Hello,

I am form Croatia, and i have a 93 4runner 3.0 v6 sr5 4x4 auto 150 000miles.. with a LPG converion instaled.
The mods : No cat., new 60mm(2,36") exhaust from stock header to back with one silencer, new O2 sensor, ISR mod, and a complete maintenace(new oil`s, plugs..), 33x12,5, and a 1,5-2" lift..

The main problem is of coure the bad mileage, and a lack of power...
I get an average of 9-10mpg mixed driving
And the power lack is strange, when i floor it, form idle to about 3000rpm the acceleration is "ok" but after that the acceleration is very bad, so i get better accelerations if i keep it under 3000rpm.. I dont know if this is normal because the 3vze is wery rare engine in a 4runner here so i have nothing to compare it with..
The engine runs wery smooth, it starts great even when it is realy cold outside..

The mileage is the same using petrol(95 octane) and lpg...

The previous owner did a head rebuilt so i was wondering if there is any posibility that the timing is wrong(missed by a tooth) and the engine still runs smooth???

any help is more than welcome...

thanks for your time,

teo

 

We don't call it the 3.slo for no reason

Welcome to Yotatech

:wabbit2:

 

the 3.slo.

It sounds to me like a timing problem. Try to set the timing and see what happens.

 

Welcome to the family... that mpg seems a little low as well... might be related to the possible timing issue...
the 3.0 is a good engine when properly maintained no matter what anyone else says...

btw what part of Croatia are you from?

aviator

 

The poor mileage may also be related to you running LPG instead of gasoline.

 

He said its the same with gas or lpg

 

Thats the rare option huh?
Maybe thats for a reason

 

There could be a lot a little things wrong with it. Does the check engine light come on? Have you checked for any diagnostic codes? a bad tps or not properly set tps will give you bad performance. The ignition or cam timing being off could give you bad performance. Maybe perform a compression check so you can get an idea of whats going on inside the motor.

 

x2 on timing. Sounds like it's retarded a fair bit.

I also have heard that 9-10mpg is reasonable for a LPG setup... this should not be the case on 95 octane! 95 octane in a 3vze... should let you advance timing a lot, and still get 20-24mpg.

 

Welcome to Yotatech!

LPG is 105 Octane. your timing is too retarded, and the engine was designed for 87 Octane. I only got 14 / 15 MPG with mine so do not expect miracles.

I had a 3.slo that now has a spun rod bearing due to a roll over. its getting a 22R next since I found a bellhousing.

your TPS is probably gone with 150k on it. My guess is you have no engine braking.
my thinking is get a new TPS and then send the throttle body, plenum, & TPS out for overhaul, overbore, & powder coat.

 

Thanks for the answers...
Today i made some checks and here is what i found out...

cam timing is ok
ignition is around 12
and the compression is ok too
and there is no diagnostic codes for the engine or the auto transmission..

skypilot, the engine braking is normal

aviator, i am from Rijeka

i am running out of ideas....

 

Try advancing the timing some more. Put in the jumper and run it up to 15 degree's. You have a lot of room on the octane numbers.

Next I want you to run the FSM check on the distributor coils. Mine I know is bad and it had power issues. if the are out of spec I heard the "richporter" brand distributors were in spec unlike other rebuilt unit.

 

Pretty countryside near your town teo... I was just looking at some pics of some vineyards in Istria...

 

skypilot : Waht is the "FSM check"? I am having trouble finding that in the repair manual..

aviator : Thanks... it is nice here...

I made a trip few days ago, and here is what i tested... i made 154,7miles with 46,5L of LPG so this is 12,5mpg but i drowe it like a granny, top speed was 40mph and the rpm newer passed 2800rpm.... and all open road... so this is the best that i can get...

is there any chance that the engine thinks that it is running cold and because of that putting more fuell.... but at the same time the dial shows normal temp. and transmission using O/D, and of course no codes....

 

There is a procedure in the Field Service Manual aka FSM for testing the distributor coils that feed data to the ECU.

One or more of them may be out of band for tolerance and that could be your problem.

Your milage is only off mine by a couple of MPG's. Also LPG has a lower energy content than normal 87 octane gasoline. So this may mean you are getting normal fuel consumption for that engine. trust me there is a reason no one likes that engine, and it is swapped out for the newer 3.4 engine.

 

What brand of plugs did you use?
Did you replace the fuel filter also?

 

...today...
tps OK
vaf OK
egr system OK
distributor coils OK

 

Is yours an auto? might be a problem with that... or maybe a little clutch slip if manual trans... could also be a problem with the air meter or fuel pressure..
it really sounds to me like a sensor is out and you're getting to much fuel... if it was only happening on benzine/essence/gasoline I'd think you also might possibly have a leak in the fuel return line but since it's also an issue on LPG that's probably not it...
It sounds like the engine is getting too much fuel for a given condition... hmmm... might also be the temp. sensor/idle up... in other words the engine keeps thinking it is still cold and is calling for more fuel than it needs...
check the vacuum system also... I had a vacuum leak one time and it messed the engine up bad...

hope you get it sorted out soon