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chinkoa



Member Since: 17 Jan 2014
Location: West Yorkshire
Posts: 34

United Kingdom 2004 Range Rover Vogue Td6 Java Black
Range rover Classic 3.5 Efi Engine RPM problems

I have an engine RPM problem. My engine will not go above 3000 RPM. Either stood in the drive. On the road when I kick it down it will not rev above 3000. It's lively enough going upt to 3000. through the gears (Auto) then it just not wants to know.

It's as though the throttle is not fully opening. (I have checked, it is) It cannot be the plugs, Rotor Arm. Dist. Cap. But I have checked all these things.and replaced the Rotor Arm, Dist. Cap. and air Filter. I dont think it is a fuel pressure peroble as the speed cut of would not give a clear cut off. (I think)

I have come rightly or wrongly to the conclusion that the MAF Meter may be the guilty party? A dirty Potentiometer that stops sending a signal at 3000RPM maybe. Any body with any real knowledge got any Ideas?

Colin Range Rover Classic 1989
Range Rover Vogue 2004
Rebuilt Series 3 1983
Range Rover P38 1997
Range Rover Classic 1989
Series 3 County

Post #591065 13th Apr 2021 10:35am
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D3Jon



Member Since: 15 Aug 2020
Location: Lincolnshire
Posts: 216

United Kingdom 2011 Range Rover Vogue SE TDV8 Santorini Black

Is your car fitted with a flap type air flow meter, or a later hot wire one?

Also, does it run the 14CUX ECU? If so could be a road speed sensor issue.

Jon 1992 RR Classic 3.9 efi Vogue
2002 L322 4.4 V8 HSE
2011 L322 4.4 TDV8 Vogue SE
===================
Previous:
1976 Series III Trayback (Aus) - 1990 110 Isuzu County (Aus) - 2005 Discovery 3 2.7 TDV6 SE (Aus) - 1993 110 V8 Snatch Landrover - 2004 Defender 90 TD5 - 2009 Discovery 3 2.7 TDV6 XS

Post #591077 13th Apr 2021 12:19pm
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chinkoa



Member Since: 17 Jan 2014
Location: West Yorkshire
Posts: 34

United Kingdom 2004 Range Rover Vogue Td6 Java Black

It' the early Flap type MAF.
How do I knoe if it's a 14CUX ECU and where do I find the road speed sensor?.
Colin Range Rover Classic 1989
Range Rover Vogue 2004
Rebuilt Series 3 1983
Range Rover P38 1997
Range Rover Classic 1989
Series 3 County

Post #591080 13th Apr 2021 1:04pm
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chinkoa



Member Since: 17 Jan 2014
Location: West Yorkshire
Posts: 34

United Kingdom 2004 Range Rover Vogue Td6 Java Black

Jon,

Internet tells me the 14CUX ECU was released in 1990. After my 3.5Efi Range Rover Classic 1989
Range Rover Vogue 2004
Rebuilt Series 3 1983
Range Rover P38 1997
Range Rover Classic 1989
Series 3 County

Post #591081 13th Apr 2021 1:13pm
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chinkoa



Member Since: 17 Jan 2014
Location: West Yorkshire
Posts: 34

United Kingdom 2004 Range Rover Vogue Td6 Java Black

Car is fitted with a landrover recon unit. 4CU PRC7440 84941A.

Still possible Speed Sensor? Range Rover Classic 1989
Range Rover Vogue 2004
Rebuilt Series 3 1983
Range Rover P38 1997
Range Rover Classic 1989
Series 3 County

Post #591082 13th Apr 2021 1:28pm
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D3Jon



Member Since: 15 Aug 2020
Location: Lincolnshire
Posts: 216

United Kingdom 2011 Range Rover Vogue SE TDV8 Santorini Black

Not sure, I don't know much about pre-14CUX Lucas systems. The 14CUX has a road speed sensor to limit top speed on 4x4 vehicles, this can work in conjunction with a gear position sensor.

I doubt your's has that, but wouldn't completely rule it out... You'll need to do some further online digging or hopefully some one comes along with more knowledge of early EFi.

Other things worth checking are that the vacuum advance pipe is still connected to the distributor and that the advance mechanism in the dizzy isn't seized. It may need cleaning / lubricating.

Jon 1992 RR Classic 3.9 efi Vogue
2002 L322 4.4 V8 HSE
2011 L322 4.4 TDV8 Vogue SE
===================
Previous:
1976 Series III Trayback (Aus) - 1990 110 Isuzu County (Aus) - 2005 Discovery 3 2.7 TDV6 SE (Aus) - 1993 110 V8 Snatch Landrover - 2004 Defender 90 TD5 - 2009 Discovery 3 2.7 TDV6 XS

Post #591085 13th Apr 2021 1:47pm
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D3Jon



Member Since: 15 Aug 2020
Location: Lincolnshire
Posts: 216

United Kingdom 2011 Range Rover Vogue SE TDV8 Santorini Black

I've done a bit of googling on your behalf and general thoughts on this system for these symptoms are:

* Flappy AFM carbon strip wearing out - check resitance / output with a multimeter for any erratic readings (should be linear with manual flap movement)
* Dodgy coolant temperature sensor - short it out to eradicate that as a potential issue
* Dodgy ECU or ECU connector from harness - wiggle / replace ECU
* Poor fuel pressure due to pump or tank debris - replace fuel filter / fit a fuel pressure gauge / replace pump.
* Poor earthing strap to engine - one guy said the *was* the cause of his 350TVR not revving over 3K - honestly!
* Vacuum leaks from perished vac hoses - especially the one to the dizzy
* Ignition coil breaking down
* Advance mech sticking (in dizzy)

Jon 1992 RR Classic 3.9 efi Vogue
2002 L322 4.4 V8 HSE
2011 L322 4.4 TDV8 Vogue SE
===================
Previous:
1976 Series III Trayback (Aus) - 1990 110 Isuzu County (Aus) - 2005 Discovery 3 2.7 TDV6 SE (Aus) - 1993 110 V8 Snatch Landrover - 2004 Defender 90 TD5 - 2009 Discovery 3 2.7 TDV6 XS

Post #591086 13th Apr 2021 2:11pm
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D3Jon



Member Since: 15 Aug 2020
Location: Lincolnshire
Posts: 216

United Kingdom 2011 Range Rover Vogue SE TDV8 Santorini Black

Worth a read on how to test the Flappy AFM:

http://www.vintagemodelairplane.com/pages/...ter03.html

Jon 1992 RR Classic 3.9 efi Vogue
2002 L322 4.4 V8 HSE
2011 L322 4.4 TDV8 Vogue SE
===================
Previous:
1976 Series III Trayback (Aus) - 1990 110 Isuzu County (Aus) - 2005 Discovery 3 2.7 TDV6 SE (Aus) - 1993 110 V8 Snatch Landrover - 2004 Defender 90 TD5 - 2009 Discovery 3 2.7 TDV6 XS

Post #591089 13th Apr 2021 2:17pm
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chinkoa



Member Since: 17 Jan 2014
Location: West Yorkshire
Posts: 34

United Kingdom 2004 Range Rover Vogue Td6 Java Black

Hi Jon,
Non of the above. To cut a long and expensive story short. I checked the advance vacumn pipe to the dist. Their is a little gizmo in the pipe that I did not understand its reason to be. After blowing through it. Full flow one way nothing the other I tried the RPM again and it had gone to 4000RPM. So reversed the Vacumn pipe so that it got a full vacumn. Guess what problem solved revs to 5,500 RPM instantly.

Further reseach says this unit (Name escapes me) is supposed to slow down the speed of the vacumn onset so that the timing does not get too far advanced for the RPM. on too many revs too soon. Helps to stop backfires. Most cars are not fitted with this unit and Landrover I understand stopped fitting them.

Conclusion my unit is Fubar IE blocked which caused the Dist. to not advance the timing and in affect throtling the RPM. Relacement cost? Circa new £40.00. Any body got a spare?

Must admit it now goes as it should. Pity about the new Rotor arm, Distributor Cap, Ignition HT. Leads, Petrol Filter. Plugs out and clean, Air Filter and Petrol Pressure Gauge. It is easy to say go for the easy fixes first, but I have never ever had a problem with a Vacumn pipe and I have never come across this little plastic Unit. All the friends and "experts" never pointed to this unit either.
Colin Range Rover Classic 1989
Range Rover Vogue 2004
Rebuilt Series 3 1983
Range Rover P38 1997
Range Rover Classic 1989
Series 3 County

Post #591690 19th Apr 2021 9:53am
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Haylands



Member Since: 04 Mar 2014
Location: Brantingham, East Yorkshire
Posts: 6164

England 2012 Range Rover Autobiography 5.0 SC V8 Ipanema Sand

At least it's fixed and has had a good service as well... Thumbs Up Pete

__________________________________________________
2012MY L322 Range Rover Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior
2002 L322 Range Rover Vogue 4.4 V8 Epson Green, Ivory Interior (Fatty Offroader) Now Gone
-Project Fatty off roader-

Post #591703 19th Apr 2021 10:53am
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D3Jon



Member Since: 15 Aug 2020
Location: Lincolnshire
Posts: 216

United Kingdom 2011 Range Rover Vogue SE TDV8 Santorini Black

D3Jon wrote:
Not sure, I don't know much about pre-14CUX Lucas systems. The 14CUX has a road speed sensor to limit top speed on 4x4 vehicles, this can work in conjunction with a gear position sensor.

I doubt your's has that, but wouldn't completely rule it out... You'll need to do some further online digging or hopefully some one comes along with more knowledge of early EFi.

Other things worth checking are that the vacuum advance pipe is still connected to the distributor and that the advance mechanism in the dizzy isn't seized. It may need cleaning / lubricating.

Jon


So I was on the right track with my last paragraph in the post above !! Thumbs Up Thumbs Up Thumbs Up

Jon 1992 RR Classic 3.9 efi Vogue
2002 L322 4.4 V8 HSE
2011 L322 4.4 TDV8 Vogue SE
===================
Previous:
1976 Series III Trayback (Aus) - 1990 110 Isuzu County (Aus) - 2005 Discovery 3 2.7 TDV6 SE (Aus) - 1993 110 V8 Snatch Landrover - 2004 Defender 90 TD5 - 2009 Discovery 3 2.7 TDV6 XS

Post #591943 20th Apr 2021 9:23pm
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