91 4runner 3VZ Wont Start/Run on Petrol

[skozzy]

This morning when driving my 91 4runner it suddenly stalled and the check engine light come on, after pulling over and trying to crank it over it only fires for moment, not enough to start. Sometimes it will start only for a second or two later the check engine light comes on then it stalls again.

If I crank it again it fires for a revolution or two then stops fireing but keeps cranking very fast (fast like no fuel in the system and yes there is 1/2 a tank of high octaine in there).

I removed a fuel line and cranked it to see if fuel was being pumped and it was, I can't say how much but it sure looked a lot to me.

I had a similar problem once before with the EFI relay being the cause, so I swapped it with the starter relay and this time didn't help.

It is dual fuel, LPG and Petrol, the LPG wont cut in unless the RPM reaches about 1200rpm. I did find by accident that if I hold the LPG button for 5 seconds it forces it to start on LPG, starting on LPG is fine, it runs fine. If I switch back to petrol the Check Engine light comes back on and it stalls.

I have had this machine for 3 years but never learned anything about it, like how to check engine codes etc.

I am guessing at this point that the fuel injecters are cutting out. So can someone give me advice on how to check the engine code and also how to test the power for the injectors. I recon I should start with that. But any other advice will help.

 

[chevtruknut]

Does it run two different fuel pumps I assume?? If so, I would start there...it runs on propane so mechanically you are fine, it is basically a fuel (petrol) problem. The injectors should run the same for both fuels. Just my two cents worth. Brad P.S. did you check the fuel pressure from petrol, I forget)

 

[the_dingman]

I'd check your fuel pump, everything in the engine bay will work the same for both fuels.

 

[skozzy]

When I switch to LPG the petrol pump is still running, we checked this by removing a hose on the pressure regulator. As for what pressure it is we don't have anything here to test that.

I assume when running on LPG the only thing being turned off under the bonnet is the petrol injectors.

My LPG system is a normal system not an injected system.

We replaced the petrol pressure regulator after noticing the top turned around, once off we tested for a leak in some water and the leak was bad, the new regulator doesn't leak. It drove for about 5 minutes with the new regulator and new EFI relay, but now it's not running once again on petrol.

Someone gave me instructions how to read the ecu error codes, I will try that in the morning some time and I also got a LED Test light which I hope to be able to use to check power at one of the injectors.

What pressure should the petrol be at ? I will check the price of a guage at an auto store, if it's not too high I will get one, else I have to take it to a work shop to be tested.

And where is the petrol pump in these things, is it in the tank or inline somewhere or a mechanical pump, after cranking the engine with the pressure regulator off the fuel that come out seemed to have some bubbles in it, can't imagine why it would have bubbles, there is no leak anywhere that we were able to see. The filter was replaced about 1 year ago.