Starting problem - Gas conversion ???
 

hi, this is my 1st post.. just bought a lovely mk3 supra which has a gas conversion. you start it on petrol and flick a switch to gas when its warmed up a little. the guy i bought it off always switched it back to petrol before turning the car off. anyway, on 2 occasions it has not started and i think id forgot to switch it back to petrol before turning it off. the weird thing is that when i try to start it the starter motor doesn't even kick in and it just clicks once when i turn the key. this bit could be down to the battery but this has been changed since the first time however i did leave a light on all day yesterday and it ran the battery down. after jumping it i drove it to a few locations and stated ok. however, on the last attempt to start it after stopping for a matter of secons it just clicked again when i turned the key. i jumped it again and the starter moter was eaging but it would not start at all. i hadnt flooded it but after lots of attempts it sounded like petrol gradually got through and it started.. i had to pump the accelerator to do this. not sure if this all makes sense to anyone ! i believe it could be something on the fuel pump or gas conversion but that doesnt explain the battery needing a jump. does anyone know about gas conversions or have any clue whats going on ? its an automatic by the way and incase anyones interested.. it runs beautifully on gas and i get 210 miles on 20 pounds ! i well recommend a conversion. cheers for any help. eggybread !

Hi there, welcome.

If the engine doesn't turn at all, then It sounds like a faulty starter relay or the wire that goes from the relay to the starter. The only way to check this is by putting the front of the car up on jack stands and pulling the brown plug on the bottom of the starter. Then taking a wire from the + battery terminal touch that to the plug on the starter. If the starter bumps then the wire from the relay to the starter is faulty. If the starter doesn't do anything, then the starter may be bad.

Mine would do this, I would go to start it and click, it wouldn't start. Just this past weekend I finally got fed up with it and did something about it. I had a spare turbo wiring harness so I used some plugs from that to make it so I could remove the components if need be. I will get some pictures up soon, but anyway, I wired from the + battery terminal to a switch in the center console. Then from that switch to the starter. I used a two wire plug beneath the center console, then used a single wire plug to go to the starter wire. It cost me about $20 in supplies, thats a good heavy switch, little over 20ft of 14GA wire, black electrical tape, heat wrap, and a small box of misc. wire ends.

I would do the test to make sure you know whats the matter, that way you can make sure the starter is fine. If the starter is bad then it would do the same thing.

Good luck.

Also, get some pics of the gas conversion system up in the show n tell section, I would like to see it.

I am also having a start problem right now, starter or the relay.

Which relay is the starter relay below the passenger kick panel?

Thanks

Right side (passenger side) kick panel, its the bright green relay. I think its on the lower left side of the panel.

Thanks! Saves me pulling the wrong one out!

compressed natural gas converted supra ?

Most likely propane. I have heard of a few Supras running systems like that. I'm working on setting up a alternative fuel system in my Supra, hoping to run it on any combustable gas.

Cheers for the replies lads, I don't know much about the gas i'm affraid... it's just that LPG Autogas, thats all i know. I'll try rigging up a switch to the starter motor.. thanks for that. However, when the starter does begin to run, the engine won't start... this is why i thought it may all be connected to the gas or maybe a safty cut off by the ecu ?? It's weird how the key does nothing for a few turns, then i get the starter motor for a few trys and then the engine begins to splutter and start. In this weather too I need to be careful not to run the battery flat or i'll get stranded ! I'll post some pics of the gas conversion when i get a sec. any other advice is much appreciated.

Well from my experience with my staring problem, after it would click a few time it would sputter and then start. Sometimes requiring me to pedal the gas a little to clear it up.

When you turn the key to the start position, the ECU turns on the fuel pump and "primes" the system, so every time you turn the key to the start position it puts more fuel in the intake. Then when it finally starts its got way to much fuel, so it will sputter or sometimes wont start.

If the car is clicking and not turning over there is a mod you can do to remedy the situation. I did this mod and have been starting normally for several months now. It involves a 30 amp relay, some wire and some terminals and splices.
The details are here.
Car not starting randomly? READ THIS (30 Amp Starter Relay Mod) - SupraMania

The gas mod sounds interesting but over here in Kuwait LP gas and Gasoline are to cheap to worry about doing a mod like that.