Bongo Fury

I just had the first year service on my Prins LPG conversion. During cold weather it had a problem of stalling during changeover to LPG, if it was stationary at traffic lights or similar. It did it last weekend on a roundabout, scary. So booked in straight away.

All now seems cured and it is running so quietly I keep thinking stalled again, but all is well. It always was a quiet engine, but seems even more so on LPG. No obvious reason for that I can think of?

The explanation I had from the garage for the stalling, is that the Bongo's diagnostics are so non standard that the LPG kit cannot "talk" to the lambada sensor on the Bongo. This means the LPG set up has to be done by hand rather than configured automatically, making it a tricky job and needing regular adjustments.

Does this make sense to the more expert? The converters I use do a lot of Bongos for several local dealers, so should know what they are talking about.

I too had the Print system fitted. just over a year ago. when they were setting it up they had a problem with the lambda sensor not performing as it should. The explanation was;
The changeover from petrol to lpg is at a particular temp'/resistance. My sensor wasn't reacting linearly and so the lpg is cutting in to early and stalling. Because of the vaste expense of a new mazda sensor I put up with it. Recently I had my 1st year service on the lpg and like magic the sensor has fixed itself.

I hope your as lucky.....
Regards
Terry

The lambda sensor tells the ECU how much oxygen is in the exhaust, so if there's too much it will richen the mixture. This is apparently why you wont get accurate fuel consumption until you've filled and emptied the gas tank a few times so all the air has been purged out of the system and then it will weaken the mixture.

The cut over to LPG on my BRC system is controlled by the coolant temperature reaching 40 degrees in the vaporiser. I don't believe the lambda sensor is directly responsible for the switch over, but if faulty could result in the mixture being too weak or rich. However, that would affect running on petrol too.

i had stalling problems on my convertion. was fine for 2 weeks then started. very random. also some times it would feel like it was being starved of gas. when i took it in they wired it up and took it off for a spin.

they found that the bongo was giving out false rev readings. where they plug the sensor in it was blipping from 2000rpm and then down to 0 in a split second. (even though it was reving at a constant 2000rpm). so the lpg system was reacting to this. hence the stalling. all they did is move the sensor connection as close to the monitoring point and since then have not had any problems. they dont know if it was the cable or not. but hey ho.

luke

Hi,

Had same experiance with my LPG conversion. It became an issue when the air tempratures started to fall. I fortunatly have an LPG converter close by who has many years of experiance. So I took my van there as it was a 300 mile round trip to get it back to the origonal installers.
He explained that he saw many LPG conversions with this problem short after install & the most common cause of stalls on change over from petrol to gas is engine temprature. If the engine is not warm enough the evaporator for the LPG which is in liquid form is not heated enough to be evaporated correctly, hence the engine stalls. Most evaporatores are heated by the water system ( appaerntly there are some electrically heated ones) so rely on the engine temprature.
A minor adjustment on the setup to switch at a slightly higher tempraturethan it had been set at cured it for good.

Cheers

That sounds exactly the problem, the temperature setting for the fuel changeover. It was slightly off, probably caused by being unable to get the data from the lambda sensor. My V6 is older than all other in the club and the diagnostics probably more primitive.

I own one of the first V6s ever made, very early VIN. In a question on the forum a couple of years ago it was the oldest V6 in the club. Although the V6 engine is the same, most V6s in UK are later models with more in the way of electronics. These are probably easier to set up. There is no evidence the lambda is faulty, it runs perfectly on petrol and LPG and emissions are very good on both.

It seemed absolutely fine when I collected it, we are now snowed up, so I will find out how it is long term when I can get the Bongo up the drive. This is one of the reasons why I used a local converter, easy to get problems sorted out.

Out of intrest, what year is your V6? one of mine is a 97.

cheers

A real oldie. First registered in Japan 11th October 1995. VIN SG5W10589. One of the first V6s, as the original production was all diesel. Its built like a tank and has been incredibly reliable, just service parts for the last five years.

Registered and serviced by a Mazda dealer in Shikoku, one of the more southern islands in Japan, so no rust. It came straight from the dealer with a full service history. I even managed to find a view of it parked outside its owners house on Google Earth. Not a very good one as it was in a very rural area, but clearly a green bongo.

New Forest Terrier wrote:A real oldie. First registered in Japan 11th October 1995. VIN SG5W10589. One of the first V6s, as the original production was all diesel. Its built like a tank and has been incredibly reliable, just service parts for the last five years.

Registered and serviced by a Mazda dealer in Shikoku, one of the more southern islands in Japan, so no rust. It came straight from the dealer with a full service history. I even managed to find a view of it parked outside its owners house on Google Earth. Not a very good one as it was in a very rural area, but clearly a green bongo.

Hi could you give the details of the google earth,I have friends in that area.