LPG Discussion Forum

Question!

Electrics/interior of the car all back together so plugged in the laptop to read "live" sensor values and check that they look plausible. All ok (and the ECU is only showing 14 hours service; 10 on LPG and 4 on petrol - win!) except for reducer temperature.

The ECU reckons that the reducer is at 34C and gas at 14C. I'd say 15C was about right as the engine hadn't run and it was neither cold nor warm out.

AEB King ECU. Tomasetto "Arctic" reducer with what I assume is the temperature sender from the AEB kit screwed into the side of it. Brass thing, brass hex to screw it n; black and yellow wires; M6 thread:

http://autogas-lpg.co.uk/spare-parts/77 ... ystem.html

Am I looking at a sensor that's goosed, wrong, or incorrectly set up? Don't see any options in the King software for choosing which is fitted.

I wouldn't assume anything about 'lucky finds'.
Use a meter on ohms range to check the sensor, look up the expected resistance/temp for a 4.7 or 5K NTC thermistor.
Check for goood earth via black wire.
Beware the wiring to the two temp sensors crossed, that's easy to do.
Beware that not all ECU readings might be sensible before RPM first detected.

Beware that not all ECU readings might be sensible before RPM first detected.

This!


We hadn't been able to start the car until today (no exhaust cat-back, courtesy of a truly delightful eBay seller by the name of carpartssaver selling Rover 820 exhausts with completely the wrong flanges, until a Bosal unit from mpartd08 arrived today) but as soon as the engine was running the King ECU's reported values became sensical.


Added the filler (90 deg JIC bayonet, towbar mounted inside one of those black pots) and pipework (500 mm JIC hose, straight on one end, 90 deg on the other) and boshed in 62 litres of lpg. (80% of 77L) Hit the autocal button on a hot engine and out popped 200% at tickover with the injector sizing right in the middle of the recommended range. (semi-sequential remember) Lucky drilling by the previous owner - will check size for the record tomorrow.

Runs very well, lambda dancing as it should in closed loop, and Tinj for petrol doesn't change regardless of fuel type. Needed 1/3rd to 1/2 extra-inj sensitivity and that was it. Pulling out 5% fuel out makes it feel flat in the "moderate throttle 1500-3000" range, so outside closed loop the bum-dyno says that the fuelling is about right, so I'll leave the absolutely default map in there. (drives so much better than the old single point systems on these engines ever did)

The 1 second valve opening thing discussed earlier does not work as I thought the manuals described. When you choose gas, it does indeed to a one second "purge" on the electrovalves. This happens immediately after the 25 second delay period after the engine is up to temperature and the system is waiting to switch to gas when you accelerate. (It doesn't do it after it decides to switch; it does it when it is ready to switch) The system then waits for threshold revs and accel and switched immediately to gas. Effect in the real world? The petrol ECU doesn't respond to the coolant temperature sender jumping to "hot" and back to "cold" again fast enough for it to matter a damn. Gas then comes on for good and the petrol ECU gradually switches to the warmup trim, with no delay relay needed. Switchover at minimum 20C; minimum 25 second delay; 1300 rpm in acceleration. Just high enough revs so that it doesn't switch at idle, but low enough so that you're never caught switching as you're pulling away at a junction. (you rev the engine higher than that)

Photos:

Frontend:







Strain-relieving the MagicJet injector wiring is tricky. Rail is mounted to the back of the inlet manifold on a piece of 3 mm plate. Two bent bits of stainless hold the gas injector wiring and the AEB fuel injector plug/socket. Third piece of 1.6 mm plate and an exhaust clamp for the fuel filter. AEB025 and the ECU on the bulkhead (rivnuts are awesome), reducer fits to a piece of 20x20x2 mm box section that bolts to two captive nuts on the suspension turret. Having solenoid valve, liquid filter and reducer all in one is great. Spade connectors are rubbish though. I do not like these in an automotive environment as technology has moved on since 70s electrics.


Interior:



Switch is mounted out of the way on a flat piece of dash. I've wired a changeover relay to the electrovalve. This is wired to a warning lamp on the dash. Lamp on = petrol/out of gas/something wrong with your gas setup, lamp off = gas.


Tank and filler:















No valve box, as the entire tank is underslung. This saved some faffing - much simpler to fit pipework heh! If it were my car, I would have removed the rear anti-roll bar* and stuck to a flat floor rather than lifting it 50 mm. Filler is on a bracket welded to the towbar (40x40x2.5 mm box onto the bar, to a 4 mm plate that carries the filler/towing socket) and as high as is practical. Easy enough to use and should survive ferry ramps and suchlike! Tank got 3 coats of paint and schutz. Valves will get waxed now that they're known to work/not leak. There's a cover plate over the top of that lot sealed to the tank frame, then two chunks of "spaceboard" foam either side to level the floor.

*the police spec springs AND the vitesse anti-roll bar is too much roll stiffness on the rear; far too tail happy. Drop the rear bar off (or switch to a standard spring rate but with longer springs) and you restore the handling balance. You also buy space to fit the tank lower without clouting it with the bar.


Careful when routing the LPG pipe over the rear wishbone. Far enough away from the inboard pivot to get maximum clearance at full bump; far enough inboard to miss all the handbrake cable bracketry. (it isn't obvious, but the lower wishbones get damn close to the rear crossmember at full bump) 6 mm pipe would have been simpler, but both the tank and the reducer took 8 mm and I had the 8 mm pipe to hand.

So what do you reckon then ? Aeb or Stag ?

Neat. Although I assume that the croc clip on the battery in the first picture is a temporary arrangement rather than the King ECU power supply?
With the filler, is there any reason you've gone for one with a 90° outlet? My first thoughts were that a straight one would be neater, but then I thought that if yours gets a knock from underneath it may swivel the pipe rather than fracturing.

I'll let you know once the Jaguar runs Tubbs

Stag all the way for me though. The AEB hardware is nice enough, and the wiring harness is better thought out, but the "integrator" business model and the software/manuals ruin it for me. One bloke makes it. Another "integrates" it. "Integration" means taking the perfectly functional hardware then crippling it by disabling features/restricting choices, then taking a manual in Italian and translating them badly (and incompletely) into English. It can "save you from yourself" I guess, in the same way that an iPhone "saves" the user from doing anything stupid/useful vs a rooted Android handset, or an iMac "saves" the user from doing anything stupid/useful vs a Windows or Linux box. For many applications this works ok (rover it doesn't matter a damn) in a bung it on, hit autocal, hook up OBD, then send the customer away type scenario.

The Stag stuff is made by one bloke, supported by that bloke (who speaks Polish/English equally well and translated the full instruction set), but more importantly is supplied "open" and not "locked down" at all. It doesn't do petrol addition. The wiring harness doesn't have a separate tank valve wire. It does read wideband oxygen sensors, and this feature alone sells it over an AEB system for the Jaguar. (caveat - I've only played with that King ECU and software so far; perhaps other AEB vendors don't disable all the checkboxes/hide all the features/write crummy manuals)


Croc clips are the battery charger! (Charger sits on the front crossbeam in front of the engine/exhaust manifold, plug out the bottom, extension lead under the car, and it'll sit outside all night without getting rained on. Just remember to remove before driving off. ) 90 degree filler is what came with the kits, so a 90 degree hose is what it got. Straight would be neater but that'd be buying two bits.

Bear in mind though that you are talking about a King customised AEB ECU which is the budget cut down version. You'll find a lot more options in the other versions. My only comment, why set it to change on acceleration? If you set it to change on deceleration then there's no danger of a hiccup when pulling away from a junction, it will change as the revs drop for a gearchange.

You are wrong there my freind ! If you drop into terminal you can completely screw up a mac...but the front end that people generally see is completely bullet proof from screw ups ! If you want your iphone/ ipad to do shit you just jailbreak it. But the battery life suffers a bit.
Emer has no options that you cant tick/ greyed out boxes. Start on gas, not having to connect up the coil wire and count injector pulses. What firmware are you running ? Have you updated it at all ? In the ecu reprogramming tab. All the Emer ecu's come with version 4 or something and you update them first thing before calibration. Firmare v10.5 or sometsuch. So have a look in the ECU reprogramming tab.

I think a point is that AEB derived system's aren't usually geared to serve for Frankenstein's Monster systems, with e.g. sensors and injectors from different makers. Bit like you can't fit a Dell keyboard into an HP laptop, whereas its no problem with a desktop. All laptops are therefore "crippled"

Think it's horses for courses really, rather than one is 'better' than the other. Tinkerers (which by their nature a lot of DIY installers are) will prefer as much flexibility as possible. Others - so long as the system works effectively - will just prefer to fit and forget. I probably fall into the first category, so might have to consider a Stag system for the next conversion I do...

Very salient point there mat. Its true i suppose, us pro installers just want them to work with the least fuss and hassle. And carry on working long after the warranty period with no headaches.
Thats what makes happy customers and in turn a positive LPG experience and they can go off and bore any one who will listen and the industry grows and grows. If it keeps having to go back and be 'fiddled' with it doesnt have the same effect.

No franken-kit - it's all a package/as recommended by King. (Tomasetto Arctic at 1.27 bar; MagicJet injectors; AEB025 and AEB water temperature bung)

King software:
http://autogas-lpg.co.uk/content/10-Download-KING

AC software:

http://www.ac.com.pl/en/doc/383/setupacgassynchro-9007
http://www.ac.com.pl/en/doc/346/instruc ... nd-manuals

Even if you aren't changing the default behaviours (say, when it alarms or does something about low/high gas pressure, or what it does when these events occur), you at least know exactly what the system is going to do. The map collection on petrol/gas and display spank the 2D table for the King system, and the oscilliscope recording with all the fuel trims from OBD in place etc is easy to use and interrogate.

Most of the truly annoying features (deliberate limitations/restrictions in firmware) would appear to be "King AEB" rather than "AEB" though. Can one buy the "Emer AEB" as non-trade? What are the other flavours of AEB like?

I think if you spoke to Tinley tech niceley they may let you have an Emer system. Your install's are all pretty tidy and you do seem to have good engineering practice. I know he does browse the forum. So I'm sure he knows who you are by username. You can only ask afterall.
Software wise they are pretty similar. But the hardware you bolt on top is what makes the system really.

Father and kid brother have bimbled about in this and there is one point where the mapping is lack - overrun fuel cut.

The MEMS kills fuel on the overrun, then appears to bring it back in gradually/gently with multiple injections before running "normally" so to speak. Disregard the smaller injections and you get a harsh fuel cut. Listen to the smaller injections and you've got too much enrichment on accel/in transient.

I can correct this on the Stag system - you map them out with the 3D multiplier maps and corrections. Listen to micro injections at low MAP but not at cruise/high MAP and you've injected for fuel cut but not extra injected extra fuel for accel. Doesn't appear to be a way to correct this with the King software - just choose the lesser of two evils with the mystery sliders.

Had another play with the overrun fuel cut-off. Schoolboy error it would appear - the MagicJet injectors were bottoming out spectacularly. Ok on idle (just) but as soon as you hit overrun, and/or got a microinjection, it was stuffing in huge dollops of gas, missing, then recovering. (this shows up as lean on an oxygen sensor by the way, when it misfires)

Nice of the ECU to flag absolutely no error for this.
Even nicer of the ECU to set a truly insane minimum opening time (3.8 ms) too.


Special AEB CK8 file for MagicJet injectors
Thanks to Simon P (supercharged Lexus V8 in the Range-Rover) I received a copy of the "special no warranties expressed or impled" CK8 file from AEB. Link here:

http://www.cosic.org.uk/MarkoStuff/lpg/ ... t-rev1.ck8

They've modified it to allow the MagicJet injectors to fire down to 2 ms, not 3.8 ms. Whilst they are officially supported, and bundled in the frontend kits by the integrators, I don't think you stand much of a chance using them with an AEB ECU unless you've got the non-standard config file, thanks to the insane minimum opening time.

(I can understand the logic of not trying to idle below 3.8 ms, if they've been found cheap/nasty/not stable below this by AEB, which is what the emails/disclaimers that Simon P received seemed to state, but you do need the ability not to shovel loads of gas in on the overrun, and the standard config file won't let you do this)


Anyhow - here's the new map and whatnot for an 820 on MEMS:














A few "funnies" that might be useful to know:

ECU options greyed out
Various options in the King software (start hot engine on gas, extra injection cutting) are greyed out when you are connected to the ECU. To select these, you need to load the config from the ECU, save the config file on disk, disconnect from the ECU, choose those settings, save the config file on disk, then reconnect to the ECU, then load the config file to the ECU. Explanations as to how this possibly makes sens welcome on a postcard, but it could save some head scratching!

Microinjections, overrun, and fuel cut
You'll see that my map runs from 1.0 ms to 8 ms. MEMS on the naturally aspirated 2.0 engines injects between 1.0 ms and 8 ms only. Idle is about 2 ms. Mild overrun, the sort that you get lots of transients through in a car park or traffic, is about 1.5 ms. MEMS does micro-injections of 1.0 ms AND in overrun will drop down to 1.0 ms before going to complete fuel cut. I've hard-coded a big fat zero in for 1.0 ms. This kills the microinjections in a way that you have control over, rather than relying on guesswork from the AEB ECU. It doesn't miss them on gas during accel etc.

Being a pikey, I took out 1.25 ms as well, and made 1.5 ms partially fuelled. Making the fuel cut more aggressive basically, as you spend a surprising amount of town driving in that area. (factory fuel cut is over 2600 rpm only, and when completely off the throttle only) Sir who isn't great with a manual gearbox test driving a brand new Rover might not have liked it back in the day, but the rest of us can drive around the transient quite happily. Push it any further and it becomes annoying.

There's an exception at tickover. Too aggressive with the fuel cut here and if you dip the clutch at the wrong moment in a car park you can find yourself in the zero part of the fuel map. You don't get very far with this.

Starting/cranking and idle
Below a certain rpm (I think 400 or so), the MEMS ECU goes into cranking/starting mode. Lots of micro injections and general strangeness that the gas ECU won't appreciate. Don't try to start the hot engine on gas. I've also set it to drop to petrol at 600 rpm (idle is 850) because *if* you're about to stall it, and you happen to dip into the cranking rpm, then it will stall on gas as all that general strangeness kicks in. Pop to petrol and it'll recover fine then switch back to gas again.

General tuning
I found it easier to look at lambda rather than petrol injection times when mapping. Fiddle until you get lambda doing the rich-lean-rich-lean dance the quickest. It'll do this when the petrol injection times are the same on gas and petrol. Much faster than switching between fuels and waiting for the 25 seconds the King ECU demands to elapse.

Idle, overrun at 3000 rpm, 6 ms at 2000 rpm, and 3 ms at 2000 rpm are the most common bins that the dot sits in whilst driving. It's a torquey engine that seems to like being flogged around the 1500-2500 rpm range during accel, then cruises in the 3 ms bin. I kept it stoich up until 7 ms and 4,000 rpm, or 3 ms over 4,000 rpm. Above those loads I leaned it until I'd see the odd "lean" show up on the lambda then added 10% (so that it's always showing rich) and it seems to like this.

At idle with a good oxygen sensor, MEMS switches about 3 times per second. Time to replace if it's slowed down to 1 change per second. This is much quicker than the run-of-mill narrowband oxygen sensor equipped engines of the late 80s/90s, and if you do the blowtorch test on one of the MEMS sensors you'll see that it responds much faster than a generic narrowband. If you've got a car that's misbehaving, check that it hasn't had a universal fitted - they don't work with this engine management system...

http://www.gendan.co.uk/product_O24WIREB.html


Nozzles are 2.8 mm; reducer pressure 1.27 bar. (1.27 +0.05/-0.2 in practice; not the most stable)


Will report back with economy on gas

markocosic wrote:Various options in the King software (start hot engine on gas ... are greyed out ...
Don't try to start the hot engine on gas.

I think you answer yourself. Many engines have start-up strategies that are inappropriate for gas, restricting to "emergency use" or suchlike prevents complaints from consumers (with an added justification that it exercises the petrol system against death from baked disuse).

I'd go with that if it were completely unavailable but the (often sensible) "ignore extra injections" box was readily tickable. That it's available but the software arrangement is complete gash leads me to think that it's more of a Friday job. (combined with software that often crashes and nonsensical injector drive setups)

The 25 sec minimum on petrol is sensible. It'd be handy to have the option to disable it whilst mapping, but isn't vital.

Emergency starts on gas, with a limit to the number before you have to plug in a laptop and reset it, is sensible. This isn't what this particular ECU offers though.

Which version of MEMS does the 820 use?

Only asking as my selection of MG/Rovers run at least 3 different versions.

Pass on that. It's an end of production 820; Mk2b or post 1996 facelift with the wasted spark setup.

And the results are in:

First fill (faffing around mapping) got 23 mmpg over about 45 miles. Another fill after a week of faffing around locally also got 23 mpg in town. On the long run from Pembrokeshire to Nottingham he managed 30 mpg on gas. Both are less than petrol, but not as much less as they ought to be going on 26 MJ/litre for LPG and 34 MJ/litre for petrol.

If you use the average prices here:
http://www.petrolprices.com/

Then it's the costs the same as a car doing 44/57 mpg on petrol or 45/59 mpg on diesel.

I'm ignoring the 25 seconds of petrol on startup mind! He'll have to chuck a fiver's worth in every 3 months or so. It'll do he says!