80,000 Miles - especially for modified vehicles or those that have come in for tuning.

I replaced the MAF about 20,000 ago just after doing the engine (and subsequently the auto which turned out to be the MAF clogged with oily water). Not 100% on it's source. Can you advise (PM) on dollars to send out one from a known source.

Originally Posted by Mark Adams

What many of my overseas clients choose to do is to fit another similar used ECU to their vehicle temporarily, and send the original over here. Once the upgraded original comes back to them, I can then clone a standard tune into their spare ECU so that they then have an interchangeable standard one.

Mark,

How does a client here fitting a different ecu and sending the original to you for modding differ to sending a spare to mod while driving on the original? I know there's security issues but if it'll drive on a spare while you're working on the original then wouldn't it drive on the modded spare after you've worked on it?

So, is the MAF and and the AFM the same thing?

My 4.6L doesnt seem like it's any better than the standard 4.) as well, and it seems to struggle in the mid range as well. Always looking for ways to help it run better.

MAF & AFM = same.

They tend to fail slowly and painfully.

So I'm confused - not hard actually

I have recently acquired a D2 with near new 4.6 crate motor fitted. It would appear no other settings were touched as my mechanic said he had to tell it it had a 4.6 under the bonnet or something similar (I've come from 5 years of Td5 ownership, this is my first V8) as it was pinning. Whatever he did, its a little better.

So what do I have to do to get the most out of the 4.6?
a) replacement ECU from Mark
b) replace air intake components with those from a P38?
c) all above?

Thanks guys!
Peter