D-gas versus Dieselgas

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Originally Posted by PAT303

Paul You have it set up I would get it to work.Mate it is a simple system,do some trouble shooting as to boost pressure and gas jet size.Mine works well,so should yours. Pat

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Pat, I have tried practically everything over the last five months. A local D-gas installer fitted cabin gauges for manifold pressure and gas pressure and pronounced the results perfect. I have tested for over a thousand kilometres with every jet between 20 and 50. I have purged and re-filled the gas tank. I have adjusted the hob switch. The gas injection point has been moved from the manifold to the outlet of the intercooler. I have exhausted everything that D-gas, the orginal installer and the local installer can suggest.

Pat, I have said to myself many times what you advise "It is installed now, get it working" but there is just nothing left to try, unless the third control box is also duff. If the third box is duff, I just don't want such an unreliable system that can potentially blow my engine.

Thanks anyway though for the advice.

Cheers,

Paul

You've got me there Paul.Does the engine run,powerwise OK without the gas?.From what I have read on this forum,JC is a big advocate for it is to run more diesel through them and that is what I'm going to do when the dyno tune gets done.The bloke that runs ultra tune in town also does a lot of LR dealer work as we don't have one and I found him very switched on with LR motors so for me giving him free reign to tune the engine right,it's still factory set from 10 years ago and running gas I think I will be happy with the result.There is nothing left for you to check but I can't understand why your engine doesn't like gas.I wish I could be of more help. Pat

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Originally Posted by PAT303

You've got me there Paul.Does the engine run,powerwise OK without the gas?.From what I have read on this forum,JC is a big advocate for it is to run more diesel through them and that is what I'm going to do when the dyno tune gets done.The bloke that runs ultra tune in town also does a lot of LR dealer work as we don't have one and I found him very switched on with LR motors so for me giving him free reign to tune the engine right,it's still factory set from 10 years ago and running gas I think I will be happy with the result.There is nothing left for you to check but I can't understand why your engine doesn't like gas.I wish I could be of more help. Pat

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Thanks for following this through with me Pat. If I could think of anything else to try, I would give it one more go. I will be very interested to hear what you say after he dyno run on the 8th. Unfortuantely mine is booked in to have the system removed on the 2nd and I can't bring myself to cancel the appointment.

Without gas, my engine is a ripper. With my wind-sock shaped slide-on camper and weighing in at 3.7 tons I can cruise at 105 KPH comfortably, only big hills and big head winds slow it down and it still only uses around 12 litres/100 k's. It has more low-down power than either of my TD5's. I have never seen the EGT above 500 degrees and that up a lonnnng hill with a headwind and 40 degree outside temp. I wouldn't like to fiddle with the diesel tuning just to get it to work on gas.

Cheers,

Paul

I had the D gas system fitted back in April and at first it performed exactly as advertised, then I ran foul of the faulty solenoid switch and then the problems with the dodgy seal.

Because I headed up north for the winter the swopping of units was a somewhat protracted affair.

When I returned to Perth in September I had unit number 3 fitted and today refilled both diesel and gas after clocking 470 k's having used 47.6L of diesel and 12.66l of gas.

The figures of 10L per 100K around town I am happy with, the 26.6% gas to diesel I am not.

I have agreed with D gas to run another tankfull of fuel through the system and then they will look at the issue of the size of the gas jet to be used.

I have for the first time since buying the vehicle needed to put oil in the engine, just 1 litre , but I had been pulling a 2.5tonne caravan for 6,000K's so maybe that was why.

I am also not too happy with the guage for the LPG which goes from full to quarter full in the blink of an eye.

Throughout the problems I have had the attitude of Dgas has been consistent in that they have always been very keen to resolve the problems and have found local agencies to help with problems when I was away from Perth.

Ultimately I believe my system will give me what I paid for sadly a bit later than I would have liked so next year I will start to recover the $750, after govt rebates, the system cost me.

Sorry to hear about your troubles, Wilbur, and I hope they get sorted.

Thanks for starting the thread, it's turning out to be a beauty.

Cheers
Simon

I'm a bit disappointed I couldn't be of more help but today driving home from work I turned the gas on and off and there was without doubt a pick-up in performance running gas,I can't give a fuel usage as my no.4 injector is leaking so that will have to wait.I will open a new post after the dyno run and put up the result's. Pat

Pat, yes I do think a Tdi fuelling tweak and pump timing improvement(plunger lift to 1.6mm) will also help the gas to be more effective. Also, critically valve clearances need to be perfect (.008" / .208mm) to make full use of the gas/ diesel mixture.

Paul, when did your Tdi last have the tappets set? And, has there been any fuelling upgrades done, 500 degrees seems too cold (IE standard fuelling) for upstream temps. I typically can adjust these to give 600+ and the difference is remarkable. Did one recently in a 110, and because he is now in a higher gear up hills etc, he is now using LESS fuel over a given distance/ trip.

JC

JC do you think that it is possible to go too far?.I have given very clear instructions as to how much tuning up can be done on mine but it has 406,000k's on the clock so it is past it's best.One question,can you buy a replacement cap for the fuel screw?,what do you do?. Pat

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Originally Posted by PAT303

JC do you think that it is possible to go too far?.I have given very clear instructions as to how much tuning up can be done on mine but it has 406,000k's on the clock so it is past it's best.One question,can you buy a replacement cap for the fuel screw?,what do you do?. Pat

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Hi Pat,

Hell yes, without a pyro and a greedy operator can see 800 degrees and ZD30 Nissan type piston damage:eek:
406K can still be done, but set the temps to about 600MAX upstream. the timing plunger lift mod will breathe new life into it and not effect any reliability at all.
If you are talking about the plastic cover for the main fuel screw, then possibly from a bosch diesel pump rebuilder or similar, but I never bother. When I set them I just put a dab of paint on it to see if anyone has done any unauthorised tampering at a later stage:twisted:

Do you have a pyro in the cabin? I would really recommend this. Even after you set up the adjustments, you still need to monitor the temps when towing in higher ambient temperatures or with differing loads.

I sometimes set the fuelling quite high for those that want more go, but warn them to back off after 650 to 700 deg have been reached. I wouldn't dream of these settings in a non pyro equipped Tdi.

JC

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Originally Posted by Wilbur

I have never seen the EGT above 500 degrees and that up a lonnnng hill with a headwind and 40 degree outside temp.

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Figures like that make me question the probe location. Does it extend right into the gas flow or is it being "heat sinked" by the manfold or plate it's mounted in?

My 4BD1T pulls 430C upstream of the turbo on a flat road at 100km/h.