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Rangie Running Rich

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I have a 89 Range Rover Classic 3.5 Efi... The vehicle had a few problems in the last year and i ended up changing the fuel pump relay and the AFM to get the car to start without easy start. The vehicle is now running really rich and drinking fuel like its free...

I do have another coolant temp sensor and have tried this without fitting it and it doesnt seem to make much difference.

Does anyone have any suggestions on how to correct my fuel consumption.

I believe that AFM's are adjustable and can be altered to adjust the signals given to the ECU...

i do not have a smokemeter to be able to do this... is there any way that this can be done...

CHEERS,

Chris

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Go through the diagnostics manuals in the tech archive, there's flapper & hotwire in there. Work through every step methodically and come back if you get stuck / find something / fix it ;)

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Mine constantly had problems with corroded connectors on the O2 sensors making poor connection. With a bad connection it will run rich.

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If its a Flapper type EFI,

There's a Alan key screw on the top of the AFM, try screwing it right in, its the mixture adjustment screw...

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You say you tried another coolant temp' sensor but did not fit it - do you mean you simply plugged the sensor into the connector? If so and the engine was warm this would have the effect of richening the mixture as the sensor would be 'cold' in relation to engine temp.

There is also a fuel temp' sensor fitted into the fuel rail. Both of these sensors have the same resistance characteristics - a simple test is to connect a 200-300 Ohm resistor across each of the connectors - this will simulate a hot engine and therefore weaken the mixture.

Engine cold the resistance of each will be in the region of 1500-2000 Ohms. The fuel temp rail soon cools after starting a hot engine as the circulation of 'fresh' fuel resulting from the pressure regulator by-passing excess pressure - check the vacum pipe from the back of the manifol to the regulator to make sure its intact - this can cause over fuelling if the vacum isnt present.

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There is no fuel temp on sensor on the flapper, and as this is a 3.5, I'm guessing its a flapper. Fuel temp is on the hot wire only and is at the front of the fuel rail, but in reality it is only measuring the rail temp as it does not make direct contact with the fuel.

On the flappers the AFM is adjustable but that is only masking the fault and will not cure the problem.

How rich is rich ? .............black smoke and stalls, or just using a bit more juice ?

:)

Ian

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If its a Flapper type EFI,

There's a Alan key screw on the top of the AFM, try screwing it right in, its the mixture adjustment screw...

Er not exactly :ph34r:

That screw is for fine adjustment - mainly tickover,

to alter the richness of the unit invovles removing the top (Black cover) and then F'ing about with a geared wheel - not for the uniniated :lol:

You MUST fit the coolant sensor into the block and connect else it will run rich

If you wnat to bodge the coolant temp sensor 'out of the equation' - fit a 170 Ohmn resisitor to the CTS Plug Housing terminal, (remove off the CTS and shove it up "Safe" somewhere in air) this makes the system behave as though there never was one, it would then be weak to start, so remove one end of the resisitor until warm then shove it back in :)

Nige

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Thanks for all the replies fellas...

Theres a few things here im gonna try today, that diagnostics guide will help a treat...

Ill let you all know how i get on...

Cheers

Chris

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When going through the tests in the tech archive there will be one testing the air temperature sensor in the flapper which you will do by connecting a multimeter to certain pins on the flapper.

When you do this test do not connect for more than a couple of seconds as even the current of a digital multimeter can burn out the sensor.

I found this one out too late.

Steve

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When you do this test do not connect for more than a couple of seconds as even the current of a digital multimeter can burn out the sensor.

Never heard that before, only Rover could manage that sort of quality.

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IF ITS GOT FOUR WHEELS AND A STEERING WHEEL... ILL PROBABLY BUY IT !!!!

Just the above bit to reduce now then :rolleyes:

Nige

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I know this an old thread, but awesome nonetheless. Exactly what was happening to my 89 RRC. Couldn't get it to even start, but now it is running, albeit extremely rich. Tested the CTS with multimeter (quickly!) and found no resistance - so need to replace that. Don't have a 170ohm resistor handy but will get one and try that next.

One annoying thing is my RRC was built May 89 for Downunder, and depending what I am doing with it I tend to have to straddle a number of different manuals and pre89, 90onwards, and so on variants. Anyway I think I'm getting the hang of this now :-)

Great info guys, especially those manuals and tips, thanks Nige!

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