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Discussion Starter · #1 ·
Hi,

I have an ancient Renault Espace MkII Alize - 1994.
1995cc 2.0i Petrol Injection - does anyone know if it will be a J6R or J7R Engine?

An 'Old Warhorse' but still uses practically no Oil and is dual fuel Petrol/LPG - running better on the latter.
So would very much like to keep in operation - so useful.

But just recently the Engine has become very lumpy when cold - but smooths out once warmed up.
I had similar once before many years ago - turned out to be just the Choke Sensor.
But this time replacement of same has not cured the problem.

The Engine has also become difficult to start at times when warm needs foot hard down to be sure ( luckily I can start from LPG ) - on Pettrol always starts when cold.

As there seem to be other inputs to the Choke System - I want to run through how that System works.
Does anyone know of a Tech Manual for the Engine J6R / J7R?

I have the Haynes but it is very general - I want to research how the Choke actually operates - any other Sensor Input etc.etc.

Comments welcome.
Best Rgds
 

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There are several versions of fuel supply in this engine. You have to find out which one you have if you want help.

Describe your problem with fuel better then this. What happenes and when, on which fuel.
 

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As it is an injection engine there is no choke as such...unless they have done something weird.

With injection engines the normal system is that the coolant temp sensor sends temp information to the ECU and that adjusts fuel/air mix to suit...richer mixture for colder as a traditional choke would.
The ECU does it with throttle body and injection time.

I'm not sure what your LPG system would use to do the same, depends on how the system/crossover works.

It sounds as though you have changed the coolant temp sensor... which would have been my first suggestion.

Second is crank sensor also known as TDC sensor..... remove and clean.... these do get dirty and don't read as well as they should.... heat can effect..... ignore that if you have a distributer...not certain what you would have at that age of engine?
 

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Those engines came with carburettor, K jetronic and multipoint injection.

LPG may be simple plate for carburettor, "flange" for single point and multipoint injection and sequent.
Only thing it can't be, is LPG on K jetronic.
 

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Those engines came with carburettor, K jetronic and multipoint injection.

LPG may be simple plate for carburettor, "flange" for single point and multipoint injection and sequent.
Only thing it can't be, is LPG on K jetronic.
As OP said it was injection, I am assuming the multipoint from that.
 

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Aaaaa, didn't see.

Still, means nothing for LPG system installed. And that's kind of important in questions like this.
It can be multipoint or singlepoint LPG on it.
 

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Discussion Starter · #7 ·
As OP said it was injection, I am assuming the multipoint from that.
Thank you all for the input - I worked software more than 40 years so used to picking up clues etc and you have given me plenty.
It is a multipoint injection system.

The LPG is just a single point system - squirts LPG into the Inlet Manifold - but it does have a Stepper Motor connected to the Lamda to control amount of input.
Has always worked very well via an ECU that is programmable - that I can get to.
I have had to overhaul the LPG reducer valve for time to time - new diaphragm etc - general clean out.

When running on LPG the petrol pump has continued to operate - although I understand an LPG system can be wired for the pump to be stopped during LPG operation.
I have now rigged it so that I can now stop the Petrol Pump when on LPG - on basis of checking if an Injector is leaking when pressurised by the pump and petrol is hanging around in the manifold - so too much Petrol on next start up.

So as I said it is a multipoint injection system - year 1994 - 1995cc - 2.0i - Model Alize.

Clues are engine is brilliant starter on cold - on Petrol.
Lumpy running until warm - then very smooth - practically no oil being used on a long run.
After running - if left stopped 20 mins will start again on Petrol - but have to put foot well down on Accelerator to be totally sure.
If you miss the start at that point - have to wait yet again - for a Petrol start.
For me it is not electrical - I think it is too much Petrol at start - but why?

I have lifted the Fuel Bar complete with Injectors off the Engine and then turned on Ignition to point where Pump operates.
Figuring to pressurise the Fuel Bar - could see no leaks at Injectors.

Once again thnaks for all collective input.

Best Rgds
 

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Your LPG reducer is leaking.

When it warms up, hole in the diafragm opens and then small amount of extra LPG is not noticeable as much on hot engine.

You can turn off fuel pump but it is better if you introduce one more resistance in the fuel circuit. The one with same resistance as e pump and then fuel pump will work on half power, still instantly available if you run out of LPG.
Use the signal from LPG valve for that and a simple relay.

Restarting warm engine is a pain because you have to much fuel. Pressing the accelerator down to the floor is a way to crank the engine without any petrol injection. Then the engine starts on LPG only.
 

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Discussion Starter · #9 ·
Hi Moxinel,

Thank you for your reply and comments.
It is true that LPG use had moved higher than usual recently which maybe is in line with your comment ref hole in diaphragm.
Replaced it maybe 18 months ago - will take apart and clean - see what is what.

However after adjusting with the small flow adjust screw on the Lovato Reducer - am getting very good mileage for LPG - normal was always circa 250 miles per fill,
Now a bit above that - after adjustment - I am aware of too weak problems so will tweek it back.

The problem seems to be getting worse - in that sometimes I could get a normal start when hot.
Now somply start on LPG all the time - engine has to crank a bit longer to get the Gas through - but never a problem.
I will check out the Lovato and let you know what I find.

Once again - my thnxs.
 

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Discussion Starter · #10 ·
Thank you all for the input - I worked software more than 40 years so used to picking up clues etc and you have given me plenty.
It is a multipoint injection system.

The LPG is just a single point system - squirts LPG into the Inlet Manifold - but it does have a Stepper Motor connected to the Lamda to control amount of input.
Has always worked very well via an ECU that is programmable - that I can get to.
I have had to overhaul the LPG reducer valve for time to time - new diaphragm etc - general clean out.

When running on LPG the petrol pump has continued to operate - although I understand an LPG system can be wired for the pump to be stopped during LPG operation.
I have now rigged it so that I can now stop the Petrol Pump when on LPG - on basis of checking if an Injector is leaking when pressurised by the pump and petrol is hanging around in the manifold - so too much Petrol on next start up.

So as I said it is a multipoint injection system - year 1994 - 1995cc - 2.0i - Model Alize.

Clues are engine is brilliant starter on cold - on Petrol.
Lumpy running until warm - then very smooth - practically no oil being used on a long run.
After running - if left stopped 20 mins will start again on Petrol - but have to put foot well down on Accelerator to be totally sure.
If you miss the start at that point - have to wait yet again - for a Petrol start.
For me it is not electrical - I think it is too much Petrol at start - but why?

I have lifted the Fuel Bar complete with Injectors off the Engine and then turned on Ignition to point where Pump operates.
Figuring to pressurise the Fuel Bar - could see no leaks at Injectors.

Once again thnaks for all collective input.

Best Rgds
ERROR ERROR..

LPG is SINGLE POINT system - not Multi Point - my fault - I apologise.
 

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You said it's a single point, LCS system.

New diafragm on used reducer does not last as long as new reducer.
You got better mileage by adjusting but without reading from lambda sensor you may be driving on lean mixture, not good for engine. If you don't have a waveform, setting is not good.
In fact, the only real adjustment is with exhaust gas analyser.

Starting warm engine depends on the conditions in reducer, how much gas is running through the tear.
 

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Discussion Starter · #12 ·
You said it's a single point, LCS system.

New diafragm on used reducer does not last as long as new reducer.
You got better mileage by adjusting but without reading from lambda sensor you may be driving on lean mixture, not good for engine. If you don't have a waveform, setting is not good.
In fact, the only real adjustment is with exhaust gas analyser.

Starting warm engine depends on the conditions in reducer, how much gas is running through the tear.
Hi,

New diaphragm set on the way will give it a go - let you know what transpires.

Thnxs & Best Rgds
 

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Discussion Starter · #13 ·
HI,

OK - like I said I will be getting the Diaphragm circa Monday next and will fit soonest - even if turns out not that - preventative maintenance not a bad thing.

But one thing I do not understand - and don't get me wrong - grateful for your input and it makes sense
But the warm starting problem is there if the Petrol /LPG Dash Fuel Switch is to either.

I thought if switched to Petrol - there is a 'Cut Out' Solenoid Valve that prevents any LPG Flow whatsoever?
So that Hole or not in the Diaphragm should make no difference?

Usual is to always run with Fuel Switch set to LPG - the LPG ECU set to switch over to LPG at first time to pass 1500 Revs. ( 'Cut Out' Solenoid Valve opens ).
It then stays continuously on LPG - with Stepper Motor regulated by the Lambda Signal.

So in reality the car always starts on Petrol - with the switch over at 1500.

As usual brilliant first time start this morning from Cold - first piston up and off she goes but same old same old when Warm.
Only way to start when Warm is to go for an LPG start by toogling the LPG switch when ignition ON - which over-rides the ECU 1500 Revs stuff.
Allow engine to cool maybe 30 minutes and normal start once more no problem.

Best Rgd
 

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I had that LCS on my car for about 10 years.
Cheap, almost no maintenance, once set does no need adjustment, no injectors....excellent.

Yes, when you turn the engine off, electromagnetic valve closes flow of LPG to the engine.
But LCS reducer is big, much bigger then multipoint reducer. It contains some amount of liquid LPG which evaporates as soon as is it is allowed to expand (tear in diaphragm).

As the engine is warm, it does not need "choke" so injected fuel is minimal.
Even small amount of excess fuel (LPG) makes for rich mixture and hard start.
Again: every fuel injected engine will inject NO FUEL if you press the accelerator to the floor on cranking. That's the way of airing the engine if you flood it.
And your engine starts in those conditions, means that it must be getting some fuel, most likely from tear in diaphragm of LPG reducer.
 

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Discussion Starter · #15 ·
I had that LCS on my car for about 10 years.
Cheap, almost no maintenance, once set does no need adjustment, no injectors....excellent.

Yes, when you turn the engine off, electromagnetic valve closes flow of LPG to the engine.
But LCS reducer is big, much bigger then multipoint reducer. It contains some amount of liquid LPG which evaporates as soon as is it is allowed to expand (tear in diaphragm).

As the engine is warm, it does not need "choke" so injected fuel is minimal.
Even small amount of excess fuel (LPG) makes for rich mixture and hard start.
Again: every fuel injected engine will inject NO FUEL if you press the accelerator to the floor on cranking. That's the way of airing the engine if you flood it.
And your engine starts in those conditions, means that it must be getting some fuel, most likely from tear in diaphragm of LPG reducer.
Thnxs so much for your time.
If you have never been - you would be an excellent software man.
Let you know - outcome.
Very Best Rgds
 

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Once you get the new diaphragm in hopefully will clear the issue.

IT would make sense.
The starting issue when hot and your solution (foot hard down, wide open throttle) was normal for carburetor engines that had been flooded.... loads of air to hopefully blow out excess fuel.
IIRC, LPG is heavier then air so if any leak or the valve not shutting fully the gas is likely to collect and stay in the intake until time enough has passed to dilute/drain. Gas on its own without air (oxygen) will not ignite.
 

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Yes, WOT on fuel injected engine does the same, clear the cylinders with max air and no fuel at all.

LPG is heavier then air and it would stay in the intake plenum if leaking on reducer. Same thing happenes with sequent reducer leaking on diaphragm but there LPG is coming through a compensation tube.
With LCS, mixer is placed just behind throttle blade. Even with engine off, higher pressure of LPG in reducer is pushing it into the intake. As throttle is closed, LPG stays there for a while and then you have trouble starting hot engine, too much fuel.
 

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Discussion Starter · #18 ·
Yes, WOT on fuel injected engine does the same, clear the cylinders with max air and no fuel at all.

LPG is heavier then air and it would stay in the intake plenum if leaking on reducer. Same thing happenes with sequent reducer leaking on diaphragm but there LPG is coming through a compensation tube.
With LCS, mixer is placed just behind throttle blade. Even with engine off, higher pressure of LPG in reducer is pushing it into the intake. As throttle is closed, LPG stays there for a while and then you have trouble starting hot engine, too much fuel.
 

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Discussion Starter · #19 ·
Yes, WOT on fuel injected engine does the same, clear the cylinders with max air and no fuel at all.

LPG is heavier then air and it would stay in the intake plenum if leaking on reducer. Same thing happenes with sequent reducer leaking on diaphragm but there LPG is coming through a compensation tube.
With LCS, mixer is placed just behind throttle blade. Even with engine off, higher pressure of LPG in reducer is pushing it into the intake. As throttle is closed, LPG stays there for a while and then you have trouble starting hot engine, too much fuel.
Hi Moxinel & Dancing Dad,

Thnks for all.
Hi,

Said I would detail when problem solved - interesting - discovery pure luck.

Completely renovated the Lovato Reducer - went well - done before - now very smooth.
But did not solve the problem of bad starting when hot.

After much research - read it might be Car ECU aging - took of Covers to get at Seimans Ref Nos - needed in a hope to find a similar at a Breakers.
2 Relays are housed in with the ECU - 2 layers of Covers deep.
On the Espace at that time - Relays seem dotted everywhere.

One Relay was loose so fixed for it to be anchored.
Tried to start engine - noticed the Petrol Pump did not 'buzz' as usual when I turned ignition on.
Sudden 'flash' of inspiration!
Went back to Relay - 'jiggled- - back to ignition - Pump sprang into life.

Replaced Relay - problem gone - have also gained a bit of preventative maintenance on LPG side.
Still 'nervous' each time I start car - but every time a winner!
Thnks for advice and help with 'morale' when needed.

Best Rgds.
Chaser
 

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Well, fuel problem it was.
Weird is that petrol fuel pump worked every time on cold and did not work every time on warm engine. That was kind of misleading but still, new diaphragm is a pointer to problem somewhere else.
 
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