rangerovers.pub
The only place for a coil spring is up Zebedee's arse
Member
offline
1356 posts

Would expect readings from Testbook to be slightly different to readings from the LPG ECU anyway, not that there are many of the same type of readings to compare between the two. You won't be able to see gas pressure in Testbook.

Where's this.. I'd guess maybe near Tanhill or Holmfirth? I sometimes go for a drive around Tanhill and to the highest pub in England in summer.

Years ago I bought a BMW750 from Paignton, Devon and set off from Yorkshire to collect it in a Volvo with a rather large car trailer on the back. Stupidly I followed Satnav, which took me down some really tight country lanes with very sharp bends and a river ford. It was the early hours of a very cold morning when I got to the ford, had to take my shoes and socks off to check depth before crossing. Made the crossing then at the other side of the ford was a steep wet hill, front wheels kept spinning all the way up. Last time I'd use Satnav for a trip when towing and last time I'd want to pull something so heavy such a distance using the wrong type of vehicle lol.

Morat wrote:

that and you're not allowed to jump the queue ;)

I haven't forgotten you mate ;-)

@Dhallworth - The differential pressure shouldn't be as high as 2.47 bar, you will have problems if that reading is true. If the pressure is really as high as that it'll point to a problem with the reducer. If the pressure isn't really that high (yet it reads that high) it 'll point to a problem with the pressure sensor, loom or ECU.

What happens to manifold pressure when running on petrol? Were aircon, lights, etc on? In park or drive? I ask because most AEB systems on P38 V8's read just over 0.4bar manifold pressure at idle with warmed engine, if your manifold pressure drops lower when running on petrol it's because the engine is struggling more to run at idle on LPG (ICV opens more to keep rpm at idle). If that's the case it could be that even with half decent calibration and injectors that are in good working order the injectors are still giving inconsistent fuelling due to high pressure (as mentioned above). The pressure sensor is really two pressure sensors in one (manifold / gas), a problem on one sensor may or may not affect the other sensor, as sensors get old they sometimes show slightly incorrect readings but that doesn't always affect good results. As ECU's age the AD converters and/or reference voltage to sensors can see the ECU show slightly incorrect readings, again this doesn't always mean an immediate ECU replacement is necessary.

Yes I install and repair vehicle LPG systems for a living, could sort it if you like. But you could be closer to having fixed it yourself already than it seems, hopefully the new cable will work and point to an easy fix such as low reducer pressure, in which case we'd hope turning the pressure adjuster on the reducer will bring pressure back up. That said I wouldn't have bothered rebuilding a Tartarini reducer if the initial problem was low pressure, the kits will repair a leaking reducer but are less likely to repair a reducer that failed on pressure, they don't include all internal bits or the housing... and it seems whatever problem you had before the rebuild was the same problem you're having now?

Two vehicles here for repair at the moment: Supercharged Rangerover with a BRC system just came in which takes a lot of cranking when it's been running on gas, so I'll be looking for a leaking reducer diaphragm / petrol return which continues to dump petrol pressure when the engine is switched off / poor calibration on that one. Merc E500 with LPGTech, Antarctic reducer, V30 injectors with the same long cranking problem, already found the reducer on this one is leaking gas into the manifold and started fitting a new reducer.

V6 software will usually work on anything that V5 does, there was quite a change in terms of compatibility between V4.X and later versions with one of the biggest changes around V4.7 for most AEB stuff. 2005 Is quite old, I'd expect V6 to work but if it doesn't you might need pre V4.7 to work, maybe even V3.X. That said, Tartarini version numbers didn't always follow general AEB trends, the software works in a slightly different way too.

The interface setup you tried may have only 3 wires on the serial side?

Gilbertd wrote:

I can't remember if the pictures of the connections are of the plug on the cable or the plug on the ECU. Easiest way to check if you have a Leo/Millennium is to identify the 12V pin and work the others out from there.

Your diagram shows pinout looking from the rear of the interface cable plug, or to put it another way the diagram shows pinout looking at the LPG ECU's plug from the front socket end. I just compared to one of the AEB interface adaptors I linked to above.

As OB said you'll know when you can see readings but it'll probably need the reducer output pressure turning up.

Early software might need low com port numbers, later software usually works on just about any com port. Early software may need com port selection.

Depending on age of ECU you might need early / late software. Latest software is version 6 and is the most compatible version (works with most year ECUs unlike say V5 which is less likely to work on very early or very late ECUs) so V6 software is a good bet.

Pulling the LPG ECU fuse can sometimes sort connection failures (after putting the fuse back in of course). Molex pins soon get corroded if exposed and can even snap off sometimes leaving the snapped pin in the female end. You'll have noticed in Gilbert's diagram that the Tartarini Molex is pictured the other way up to the other system Molex. Some interfaces (mostly out of those that use USB to serial dongles before the actual interface but also some USB ones such as ESGI's own brand cable) which work OK with Leonardo's won't work with sequential systems, these tend to have 3 wires to the serial connector at some point in the chain as opposed to 4 wires.

OK thanks Gilbert.

I wonder who converted it, someone must be sweating! No worries, I always make triple sure with fuel returns lol!

On The Sun link there's talk of the interior looking burned out

Can anyone tell if this will be a BMW or Jag engine'd model?

If Jag engine'd I wonder if under bonnet petrol return piping has come off..

Hehe I thought Gilbert might post with wiring diagrams, nice one ;-)

Can see on the diagram how it's possible to wire a single Molex plug to work with both the usual AEB connection and the Tartarini connection, you just need the 2 additional pins on the 2nd row connecting to work with Tartarini.

If you bought the AEB cable you'd need the adaptor too.

As said, you can use your cable but you'd need to make the mods I talked about. If you look at your interface Molex and your LPG system Molex the pinouts don't match up, you'll have a couple of wires that connect when you plug the Molex ends together but will need to (at least temporarily) hardwire the couple of wires that the Molex connection doesn't make (because Tartarini Molex pinout is different to other AEB system Molex pinout).

Or you could buy another 8 pin Molex connector and wire it to your LPG system, that way you'd wire the new Molex plug the same as your Leonardo system's Molex plug so and it would work with your existing cable.

Clue to me is in where you said your cable works perfectly with your Leonardo and Millenium ECU's - Those ECU's will have the 8 pin (only a few pins used) Molex type connector as opposed to the later AEB type 4 pin Supaseal connector. Tartarini systems that use the Molex connector have a different pinout on the connector (some of the pins on the second row are used as opposed to other AEB systems that use pins all on the same row).

Your cable will work if you just chop into 2 wires on your interface (the wires that are not connected by the Molex connection) and the relative same wires on your LPG system's interface connector cable - just make a temporary patch using bits of wire to make the connections that your Molex connection isn't making. You should be able to compare wire colours to your Leonardo / Millenium system. Or instead of messing with USB to serial dongles, chopping into wiring or buying a cheap supposedly Tartarini specific cable you might prefer to buy a proper AEB USB to Supaseal cable and a AEB Supaseal to Molex interface adaptor. The Molex connector on the adaptor is wired for both normal AEB type Molex connectors and Tartarini type Molex connectors.

Morat will be right, it seems the software you're using expects to see a USB dongle plugged in to allow the software to work. USB dongle has nothing to do with your interface cable. Which begs the question - What Tartarini software are you using and on what version of Windows? The correct Tartarini software for your system shouldn't need a USB dongle to run (though a dongle could be plugged in to open up a few more options such as temperature correction) but even correct software can do funny things if running on the wrong version of Windows, sometimes if running on certain versions of 64bit Windows.

If nobody else beats me to it, later on this evening I'll post a Dropbox link to software that should work.

As OB said the LPG map shouldn't have changed, if it has changed it'll probably be because there's a problem with the LPG ECU.. They can lose mapping info when the battery is disconnected when they're old, so if the problem's as simple as that a remap may be an almost total cure (save for the fact the map would be lost next time battery is disconnected). The ECU losing mapping info is unlikely though, far more likely there's an issue with the reducer, injectors, pressure sensors, temp sensors, in which case mapping won't fix it but the interface will allow you to see readings and (likely) allow you to switch individual cylinders back to petrol (to find problems with individual LPG injectors).

Rcutler wrote:

I am on there and saw this early...

https://www.pistonheads.com/gassing/topic.asp?h=0&f=&t=1607892&d=13880.58644

Referring to the AAA1 number plate on the Rangerover?
Since you pointed that thread out I've posted on it - I once converted a big red modded 2010 Dodge Ram pickup truck to LPG, reg P11OCK lol.

'P38 Appreciation' thread on Pistonhead forum (https://www.pistonheads.com/gassing/topic.asp?h=0&f=91&t=1712581)
Found the link just by searching for 'LPG'.

Happy New Year!

Yeh I wouldn't disagree with any of that, I think installers got used to fitting in parallel because parallel will work on just about anything.

Nearly used an electrical analogy myself... just that in the case of 2 resistors in series for a given flow of electric the resistor with highest resistance would be heated most and the second component in direction of flow would be unaffected by heat dissipation by the first lol ;-)

Off point a bit - On the recent BMW745 I converted I could have taken the easy route of plumbing the reducer in series or in parallel with the 10mm oil cooler / alternator water feed and I know some installers do that but I plumbed it in parallel with the 19mm heater pipes... the short pipe from the rear of the engine that goes through the bulkhead to the matrix is a bugger to access. Some vehicles have a water shut off solenoid on the engine itself (such as 4.0 V6 Cologne's in Ford Explorers, more recent Merc V8's / V12's), got to disable the shut-off on those or regardless of parallel or series the reducer will get cold when the heater is off. Disconnect the vacuum pipe on Explorers, remove the plunger or disconnect the electrical feed on the Mercs depending on type. .