Lpg Converted Previa Cut Out / Idle Problems.

[Custador]

Hello,

I recently bought a '98 Previa auto-box that has been LPG converted; it had a few issues to sort out, most of which I've sorted out, but one of which I can't figure out.

When I start the car, it chugs for a second or two until I give it some gas. If I come off the gas too fast, the revs drop way low and the engine cuts out. I've tried adjusting the idle up at the cable on the throttle-body, but as soon as the engine is stopped and restarted the problem comes back. It only has this issue when running on petrol and when running cold - with the engine cold, if it switches over to LPG the same thing happens as soon as I come off the gas peddle - revs suddenly drop through the floor and it stalls. Bizarrely, once the engine is up to temperature and has switched over to LPG, it runs like a dream. It will still stall if switched back to petrol while stationary though.

I have cleaned out the PIM sensor, the filters and the vaccuum hose between it and the throttle-body (and lost the bolt that was holding it to the floor-pan in the process - it's now gaffer-taped up out of the way), but that hasn't solved it.

Basically - HELP!

Thanks in advance,

Custador.

[Ericf]

Hello,

I recently bought a '98 Previa auto-box that has been LPG converted; it had a few issues to sort out, most of which I've sorted out, but one of which I can't figure out.

When I start the car, it chugs for a second or two until I give it some gas. If I come off the gas too fast, the revs drop way low and the engine cuts out. I've tried adjusting the idle up at the cable on the throttle-body, but as soon as the engine is stopped and restarted the problem comes back. It only has this issue when running on petrol and when running cold - with the engine cold, if it switches over to LPG the same thing happens as soon as I come off the gas peddle - revs suddenly drop through the floor and it stalls. Bizarrely, once the engine is up to temperature and has switched over to LPG, it runs like a dream. It will still stall if switched back to petrol while stationary though.

I have cleaned out the PIM sensor, the filters and the vaccuum hose between it and the throttle-body (and lost the bolt that was holding it to the floor-pan in the process - it's now gaffer-taped up out of the way), but that hasn't solved it.

Basically - HELP!

Thanks in advance,

Custador.

That's the way it is with some LPG conversions on Previas (and possibly other makes/models). The engine needs to be warm to 50f before the LPG system will work. Something you will just have to get used to. It will be worse in winter. But after 10 mins of driving on petrol it should easily switch over.

[GentleGiant]

Cold start valve may be duff, try changing it.

We had a similar problem on a petrol "K" reg, Toyota faffed about and even convinced my mum to have the engine rebuilt; STILL didnt cure it; it was an independent garage that diagnosed the faulty cold start valve; runs like a dream now.