General mapping tips?

[Budgetbond]

Thanks v much guys (soz not been on here much I haven't been using my car much in lockdown but haven't had any probs with it running or emls I haven't forgotten you tho) I'll check the obvious connections haven't come loose tommorrow.

However I'm not sure exactly whether my map nozzle is plumbed in completely effectively anyway. In initial haste I just attached my map hose to an existing port in the inlet manifold that powers a butterfly valve (a flap that restricts air flow at low revs) instead of drilling.
I've played around and tried to optimise this set up but I wonder if I'd actually be better off now drilling it into a more effective position.

The problem is my reducer is positioned close but at the completely opposite end of the inlet manifold to the throttle body, I'll try and get you a pic, so at the mo I've got quite a long map hose going into the port it's attached too.I

Could anybody suggest a better spot to drill the manifold, id like to get a short hose, but would like it effectively placed.

[Budgetbond]

IMG_20200719_202229_hdr.jpg (614.75 KiB) Viewed 4488 times

[Brian_H]

Ideally you want somewhere near the throttle area - Sometimes you can find a spare port to use, other times you have to drill a hole and put a nipple into it. Don't know your engine to suggest anywhere without seeing it, but it sounds like your current location maybe isn't suitable.

The length of the reducer vacuum line generally doesn't seem to matter, one of mine crosses from the front of the engine on one side of the car to the reducer in the furthest corner of the engine bay and is probabbly over a metre in length overall.

[LPGC]

1.02kpa or 102kpa? If 102 check the piping between the manifold and pressure sensor hasn't come off somewhere (including connection to the reducer if you've used a T in the vac lines).

[Budgetbond]

Yeah Cheers guys, shouldve checked really but my map vac hose had come loose where I'd t'eed it in to an existing port near the throttle body. It's not totally secure and I think I need to drill a separate nozzle into the manifold really for max effectiveness, it's just a case of where?

I've re-autocalibrated it (can't wait to get it done properly) but it's slightly hesitatory from idle when stepping on the gas.

What are the usual suspects, briefly, when it seems to hesitate a bit? (Maybe my vac lines still a bit loose)

Do people say it's generally more important to have the map inlet closer to the throttle body than in keeping the hose actually short then?

And do people try and secure their hoses to prevent flex at all and does that make much difference?

Btw thanks for the assistance it's good to be back on here, I still think there's good potential for lpg long term when we're out of this lockdown etc.

[Brian_H]

On the hose flexing point - you need to allow it to move so it doesn't pull it off at either end as the engine moves etc. I usually just use a cable tie at a few points to stop it getting tangled in anything else and leave a little slack on the ends to allow for any flexing that might happen. On the hesitation it could be a few things, calibration being one of them, though long pipe runs can also have an affect. Long in this case is the length from the exit point of the injector to the point where it meets the petrol injector. Ideally your spud (nozzle drilled into the inlet) will be very close to the position of the petrol injector.

Auto calibrate might get it running, but won't ever get as good results as someone who can interpret whats going on and setup the correct values over the whole range of conditions. Your looking ideally to see the same trim values appearing when switching between fuels on the car to know you've got it right.

But really first thing to do is sort the map sensor out properly so the hose can't just fall off - silicon vacuum hose can be an easy way to solve that, as it will slide onto hose barbs and stay in place without needing clips, making for a neater appearance as well.

[LPGC]

102kpa as I suspected then...

There are many usual suspects... Assuming setup is OK in the first place (parts fitted in correct positions) or you'll never get good results - Autocalibration will only get calibration something like correct around idle, the rest of the map won't be correct until it has been manually mapped. Injectors can be too slow (but this won't be your problem), nozzle size and pressure combination can be incorrect, the petrol system might feature 'extra injection' which can cause problems during acceleration, most ECU's can directly filter extra injection pulses but ESGI cannot (there are some workarounds but some workarounds involve changing aspects of setup / piping).

As Bri says for the piping and vacuum hoses.

[mgrover]

question on mapping. i've somehow got it to match the petrol trims roughly, maybe it could be a tad richer but thats simple enough. but it pulls hard and well throughout the rev range with no misfiring which is great, but theres a very harsh lurch when i take my foot off the throttle, i assume its cause the injectors are going to 0 is there anyway to soften this? or do I need to map that out so to speak. AC Stag system btw.

[Brian_H]

@Budgetbond I'd also consider getting the (lack of) valve saver situation looked at if you want to keep this going longer term.

@Mgrover - Is that on your 4.2 SC Rangerover?

[Budgetbond]

Cheer s, yeah you're right about the kpa, sometimes it's hard seeing the software on the laptop, I'm unsure on how to adjust pressure and whether/when it could be needed, I know there's a nut on the reducer I just left from the previous set-up, my pressure and P1 now fluctuate, there are pressure setting sliders in the software ones a P1 min another's a max setting set on 1.2 bar/120kpa I've tried adjusting them, but they seem to change after an autocal a bit, I don't know whether I should try and change them to optimise it a bit/whether it'll make any difference.

Bar the odd italian tune up I mostly want mine efficient upto just after peak torque only really going upto less than 5k revs cos most of my running is pretty economical anyway.

And cheers Brian for the heads-up on the valve-saver, I know it's recommended at the mo I'm trying to combat it in a couple of other ways, but with the opportunity to put a few more miles under my belt I'll look into it more. I did go to see an ex-taxi running one of my engines and they just had a tube going into an open upright plastic milk bottle with some oil in it!!

Am looking forward to getting it mapped properly to get it running efficiently, I'm looking forward to the opportunity to do a bit more touring, recently started doing the Sun holidays handy at the min and dirt cheap.

[Brian_H]

Cheer s, yeah you're right about the kpa, sometimes it's hard seeing the software on the laptop, I'm unsure on how to adjust pressure and whether/when it could be needed, I know there's a nut on the reducer I just left from the previous set-up, my pressure and P1 now fluctuate, there are pressure setting sliders in the software ones a P1 min another's a max setting set on 1.2 bar/120kpa I've tried adjusting them, but they seem to change after an autocal a bit, I don't know whether I should try and change them to optimise it a bit/whether it'll make any difference.

Bar the odd italian tune up I mostly want mine efficient upto just after peak torque only really going upto less than 5k revs cos most of my running is pretty economical anyway.

And cheers Brian for the heads-up on the valve-saver, I know it's recommended at the mo I'm trying to combat it in a couple of other ways, but with the opportunity to put a few more miles under my belt I'll look into it more. I did go to see an ex-taxi running one of my engines and they just had a tube going into an open upright plastic milk bottle with some oil in it!!

Am looking forward to getting it mapped properly to get it running efficiently, I'm looking forward to the opportunity to do a bit more touring, recently started doing the Sun holidays handy at the min and dirt cheap.

The flashlube or other brand bottles aren't much more sophisticated than that, its only really the dosing bit thats slightly more tricky to get working really. until you get to the electronic type anyway! but bear in mind that the fluid isn't cheap, so you want some sort of metering going on with it to get the benefit of it.

The sliders if they are the ones on the panel gas tab labelled P work would be the reference pressure, and the p min should be the pressure it switches back to petrol at. Reference pressure being what pressure the map relates to (the ecu should compensate for this depending on the actual pressure being delivered, think of it as a baseline - so you should setup the reducer to provide the pressure you actually want by turning the adjuster on it till the desired pressure is given - do that while the reducer is warm and engine running on gas, then set the p work pressure to reflect that pressure before you start mapping).

[mgrover]

It is indeed the 4.2 SC

[Budgetbond]

Anyway, I've reconnected my map vac line into its original position temporarily but I will relocate this by drilling the manifold in due course, but I was sort of mystified as to why the lpg system and on petrol too it still seemed to run fine without triggering any eml light surprisingly perhaps?
Anyway my cars running fine again, and my car got through the mot emissions test on lpg which was good and a slight relief after the work id put in (I did clean up my 02 sensors and catalyst which did 'seem' to make a bit of a difference)

Am still slightly confused over the pressure settings and how they can be easily tweaked?

The P1 min is the fuel pressure coming from the tank by expansion, so generally what's the min supplied pressure from the tank required to still run on gas?

And the reference baseline lpg pressure level in the software and the nut on the reducer, how and do they need to be setup or changed correctly or does the software just make the necessary ginj adjustments based on whatever inputs it receives?

[Gilbertd]

The P1 min is the fuel pressure coming from the tank by expansion, so generally what's the min supplied pressure from the tank required to still run on gas?

No, the gas from the tank is still liquid at around 10 bar (145 psi), the reducer vaporises it and reduces the pressure to whatever it is set to supply the injectors at. Pmin is going to be when it switches back to petrol because there's no liquid left and only vapour is arriving at the reducer or you are using it faster than the reducer can handle so the output pressure drops.

[Budgetbond]

Hiya Richard how's it going hope you've been doing alright, yeah so I sort of assume if your P1 min pressure was set too high it would switch back to petrol when there was still usable lpg levels left in the tank?

[Brian_H]

Hiya Richard how's it going hope you've been doing alright, yeah so I sort of assume if your P1 min pressure was set too high it would switch back to petrol when there was still usable lpg levels left in the tank?

Yes, but its a balance between having it shut off too quickly, and finding it suddenly switches back when you goto acclerate. I think Simon said some sort of guide level as a proportion of the reference pressue, but can't be sure on that. Looking at one of mine, the working pressure is set to 1.2, min pressure 0.6, another is 1.5 and 0.7, and 1.1 and 0.5. So that would suggest around 50% of the reference pressure is where you should aim your p1 pressure to be set to. Though it might be slightly different with your kit as to what would be recommended.

[Budgetbond]

Thanks Brian yeah I've heard those sort of figures banded about and the 50% ratio I'm sure there must be some sort of correlation.
I'm just starting to try and monitor my consumption/range from the tank and it sort of seems that between 225-275 miles (which I'm getting approx from a 55l tank) is what people generally seem to get regardless of what engine theyre running and the size of there tank, but I could be mistaken there?

[Brian_H]

That's around what I get from 55l on a 2.3 engine. I can get around 300 on a 1.8 with 48 litres. The v8 manages around 300 miles from 100 litres if it's on motorway, less around town.

You'd do better to work out what you can get out of a set amount of petrol and look to get somewhere around 60% cost on lpg. Though depends how cheap you can find it for too.

[Budgetbond]

I'm just getting used to it really a tank refill for me seems to take about 38l 's in and I think I'm averaging about 250 miles outta that, it's a 1.8, but somebody was driving behind me today and said my exhaust was qu whitey smokey I wonder if I'm running quite a bit rich anything above an autocal idle, could prolly do with a good mapping, I wonder if just general ordinary driving around for me with my laptop plugged into it would help in that regard in the interim?

[Brian_H]

If the engine was relatively cold at the time and on gas, thats probabbly just steam, you will get a bit more water vapour on gas. Usually not visible once its warmed up properly though.