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. .

Series or parallel plumbing might be as broad as it is long (probably a pun in that somewhere).. On the one hand if the heater circuit won't flow much volume but has a lot of pressure then series plumbing might be best, on the other hand if the heater circuit will flow a lot of volume but doesn't have much pressure then parallel plumbing might be best.

Seems in practice on most vehicles the heater circuit would flow a fair bit more water if it weren't for the restriction imposed by the components external to the engine (matrix and reducer), so in the case of series plumbing this would point to the matrix affecting flow through the reducer and the reducer affecting flow through the matrix. But on the other hand in the case of parallel plumbing the heater circuit won't flow so much more total water that the matrix / reducer won't each get less flow.

Parallel plumbing may have become the norm because there are plenty vehicles which shut off flow of water through the matrix when the heater is turned fully off or set to the full cold position (like the Honda CRV I'm currently converting which has a mechanical cable'd flow shut-off valve in the engine bay, BMW's and modern Jags that use electronic flow regulators to driver/passenger side individual matrix's, Merc's that use a pulsing solenoid to restrict total flow, some vehicles including some Mercs/BMWs have an electric circulation pump to aid flow at low rpm and can even allow the heater to work for a while when the engine is off). Any vehicle that has such flow metering valves / shut off valves has to be plumbed in parallel.

For sure if we're finding the heater doesn't work as well with one route of plumbing we can take the other route but I don't think it's clear cut. I haven't noticed a drop in heater regardless of parallel or series plumbing on a P38 but that could be because I haven't owned one! Different model 'factory fit' vehicles even from the same manufacturer (eg Vauxhall) and with the same engine / heater matrix use series or parallel depending on the specific vehicle model and year. I have 'repaired' some factory fit Vauxhalls that wouldn't run on gas because the heater matrix was clogged, obviously these were plumbed in series. Dunno what could be read into this but on vehicles that have a heater matrix in the front and another heater matrix in the back (such as my GrandVoyager) the matrix's are plumbed in parallel... But for sure my heater gets hotter just after the throttle has been blipped (rpm increased) than when the engine is sat at idle and I put this down to a flow thing (water pump speed increases with rpm).

Whether series or parallel plumbing is best might depend on all of: model of vehicle, type of reducer, condition of components (e.g. partially clogged matrix or reducer). Series plumbing does bring about the question of whether the matrix or reducer should be first in line for hot water and how hot the water will be to the second component in line under various conditions.

Gilbertd wrote:

I would hope, on a 2002 Thor, it would be sequential, anything earlier would be a nightmare on something that age.

Yes there'd be more negative implications fitting less than sequential on a 2002 P38 than on older models. Because of that and also because the sequential system is likely to be easier to repair I'd hope it was sequential too.

I didn't realise it was a 2002 model, did have a look at his earlier posts (mostly to see if there was more info on type of system), now realise I could have just looked at his vehicle list and seen the VSE is 2002...

Gilbert knows this so this for others info - Etagas is multipoint but isn't sequential. Etagas would have most of the same drawbacks (related to not working as a slave to the petrol system) as any of the other none sequential systems. It is possible to get around the additional issues that arise from fitting any type of none sequential LPG system to a more recent model P38 by adding an AEB OBD Ufix but this still wouldn't make for an LPG system as appropriate as a sequential system. Ufix's read petrol fuel trims from the OBD port and feed an emulated lambda signal back to the petrol ECU to keep petrol fuel trims at zero when running on LPG. But it's unlikely a Ufix is fitted and, depending on year the VSE was converted, unlikely anything less than sequential was fitted. A Ufix isn't necessary at all if the LPG system is sequential, if a Ufix was fitted with a sequential system it would be a sever detriment rather than a benefit.

Best to ask at this point if the Tartarini system is a basic mixer system, Tec97, Tec99, Etagas or a sequetial system?

Most LPG vaporisers use 16mm 5/8" water connections but some vaporisers (including some Bigas vaporisers) use 10mm water hose. If the reducer uses such small diameter water fittings it would of course be best to keep the reducer plumbed in parallel with the heater matrix.

It's unlikely water hose was that stiff when fitted, best advice would be to change any pipes that have gone stiff. I've seen some so brittle it was easy to snap them like a twig... This can happen if gas hose is used instead of water hose, if water hose isn't compatible with the type of coolant, or if hose has been subjected to carrying exhaust gasses (HG problems etc).

Side point - Some of the Bigas 'twin' sequential reducers (effectively 2 reducers bolted back to back using a common water circuit and gas feed but with separate gas outputs which are then usually 'Y'd together) use only a single 10mm water feed. I suppose we could work out the flow rate of LPG needed to produce 400bhp and the cooling effect of vaporising that flow rate of LPG, could compare that cooling effect to the heat stored in water and the water flow rate through the 10mm pipe.. it'd need a greater flow rate than straight calculation would suggest because the heat exchange won't be 100% efficient. I know in practice on a lot of powerful vehicles the 400bhp reducer with 10mm water feed does seem to drop in temperature more than most reducers (with 16mm feeds) when pushed to flow a lot of gas continuously.

No easy way to tell whether they're 2.5 inside, You could just drill the nozzles out anyway.. If they're restricted to around 2.5 inside and you run the same map it won't run much richer than now but if they're closer to 3.0 inside you'll have to lower the numbers in the map, which could avoid your problem.

Or you might want to come back with the info I asked for a couple of posts above first, chance you could just up reducer pressure instead of drilling nozzles out.