Rover 3.9i Running Rich troubleshooting

Wooh, no need to go crazy,


Just start with a filter and oil change of the gearbox if its condition is unknown. I might sort it out, it has for me in the past.


I use the Nulon multi vehicle synthetic ATF. It's a bit expensive but it works for me and goes in anything. But a decent DexIII will be just fine and a heap cheaper.


Also check the kick down cable is set correctly.




Filter Kit to service Land Rover Defender/Discovery/Range Rover auto gearbox

Quote:

---

Originally Posted by bee utey

No oxygen sensors on a 3.9 in Australia. :)

---

Oh ok - just that a friends 101 has a 3.9 running a 4CUIX and it has O2 sensors - obviously not original.

Maybe if the D1 had O2 sensors it would not be running rich then :)

garry

Quote:

---

Originally Posted by FisherX

Wooh, no need to go crazy,


Just start with a filter and oil change of the gearbox if its condition is unknown. I might sort it out, it has for me in the past.


I use the Nulon multi vehicle synthetic ATF. It's a bit expensive but it works for me and goes in anything. But a decent DexIII will be just fine and a heap cheaper.


Also check the kick down cable is set correctly.




Filter Kit to service Land Rover Defender/Discovery/Range Rover auto gearbox

---

Phew! I thought the Amazon kit was a bit over the top!

I plan on doing the filter soon - just need to find the time and a willing offsider. Have the filter and penrite Dex III waiting for me in the garage.

Kickdown seems to work fine judging by the response compared to the light/medium/heavy throttle vs load as detailed in the workshop manual.

Quote:

---

Originally Posted by drover81

Thanks guys - hope all had a good Aus day.

Since the last post I've got rovergauge working (finally - lesson learnt - get the genuine FTDI device (i.e. not cheapo chinese knockoff)). No fault codes in the ECU.

Swapped the thermostat - Also spent a fortune on coolant as I didn't clean the surfaces on the thermostat housing as well as I should have...!!!
Now runs at a steady 90/91degC & idles at approx 690/700rpm (which I believe is high - should be closer to 600).

New NGK plugs all round.

Cleaned the MAF with appropriate cleaner - no idea if it was dirty to begin with - regardless, it should be as clean as it can be.

Still to do:
1. Check/tweak the MAF resistance as per aRRon's advice.
2. Check the temperature sensor - although I think this may be redundant if the ECU is reading the correct temperature.

Cheers

---

So, I filled it up (took 40L for 110km!!!).
Then tweaked the MAF resistance from 480ohms to 80ohms, and drove the car 100km (combination of 30 hwy/70 city).

I have noticed a few things since tweaking the MAF:
1. It seems like the engine is more responsive, and the auto seems to take a bit longer to change through the gears (i.e. car revs higher compared to the same road speed). Not sure what's happening here as I have no experience with auto boxes.
2. The idle when warm settles down to close on 600rpm when in D. Drifts up to 700rpm when in N or park.

And then!
I then filled it up 91ulp... 35 litres for 100km! This is just madness! :mad:
I'm driving with a light foot and can't understand what's the deal. It doesn't help that I think everything is going fine until the fuel gauge jumps between 3/4 full and half full and back again after the first 1/8-1/4 of the tank is used.

I still have to check the compression (missed that comment before).

Have you checked the valve timing? i.e. turned over the engine, checked the rockers are opening at the correct angle? Quite a common issue - worn camshaft, crook lifter (usually get a pretty average tick noise in the valley) and worn rockers. You won't need a degree wheel, but if you have one, it can help. (print one out on your computer and stick it to some cardboard /metal/plastic if you can't buy one) Basic engine 101 stuff. Make sure your timing is set correctly, make sure your camshaft has correct lift. (forget about rocker ratio factors and other crap, you just want to make sure it's opening and closing at exactly the correct moment. any obvious wear on the crest of a cam lobe will be evident at max lift when using a dial gauge on the rocker shaft (pushrod side).

Even though hydraulic lifters are designed to eliminate repetitive valve lash setting, they will not compensate for a worn camshaft. A worn cam means less lift at the valve, which equates to inefficient induction - or basically asthma for an engine. i.e. it might be breathing, but it's not getting the oxygen (and fuel) that it needs. So while the ECU is shoving the fuel down it's throat, there's not enough air to complete the efficient combustion, which basically means it's running rich. Too rich. and because it's not making power effieicntly, you sink the boot in to make it move, which just drops more fuel in.

Check your plugs. are they fouled? sooty? even wet? that's another sign.

fuel pressure regulator can also be stuffed. That's something that you'd troubleshoot after you checked your EFI basics (i.e. timing, spark, then air/fuel)

Make sure you have a good well lubed and CLEAN dizzy as well. I don't mean new cap and lucas rotor, I mean check under the cover that the hall sensor and trigger are clean and you have the correct clearances. Check the vac advance is working. Make sure the advance weights aren't stuck or sticking... Ensure the static advance is set to around 12deg btdc. No other vacuum leaks etc.

If you haven't seen the bee-utey distributor module relocation thread, I heartily suggest you also undertake this, simply as part of basic rover v8 maintenance - then you can cross ignition issues off your 'list' of things to check.

It's not really a complicated setup. Just treat the engine as if it were 3 separate systems. inspect and diagnose them separately - A mechanical air pump, a fuel system and an ignition system. if you can be sure everything is functioning within spec, then you'll solve the problem. The trouble is, you will not know until you check and verify each individual system.

These things will actually 'run' with a lot of lattitude / tolerance for wear and even obvious fault. What many people don't actually realize, is that just because an engine idles smoothly, or 'makes power' or even 'tows good' does not mean it's actually functioning within spec.

The efi thing isnt meant to confuse. In reality it is simply a fuel metering device, which is 'timed' instead of being constant. When the sensors are tested (follow the test procedure) and found to be within specification, you move to the next component and test it. When everything is found to be within spec, then you place the system 'under load' and take some sample values from the sensors / components whilst under load and compare those to the specification. If they fall outside the spec, replace them.

In the 14CUX system, the obvious areas to look at are the MAF sensor (clean and correct resistance values), the temp sensor (correct values over range of operation - i.e. cold, warm, hot) and the resistance of the two injector loom banks (4-4.5Ω each side). Then the idle air bypass / idle speed controller (back of plenum) is clean and functioning. That's not everything, but it's a good place to start your checks.

for the fuel system, fuel pressure, fuel filters and fuel pump, as well as the hoses (kinks/rot/blocked etc) will have an effect. If you want to test for leaking injectors, ign on, have the fuel rail and injectors removed from the manifold, and observe for leaks. they should not leak at all, but there is a 'limit' in the manual which says maximum of 2 drops per minute from any injector. I'd suggest that if you see any leaks within 5 minutes, count them and then have the injectors cleaned ultrasonically / reconditioned / replaced (depending on your budget).

Ignition system is simple. new plugs in the correct heat range. a GOOD set of leads (magnecor is quite possibly the best set you can lay your hands on, or genuine bosch - not anything PRC made) and then pay attention to the distributor module and it's wiring (clean terminals, good wire) and the mechanical function of the distributor itself (rebuilding one is not a difficult job, but mechanical sympathy helps). Again, Bee-utey's thread is worth reading, and setting your static ignition timing to approx 12deg btdc will make a difference.

Lastly.... despite what people say to the contrary, avoid the use of ethanol-additive fuels. All this will do is serve to prematurely rot the fuel system, gum up the injectors, absorb moisture and cause internal rust and because of the octane rating and the fact the engine was never designed to burn it, a noticeable increase in fuel consumption. So stick to 95 as a minium and where possible run 98, to ensure your fuel system is clean and free of crud. 98 also allows you to dial in more advance if you want.... but watch your temps!

Over on the british v8 org site there was a reference to the rover 14cux efi system, but there are also heaps of other sources, including RAVE, and plenty of experienced mechanically minded members here who can help.

good luck with resolving your issues, I often find breaking things down into the simplest segregated form helps to troubleshoot, and often leads to a straightforward diagnosis.

Quote:

---

Originally Posted by Mercguy

Have you checked the valve timing? i.e. turned over the engine, checked the rockers are opening at the correct angle? Quite a common issue - worn camshaft, crook lifter (usually get a pretty average tick noise in the valley) and worn rockers. You won't need a degree wheel, but if you have one, it can help. (print one out on your computer and stick it to some cardboard /metal/plastic if you can't buy one) Basic engine 101 stuff. Make sure your timing is set correctly, make sure your camshaft has correct lift. (forget about rocker ratio factors and other crap, you just want to make sure it's opening and closing at exactly the correct moment. any obvious wear on the crest of a cam lobe will be evident at max lift when using a dial gauge on the rocker shaft (pushrod side).

Even though hydraulic lifters are designed to eliminate repetitive valve lash setting, they will not compensate for a worn camshaft. A worn cam means less lift at the valve, which equates to inefficient induction - or basically asthma for an engine. i.e. it might be breathing, but it's not getting the oxygen (and fuel) that it needs. So while the ECU is shoving the fuel down it's throat, there's not enough air to complete the efficient combustion, which basically means it's running rich. Too rich. and because it's not making power effieicntly, you sink the boot in to make it move, which just drops more fuel in.

---

Half thought the camshaft might be an issue, but what you say seems to make sense. I'll have to have a deeper look. I've read where some Rover V8s at 0deg aren't at TDC...

Quote:

---

Originally Posted by Mercguy

Check your plugs. are they fouled? sooty? even wet? that's another sign.

---

Replaced the plugs - the previous ones were black, so that confirmed to me it was running rich.

Quote:

---

Originally Posted by Mercguy

fuel pressure regulator can also be stuffed. That's something that you'd troubleshoot after you checked your EFI basics (i.e. timing, spark, then air/fuel)

---

Will check.

Quote:

---

Originally Posted by Mercguy

Make sure you have a good well lubed and CLEAN dizzy as well. I don't mean new cap and lucas rotor, I mean check under the cover that the hall sensor and trigger are clean and you have the correct clearances. Check the vac advance is working. Make sure the advance weights aren't stuck or sticking... Ensure the static advance is set to around 12deg btdc. No other vacuum leaks etc.

---

Dizzy is clean. Static advance approx 9deg BTDC. Vacuum advance works.

Quote:

---

Originally Posted by Mercguy

If you haven't seen the bee-utey distributor module relocation thread, I heartily suggest you also undertake this, simply as part of basic rover v8 maintenance - then you can cross ignition issues off your 'list' of things to check.

---

Had a quick search - still to fully understand it, but getting there.

Quote:

---

Originally Posted by Mercguy

It's not really a complicated setup. Just treat the engine as if it were 3 separate systems. inspect and diagnose them separately - A mechanical air pump, a fuel system and an ignition system. if you can be sure everything is functioning within spec, then you'll solve the problem. The trouble is, you will not know until you check and verify each individual system.

These things will actually 'run' with a lot of lattitude / tolerance for wear and even obvious fault. What many people don't actually realize, is that just because an engine idles smoothly, or 'makes power' or even 'tows good' does not mean it's actually functioning within spec.

The efi thing isnt meant to confuse. In reality it is simply a fuel metering device, which is 'timed' instead of being constant. When the sensors are tested (follow the test procedure) and found to be within specification, you move to the next component and test it. When everything is found to be within spec, then you place the system 'under load' and take some sample values from the sensors / components whilst under load and compare those to the specification. If they fall outside the spec, replace them.

In the 14CUX system, the obvious areas to look at are the MAF sensor (clean and correct resistance values), the temp sensor (correct values over range of operation - i.e. cold, warm, hot) and the resistance of the two injector loom banks (4-4.5Ω each side). Then the idle air bypass / idle speed controller (back of plenum) is clean and functioning. That's not everything, but it's a good place to start your checks.

---

MAF, TPS & Temp Sensor appear correct. Have to check the idle bypass.

Quote:

---

Originally Posted by Mercguy

for the fuel system, fuel pressure, fuel filters and fuel pump, as well as the hoses (kinks/rot/blocked etc) will have an effect. If you want to test for leaking injectors, ign on, have the fuel rail and injectors removed from the manifold, and observe for leaks. they should not leak at all, but there is a 'limit' in the manual which says maximum of 2 drops per minute from any injector. I'd suggest that if you see any leaks within 5 minutes, count them and then have the injectors cleaned ultrasonically / reconditioned / replaced (depending on your budget).

---

Okay, another thing to add to the list of checks.

Quote:

---

Originally Posted by Mercguy

Ignition system is simple. new plugs in the correct heat range. a GOOD set of leads (magnecor is quite possibly the best set you can lay your hands on, or genuine bosch - not anything PRC made) and then pay attention to the distributor module and it's wiring (clean terminals, good wire) and the mechanical function of the distributor itself (rebuilding one is not a difficult job, but mechanical sympathy helps). Again, Bee-utey's thread is worth reading, and setting your static ignition timing to approx 12deg btdc will make a difference.

---

Noted

Quote:

---

Originally Posted by Mercguy

Lastly.... despite what people say to the contrary, avoid the use of ethanol-additive fuels. All this will do is serve to prematurely rot the fuel system, gum up the injectors, absorb moisture and cause internal rust and because of the octane rating and the fact the engine was never designed to burn it, a noticeable increase in fuel consumption. So stick to 95 as a minium and where possible run 98, to ensure your fuel system is clean and free of crud. 98 also allows you to dial in more advance if you want.... but watch your temps!

---

Really?? I can understand the ethanol issue, but the higher octane in a low compression engine? Thought octane rating became more important at higher compression to avoid detonation.

Quote:

---

Originally Posted by Mercguy

Over on the british v8 org site there was a reference to the rover 14cux efi system, but there are also heaps of other sources, including RAVE, and plenty of experienced mechanically minded members here who can help.

good luck with resolving your issues, I often find breaking things down into the simplest segregated form helps to troubleshoot, and often leads to a straightforward diagnosis.

---

Cheers!

Rover 14CUX Hot Wire Mass Flow EFI: Service and Troubleshooting

link may be of use .

G`day , when are your plugs sooty is it after a hwy run or at low speed ?

If you haven`t diagnosed when it`s happenening , you need to because it seems like the plugs are trying to help you .

Is it all 8 or only one bank 4 or only one or two cylinders .

8 would be something in either air or fuel as is not enough air or too much fuel .

4 a bank would be electrical .

1 or 2 could be an injector dribble ETC

When you cleaned the maf did you clean the wires ( not the connector plug but should check the contact of the pins ) ?

If you looked up how a vacuum gauge works you`ll know it will tell you of the cam .

Not sure if I'm going crazy or something, but does the 14CUX learn at all? I've partially filled (probably because I'm a little impatient) after about 100kms of driving. Last two fills:
28L/106km (approx 27L/100) and,
17.7L/83km (approx 21L/100).

I haven't changed anything since the previous fill (35L/100).

Either it's learning, or something has fallen into place, or I'm just going nuts.

Quote:

---

Originally Posted by PLR

Rover 14CUX Hot Wire Mass Flow EFI: Service and Troubleshooting

link may be of use .

G`day , when are your plugs sooty is it after a hwy run or at low speed ?

If you haven`t diagnosed when it`s happenening , you need to because it seems like the plugs are trying to help you .

---

Only replace one set so far, and that was after a hwy run, followed by some low speed stuff.

Will have a look after a hwy run and see if things change.

Quote:

---

Originally Posted by PLR

Is it all 8 or only one bank 4 or only one or two cylinders .

8 would be something in either air or fuel as is not enough air or too much fuel .

4 a bank would be electrical .

1 or 2 could be an injector dribble ETC

---

All 8

Quote:

---

Originally Posted by PLR

When you cleaned the maf did you clean the wires ( not the connector plug but should check the contact of the pins ) ?

---

the sensor wires - pulled the MAF off and drowned the little venturi with MAF cleaner.

Quote:

---

Originally Posted by PLR

If you looked up how a vacuum gauge works you`ll know it will tell you of the cam .

---

Sounds like a good idea. Where's the easiest place to plumb into - one of the Plenum connections?

G`day ,

anywhere that gets full vacuum not where the distributor gets it from .

If your plugs are still dark follow them .

The cam can affect economy and if you plugs all had good colour would be worth discounting .

Appears a couple of recent messages seem to have gone missing from this thread... anyway...

Latest fill - 35.3L/136km (25.96L/100).

Re-checked the timing and realised that the advance I had was about 20deg BTDC!!! Brought it back to about 13deg BTDC. Vacuum gauge seems steady and settled at about 18inHg of vacuum at idle. Will keep an eye on it.