mapping help/tutorial

[NigelD]

I posted this in another thread but think it will get missed/lost and maybe it deserves a thread of its own :-


does anyone know if their is a tutorial out there on the web on mapping , it would help me get my head around whats going on with my motor for my own benefit

anyone???

for instance , my installer has set up the map on my car again after a quick recal a couple of weeks ago , he calibrated then added 50% due to the car being supercharged , since then its been tweaked back a few times due to running rich on both banks , its had 10% knocked off then a few 5% reductions so by my calculation , the map is now sitting at about 121% of the original calibration, the cel is taking much longer to announciate but now shows rich both banks again but also a lean code for good measure, just trying to get my head around what the next move will be

[classicswede]

There are vidoes out there but what system do you have. From your comments I would say AEB

Here is a good video on how not to do it https://www.youtube.com/watch?v=jjJik3RMH6o

I've had a bit of a search and can not find any good video.

You need to be working with an OBD scanner so that you can set the map correctly. From your comments about having both rich and lean codes the map is likely to be way off. I would reset the map and start from scratch.

[steviewonder]

I found this guide which I plan to follow:

http://lpgconversioninfo.blogspot.co.uk ... m.html?m=1

[classicswede]

There are a few points in that I would not agree with and some of the information does not go into enough depth. It does also asume you have the latest ECU version.

[steviewonder]

Any tips or advice for someone with a similar system?

[NigelD]

There are a few points in that I would not agree with and some of the information does not go into enough depth. It does also asume you have the latest ECU version.

it looks very good to me as an absolute beginner - would you be so kind to say what you disagree with and your reasons for disagreeing and give us a pointer on the best way forward as an alternative


cheers Nigel

[Tubbs]

I think that's pretty concise actually. And will definitely get you somewhere close.

[classicswede]

I will cover a couple of points here

Quotes are taken from that link

"If the engine is being run as 2 banks, when running on gas, compare the two Tinj.Petrol timings. They will be different, but if one bank is consistently more or less than the other, you should adjust the Fuel Trim Bank 2 until the timings are about the same. If Tinj.Petrol for bank 2 is, say 10% higher than bank 1, add 10 to the Fuel Trim Bank 2 figure and vice versa. The trim figure can be negative. Repeat the above until the two Tinj.Petrol values average around the same."

a bad start in some ways. If you have 10% difference in fuel trims it means you have a problem that needs to be fixed rather than masked by this feature. It should go on to tell you to check for variation on petrol (but don't expect the variation to be as drastic. Variation from bank to bank can be caused by a manifold air leak or incorrectly plumbed in injectors. If you have variation before even considering making adjustments with that feature check % variation at idle, raised idle with no load and under load. Variation at idle only indicates more likely an air leak when variation under load only suggests a fuel supply problems such as incorrect orientated Y connector and squashed hose.

"1.Fuel Type – LPG
2.Injectors – select the option that matches your LPG injectors
3.Type of Revolution Signal – if you have not connected the brown wire, remove the tick from the box. If you have connected the brown wire (we recommend this) tick the box and select Standard from the dropdown list.
4.Ignition Type – select One Coil if you have one coil per cylinder, otherwise select one of the other options. At this point it is not important which option is selected.
5.Inj. – most engines have a sequential injector firing pattern, so select Sequential. If your engine fires all petrol injectors at the same time, select Full-Group. MJ-Sequential is for engines that fire each injector multiple times per cycle and is quite rare.
6.Reducer – enter the operating pressure (when running on gas) of the reducer (this may be fixed or variable.
7.Cylinders – enter the number of cylinders
8.Valvetronic – tick the box if your engine is of this type (e.g. some BMW engine)
9.Type of Change-over – In-acceleration if you have an automatic gearbox, In-deceleration for a manual box.
10.Leave all other fields as standard for now."

With the newer ECU's I have found that the RPM will glitch a lot with the RPM wire connected and only glitch a little without it. No big deal there and only opinion. The type of signal is standard for 12volt signals and weak for 5 volt ones. Point 6 could do with more detail and explination

Back to the first page is does look to assume that you have just done an autocalibration but misses off the first step of mapping if you have done that. First thing to do is check tickover and is so very easy to do. You would think it would also suggest using a OBD scanner if you have one.

If I wanted to be super picky there are loads of points I could pick up on but over all it is not a bad brief guide on what is involved.

Its not a bad starting point but does not cover sorting out a map that has problems

[NigelD]

cheers classicswede , thats very much appreciated , and thanks for taking the time to reply and

thanks for the info

[classicswede]

The other thing you will also need to consider is the shape of the map as where is the highest and lowest numbers. You can see the correct shape on the base map. You also want to take care not to get any jumps from one box to the next. You should have no more than 5% difference from one box to the next.

[Tubbs]

I kind of disagree with you on the uneven banks thing dai.
Personally I always look at the fuel trims on petrol both banks. And see if they are even.
A lot of the time they are out by a few percent of each other (LTFT). And a can of carb cleaner shows up nothing untoward. So as the conversion progresses you have a look at vac pipes and the like.
When you get to initial calibration the injection times are out. So what do you do ? Tell the customer he needs two new lambda sensors. Possibly cats as well because the injection timings Arnet perfect ?
It could also be down to petrol injector wear, or even engine wear due to insufficient oil change schedules. We don't often convert brand new cars. They are generally 30-70k and up. And a good few years old as well. We just convert them to LPG. And deal with any issues they have that may impact on the running of LPG acceptably, like changing plugs, ignition coils, looking for potential air leaks.
Praise AEB for the fuel trim bank 2 option. It's a very well thought out idea.

[classicswede]

Most systems have that kind of function and some of them are much better. It is a flawed function and using it tends to cause more problems than it solves. The OMVL Piro had the best system for doing that kind of thing with 2 totally separate maps, just a shame there were/are so many other problems with the Piro.

When the imbalance is there on petrol there is little point is making it right on LPG and better to leave the same level of imbalance tbh. Either that or fix the real problem.

[Tubbs]

As I said though. Sometimes the problem is not financially viable to fix. I generally leave it be unless the trims are miles off as well. In certain instances it's a really useful tool. If the banks are running - on one side and + on the other. Pulling them back together is helpful.

[classicswede]

but the real point is it is most certainly should not be using that feature as a first move.

[Tubbs]

I don't know. It kind of explains the feature pretty succinctly.

[classicswede]

But it totally misses step one of what you would us the feature for.

As the guide is for DIY use it should cover the basics

[LPGC]

These days AEB systems have one of the worst bank trim features out of all systems that have such a facility, and the vast majority of systems have the facility. Many systems allow an individual trim to be set for each individual ECU channel (i.e. 8 trims on an 8 cylinder ECU), aren't fussy about which ECU channels are used on which banks or which cylinders within those banks. Other systems allow individual channels to be assigned to bank2 and a trim to be set for bank2 but are similarly not fussy about which ECU channels drive which engine cylinders - Obviously it shouldn't and doesn't matter on a truly sequential ECU with individual trims or channel/bank assignment, because the truly sequential nature won't pulse an LPG injector until it's corresponding petrol injector pulses...

AEB systems probably don't allow individual cylinder trims or channel assigning due to backwards compatibility issues - it wasn't very long ago that AEB systems only measured petrol duration from the front cylinder of each bank (blue wires) and dosed all the LPG injectors on the same bank with the same fueling.... reminds me of the old 'AEB systems are not truly sequential' debate on various threads on this forum! Even with modern AEB systems it is still necessary to wire each cylinder to the correct ECU bank loom because the ECUs don't allow channel/bank assignment, and although these days they do read individual petrol injector duration and are seemingly truly sequential (well at least the metal bodied ones seem to be) it would seem to be an unnecessary risk of wasting time to try wiring them any other way than the usual brgy from front cylinder to back to put the truly sequential aspect to the test, though I do intend to try it one day when 'free' time allows! Even ESGI allows individual cylinder trims and isn't fussy about which channel is connected to which cylinder, because ESGI has always been truly sequential... As long as an ECU channel's input and output relate to the same cylinder it doesn't matter which channel is wired to which cylinder, not even for bank trims, and most none AEB systems are now like that.

In fairness I can see both sides of the argument regarding setting fuel trims, though I agree with Dai they should only be needed in certain cases and then aren't ideal... Sometimes trim widening issues (when running on LPG) are simply due to poor mapping... for instance, if you have an engine idling at 2.7ms and you adjust calibration points at 2.5 and 3.0ms, then if the 3ms point is set too lean and the 2.5 too rich the difference in trims may be exaggerated at idle with the bank with least duration going further into the minus and the bank with the most duration going further into a positive trim. Such trim issues are usually only seen during initial calibration and disappear as soon as calibration gets a bit more thorough/accurate. If the trims widen under load/higher rpm then it's reasonable to suspect a difference in flow between gas feed to each rail, so maybe time to check the pipe runs. If the trims are wider on LPG across the entire load/rpm range then it is reasonable to suspect injector issues (since injector feed pipes won't be affecting low loads but as an extreme example different nozzle sizes on different banks would cause this sort of entire map range bank trim issue). All the above mentioned points would be due to LPG system install or calibration issues..

Only if the trims are fairly equal across most of the range but widen at lower load/rpm with a warm engine would I really suspect an engine issue as opposed to an LPG system install / calibration issue, maybe due to cylinder leakage or different air flow into each cylinder, could even be lambda sensitivity or it's heater operation. But even in this case, setting a trim is at best a compromise because the LPG bank trim will be applied across the whole map when you only want to correct the low load/rpm situation. Interestingly, it is possible on some systems to dial out low rpm/load cylinder leakage issues in a different way using a bit of a fudge method - injector offset makes little difference at higher loads but a big difference at low loads/rpm, so adjusting the offset can be a means to obtain closer trims across the range, but is still a compromise.

I really don't like to see high bank trim figures, always wonder what open loop wot fueling will be like when I'm not there to check the mixture with a code reader or watching lambda values... As installers we like to think we have great control over fueling when it comes to mapping etc, and it is true that we do, but then there's the necessary evils of temp correction and pressure correction, granted all easy to get your head around on the face of it... But consider this, 100 - 10% = 90, 90 + 10% = 99 (not 100), simple maths of course, but does anyone ever stop to think how the order of which all these corrections can effect fueling and bank trims? It's not unusual to see different bank trims at different engine temps, this could be due to engine tolerances due to metal expansion (leakage), hydraulic lifter bleed-down speed, lambda response at different temps, injector response at different temps, or maybe just the point in the calculations when the bank trim is figured in...

Simon
http://www.Lpgc.co.uk

[NigelD]

just to bump this again and ask for a bit further advice if I may

having gotten royally pissed off with the continuous CEL and running rich both banks , I have now ran a recalibration on my king ecu,

I have selected a squirt of petrol to come in at 3500rpm amount of 8ms and timed 8ms , (as an extra precaution for VSR ) I'm not alarmed that I will be using some petrol

I have selected extra inj sensitivity at 1.5ms and extra inj.ident time at 1.4ms , the enrichment in acceleration is right to the plus side.

one thing that I have noticed now is that now on the display menu the injectors measurement is highlighted just into the too small indication.

is there anything I can do to adjust this or is it a problem for further tuning?

, the car is running fine without any lumpiness and changes back and forth from petrol to gas with no issues .I intend to map further under varying loads but wondered if this would give me any issues.

I have given up with my installer after months of fucking about and intend to sort this myself if possible but may need some recommendations for someone to map it in the Newcastle area in the future (if I can't get it right )

as a reminder its a 4.2 s/c range rover

thanks in advance NigelD

[NigelD]

having gotten royally pissed off with the continuous CEL and running rich both banks , I have now ran a recalibration on my king ecu,

I have selected a squirt of petrol to come in at 3500rpm amount of 8ms and timed 8ms , (as an extra precaution for VSR ) I'm not alarmed that I will be using some petrol

I have selected extra inj sensitivity at 1.5ms and extra inj.ident time at 1.4ms , the enrichment in acceleration is right to the plus side.

one thing that I have noticed now is that now on the display menu the injectors measurement is highlighted just into the too small indication.

is there anything I can do to adjust this or is it a problem for further tuning?

, the car is running fine without any lumpiness and changes back and forth from petrol to gas with no issues .I intend to map further under varying loads but wondered if this would give me any issues.

I have given up with my installer after months of fucking about and intend to sort this myself if possible but may need some recommendations for someone to map it in the Newcastle area in the future (if I can't get it right )

as a reminder its a 4.2 s/c range rover

thanks in advance NigelD

[LPGC]

Nigel,

A fair drive but I do get a lot of people from the Newcastle area coming to me in Yorkshire... Have converted a large number of S/C Rangerovers and always get good results. AEB ECU (King), what injectors and reducer(s) do you have fitted?

Simon
www.Lpgc.co.uk