Renault Megane 1.6 16v

[luisfl]

Hello,
I'm from Portugal and would like to get your help.
I have recently installed a LPG Prins VSI 2.0 in a Renault Megane 1.6 16v, but I have a problem.
As normal, the car always starts first with petrol and then switches to LPG, but when the engine is cold and I turn on the car is a problem. Combustion is very weird and wrapped, chokes and does not develop. Once heated and passes into LPG is ok.
Resetting the original ECU helps to fix the problem, but then reappears.
My installer told me that this is due to a lean mixture of fuel because the ECU gets confused. He also told me that if my system was Italian (BRC or LANDI) would be easier to adjust the injection map, but with this prins system is not possible. He told me that the solution is to install a sensor that causes the car's ECU to read a lower temperature, thus to enrich the mixture. Once it reach 25 degrees this sensor is disconnected and the ECU is reading the original temperature sensor.
Someone could help me? Does this make sense?
Thank you.

[LPGC]

Hi,

When any sequential system has been installed, including the Prins VSI systems, it then needs to be calibrated or it is unlikely to work properly.

You say the engine runs better on LPG when it has warmed up, but even when warmed up the engine warning light still comes on...

It seems the installer you went to is suggesting wiring in extra parts to fool the system into believing that the reducer temperature is colder than it actually is (and only when the engine is running on petrol). This is easily achieved, could make the system change onto LPG when the engine has warmed up more, and might help - BUT it is a bodge and it is still almost certain that the vehicle wouldn't tun properly on LPG.. because the system still wouldn't have been calibrated properly.

It seems you don't have the facility to calibrate Prins systems and the installer you went to doesn't have the facility to calibrate Prins systems, which is why he is suggesting the bodge.

If you have the facility to calibrate the Prins system, you can make it change onto LPG at a warmer temperature without changing wiring, and you can also properly calibrate the system. This is a far better approach than trying to work around the problem by wiring in extra components like the installer you visited suggested... But I would give the installer some credit for his lateral thinking - I did similar once to repair a very strange system of unknown origin.

To calibrate the Prins system, you need the Prins interface cable, Prins software, and a 'key' (password). Without the key, you can't adjust anything so the interface and software wouldn't help except to help you see what is wrong (but not able to correct it without the key).

If you were in the UK, I would recommend you visit me so I could calibrate the system. Since you are in Portugal, I suggest you visit a Prins installer there - But do get a quote for the calibration first, as to say a lot of Prins installers over-charge is putting it mildly, and they may do the same in Portugal!

Hope that helps,

Simon
www.Lpgc.co.uk
07816237240

[luisfl]

The system he wants to ride is more or less like this:



Uploaded with ImageShack.us

[rossko]

That doesn't change Simon's advice. Get the Prins system set up properly, no extra parts are needed.

[luisfl]

The only problem is when gasoline (colder worse). When switching to LPG is good. I have no warning light on.

My installer has access to configure the system. It was he who installed the system. Therefore he will have the cable, software and password. He is not the representative of Prins in Portugal, but works in partnership. The representative is in the north of the country and I'm further south.

The installer told me that other systems (eg BRC) let you adjust the injection map value to value, but this system (Prins) uses the injection map of the car by applying a correction factor (to correct the difference in fuel).

Initially, I think he did reset the ECU to the car and got better, but then returned to the same.

However he told me that some ECUs were in conflict, and that mine would be one of those cases. (Siemens Sirius 32, I think ...).

He told me that the ECU was learning the parameters of driving on LPG. Thus, when the car is started petrol blending is poor (because the LPG has more octane).

So he set up that system in the drawing.

However I get the car, but still had problems. When he made the switch to LPG, shut down. Problem ... rich mixture.

At this time I do not have the car, because the installer is attempting to place another sensor that can shut off sooner, in order not to be a rich mixture when the LPG is activated.

In Portugal a few installers know the system of Prins. As I am no longer trust my installer and I do not want to offend by speaking with the importer, I come here to ask for advice who knows much about it.

Even though apparently the problem is resolved, I will get suspicious if one day later will not cause other problems in the car.

Sorry if I explained poorly.

[Gilbertd]

The problem isn't resolved, it has been modified to try to cover up the problem. The system needs to be calibrated, just the same as any other system but it seems that your installer isn't capable of doing it. Find another installer that does know what he is doing........

[woody]

Hello,
I'm from Portugal and would like to get your help.
I have recently installed a LPG Prins VSI 2.0 in a Renault Megane 1.6 16v, but I have a problem.
As normal, the car always starts first with petrol and then switches to LPG, but when the engine is cold and I turn on the car is a problem. Combustion is very weird and wrapped, chokes and does not develop. Once heated and passes into LPG is ok.
Resetting the original ECU helps to fix the problem, but then reappears.
My installer told me that this is due to a lean mixture of fuel because the ECU gets confused. He also told me that if my system was Italian (BRC or LANDI) would be easier to adjust the injection map, but with this prins system is not possible. He told me that the solution is to install a sensor that causes the car's ECU to read a lower temperature, thus to enrich the mixture. Once it reach 25 degrees this sensor is disconnected and the ECU is reading the original temperature sensor.
Someone could help me? Does this make sense?
Thank you.

What a load of bollocks,the the person resposible for putting the parts under the bonnet [you could,nt call him an installer] is talking out of his rear end, he obviousely has no experience with VSI 2 or indeed understands the fundamentals of LPG injection systems.
Set up right it will work faultlessly.

To put LPGC right there is no key, the code he refers to is sent to the installer from Prins BV this allows you to download the software,Simon do you have the official software from Prins??

Get it properly calibrated and it will work.


Woody

[LPGC]

Hi again,

I thought you installed the system, but never mind...

Prins isn't as adjustable as other systems, but does allow basic calibration.
Prins allows installers to change-over temperature, the working pressure, the basic time that the LPG injectors open longer than the petrol injectors (this is called offset), a single figure adjusts the amount it multiplies the petrol injection time by to calculate the LPG injection time, and there isn't a lot else to adjust. Most other systems (except Egas) allow at least the multiplier to be variable.

In your case the basic calibration is wrong and needs correcting.

If your installer is able to calibrate the system, he should know he doesn't need to make circuits to adjust the temperature which it changes to LPG. Because he has ideas about making a circuit instead of simply adjusting the changeover temperature in calibration, I don't believe he has the facility to calibrate it.
Another point: Because of the very basic calibration that Prins allows, you need to fit very linear injectors or you can have problems. Prins usually use Keihin injectors, which are arguably the best in the business. If these (or similar) injectors are not fitted, this may make calibrating your system properly very difficult.

Another point: Because of the very basic calibration that Prins allows, particularly the none-variable multiplier, you need to fit very linear injectors or you can have problems. Prins usually employ Keihin injectors, which are arguably the best in the business. If these (or similar performing) injectors are not fitted, this may make calibrating your system properly very difficult.

I was expecting the circuit to look like the one you pasted. If your installer has facility to calibrate the system, he wouldn't need to make a circuit to adjust the changeover temperature. For this reason, and also for most of the things you said the installer told you, I believe the installer is lying when he says he has the facility to calibrate the system, or has fitted injectors that are not going to work, or simply doesn't know what he is doing.

You should now go to an installer who can calibrate Prins, get them to do so, and your installer should pay!

Simon
http://www.Lpgc.co.uk
07816237240

[rossko]

He told me that the ECU was learning the parameters of driving on LPG.

That part sounds correct. But - the idea is that (when the gas is set up properly) the petrol ECU sees no difference between gas and petrol, and there is nothing different to learn. The installer's art is to set the gas up so that it works like that.
It does sound like your man needs a bit more practice or guidance setting up the VSI-2.

There isn't much we can do about it from here. A suggestion; perhaps let your man take your car to the importer/representative so that it can be set up properly now, and also he can learn how to look after it in future. Everybody wins. He can save face by calling it an extra difficult and unusual car if he likes.

[luisfl]

I forgot to tell that the installer also said that one possibility (although very complicated to implement) would be to replace the ECU of the car with a different one (eg Bosh). Perhaps there was no more conflict with the ECU LPG system.

I'm confused. I chose the system of Prins (more expensive) with Prins Valve Care because I had the idea that it would be better than a BRC, Landi Renzo or Tartarini.

It is for these reasons that I start to not trust the installer.

[Tubbs]

You have had 2 Prins installers (woody,rosko) tell you the same thing now. Your installer doesn't understand what he is doing and is trying to mask the problem by doing some bodge to fool the petrol ecu into believing its at a different temp.
And now saying that maybe he has to change the petrol ecu for a different type. Honestly i would run from him to the importer and get them to sort it. Even if its a day out of your life. You could be going back to this joker for weeks, loosing more time and getting more annoyed. A 1.6 renault megane is not a problem. All injection systems add a correction factor to the LPG. Its certainly not specific to Prins.
If it is indeed running too rich when it switches over why has he not just set the changeover temp threshold higher. My bet is that he has put too big injectors on for the vehicle. But thats just a wild guess.

[Gilbertd]

You chose a good system but the wrong person to install it. He does not understand, or does not have the correct software to work with Prins. You need to take the car to a different, Prins approved, installer to get it correctly set up.

[woody]

According to the Prins website there is only 1 official importer in Portugal

LPG
Rua do Mirante 91
4415-491
Grijó


T. +351 (0)22 744 22 90
F. +351 (0)22 744 22 90
mastergas@hotmail.com
http://www.mastergas.pt

This would be the first port of call i reckon , see what they say and go from there.

woody

[hardcorepit80]

I think what that Portugal installer mean is Prins Temperature Emulator. But as everyone else I think its setup problem...
Temp. emulator can be use for VAG cars "unwanted enrichment", never heard about that problem in Renault.

[luisfl]

According to the Prins website there is only 1 official importer in Portugal

LPG
Rua do Mirante 91
4415-491
Grijó


T. +351 (0)22 744 22 90
F. +351 (0)22 744 22 90
mastergas@hotmail.com
http://www.mastergas.pt

This would be the first port of call i reckon , see what they say and go from there.

woody

Yes, this is the importer in Portugal. It is in the north, near Porto. I'm further south, near Lisbon.

[luisfl]

I think what that Portugal installer mean is Prins Temperature Emulator. But as everyone else I think its setup problem...
Temp. emulator can be use for VAG cars "unwanted enrichment", never heard about that problem in Renault.

According to the installer:

The procedure is to make a circuit with a relay and a temperature sensor (30 degrees) that will force this value 4500 ohms (which corresponds to a temperature of -5 to 0 degrees), and being deactivated by the sensor itself or through the relay kit gpl. Starting 30 degrees since the ECU can read the original signal from the sensor.

Something like that!!!

[Tubbs]

Thats all well and good, but the advice still stands, he is masking a problem rather than fixing it.

[Gilbertd]

and it will still run like a dog on petrol the next time you start it up. By fiddling the temperature sensor it will run OK on gas but going back to petrol it will still be wrong. Get it to someone that understands Prins. It may be a long way but it will only need doing once, then it will be fine.

[LPGC]

Hello,
I'm from Portugal and would like to get your help.
I have recently installed a LPG Prins VSI 2.0 in a Renault Megane 1.6 16v, but I have a problem.
As normal, the car always starts first with petrol and then switches to LPG, but when the engine is cold and I turn on the car is a problem. Combustion is very weird and wrapped, chokes and does not develop. Once heated and passes into LPG is ok.
Resetting the original ECU helps to fix the problem, but then reappears.
My installer told me that this is due to a lean mixture of fuel because the ECU gets confused. He also told me that if my system was Italian (BRC or LANDI) would be easier to adjust the injection map, but with this prins system is not possible. He told me that the solution is to install a sensor that causes the car's ECU to read a lower temperature, thus to enrich the mixture. Once it reach 25 degrees this sensor is disconnected and the ECU is reading the original temperature sensor.
Someone could help me? Does this make sense?
Thank you.

What a load of bollocks,the the person resposible for putting the parts under the bonnet [you could,nt call him an installer] is talking out of his rear end, he obviousely has no experience with VSI 2 or indeed understands the fundamentals of LPG injection systems.
Set up right it will work faultlessly.

To put LPGC right there is no key, the code he refers to is sent to the installer from Prins BV this allows you to download the software,Simon do you have the official software from Prins??

Get it properly calibrated and it will work.


Woody

Oops! Silly and misleading of me to call 'a code sent from Prins BV' a 'key' Woody, I appreciate you pointing that out, sadly a tendency of mine is to lower myself to sarcasm when someone points out when I'm grossly incorrect, I'm just glad I can resist tonight (sorry I mean this morning). Since I now know we need to being exacting in our use of words because no-one reading this will otherwise understand what I mean, I trust you were doing the same when you mentioned the installers bollocks in the context of this thread? Yes I have the code / key from Prins BV, no it didn't come to me directly from Prins BV. Do you reckon that affects what the code does, or my understanding of Prins, or my abilities?

Although I've fitted a few Prins systems, they represent a small percentage of the systems I've fitted, but I have repaired a great many Prins systems and often at much lower cost than quoted elsewhere. In fact, I've found in many cases where expensive replacement parts have been advised elsewhere and then a customer has visited me for a second opinion, those parts have miraculously started working perfectly well by the time the customer got to me but unfortunately somehow a minor low cost component has gone wrong. Still, lucky for the customer and Prins reputation eh!

I do install Prins, occasionally when customers still ask for it after I have advised them to spend less of their money / spend it more wisely. Keihin injectors are probably 80% of the reason why, back in the day, Prins earned the good reputation that it deserved at the time and still maintains, 5% probably goes to the Prins reducer which is still good (reliable, pressure stable and allows pressure to be ramped up to over 2bar should the installer decide the higher pressure differential and pressure stability of the reducer means they don't have to bother fitting a map sensor that might improve the system further). That leaves 15% that I'd put down to the lack of (and no need to improve upon due to the Keihin injectors) Prins ECU's calibrational abilities - By this I meaning there is less for the installer to get wrong during calibration.

Prins reputation was earned back in the days when most injectors (i.e. injectors fitted to other systems) performed poorly and were unreliable. These days Keihin injectors don't have to be fitted with expensive Prins bits, they can be obtained and fitted as part of any system. Due to the lack of calibration ability of Prins compared to other systems, reputations might be very different if, back in the day, other systems had Keihin injectors and Prins had the poor injectors that other systems had.

Other systems can emulate the injector output signals (the injector output signals being the sole aspect that determines the performance of an LPG ECU) of a Prins ECU if the installer puts the same number in every calibration box of the other system (flat maps the system). But most injectors were not and are still not as linear as Keihin, and flat maps with most injectors would cause problems. The maps of other system ECU's that were (and still are) adjustable at many points for load (and also many points for rpm on many systems) could be set with the same number in every box if Keihin injectors were fitted - and give the same results as a Prins ECU. Put another way... If you have a system comprising random ECU, Keihin injectors and Prins reducer, it can give at least as good results as a system comprising Prins ECU, Keihin injectors and Prins reducer. If you have a system with Prins ECU, random injectors and random reducer (random includes Prins reducer) it won't work as well as a system with random ECU (random not including Prins ECU), same random injectors (random not including Keihin injectors) and same random reducer. So the Prins ECU goes down as a bad point for the Prins system in my book, Keihin injectors being the Prins systems saving grace. Keihin injectors can be fitted with other ECU's and this can make for a better calibrated and better performing system than Prins. But these days, why spend so much on Keihin injectors when other injectors are available that are reliable, high performing and a fraction of the price. Why spend so much on an ECU that doesn't allow a different multiplier at different loads and is overly expensive? Why shoe-horn bulky components into compromised mounting positions in tight engine bays? There is one potential plus to Prins ECU's abilities, and this is that they can be set up to adjust mixture to keep Lambda at a set voltage during full throttle open loop running, but I don't see many Prins systems installed where the installer has used the feature.

This isn't aimed at Woody or anyone in particular (although I have a few in mind that I'm not going to mention) - Fair play to all the Prins installers that are open minded to other systems and that do proper diagnostics and repairs without charging the earth - But there are those that want to remove an easily repairable LPG system to replace it with Prins, which I'd say is ignorant, arrogant and bad news for their customers. Some Prins installers may think there is still a large gap between Prins and other systems in terms or performance or reliability. Some may prefer, or maybe skills better match, only needing to enter a couple of numbers for a calibrated system instead of the more involved mapping of other systems. If someone is used to calibrating systems by entering a couple of numbers, what are the odds that they'll be less skilled at calibrating systems that need more involved mapping? What are the odds that someone who thinks all other systems are poor will advise a customer to spend a lot of money to replace the system instead of fixing the existing system for little money? What are the odds that an installer who gets a car in with a system they are unfamiliar with will tell the customer they need a complete new system when they know a new system is the only way they can get the customer's business? Some may like to think they are still part of an exclusive installer network for these expensive components which any of us can obtain and fit these days. Some installers would be better rounded in their profession (which should be LPG system installer/repairer, not specific brands LPG installer/repairer), if they injected a hefty dose of open-mindedness and lateral thinking.

I obviously agree with many of your points, which are similar to the points I made first and in fairness I gave the foreign installer a bit of credit for his lateral thinking turned bodge at the same time. Although I don't have a good impression of the installer from what we've learned, he did demonstrate some lateral thinking and many installers are seemingly lacking in that department - Not judging on anything in this thread, but judging on customers reports.

Simon
LPGC

[Gilbertd]

and for a man in Portugal with a badly set up Prins system, all of the above is totally irrelevant to the thread........