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Adam G
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Hey guys:

Been a while since I've posted on LRO, been over on RangeRovers.net. Hoping the community here can help with some insight into my RRC.

Kind of can't figure this one out. Over the past year I had been running a 4.2 fuel map chip on my RRC with a 4.6 block upgrade. Reason was I had broken a pin on my Tornado chip pulling it from a fried ECU. I had also been running the cleaned, but original Lucas injectors. Things were ok fuel trims weren't really balanced, but within about 20%. I had assumed this was on account of the 4.2 map in a 4.6 block. I have wanted to get that tightened up on account of my mpg being around 9.

After about 4 months, I got my Tornado chip back from Mark Adams. In those months, I had also aquired 8x upgraded Bosch injectors (4 hole), the direct replacement everyone does (yellow). They came from Motorman, on eBay, well respected.

The new injectors went in easily. I decided to pull the 4.2 chip and go back to the 4.6 Tornado chip while I was at it.

A few tanks later, I was checking my mpg. No change since my abysmal 9 mpg.

I thought that was really disappointing news after the upgraded injectors (which, I noticed ran MUCH quieter and smoother).

So I checked fuel trims to see if the fuel map was working better with the new injectors. I was surprised to find that the long term fuel trims were -83% and -100%.

Uhg. So I ran it for another tank, and it ended up moving around a bit, and landed somewhere around -38% and -70% or something. It sat there for a tank. It went back to -90s... so I reset the ECU and ran for another tank or two. Again, back to the -100 LTFT on one bank, and -70 something on the other.

Some more info, I have worked on the ignition system, and fuel delivery for the past year or so here goes:
-MAF reads 1.8V, (haven't checked the resistance curve thought), smoke tested,
-No vacuum leaks except a very small (normal) one at the throttle spindle gasket.
-TPS checks (voltage and map looks good),
-IACV is ok (replaced, just for fun),
-Fuel Pressure Regulator,
-Vacuum advance,
-rotor arm is red, cap is good, wires are good, NKG plugs as preferred, etc etc.
-Compression checked, and even, somewhere around 135 warm with starter IIRC.
-Sensors all working, coolant temp, fuel temp etc. Rover gauge also shows they are all reading just right.
-O2's are new, I've watched them cycle on my oscilloscope. Clean and normal signals.
-Distributor has been checked, gap is set perfectly.
-Pulse off amplifier and coil look just right. New coil was installed, new amp installed.

Fuel, compression, spark. All good.

Timing I've had from 12 to 5 BTDC. Really doesn't seem to make any difference. In fact, when I bought the truck it was 12 ATDC and it ran almost the same, and got the same gas mileage! Checked that the mechanical advances are working. Seems so when I rev, to jump to around 20 or 30 degrees accelerating.

WHAT am I missing? Is there something that the previous owner could have done that simply makes this engine inefficient? Is there anything else that I might be missing? Note, he also installed a crower cam with the block upgrade.

The only other thing I'm left to consider is that:

1: The injectors are not really the right flow rate (Makes no sense because everyone else has used them, and I've checked each one opens/closes)
2: This isn't actually a 4.6 block. Tornado map just isn't right.
3: I need a new distributor : Maybe the timing curves are just not working, so the timing is just not efficient? Or the spark

I feel like, maybe this is just a lost cause, and just needs a ground up rebuild. My expectation would be that this truck would be super straightforward to work on, which it is. All the variables are accounted for, but they just don't add up. Can't tune this thing at all.

Thanks for any ideas guys.
 

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Hey guys:

Been a while since I've posted on LRO, been over on RangeRovers.net. Hoping the community here can help with some insight into my RRC.

Kind of can't figure this one out. Over the past year I had been running a 4.2 fuel map chip on my RRC with a 4.6 block upgrade. Reason was I had broken a pin on my Tornado chip pulling it from a fried ECU. I had also been running the cleaned, but original Lucas injectors. Things were ok fuel trims weren't really balanced, but within about 20%. I had assumed this was on account of the 4.2 map in a 4.6 block. I have wanted to get that tightened up on account of my mpg being around 9.

After about 4 months, I got my Tornado chip back from Mark Adams. In those months, I had also aquired 8x upgraded Bosch injectors (4 hole), the direct replacement everyone does (yellow). They came from Motorman, on eBay, well respected.

The new injectors went in easily. I decided to pull the 4.2 chip and go back to the 4.6 Tornado chip while I was at it.

A few tanks later, I was checking my mpg. No change since my abysmal 9 mpg.

I thought that was really disappointing news after the upgraded injectors (which, I noticed ran MUCH quieter and smoother).

So I checked fuel trims to see if the fuel map was working better with the new injectors. I was surprised to find that the long term fuel trims were -83% and -100%.

Uhg. So I ran it for another tank, and it ended up moving around a bit, and landed somewhere around -38% and -70% or something. It sat there for a tank. It went back to -90s... so I reset the ECU and ran for another tank or two. Again, back to the -100 LTFT on one bank, and -70 something on the other.

Some more info, I have worked on the ignition system, and fuel delivery for the past year or so here goes:
-MAF reads 1.8V, (haven't checked the resistance curve thought), smoke tested,
-No vacuum leaks except a very small (normal) one at the throttle spindle gasket.
-TPS checks (voltage and map looks good),
-IACV is ok (replaced, just for fun),
-Fuel Pressure Regulator,
-Vacuum advance,
-rotor arm is red, cap is good, wires are good, NKG plugs as preferred, etc etc.
-Compression checked, and even, somewhere around 135 warm with starter IIRC.
-Sensors all working, coolant temp, fuel temp etc. Rover gauge also shows they are all reading just right.
-O2's are new, I've watched them cycle on my oscilloscope. Clean and normal signals.
-Distributor has been checked, gap is set perfectly.
-Pulse off amplifier and coil look just right. New coil was installed, new amp installed.

Fuel, compression, spark. All good.

Timing I've had from 12 to 5 BTDC. Really doesn't seem to make any difference. In fact, when I bought the truck it was 12 ATDC and it ran almost the same, and got the same gas mileage! Checked that the mechanical advances are working. Seems so when I rev, to jump to around 20 or 30 degrees accelerating.

WHAT am I missing? Is there something that the previous owner could have done that simply makes this engine inefficient? Is there anything else that I might be missing? Note, he also installed a crower cam with the block upgrade.

The only other thing I'm left to consider is that:

1: The injectors are not really the right flow rate (Makes no sense because everyone else has used them, and I've checked each one opens/closes)
2: This isn't actually a 4.6 block. Tornado map just isn't right.
3: I need a new distributor : Maybe the timing curves are just not working, so the timing is just not efficient? Or the spark

I feel like, maybe this is just a lost cause, and just needs a ground up rebuild. My expectation would be that this truck would be super straightforward to work on, which it is. All the variables are accounted for, but they just don't add up. Can't tune this thing at all.

Thanks for any ideas guys.
First, was it always 9mpg? why does 135 compression seem low to me. I have a 4.2 with a tornado chip. I am going to test it this week with the old chip back in. My rebuild has 3k miles on it. it runs perfectly. It has a piper torque max cam.. not sure how it compares to your crower..My rover gets the same mileage at 8 to 15 btdc and runs almost exactly the same. That always bugs me..lol ..Do you have a 4.6 intake and MAf sensor? They have a voltage setting and a rewire if you ad the 4.6 MAF to a lesser engine-ecu.. thats on the rpi website someplace.. what transfer case is in this, viscous or lt230? if Lt230 what gear ratio? what is your rpm at 70 mph? I am told it should be 2650. What size tires are on this range rover? I have noticed that my rig gets less mileage since the chip install. My parts came from RPI, you could email them and see if they have an answer for you? That Ian over there is extremely bright about these rovers..
 
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