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[JamesV6CDX]

Just as a recap, my LPG conversion consists of:

* 90 litre 4 hole tank, in the boot
* 8mm poly liquid feed
* Stag 300 original ECU and loom
* Valtek 3ohm LPG injectors, drilled out to 3mm, delivering gas into nozzles next to petrol injectors
* KME Gold reducer, with dual outputs (recommended as "the daddy" of LPG reducers!)

When I fitted the kit to the car, it pretty much worked "out of the box". Aside of the fact I've always had a "fuel trim bank 2 error" code, only ever on LPG.

I decided to have a go at getting the mapping a little better, to try and sort this out.

I set the LPG pressure at around 1.2 bar, and run the auto calibration. This completed with total sucess, no problem at all.

Running it on gas after that, to collect the mapping curve, anything after around 5,000 RPM incurred a "injectors fully open" error code, in the LPG ECU, which subsequently caused the next gearchange to be VERY rough, like the engine had momentarily cut out.

Looking at the software, I could see the multiplier had been set by the calibration, at around 1.4. I can't remember my previous conversions, but, doesn't this seem a little... too much?

Interestingly, if I reduced this multiplier to around 1.2, the engine would rev quite a bit higher, before throwing the "injectors fully open" code

The only way to seemingly let it redline, on LPG, without logging this error, is to up the pressure to over 1.4 bar, which, surely, is way too high? Especially on a powerful, dual output VAP?


I have experimented with lower pressure, etc, but not really getting great results. At the moment, the pressure is set at 1.2 bar, and I've configured it to flick back onto petrol over 5,500 rpm.

I can' live with this, but, it can't be ideal... surely this can be set up to run all the way up through the range, on gas.

I'd appreciate any input from fellow LPG'ers - especially those running the KME gold vap.

I would ideally like to upgrade to the faster injector type, but at the moment, to be honest, I have more important family stuff to be spending money on, so I'd like to try and work with what I have

Thanks for your time

Cheers,
James

[JamesV6CDX]

Just to add - lambdas are fine, and do not show as going lean, when hoofing it

[TheBoy]

Sounds like you need to spend more time on manual calibration

[Lazydocker]

Not tried the red Valteks on the KME but the Motogas injectors I was supplied (still 3 ohm) only needed drilling to 2.3mm and 1.1 Bar pressure... Mine runs faultlessly to the red line every time

[JamesV6CDX]

Not tried the red Valteks on the KME but the Motogas injectors I was supplied (still 3 ohm) only needed drilling to 2.3mm and 1.1 Bar pressure... Mine runs faultlessly to the red line every time

Cheers LD... we did question this some time ago, but I believe Mr Wood was of the opinion 3mm was correct for the older injectors, such as mine... I may stand corrected, tho...

[Lazydocker]

Not tried the red Valteks on the KME but the Motogas injectors I was supplied (still 3 ohm) only needed drilling to 2.3mm and 1.1 Bar pressure... Mine runs faultlessly to the red line every time

Cheers LD... we did question this some time ago, but I believe Mr Wood was of the opinion 3mm was correct for the older injectors, such as mine... I may stand corrected, tho...

It's a learning curve The newer injectors have taking some trial and error too TB's were drilled to 2.5mm initially and that turned out to be too big

TBH, I find the new kit with the KME's much harder to get mapped right... I've got to re-map one next weekend that was rushed a little first time around and it's just not accurate enough

[sassanach]

i'm curious,how dose the vapouriser affect mapping?

[Lazydocker]

i'm curious,how dose the vapouriser affect mapping?

All the one's I've done have different injectors too But the KME is dual output and much, much more stable

Perhaps it's a coincidence but these new kits seem much harder to get spot on, taking much longer and a few attempts to get it right whereas the original kit I could almost get bang on out of the box

[Kevin Wood]

Sounds to me like it's going lean if upping the pressure is helping. Either that or it's the standard lag issue with those injectors.

If it's not going lean, you could try leaning it out a little at the top end of the map so see if the injectors fully open can be avoided without it going lean. Failing that, more pressure.

If it needs 1.4 BAR give it that. As long as it will still idle happily without surging it should be OK.

Nothing 100% solves the surge with those injectors, though, IME. They are just too slow to fuel it accurately at 5k+ IME.

[Lazydocker]

It does make me wonder if it is those injectors that were causing the issue all along

[sassanach]

so basically then valteks as supplied are crap!!!, they were on my sts and they struggle with my 4.6 rangie

[Lazydocker]

so basically then valteks as supplied are crap!!!, they were on my sts and they struggle with my 4.6 rangie

The kit isn't supplied with them any more

It does seem to be them that are the issue, although the old reducer was very unstable (pressure wise) whereas the KME Gold as supplied now is much better and seems to cope much better

[sassanach]

what's used now then?

[Lazydocker]

what's used now then?

Most have come with 3 ohm Motogas rails, which seem better

[JamesV6CDX]

So, is the general feeling, that it would be worth me considering an upgrade to the faster injectors, in the long run?

Will the fast ones be OK with the basic Stag ECU?

In the mean time, as long as it's not going lean, I guess there's no harm in keeping it set to run on petrol over 5.5k..?

Cheers,
James