Hi all, i have a 92 4runner on lpg/petrol which is extremely inefficient, the problem has cost me hundreds in mechanic bills and only improved slightly. I've had the cooling system flushed, TPS checked and set, retuned with new leads and plugs, throttle body cleaned out. im getting 200kms max to 65litres of lpg. petrol not much better. im desperate for any acdvice at this point!
2nd gen, very inefficient. please help!
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mikebontoft
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How long have you had the vehicle and do you know how long it has been a dual fuel vehicle? It is an aftermarket LPG conversion, correct?
LPG will not get as many kms as petrol will. It just doesn't burn as well, and power is reduced.
You may want to check what the timing advance is, as most of these installations require the installer to physically advance the timing. The LPG computer will retard the timing by adjusting the signal to the coil.
I know it's a little confusing, but if the system is working properly then the timing should be the same as factory for petrol, and advanced for LPG. If someone messed up your timing it can mess with the programming of the LPG computer.
It is also possible that the injectors from both LPG and petrol are operating at the same time, or one of the LPG solenoids is leaking while on petrol. Or, your fuel pump is not shutting down while on LPG and it is causing the injectors to leak.
Sorry, I know it's a lot of stuff that probably doesn't help. Can you be more specific on exactly what has been done, and what type of engine it is?
LPG will not get as many kms as petrol will. It just doesn't burn as well, and power is reduced.
You may want to check what the timing advance is, as most of these installations require the installer to physically advance the timing. The LPG computer will retard the timing by adjusting the signal to the coil.
I know it's a little confusing, but if the system is working properly then the timing should be the same as factory for petrol, and advanced for LPG. If someone messed up your timing it can mess with the programming of the LPG computer.
It is also possible that the injectors from both LPG and petrol are operating at the same time, or one of the LPG solenoids is leaking while on petrol. Or, your fuel pump is not shutting down while on LPG and it is causing the injectors to leak.
Sorry, I know it's a lot of stuff that probably doesn't help. Can you be more specific on exactly what has been done, and what type of engine it is?
2ndGen4runner4x4
New member
That translates to about 7 or 8 miles per gallon. Yep, something is wrong... you should be getting maybe twice that.
Is it possible that someone is stealing your gas when you arn't around?
Is it possible that someone is stealing your gas when you arn't around?
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thanks guys, conversion was done about 15 years ago.
its a v6 3.0 3ze. LPG system has been checked by 2 different mechanics. it idles very high and eraticly, up to 1500 rpm. in gear about 1000, TPS helped but did not resolve. I've owned it for a year and its been consistently inefficient
its a v6 3.0 3ze. LPG system has been checked by 2 different mechanics. it idles very high and eraticly, up to 1500 rpm. in gear about 1000, TPS helped but did not resolve. I've owned it for a year and its been consistently inefficient
mikebontoft
New member
OK, I figured it was a 3vze. If you get the chance, could you post a picture of the engine? I'm not sure if they used a fogger system or separate injectors in yours. I have seen a throttle body plate and the fuel is "fogged" into the system at a low pressure. I suspect you have a constant LPG leak into the manifold if it uses the spacer. You may have a failed solenoid or a torn diaphragm inside the solenoid assembly allowing leakage. Somewhere near your tank there should be a manual shutoff valve in addition to the valve on the tank. Turn both of them off and run the LPG until it switches back to petrol. Hopefully it will run better if there was a leak.
1998 is new enough for separate injectors, but I bet it has that TB spacer.
It may have been checked over by two different mechanics, but unless they know how CNG/LPG systems work, they're just poking around at stuff.
edit: I should correct something I said earlier. Your mileage on either fuel is expected to be about the same, but power is reduced on LPG.
1998 is new enough for separate injectors, but I bet it has that TB spacer.
It may have been checked over by two different mechanics, but unless they know how CNG/LPG systems work, they're just poking around at stuff.
edit: I should correct something I said earlier. Your mileage on either fuel is expected to be about the same, but power is reduced on LPG.
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