dhallworth wrote:

I ordered a Tartarini reducer the other day as the company had one left in stock and they were doing it for a good price. That's arrived today but I'm not fitting it yet just incase it's not needed. It's nice and shiny though.

I've had a good look at the front and rear today. I can see the solenoid on the tank, there's no filter there, here's a picture of the solenoid that's fitted just before the reducer:

Looking at that, I can't tell if there's a filter in it or not, there's a brass body that sits near the bracket, if there is a filter in there it must be a tiny one, the filtered solenoid on our other LPG RR has a noticeable bowl that the filter sits in underneath it.

Since undoing all of the tension on the pressure adjusting bolt the car seems to run better, it idles fine on LPG, I can accelerate to 30 on the flat but if I try and go past half throttle or hit a slight incline you can feel it starting to choke, keeping your foot in the same place and switching back to petrol makes a notable difference in acceleration.

With the screw undone totally at idle the pressure is still sitting at 2.4 bar, when driving normally it drops to 1.6 - 2.0 bar and when you floor it, it switches back to petrol.

I put the suspension on high earlier and slid under it for another look at the pipe, I can't see any marks on it that would suggest it's been crushed.

David.

From the back of the solenoid housing it looks like theres a large nut (on the side that faces the bracket). Your filter should be in there.

I'd suspect its one of these?
http://tinleytech.co.uk/shop/lpg-parts/tartarini-liquid-filter-element-service-kit/
There are measurements there to confirm once you've got it out though.

Would be worth stripping the rest of it while your there to give it a clean up (the post bit the solenoid sites on as these are known to occasionally get gummed up).

And yes, it will be tiny, its the same sort if not identical to those used on the factory fit Koltec/Necam systems by the look of it (valve slightly different as its mounted remotely, but otherwise looks pretty much the same)

Thanks Brian.

I'll have a tinker tomorrow evening hopefully and try n get the filter out.

David.

How much stick do you have to give it before it cuts back to petrol? How does it drive on LPG now?

If it drives OK on gas before it cuts back and you have to give it a lot of stick before it'll cut back, some people would be prepared to leave it like that as long as fuel trims / lambda readings are OK. There may be an option in software to add some petrol to fuelling at high engine loads (and/or switch temporarily fully back to petrol when you put your foot down but resume running on gas when you lift off the throttle a bit), where these options are available they can prevent cutting back to petrol because the reducer isn't worked as hard (or even worked at all) when you put your foot down. Not the best setup situation for an LPG system but can mean no further expense on parts and little change in running costs if you seldom boot it to the point the above options are active. You wouldn't want such options set to the point they are applied often or you'd end up saving less money by running on petrol too much.

Before it switches back to petrol you have to give it a fair prod but from about 50% throttle you can feel it has no power.

There's a gentle slope from the motorway up a B road to get home, the old P38 on LPG will come up that in Sport mode with your foot welded to the floor, on this one I can't get over half throttle and it can't accelerate up the hill, it will just about maintain speed.

Getting onto the dual carriageway from the roundabout locally I can accelerate to about 40 - 45mph as long as it's gently but after that it's full of hesitation and doesn't want to go anywhere.

Unfortunately LPG plans are on hold for a couple of days as I noticed a huge puddle in the drivers side footwell the night before last. The heater matrix O rings are leaking badly. I've been in with a wet vac and have lifted the carpet and put padding under it to try and absorb some of the moisture from the foam and to attempt to keep any wetness away from the BECM.

There's always something!

David.

Does the lack of power seem just throttle related or more 50% throttle above a certain rpm? Does it seem to happen at the same time as pressure falls away?

Good luck with the heater matrix problem.

From the way that filter/solenoid is mounted, I doubt if anyone has ever cleaned or changed the filter element. You never know, it could be clogged solid.....

Lpgc wrote:

may be an option in software to add some petrol to fuelling at high engine loads (and/or switch temporarily fully back to petrol when you put your foot down but resume running >on gas when you lift off the throttle a bit),

I think there is that option Simon. If you remember when we were setting mine up, we had a moment or two where that was happening until you tinkered with the software. I think it's under the "Erichments during acceleration" tab. Which makes sense.

blueplasticsoulman wrote:

Lpgc wrote:

may be an option in software to add some petrol to fuelling at high engine loads (and/or switch temporarily fully back to petrol when you put your foot down but resume running >on gas when you lift off the throttle a bit),

I think there is that option Simon. If you remember when we were setting mine up, we had a moment or two where that was happening until you tinkered with the software. I think it's under the "Erichments during acceleration" tab. Which makes sense.

I think you'll be right. Most Tartarini systems have the option but the ECU's change over the years and very early ones won't have the hardware ability to support petrol addition. Unavailable settings are supposedly (and usually) greyed out in versions of software that came out later than hardware but some combinations of software, hardware and firmware can leave unavailable settings looking available... would expect if this were the case then setting petrol addition would just provoke a full return to petrol (with return to gas when rpm falls).

I've not had a chance to revisit this yet as the dash is in pieces for heater matrix o rings and bulb replacement in switches.

I took that solenoid off and replaced the filter in it, the old one was pretty clean inside and out. I'm working this weekend but am hoping that an hour or two on Monday will see it all back together.

The way the car was on LPG, if I had the trailer behind it I don't think it would make it up the slightest of inclines. It's nowhere near right on LPG yet, my multipoint Discovery 2 I had years ago that was never right on LPG either would run rings around this thing at the moment!

David.

Well, I got a quiet day at work today and managed to work from home.

The sun was shining and it was pleasantly warm so I decided I'd get some more time in on the P38.

I decided before I refilled the cooling system after doing the heater matrix o rings I'd swap out the reducer seeing as I was in there anyway, because of where the reducer is mounted, changing the front air spring was going to be a nightmare once the reducer was in so I changed the drivers side air spring and before fitting the pipework back into the reducer I fitted a new ABS accumulator.

Tomorrow I'm hoping to get the passengers side air spring replaced and then get the interior reassembled. Once that's sorted I can then look at getting the LPG sorted again. First things first I'll check and see if that pressure has dropped from 2.4bar.

I'm probably going overboard with the work I'm doing to this one but I've got no plans to get rid of it so I might as well make it perfect.

David.

Both front airbags are done, the LPG filter is changed and the solenoid refitted, the new vaporiser is fitted, the dashboard has been reassembled with new bulbs in anything that wasn't illuminating.

Today I had it running, bled the cooling system through, put the suspension to full height and disconnected the battery, wandered around the back of the car and could hear a hissing noise and could see the car sagging. Slid under and had a peek and found the rear airbag with cords hanging out of it. The front stayed up this time which is better then it was before, however the back has decided it wants new bags too!

By the time I'm finished this, it'll be like a new car!! Anyway, Island 4x4 order has been dispatched already so with a bit of luck we'll get a bit more dry weather.

David.

Well, the P38 is now back together, almost. Have left a couple of panels off under the dash to keep an eye on the o-rings.

All 4 airbags replaced and she seems to be staying level, soapy water on all of the air unions seemed to confirm there's no leaks and leaving it in high with the battery disconnected confirmed there was no dropping over about 4 hours.

The brakes feel better now it's got the new ABS accumulator fitted and the ABS pump isn't running anywhere near as often.

It now very lumpy at idle on LPG and then cuts out after a few seconds so the new reducer I've fitted needs setting up. A job for when the rain stops as I need my laptop balanced on the slam panel to do it.

The heater matrix o rings seem to be holding but my trip to Dumfries in the morning will confirm that. A big thanks to Gordon for giving me a hand with them. Now I just need to get anti freeze out of the drivers side carpet.

Hopefully we're now making some progress with the car and we can use her a bit now before we need more spattering :)

David.

OK, time for an update.

The car is running great at the moment and seems to be behaving really well so I thought I'd get a look at the LPG as we're going away for a few days tomorrow or Tuesday.

The new reducer is fitted, plumbed in and appears to be doing it's job. After a bit of twisting the adjuster screw I've got the pressure to sit at 1.32bar. It didn't seem to want to come above that as I was aiming for 1.4bar as per Simon's previous suggestions.

I headed off up the lane and initially there was a few pops that sounded like they were in the exhaust under the car so I ran it on petrol for 1/2 mile and then switched back to gas. The car now runs on gas better then it did when I got it but it's still not right.

When climbing hills it feels lumpy and underpowered even when I'm not using 50% throttle. If you floor it the engine sounds as if it's bogging down and makes a funny noise and at idle it's lumpy. Switching back to Petrol cures all of these issues. If you're coming up the hill with your foot in a constant position, switching back to petrol makes a huge difference to the pull of the car. On LPG it's hunting through the gears when trying to climb the hills.

One thing I did notice with the laptop out is that since changing the reducer the gas pressure is now constantly in the 1.2 - 1.3 bar even at wide open throttle whereas the old reducer wasn't sustaining the pressure at full power.

Both the liquid and vapour filters have been replaced, and the reducer has been replaced.

I've got a text file and a colourful graph from the LPG software but they don't mean much to me!

David.

Post the graph if you can, that might help to identify what it is doing (depending on what it is showing of course)..

Here's the graph. It's crap quality as it's a picture of the laptop screen. From what I saw the petrol and gas injection seem to mirror each other very closely on the graph.

Here's the pressures sitting a bit more stable now :)

David.

If I'm reading the graph correctly, it looks like at idle the gas injection time is higher than the petrol injection time, which is as it should be (and confirmed by the second screenshot). However, as soon as you give it some throttle, the petrol times (purple line) are higher than the gas times (grey line). They should be between 1.2 and 1.5 times the petrol times which suggest the fuelling map is way out. Just to confuse things further, the lambda doesn't appear to be switching properly. When given some throttle is appears to go rich (1.0V lambda output), which doesn't follow with the injection times. Does the Tartarini software have an autocal feature? It might be worth saving your existing settings, in case it makes it worse, and doing an autocal if you can.

Thanks Gilbert.

I've got 2 lambda sensors here, I might try and get them swapped out tomorrow and then run the auto calibration feature on it and see what happens.

David.

Before swapping sensors, check that they are switching correctly on petrol. They should flip flop between 0 and 1V every second or so.

I had a fault showing for the two lambda's when i waved Testbook at it recently. If you clear it the fault stays away for a while but does come back.

I'll have another prod at it tomorrow.

David.

I went out and grabbed some screenshots of mine for you. Dunno whether it'll be of any use to you but my car runs pretty good at these settings. Ignore the lambda's as they're not connected to my gas system.

Car was just about up to running temperature and running at idle.
Injection is set to sequential
Reducer is set to 1 bar
Temp for changeover is 35

Here's my map