Think Tank Run Dry on Non Starting 3.9 RRC

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Saint.V8

Dyed-in-the-wool 100% RR Junkie
Full Member
Hello fellow members, I have reached the end of my knowledge when it comes to non starting engines...

Brief History...4 weeks ago was going out in the RRC, topped up with Petrol and Gas, drove to Tesco cash machine stopped engine, cash machine out of order, jumped back in, started, drove to another cash machine, as I went into the car park, it had a rumble strip entrance...as soon as I went over that the steering got really stiff, thought Damn Pump or Belt has gone U/S, then realised engine had stalled. Coasted in parking space, went to cash machine, returned and she wouldn't start.

Checked coil connections, all good.....checked cap, all good....checked leads, plugs, rotor arm, ignition amp connections...all good.

Called RAC, he arrived check spark....a bit weak but should be enough to at least do something, tried Easy Start, nothing. Removed coil and checked...found ok.

Recovered home, since then have replaced, cap (OEM), rotor arm (OEM), leads, plugs and coil (Bosch). Still nothing.

Checked all over for loose/disconnected connections...none.

Remade all connections to coil, still nothing.

Followed the RRC workshop Manual for 1991 Lucas Hotwire to test the various inputs to the ECU, all reading as specified.

Distributor has been out, stripped, cleaned and replaced, air gap set and timed with strobe (allbeit only turning over on starter!)

Fuel Pump relay and ECU relay replaced, Fuel Pressure checked with gauge, holding at 38-40psi as per the book, no reduction in pressure over a 1 minute period also as per the book.

Turned her over for approx. 30 seconds, quickly whipped out the plugs to check for fuel, plugs dry. They don't even smell of petrol. Seems like the injectors aren't opening.

She was running on gas at the time of the stall, and always starts on petrol, I cannot find a way of starting on gas, the system is (as far as I can tell) a Lovato M198 Single Point system.

I am now stuck, it would appear the injectors aren't opening. This I assume is the problem. Any help is greatly appreciated.

The ECU takes a signal from the -ve side of the coil trhough a resistor to indicate the engine is running/turning overand should pulse the injectors accordingly, this cable has been checked back to the ECU and is as per the book.

The Gas system also takes the same signal to indicate the engine is running.

When running on gas, I think there is an 'injector Emulator' that feeds a signal back to the ECU to fool it into thinking that the injectors are working when they aren't, as the gas system shuts down the injectors when on gas. (this is what I believe happens, as I can't find any information on the Lovato system or how it was installed)

To throw something into the mix, the fuel pump relay was bypassed (not by me, by the gas installers I assume) so the pump is continuous, but the fuel pump relay still clicks on for a second or two at the ACC position on the ignition then off (as it should) but doesn't click back on when the engine is turning over, could this be a sign that the ECU doesn't think the engine is turning over when it is and as such not opening the injectors, indicating a fault in the -ve signal from the coil even though this has been checked as good?

Could it be the ingition amp is shot? even though I am getting a spark, allbeit a little weak, but the signal as the coil switches to earth is a little weak?

Or is it the ECU has gone down the tube all of a sudden?

Is the Injector emulator fooling the whole thing and stopping the ECU from opening the injectors?

HELP!

It has been 4 weeks without the RRC and it hurts.....

I am so sorry for the length of this post, but it is a culmination of 4 weeks, every evening, rain or shine to try and figure this out and I know the more detail the better sometimes....sorry.

Any ideas??

Bbest regards,

Anthony.
 
Just read recently read that "IF" your RRC had a little backfire then the ECU won't allow you to start again. Have you tried swapping over your ECU with a known good one to see if it needs to be reset or cleared?
Sounds like there's lots you have done to find the prob but it may be something very silly. Try go over the exact way it came about that it wouldn't start, even the slightest little detail may help the solution.

DC
 
Sounds like there's lots you have done to find the prob but it may be something very silly. Try go over the exact way it came about that it wouldn't start, even the slightest little detail may help the solution.
Sounds like Dc might be right seeing as the problem started by going over the rumble strip-but it could be a a loose wire anywhere!
Not much help but it sounds like your looking in the right places!:confused:
 
Hi,

I am sure it is probably something very silly, but I'll be damned if I can find it. Not sure why it cutout in the first place, one minute sweet as a nut, the next dead, nothing, nada, zip.

It is really frustrating, not had the vehicle very long, and was the result of months of begging the other half that I wanted another Range Rover...

(Had an '88 3.5 Vogue SE for 3 years - Sold as project as failed MOT to badly for me to do myself and didn't want to scrap it, '96 P38 4.6 HSE - Sold due to employment location change, '97 P38 4.6 HSE - Got it once location moved back closer to home, Partners Mini Classic died P/Ex'ed P38 for new Beetle for her)

Missed having the use of a Range Rover so got this one, ran beautifuly, never missed a beat, never backfired, quiet as a mouse until you blipped the throttle and got that most amazing sound that only a V8 can produce, I was in heaven.

Now this, I can't believe it....Please help...I can't think of anything else to try...

All the very best,

Anthony.
 
Depends on you LPG system, but to start mine on gas you do the following. Turn ignition on and move the switch to petrol position. After a few seconds move it back to Gas position and then start. It takes a bit starting when on gas so make sure battery is fully charged.
 
Quick update,

Tried forcing an emergency start on Gas...nothing, I don't think there is a Gas Start option on this system....

Checked fuse links...all good.

Removed all dash panels....doen't look like there is an Injector Emulator fitted, it must cut power to the injectors via one of the relays mounted on the bulkhead...changed both for good ones....still nothing.

Don't suppose anyone lives close to the Woking area who has an ECU we could try??

Keep up the good work,

rgds,
Anthony
 
Hello Again,

The inertia Cut-off switch has been removed by a previous owner or the Gas Installers...cos it isn't there, the wires have been jointed together....this was one of the first things I checked for.

Checked for a positive feed to the injectors which is there, so the ECU isn't switching them to earth or the Gas system has interuppted this signal, not sure how to check this yet..!!

One curious thing though, running back through some of the checks on the LT wiring on the coil.....

The book states that the voltage with ignition OFF should be 0 volts between Battery Positive and Coil Negative...switch ignition ON, this should still read 0 volts, crank the engine and the voltage should rise.

When I checked these readings I am getting 12 volts between battery +ve and coil -ve with ignition OFF. Switch the ignition ON this then read 0 volts, crank the engine and it rises as it should. Very interesting....any ideas?

Does this indicate an ignition amplifier fault? Also I seem to have 2 amps...one on the dizzy and one mounted on an ali plate with the coil?? Again any ideas why this is?

thanks so far for all your assistance.

Anthony
 
Ok, now I am confused....

The positive feed from the ignition switch (white wire to coil +ve) grounds to earth with ignition OFF and reads 0 volts.....if this is a feed from the ignition switch, why does is go to earth on ignition OFF....?

With ignition on, this reads 12 volts.

When connected to the coil and ignition OFF, 12 volts can be read from battery +ve to coil -ve because this white wire goes to ground with ignition off, and seems to ground through the coil???????

With ignition ON the battery +ve to coil -ve reads 0 volts as it should becasue the coil is being grounded via this white wire....any ideas why this is so??

Should I run a ignition positive wire to the coil +ve and see what happens..??

HELP...?? this is doing my nut in now.....!!

Rgds,
Anthony.
 
It's bank holiday and we're all out playing ;) The second ignition amplifier sounds like an RPi A&R power amp - boosts ignition to about 50kV from 35kV. With this fitted you advance the ignition timing 14 degrees so it runs better on gas, but when on Petrol the amp retards the spark by 14 degrees. If this is not working, I would imagine that trying to start with an extra 14 degrees of advance is going to cause a problem, but then again it could be many things. Just my 2 pen'orth
 
Hi Saint.v8,
Have you got a manual or Haynes for this Classic ? RAVE is available for free download.

If you read up on checking the dizzy it will explain how the electronic ignition works.
If the ampifier fails you will not get any spark, same for the pick up coil in the dizzy. The reluctor plate produces a pulse to effectivly ground the negative side of the ignition coil and the amplifier ony produces a larger pulse.
This is described in detail in the Haynes manual, and also has a check list to systematically check for faults. I think it is a copy from Rovers manual.

See for a little more help Range Rover Remedies

Is this problem just on gas and your car runs well on petrol? If it is, then it is unlikely to be a problem with the voltages othe coil.

Beware of non genuine ignition components as they cause peculiar faults.

Keep plodding on you wil get there eventually

Fred
 
Many thanks for all your support on this....

I do have the Haynes manual and have been through every test they describe, I also have the RAVE system and EPC also....done all those tests too....

everything I have tested indicates that there should be no reason why it shouldn't start....except that the injectors aren't opening etc....

I am going through everything systematicaly to eliminate everything possible....and according to the book with ignition OFF there should be a reading of 0 volts between battery +ve and coil -ve....this I checked and I am getting 12 volts....until I remove this white wire from the +ve side of the coil.

With ignition ON this should still read 0 volts....which it does....so I metered out this white cable (+ve supply to coil) to earth with ignition OFF and it reads that it is earthed.....switch ignition on and volt meter this to earth and you get 12 volts....so why does it revert to earth with ignition OFF.....??

Get your thinking caps on chaps...this is a toughy..!!!!!

rgds,
Anthony.
 
Hi Fred,

Nope...won't start on Petrol....the gas system is setup to start on petrol then change over to gas once engine speed goes over 1500-1600rpm.

I have tried the various emergency gas start options mentioned here but I don't think the system fitted allows this.....I think it was fitted back in the mid to late '90s looking at the components..!!!!

This is a baffling one....I have owned Range Rovers for the past 8 years and this is the first time I have had one that will point blank refuse to start....and I am starting to run out of things to test/check/change/try in order to get her working again....

All ideas and comments welcome.

Rgds,
Anthony.
 
Thanks for the input Tervueren, but I find it hard to believe all 8 injectors would get blocked at exactly the same time, because when she stalled it happened all of a sudden, not hiccup, cough or misfire...it was as if someone had switched the ignition off.

Also, only the week before I had completed roughly a 100 mile run on petrol...(cos I run out of gas!) and I always ensure that atleast once every two weeks I run her on petrol for a day to keep things clean.

Once again many thanks.

Anthony.
 
Thanks for the input Tervueren, but I find it hard to believe all 8 injectors would get blocked at exactly the same time, because when she stalled it happened all of a sudden, not hiccup, cough or misfire...it was as if someone had switched the ignition off.

Also, only the week before I had completed roughly a 100 mile run on petrol...(cos I run out of gas!) and I always ensure that atleast once every two weeks I run her on petrol for a day to keep things clean.

Once again many thanks.

Anthony.
Thats what I get for not reading the whole thread :eek:
Still bet it's lpg related though, is there a way of disabling the lpg system ?
 
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