Master
SupporterMorning all,
Ok, heres the skinny,
I've got a RRC with a 4.6 and a Disco 3.9 14CUX ECU, that was installed by les richmond. It gets about 180-220 a tank! Yep somethings wrong. My partner was following last nnight and she noticed that its was blowing black smoke when I floored it.
I've rang LR and I asked did they rechip it, response was, na we just make is run richer. Tomorrow I'm going to pull the ECU out and have a look if its been rechiped to run a 4.6.
If not, well here comes the mark Adams chip, BUT question is before I start buying stuff,
Is ther something else thats can cause this?
If not how do I retune it so it does use soo much fuel when I put the new chip in.
Cheers NAT
AT REST
Always check the ECU temp sensor first, around 300 ohms at operating temp, it's the 2 wire plug that can be confused with no.1 injector plug.Originally Posted by nat p
Then find/borrow a standard ECU to swap and check. The standard ECU generally runs too rich anyway, it shouldn't have any trouble pushing enough fuel to run a 4.6, at least for normal driving.
So you have a RRC and a Disco .... If the Disco gets good economy ... Then just swap the MAF out of the Disco to the RRC
At a guess they fiddled with the MAF .... Allen key adjustment on top of the MAF, Multimeter and turn left or right to adjust the voltage
x2
Also check the vacuum advance works and check the position of timing
Cheers
Mike
Master
SupporterSorry I mean to say running Disco top end. as in ECU manifold etc
Then either .........
MAF .... Allen key adjustment on top of the MAF, Multimeter and turn left or right to adjust the voltage
OR .....
Find a mate with a disco and swap em .... 10 miniutes max to do and a whip around the block.
OR.... LR made it richer ... Tell em toooo rich, re-ajust it ... (freebie)
But check the sender unit and vacuum advance first ....
Master
Supporterwhat voltage should it be?
Wizard
SupporterThere's no voltage, it's a resistance measurement.
Out of the back of the air flow meter (when the engine is warm) you need to measure the voltage between the outer two most wires. Commonly 1volt is suitable for a standard 3.9 (the less voltage there is, the leaner it runs). As a 4.6 draws a lot more air, it needs more fuel, so 1 volt would make it run too lean, so it's a bit of a guessing game for you.
LR more likely wound the adjustment screw right out, so you may get 5 volts or something like that. I would suggest 1.6 - 2 volts as a starting point, but you don't want to run it lean, as then it runs hot, and you've got slipped liners, cracked block etc etc.
Ideally you want to put an exhaust gas analyser up the exhaust to do this properly. However, the problem is that, the air flow meter can only measure up to a certain amount of air going through it (4.2 lt is generally considered the largest is can handle), and anything above this will not result in any further fueling. So when you race up the revs, it will run lean. This is where the Mark Adams chip will change the air flow meter scalling to suit a 4.6. ie, a 4.6 will pull more air through the meter than it can measure.
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