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1996 Range Rover P38A
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146 Posts
Discussion Starter #41
Have you cleaned your O2 sensors?
No I havn't, but I have had them out. I did youtube about cleaning o2 sensors and I do have a sonic cleaner, but I chickend out.
I thought there was a high probability I'd ruin them so put them back in.
I'd also been warned about aftermarket sensors, just don't buy them and the NGK's are £100 a piece.
But remember, my issue was only on startup, as soon as we were on closed loop everything was fine, so I had dismissed sensors by and large.

When I found the fuel pressure regulator leaking I thought I'd found it, but no.

However, the Evap purge valve is looking good. With the valve stopped off the trims have returned to 1.25 and havn't moved for 5 starts now, it's looking good.
If I get time I'll pull the purge canister off and see if it's full of fuel.
 

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1996 Range Rover P38A
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146 Posts
Discussion Starter #42
Well, I got the purge canister off but I don't how it functions. I thought these were sealed systems, but this is open to atmosphere. If you blow down the pipe marked 'PURGE' air comes out of 'TANK' but more air comes out of 'AIR'. This can't generate any vacuum in the tank because it's an open circuit, is mine an old design?
286926
 

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  1. Just asking a silly question but has anyone put green injectors in it ? My gems got yellow yet my Thor got green ( same as my 300hp 940 Volvo) just wondering if changed ?????
Nothing to do with this topic, but yes, the injectors are different. GEMS uses 2.5 bar fuel pressure, same as previous Lucas systems. Thor = Bosch, different injectors designed to operate at 3.5 bar. A lot of Bosch stuff is used across brands, so could well be your Volvo has the same injectors.
 

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1999 P38 vogue
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146 Posts
No I put green injectors in due to putting bigger turbo etc had 310+bhp 2.3 4 pot
 

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1996 Range Rover P38A
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146 Posts
Discussion Starter #45
I've found that mine has what's known as the pre-advanced EVAPS system, AKA a complete waste of time. It's an open vented system, it's completely unmonitored and if the purge valve sticks or goes tits up you won't know a thing.

In my opinion an open vented EVAPS system is worthless, so i'll cap it off .

On mine the tank cap is still vented and the charcoal canister is also vented so there can't be any pressure buildup problems.

When i tested the purge valve it was working, that doesn't mean to say it works all the time and it doesn't mean it doesn't stick. The only code attached to this is if the coil burns out and goes open circuit. If it sticks open you've got an open pipe to the fuel tank and the manifold vacuum will keep drawing the fumes, i suspect that's what has been happening to me.
I'm not going to post ITS CURED!! just yet, i'll give it a week, but it's looking good.
 

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sounds promising
 

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1996 Range Rover P38A
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146 Posts
Discussion Starter #48
I would be looking at the stepper motor, its most likely worn out
What stepper motor are you referring to, the AIC, Air Intake Control valve? It's been out, cleaned and appears to be working as it should. If the AIC was faulty i'd expect poor idle, high or low. On the nanocom the idle speed matches the target idle speed to within a few rpm. The problem i have is excess fuel.

My problem persists, i've disconnected the LPG vacuum line in case either of the diaphragms are leaking gas into the vacuum lines, but i'm also trying to work out how to use the Nanocome's live stream data to record, i've had to send for a new card reader for my PC, as mines to old for windows 10.

If i can record the data, graph the data using the CSV viewer, i can study the chart and post it up as well.
 

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What stepper motor are you referring to, the AIC, Air Intake Control valve? It's been out, cleaned and appears to be working as it should. If the AIC was faulty i'd expect poor idle, high or low. On the nanocom the idle speed matches the target idle speed to within a few rpm. The problem i have is excess fuel.

My problem persists, i've disconnected the LPG vacuum line in case either of the diaphragms are leaking gas into the vacuum lines, but i'm also trying to work out how to use the Nanocome's live stream data to record, i've had to send for a new card reader for my PC, as mines to old for windows 10.

If i can record the data, graph the data using the CSV viewer, i can study the chart and post it up as well.
Its on the throttle body
 

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1996 Range Rover P38A
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146 Posts
Discussion Starter #51
Although the LPG diaphragms looked in good condition, I took them apart. One has clearly been leaking gas. This is not good as gas leaking here would go straight into the plenum chamber giving the symptoms I've been experiencing. I'll order new ones.



287025
 

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1996 Range Rover P38A
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Discussion Starter #52
The LPG is still disconnected, the problem persists.

Because I can see the fuel pressure decay with the ignition off, I convince myself I have a leaky injector, despite the fact I'd had them tested.

I also find an injection manifold complete with fuel rail and injectors on flea bay, click buy.

I decided to pull my fuel rail out and test it. I perched the fuel rail over two sheets of paper and pressurised it (it's still connected to the car). Nothing, not a single drop.
I keep pressurising it, watching the pressure slowly fall away. I don't know where its leaking but it's not coming through the injectors.
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Admittedly i didn't go back and search the start of the thread, but have you checked the Fuel Pressure Regulator - and that yellow hose, especially - is fuel leaking into there? did you have a non return valve on your set-up ie are you positive the input side of the fuel rail is not allowing the fuel to run back towards the pump?
 

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1996 Range Rover P38A
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146 Posts
Discussion Starter #54
Admittedly i didn't go back and search the start of the thread, but have you checked the Fuel Pressure Regulator - and that yellow hose, especially - is fuel leaking into there? did you have a non return valve on your set-up ie are you positive the input side of the fuel rail is not allowing the fuel to run back towards the pump?
That fuel regulator that you see is not in service, it's just being used as a fuel rail adapter to supply a remote fuel pressure regulator because the the original was indeed leaking.

When testing the fuel injectors in situe I did prove that fuel was leaking back to tank but I can't see how that can cause me a problem, unless I'm missing something?

I do have another theory but I shall prove it before posting, if I'm right I'm going to look like a right idiot
😥
 

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1996 Range Rover P38A
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Discussion Starter #55
We're still all in bits at the moment but this is the new fuel regulator.
I drilled the guts out of the old one so it wouldn't impede the new one, but it still does, so I'll make a new fuel rail adapter and get rid of the old fuel regulator completely.
287405
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I remember now - this was the one with the variable FPR. I'm guessing $$$'s, but if the old FPR was faulty, why not just replace it with a pattern part? IIRC the GEMS has an in-line NRV, and the Thor has one in the fuel pump. I'd probably have to sit down and think why the engineere put them there in the first place, and the precise consequences if they're not working, but if I were you I would just replace them as God intended
 

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1996 Range Rover P38A
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Discussion Starter #57
I remember now - this was the one with the variable FPR. I'm guessing $$$'s, but if the old FPR was faulty, why not just replace it with a pattern part? IIRC the GEMS has an in-line NRV, and the Thor has one in the fuel pump. I'd probably have to sit down and think why the engineers put them there in the first place, and the precise consequences if they're not working, but if I were you I would just replace them as God intended
I didn't replace the FPR with a pattern part because i don't trust them, the FPR fitted was £30. My original FPR was pushing out 40 PSI when it was working properly, which i thought was too high. I liked the idea of been able to adjust the pressure, to experiment and see what happens, and as you stated, get closer to the design spec.

I'm going to have to dig into where the NRV is, and why it was fitted. i'd have thought it was just good design 'best practice'.

But we have an electric fuel pump so the pressure is back the instant you turn the key, hence i couldn't see a leaky NRV causing a problem.

As a design feature, a pressure regulating device with a larger diaphragm is going to be more stable than a much smaller one. The P38's is tiny but there's simply no room to fit a larger one, but you could if you moved it.
 

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1995-2002 Range Rover P38A
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Don't forget the system is designed to keep the fuel pressure at a certain pressure above manifold pressure, so as throttle position changes so does fuel pressure.
 

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1996 Range Rover P38A
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Discussion Starter #59
Don't forget the system is designed to keep the fuel pressure at a certain pressure above manifold pressure, so as throttle position changes so does fuel pressure.
Yes mate, the FPR i fitted was of the 'rising rate' type.
 

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1996 Range Rover P38A
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Discussion Starter #60
Ever wondered what's inside a FPR?

Although I couldn't find any damage to the diaphragm its obvious from the resinous gloop its been leaking for a very long time.
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