LPG Hell

[j999dpt]

Hello could you guys help me i have a '97 p38 4.6 hse and want an lpg kit do i need sequencial ? do i need to have the ECU chipped? whats the best kit?

im so confused by all ive read and been told by various companies.

thanks for your help.

[geoffbeaumont]

Hello could you guys help me i have a '97 p38 4.6 hse and want an lpg kit do i need sequencial ? do i need to have the ECU chipped? whats the best kit?

im so confused by all ive read and been told by various companies.

thanks for your help.

No, you don't need a sequential kit, although they are better. They're also more expensive though, so you have to judge whether it's worth it. If you're ever likely to move the kit to another vehicle a venturi system is pretty much non-destructive as there are no injector ports cut into the inlet manifold. Venturi kits are prone to backfires and rough idling, though, especially if you're ignition isn't in A1 condition (you aren't cursed with a distributor which is a good start). Plenty of people have perfectly satisfactory results with venturis, but having had one I'd personally shell out for a sequential system.

On older V8s the ECU only controls petrol fueling and definitely doesn't need to be touched - on yours it may control ignition timing which needs to be adjusted (most systems just advance the ignition timing across the entire range, to a compromise between petrol and lpg - the best solution is a completely different ignition map for each fuel, but that's probably beyond the scope of what you're looking at). Can someone who knows the P38a better than me chip in?

I've no idea what the best kit for a P38a is (or even what's generally considered best at the moment).

Tinley Tech seem to have one of the best reputations in the business and are generally very helpfull (based on one dealing with them and comments on this forum). If you fill in your profile someone may be able to recommend a reputable specialist in your area.

[j999dpt]

thanks thats good advise.

with regard to the ECU what you said make sense now. the reason i asked about the ecu is i spoke to RPI engineering and they say their chip is advised, (im not saying there wrong in fact it makes perfect sense) but what confuses me is that no one else talks about re mapping and unlocking set timing perameters within the ecu. i assume this is because most people put on sequencial kits that work ok but not as efficatly as they could because the timing could be advanced more for LPG.

[geoffbeaumont]

thanks thats good advise.

with regard to the ECU what you said make sense now. the reason i asked about the ecu is i spoke to RPI engineering and they say their chip is advised, (im not saying there wrong in fact it makes perfect sense) but what confuses me is that no one else talks about re mapping and unlocking set timing perameters within the ecu. i assume this is because most people put on sequencial kits that work ok but not as efficatly as they could because the timing could be advanced more for LPG.

I'd ask them exactly what the chip does. Does it adjust the ignition timing or is it for improved performance on petrol (probably a waste of money for you - I'm guessing you don't intend running on petrol much)?

You need to find out for sure whether the P38a ECU controls ignition timing or not (it may be a seperate unit), and what other installers do about it - without adjusting the timing performance and economy on LPG are likely to be decidedly lacklustre.

You really need some opinions from someone who runs LPG on a P38a - I'm extrapolating from my experiences with a venturi kit on a classic, which isn't ideal.

[paintman]

Can I suggest you look at the LPG forum in the message boards section of http://www.lro.com and in particular the comments by Cruiser.

As has been said, on the early EFI classic, you can physically remove the ECU from the car & run on gas.

Certain companies are very fond of peddling their own 'special and vital' gizmos.

[David Sparkes]

Thanks Paintman, plenty of posts in there.

I only have secondhand experience of LPG on a 38A petrol, and my understanding is that the modified ECU, which is compatible with petrol running as well as LPG running, is there to minimise the blowpack potential of a venturi system on these engines.

By blowpack we mean an internal explosion with enough force to shatter the air filter box, and occasionally damage the bonnet. The mass air flow device can also be destroyed. If this happens once, I understand the repair costs outweigh any savings gained by the initial fit of the simpler system.

As a broad brush answer, I would read up on the Iwema site, and contact Hugo, of that site, for people in the UK who are using his kit, and are near to the enquirer. Gordon Finlay is good, but he is in one corner of the UK, so out of reach of a lot of people; nice area for a holiday though!

HTH

PS, If it helps, I used the Search function on the LRO Message Board, as they call them.

'38' found nothing.

'P38' + 'Search all terms', + LPG Forum only, + Display results as 'Posts', produces some promising looking returns, that cover MPG and fuel costs, as well as the technical detail.

From a historical perspective (I haven't read his later posts) Cruiser always stated strong opinions on the 38A, but didn't run one, although he did move from 'I would never own ...' to 'I might own ...'.

I didn't always agree with his opinions, but only partially because they were not based on direct 38A experience. Make your own judgement, because sometimes 'you are wrong' can mean 'I didn't want to hear that, go away'!!

[Drakes]

I have run a 98 4.6 on LPG for about 70000 miles now and have been very impressed with it. In the past I had dealt with Mark Adams (V8 genius) so I asked him to recommend a system, his answer, it needs to be sequential to avoid the risk of back fire as mentioned above. Two systems he suggested of equal quality were AG (made by Nicholson Maclaren) and Prinz(not certain of spelling). I went for the AG as I found a local dealer that I liked when I went to speak to them (they also build drag racers that run LPG and their work is so neat and tidy it has to be seen). The AG system has its own ECU that works with the vehicle ECU (I don't know how I'm not up on that sort of thing) which means that, although there is no need to, if you at some later date decide to "chip" your main ECU it links with the LPG ECU aswell.

After running it for about 10000 miles I went to see Mark and had him remap the vehicle ECU and just as he said I got the exact same improvement on LPG and petrol. I run on LPG nearly all the time but sometimes I travel to north Scotland where I end up using a bit of petrol and you can not tell the difference when driving it.

Please note these are my views as a user and not as e mechanic/fitter.

I would highly recommend speaking to Mark weather you go for LPG or not he is such a wealth of V8 knowledge and can remap your ECU to suit your particular driving style. He is in the mags as Tornado systems

[Ally V8]

Another make of LPG kit you could consider is Romano,I have several customers using their kit with good results.There is no way I would recommend a cooker ring or venturi system on a P38.I have just ordered a new airbox and inlet duct for a 99 4.0 with a dodgy cooker ring system - the old one is blown to bits.The airflow meters dont like backfires either and the £50 ebay ones arent much cop.There are two main areas that give problems,1 is the fact that few systems are set up properly,2 is that the vaporiser hoses 99% of the time have poor quality fittings and leak coolant.

The setting up needs more than a few minutes going through the autocal prceedure in the LPG software,really the only practical way to do it is to scope the oxygen sensors to get close then fine tune the LPG to get as close to what the petrol fuel fuel trims do under all conditions.This is not a 10 min job,but when its done the owner is always amazed how well the LPG works,usually commenting that they cant tell what fuel the engine is running.

Another issue is that the LPG kit needs a service now and again but most owners carry on till the engine hardly runs on LPG before doing anything about it - most of the systems go lean when they wear so overheating is a distinct possibilty - esp if its losing coolant too.

This all may sound a bit negative,but I just want to point out what I see on a daily basis - but it can be done properly and work very well.The main thing to look for is a well recommended local installer,and then ask what proceedures they use for tuning.

Gordon Finlay is very good in this respect,if you are close to him.

[j999dpt]

thanks ally V8 im building up more of a picture now, sorry just to clear up your last post are you saying that venturi systems are ok if set up correctly ? or they are not very good at all.

like you say i want the LPG to run really well thats why i want to get the ECU sorted and get the right kit.

ive seen this its a full ECU map with security unlock to allow the engine to adapt to LPG. what do you think, im going to contact Mark Adams to see if its compatable with all LPG kits, or what one he recomends.

http://cgi.ebay.co.uk/V8-Land-Rover-Engine...Q2em118Q2el1247

cheers

[Ally V8]

If you want to do this properly,DO NOT use a venturi system - go for a sequential system.The Tornado chip is fine if you really drive hard with lots of revs and wide throttle openings but otherwise dont bother.Top notch maintenance of the LPG and ignition system is far more important.

[FridgeFreezer]

RPi are very good at selling you what they have, it doesn't mean it's right. The stock ECU on yours controls the timing which means their usual box of tricks for distributor engines won't work, hence the "you've got to chip it" advice.

Sequential LPG systems will work more nicely than venturi (which as has been said, is a tarted up gas ring) but there are still bodges out there as many of them simply hijack the injector signals from the main ECU to fire the LPG injectors - cue many evil little scotchloks in your engine loom just waiting to cause trouble.

I don't know what the numbers are on all this but it would be remiss of me not to mention MegaSquirt, which could be a similar cost to a chip but would give switchable ignition maps and other groovy stuff. It's not plug-n-play but you're not shelling out for a random black box which may or may not be right for the job.

[Ally V8]

Wondered how long it would be,but its not so easy when you need to communicate with a BECM,ABS ecu,Autobox ecu,EAS ecu and a HEVAC panel.Then from XA on a Can link with the Autobox.

Fair comment,but I could throw in a suggestion for an LM1 wide band kit..........

[j999dpt]

where do the sequencial injectors get mounted on my engine (Gems). ?

how exactly does sequencial work are they like common rail diesel injectors that get supplied with LPG then fire off when told by the ECU??

[geoffbeaumont]

Sequential LPG systems will work more nicely than venturi (which as has been said, is a tarted up gas ring) but there are still bodges out there as many of them simply hijack the injector signals from the main ECU to fire the LPG injectors - cue many evil little scotchloks in your engine loom just waiting to cause trouble.

To be fair, all the one's I've seen sit in between the petrol injectors and loom using proper connectors in the same way as the injector disabling boxes in Gemima do (those just fool the ECU into thinking it's still connected to the injectors while actually disconnecting them*).

I don't know what the numbers are on all this but it would be remiss of me not to mention MegaSquirt, which could be a similar cost to a chip but would give switchable ignition maps and other groovy stuff. It's not plug-n-play but you're not shelling out for a random black box which may or may not be right for the job.

As Ally V8 says, unless the Megasquirt boys have been very busy lately, it isn't going to talk to the BECM, etc. which on a P38a is going to make for a lot of things refusing to play.

* - so since it's now running Megasquirt they shouldn't really be needed. Once the table switching input is working you can remove them if you want and just switch to an empty fuel map.

[FridgeFreezer]

As Ally V8 says, unless the Megasquirt boys have been very busy lately, it isn't going to talk to the BECM, etc. which on a P38a is going to make for a lot of things refusing to play.

They've been fairly busy, MS-II can talk over the CAN bus so it's not a huge leap to get it to make the right kinda noises to the BECM, it depends what the two say to each other really. If it's just engine telemetry and enable/disable from the alarm then it wouldn't be a massive hassle, if the two have to do coded handshaking with various serial numbers etc. it could get complicated. The flip side of the coin would be to use the GPIO board to replace the BECM but that *would* be a project. If I had the time & the money I'd fancy giving it a go though as I reckon the P38's are under-rated.

[Ally V8]

They've been fairly busy, MS-II can talk over the CAN bus so it's not a huge leap to get it to make the right kinda noises to the BECM, it depends what the two say to each other really. If it's just engine telemetry and enable/disable from the alarm then it wouldn't be a massive hassle, if the two have to do coded handshaking with various serial numbers etc. it could get complicated. The flip side of the coin would be to use the GPIO board to replace the BECM but that *would* be a project. If I had the time & the money I'd fancy giving it a go though as I reckon the P38's are under-rated.

Fridge I'm not knocking the Megasquirt in any way - I think its great what they are doing,giving people a chance to move on from carbs and often realising the true potential of an engine.The Becm sends a coded square wave to the Gems ecu,which it has to OK before it will talk back to the BECM and allow cranking, fuel and sparks.The later Motronic ones only inhibit fuel and sparks.You can capture the pulse easily on a scope - from memory I thought at the time that it would be quite difficult to get around.

Plus the fact that Gems,(And even more so Motronic) is all you need,cant see much point in changing it.

[Coastcard]

where do the sequencial injectors get mounted on my engine (Gems). ?

how exactly does sequencial work are they like common rail diesel injectors that get supplied with LPG then fire off when told by the ECU??

I have the Prinz sequential system and the injectors are mounted as close to the inlet manifold as possible (the injectors squirt directly into the manifold - i.e. you need holes drilled).

As Fridge says, they are driven by the signal to the petrol injectors (neatly spliced in with solder and the loom rebound ) and there is then a seperate ECU which presumably controls firing the LPG injectors and controlling solenoids etc. Once engine is up to a certain temp, the LPG system automatically cuts in although there is a manual overide to stay on petrol.

I would agree that if you want to do it properly sequential is probably the way to go to reduce/eliminate backfires and all sorts of other nasties that seem to raise their heads with venturi systems.

[stevet]

Just to add my quids worth. I had a 3.5 V6 Shogun and had a single point gas system fitted for a bit short of £900, it ran ok for a few years then started to backfire (felt like hitting a brick wall and the wheel falling off), it also took out the airflow meter. I could only source the part thro the dealers and (as it had to be imported) it cost £650. Had I spent abit more in the first place and had a multipoint system fitted (about £1250 at the time) I would still be in pocket now. I now have a 4.6 V8 P38 with an AG system fitted. It looks a very proffesionly fitted system and works a treat. Even tho I didnt have the system fitted the previous owner did, they have supplied me with a copy of the fitting certificate for my insurance and a list of local gas fitters who will service this system ( most will only touch stuff they fitted.). Also they tell me this system uses the cars ECU for fueling,air and temp sensing so re-chipping/mapping isnt an issue. stevet

[geoffbeaumont]

and a list of local gas fitters who will service this system ( most will only touch stuff they fitted.).

I'm surprised. That was never my experience - I had no problems at all getting mine serviced at various garages, none of which originally fitted it.

[Andyl]

I'm surprised. That was never my experience - I had no problems at all getting mine serviced at various garages, none of which originally fitted it.

I've come across installers who CAN'T work on stuff fitted by other installers, usually because they don't have the spares, or more often they don't have the right software for that brand and can't diagnose/set up the system. I've only ever had sequential systems though.

I have a couple of local installers who I buy gas from, but had to take my OMVL system to a an installer in the next county north for a service, after that I had a Prinz system, which I had to take to an installer in the next county south!

[range 46]

Hi,

I have a 96 4.6 that was fitted with the Romano rsin system 3 years ago, the system has had its fair share of problems with unexpected cut outs and excessive consumption but I think that was more to do with the installer not setting it up correctly, I have been told the prinz is a far better one, and have read many reports of people with the 4.6 swapping from Romano to prinz and the car has run great. as far as chips go keep your cash in the bank! once my system was running well I spent a fortune on the rpi tornado chips by Mark Adams and found them no better on gas than the standard, I have been told they are really only required if you have a draw through (single point system).

The real advise I would give is:-

1 Do lots of research

2 Don't take advise from an LPG fitter on the kit type

3 Pay the extra and go to the best fitter you can afford

Note.LPGA approved does not mean good!!!

[Reg]

Hi, I have run LPG cars going back to the 70's. I gave up running LPG when the installation cost skyrocketed to take account of those new fangled ECU's etc. All these cars were fitted with American Impco or Smiths systems which used a vacuum operated diaphragm working on a similar principle to an SU carburettor. The biggest system was fitted to a Jeep Cherokee using an Impco Vaporiser and a Smiths Converter. The smiths unit incorporated an air cleaner and sat on top of the carb. It was fitted with spring loaded flaps which prevented damage from a backfire. Even then the venturi ring was considered a cheap and nasty way of getting gas into the engine. I ran several Granadas a V4 Transit Van and a 2 Door Rangie all doing in excess of 90K miles each on gas. The granadas used to kill their hollow brass petrol floats if they got a backfire, they looked like someone had hit them with a hammer. Plastic floats never broke. Having said this I rarely experienced a backfire and it was usually down to overdue maintenance.

I recently acquired a P38 (Gems) which had suffered a serious engine overheat having been fitted with a multipoint unit squirting into the Plenum chamber.

To get the car going again I ditched the LPG system and put in a new Cosworth lump. On top of this I had to fork out for a new Petrol Tank and pump, a Plenum Chamber and the extra labour cost of taking those worthless bits off.

The car was also fitted with old illegal tanks which did not have shutoff solenoids fitted, the mini petrol tank was sitting on top of the gas tanks! The previous owner was driving around in a very dangerous vehicle!!

Currently I have no plans to go LPG again, but if I did a multipoint would not necessarily be my choice.

The system is only as good as the installer.

[mez]

They've been fairly busy, MS-II can talk over the CAN bus so it's not a huge leap to get it to make the right kinda noises to the BECM, it depends what the two say to each other really. If it's just engine telemetry and enable/disable from the alarm then it wouldn't be a massive hassle, if the two have to do coded handshaking with various serial numbers etc. it could get complicated. The flip side of the coin would be to use the GPIO board to replace the BECM but that *would* be a project. If I had the time & the money I'd fancy giving it a go though as I reckon the P38's are under-rated.

Sorry to drag up an old thread - i googled becm and megasquirt.

From what I can make out, connecting the becm to megasquirt on a GEMS setup shouldn't be too difficult, because it doesn't use CAN. The later thor/bosch system did use CAN.

The becm sends a message over a serial line to the GEMS and it responds by putting out the Check (mil) light. So I have a theory that all you need to do is tie the check light down and the becm should be happy.

From my searching on the subject, there seems to be lots of people asking about this sort of stuff but no one has managed to do it yet.

I'm trying to collate some facts and figures on the subject, because if i can get the engine under non gems control, forced induction or even replacing the engine with a chevy lump becomes possible in the p38.

Eliot

mez.co.uk