Arrghh!! Another new lpg problem.

[KILOCHARLIE]

Purchased a new temp sensor a couple of weeks ago and my lpg has been running fine ever since Seems to take a little while longer to switch over to gas but I put this down to a longer sensor taking a minute or so longer to heat up, or more likely not enough coolant in the coolant/water ratio meaning the system takes a bit longer to warm up.

Either way, I've taken the car on a nice long road trip this weekend and the problems started within 5 mins of setting off. All was well running on gas and then there was a loud warning noise (three short bleeps followed by a longer one) and the lpg light started flashing very fast and the car went back over to petrol. I pulled over and turned the car off and once started again it was back to working fine.

This problem has slowly gotten worse over the weekend and now the car is pretty much refusing to run on gas at all. I'm unsure whether its a loose connection or whether its to do with how much load I put on the car but it seems to be related to starting from a dead stop and putting my foot down. I've checked as much as I can under the bonnet but there's no obvious issue. The warning beep seems to beep 4 times in repeat and the car will just run on petrol until I turn off and restart. I also had an engine warning light at one point which was misfire on cylinder 8.

On a few occasions the warning beep did stop mid way thru and it went back to running on lpg, but at the moment the lpg is beeping and flashing before I even start the car. It sounds like an old digital alarm clock. I've tried slightly adjusting the pressure on the reducer after I messed up what it was originally set to when I diagnosed the faulty temp sensor. This seems to have no bearing on my problem though. My mpg was also the same on my long run this weekend. 4 miles to £1 when lpg is 63p a litre. This is the same as when using it round town even though the indicated petrol mpg had risen from 14mpg to 20mpg this weekend.

Would be grateful for any advice if anyone has any.

Thanks in advance!

[LPGC]

Tell us what system you have...

Why change the temp sensor? If it was taking less time to switch to gas before, maybe the sensor was OK... Usually when sensors fail they open circuit, and with an open circuit the temp reading is around minus40DegC so the system never switches to gas... It's possible to replace a senor with one of an incorrect spec, the system may then notice out of range signal from the sensor and generate a 'temp sensor error' causing a switch back to petrol accompanied by the switch beeping..

All speculation until we know what system you have and what you fitted.. Even then we will be in best guess mode unless you the cable and software..

Simon

[KILOCHARLIE]

Thanks Simon. My system is a autogaz AC with a Magic 3 reducer and Magic injectors. My car is an L322 range rover. My temp sensor went bad after it took an absolute age for it to switch over to lpg. When playing about to diagnose if it was a loose connection, the wire broke to it so I replaced with a screw in type widely available on lpg website which was in the correct range of resistance. It worked fine for the last few months on this.

Just been having a play this evening to try and find out what is causing the fault. Managed to get it running on lpg after a few starts. I poked about under the bonnet and nothing seemed to make it start beeping again so I'm pretty sure its not just a loose connection. As soon as I put the car into drive though it beeped and then stalled. Tried it again and managed to get it coasting down the road and with light throttle it was fine. As soon as I put any normal load on the throttle though it beeped again and switched back to petrol.

It seems this issue has got progressively worse from the start of the weekend where it needed heavy load for it to fault out, while now it just needs minimal load. Maybe I have made this worse by increasing the pressure but it didn't seem to make any difference to the symptoms when I screwed the allen key back down on top of the reducer.

Any idea what this could be? Filters were checked prior to switching the temp sensor and they seemed pretty clean. I have no idea how or where I could link up diagnostic kit to it. All i have is an obd lead for my car but would appreciate any advice where and what I would need to kit myself up!

[Gilbertd]

Low coolant level? Air lock in the reducer?

[KILOCHARLIE]

Coolant level seems fine. Given the reducer a good shake to hopefully free any air locks but all seems ok.

The fault beep didn't happen when the temp sensor failed previously. The unit stayed quiet the whole time and the light blinked slowly as when the system is warming up. Now its flashinh rapidly and beeping like an alarm clock. Anything else I could check? Is this likely to be pressure related? Seems strange that the fault is noticed even before I start the car on most occassions.

[KILOCHARLIE]

Spent another couple of hours on her tonight to no avail. Def not the temp sensor as the fault still appears when its disconnected. Checked all the hoses. Disconnected the battery, unplugged the lpg ecu (which is an AC Stag 300-8 plus btw). Tried again and it seemed to be ok. Switched over to lpg, ran for a couple of mins but then the car stalled when idling. Back to same fault again now

I'm guessing I need an interface cable for further diagnotics if no-one can suggest anything else to check. Is it best to get a usb, serial cable, wifi, bluetooth or obd one? Any suggested place to source / expected price to pay?

Thanks all

[hardcorepit80]

The warning beep seems to beep 4 times in repeat

It means injector problem.
You need lead to find out which.
Something like this.
http://www.lpgshop.co.uk/ccy-usb-lpg-in ... ovato-aeb/

[KILOCHARLIE]

Thanks mate. Will order one tonight.

Car now will switch to lpg fine when stopped. Can rev it hard in both park and neutral and its fine. As soon as I put it in Drive though, the system beeps with the fault noise, shudders slightly and switches back to petrol. Can't understand why it would do this.

Also can anyone tell me if I've done anything bad by disconnecting and reconnecting the ecu? Will this reset any maps or anything?

Thanks for any help you can give guys. Its really appreciated as I'm not very clued up when it comes to this!!

[Brian_H]

Coolant level seems fine. Given the reducer a good shake to hopefully free any air locks but all seems ok.

The fault beep didn't happen when the temp sensor failed previously. The unit stayed quiet the whole time and the light blinked slowly as when the system is warming up. Now its flashinh rapidly and beeping like an alarm clock. Anything else I could check? Is this likely to be pressure related? Seems strange that the fault is noticed even before I start the car on most occassions.

Check while your there that the reducer is actually getting hot - if it isn't its likly airlocked. If this is the case where has the reducer been installed?

The choice of lead you ask about really depends what connections you have on the laptop, if you have a proper com/serial port use one of those leads, if not then a usb one makes more sense (keep it as simple as possible)

[KILOCHARLIE]

Thanks for the reply. Muchly appreciated. Reducer is getting too hot to touch as it always has

Thanks though.