It Lives

[rob99]

After pratting about for a week I finally got the Shogun running on gas

Using the wisdom gathered from this forum I think it's ok (well nearly)

Performance wise it's no different, pulled 6000rpm through the gears in power mode up to 100 mph no problem ( private road officer)

Cannot get my head around the map settings yet, any pearls of wisdom?

Slightly rough idle, slight cough from the exhaust and not quite as smooth at idle as on petrol, any ideas?

Changed the Platinum plugs for Iridium but left the gaps as they came out of the box. Do you think I should close the gaps up a little?

Leads have done 130k I think, they may have been changed before I got the old girl.

The level sender is talking bo--ocks showing empty. Is it because I only put 18 litres in.

I'm impressed with the price of LPG. Put 4 gallons (18.2 litres) of petrol in the little tank which cost £24. Put the same in the LPG tank and it cost £13, not bad. If the cheap place had been open it would of been a tenner.

Thanks for your help

Rob

[rossko]

To recap for those wondering what he's on about ...
Secondhand Zavoli Alisei with Matrix injectors of unknown mileage and a new Zeta-S instead of JX.
Zeta-S runs significantly higher pressure than the JX so the Matrix nozzles may need resizing.
Idle T_inj on gas?

New tank, I think? What kind of level sender did you fit? What was the old one? Changing types may involve both software settings and wiring changes.

[rob99]

Hi rossko

Good memory.

This is what I have done so far.

Set reducer to 1.4 in setup screen. Tweaked Zeta S pressure down a bit to 1.4 bar, it was running at 1.6 bar.

I have soldered up the nozzles and redrilled at 2.6mm

The bar graph in the software sits bang in the middle of correct, it was showing too big until I dropped the pressure a tad,

I have used the old level sender which is a 0-90 AEB 1090 and set this in the software. I tested this before I put the tank on by plugging the multivalve in and moving the float and it worked fine on the gauge. I think I may have it in the wrong position on the multi valve (forgot to put in on before I bolted the tank in and had a bit of a mare getting the screws in)so its still thinks its empty. I'll fill it with gas tonight and adjust it so it shows full.

If you mean the gas injection time then it's at about 4.4 ms at idle. On petrol the injection time at idle is 3.4ms but this changes to 3.1ms when on gas, does this mean I'm too rich on gas? The Lamda value is swinging from about 0.18 to 0.8.

It's only very slightly rough at idle, it drives ok. It sounds more like a ignition miss.

I could not get the injector to spud pipes all the same length on the left (as you look at it) bank, cylinder 5 is about 50-60mm longer, will this have an effect on idle quality?

Is there any info available on how to tweak the map settings?

Thanks Rob

[rossko]

If you mean the gas injection time then it's at about 4.4 ms at idle.

Okay that's good. We can cross too-short injector times off the list as a possible cause for rough idle.

On petrol the injection time at idle is 3.4ms but this changes to 3.1ms when on gas, does this mean I'm too rich on gas?

Yes, a bit. On average, mind. Absolutely sure all the nozzles got modified alike? One mismatched would give you symptoms just like this, so it needs ruling out.

The Lamda value is swinging from about 0.18 to 0.8

That's good too. The petrol system has compensated for the slightly different fuelling; your roughness is not down to gross rich or lean misfires. That leaves individual fuel, air or spark issues in one bank or more probably just one cylinder.

It's only very slightly rough at idle, it drives ok. It sounds more like a ignition miss.

Entirely possible.
Also a small manifold air leak to one cylinder will behave similarly.
Worn out injectors are on the list too.
I'd eliminate those before attempting any further fine tuning.

I could not get the injector to spud pipes all the same length on the left (as you look at it) bank, cylinder 5 is about 50-60mm longer, will this have an effect on idle quality?

Probably not ... but getting them similar lengths rules out the worry when you find yourself looking for a niggle, like here.

Is there any info available on how to tweak the map settings?

Advice: leave the big map alone. If you want to fiddle, use the simplified "modify carb" table. It's just a simple 8-point map. If you need more than you can do there, it probably means there is an underlying problem.

[rob99]

Hi rossko

Many thanks for your reply.

Yes, a bit. On average, mind. Absolutely sure all the nozzles got modified alike? One mismatched would give you symptoms just like this, so it needs ruling out.

I filled the nozzles completely with solder and then opened the small end to the original 4mm size 20mm deep and then put the chamfer back in the threaded end and then dilled 2.6mm. This was done on my lathe so they should all be the same.

Entirely possible.
Also a small manifold air leak to one cylinder will behave similarly.
Worn out injectors are on the list too.
I'd eliminate those before attempting any further fine tuning.

I stripped the Matrix's and cleaned them. To my eyes they didn't look worn. All the injectors look the same

Is there any info available on how to tweak the map settings?

Advice: leave the big map alone. If you want to fiddle, use the simplified "modify carb" table. It's just a simple 8-point map. If you need more than you can do there, it probably means there is an underlying problem.

On the software I am using there is no tweaks in the Modify Carb just OBD stuff. I loaded an earlier version which had this function but this had no Map settings. Which one should I be using?


Had a play tonight and it looks like there is a slight roughness at idle when on petrol which will be made worse on gas. I don't think there are any vac leaks as I have just done the top end with new gaskets. I'll have a look at the coil packs and leads o see if there is a problem there.

it runs perfect off idle, I am impressed with this gas lark.

Thanks for your time Rob

[rob99]

Think I've found the source of my rough idle/misfire.

I ripped out the plugs and coils last night and checked the coils.
One coil had a stuck electrode so wasn't contacting the plug right and had burned the end of the electrode. Freed it off and re-turned the end a smidge, thought this was the cure. NO. Checked the coil resistances and found the one with the burnt electrode was fine but one of the other 2 was slightly high on the secondary and the other was open circuit. Seems to run fine even with the open circuit coil but LPG doesn't like it.
Ordered one new coil £100 trade bl--dy hell. Better cure the misfire!!!
Rob

[sijones]

I had to replace the coil packs on my santa fe, they were fine on petrol but as soon as lpg was on it would misfire quite a lot, i ended up replacing the leads and plugs and now it runs much better...

as a side note i did replace them at first with platinum's and recently replaced the plat's with iridium lpg plugs (NGK's), and there is definitely a difference, the engine is much smoother with the new plugs in...