T-VIS/ENGINE

[DJexor]

yesterday i went to mux to get me a new citylight and asked him to drive my hachi, 'cause i was always thinking my engine wasn't running well.
There is almost no power till 4800 RPM. When you kick the gaspedal with the economy meter green it goes faster than kick the pedal harder with the economy meter red. Look like the engine is getting too much fuel.
Above 4800 RPM it accelerates normal says mux.

Another problem. It uses between 1L/9KM and 1L/10KM gas when I drive normal. Mux had an economy drive this weekend (1L/15KM) and normaly it's something like 1L/12KM. When I use the T-VIS a lot it makes no different to the consumption.

Sometimes when I drive normal and get off the gaspedal, gas explodes in my exhaust. Look like it's getting again too much fuel.

When I checked my sparkplugs today I saw it was dry and said that the fuel ratio was a bit lean (Yesterday a lot of high revs back home from Mux.) So the ignition at that moment is quite good.

Is it possible that my TVIS is always open or my engine management thinks it's always open so it will throw more gas into the engine? What makes it very rich on fuel and no power because it gets too much gas till 4800 RPM when the TVIS really works?

[Ivan141]

Okay, just start out doing regular inspections on the engine:
It sounds like it might be a sensor problem, so check the entire vacuum
system for leaks. Then check the wiring on all the sensors you can get to.
Most of them are on the back of the cilinder head. Make sure your coolant level is correct and it might be a good idea to check the ignition timing for good measure.

[banpei]

I had the same suspiction with mine, but after checking all lines, sensors and looking at the fuel consumption I came to the conclusion mine worked fine except for the indicator light on the dash. Ofcourse the fuel-consumption was only measured shortly after I bought the car and since then I could not test the fuel consumption anymore...

If you have a failing vacuum the butterflies will open themselves and your fuelconsumption should increase dramatically when driving "economic". In the ae86 manual you can see how you can check the vacuum. You actually need a tool for it, but I checked by pushing my thumb on the hose. Dunno if this is a legitimate way of testing it.

[DJexor]

Thanks guys. After you told me about the vacuum lines I checked the AE86 manual and the 4ag repair manual. After a little studiing about several things on the engine I was able to find some things what could make this problem.

- Vacuum lines: EGR line and PCV line
- Deceleration fuel cut system faulty (because I also have an exhaust explosion sometimes)
- DP system always off (Can somebody tell me what this thing does?)
- EGR system always on

Friday I will make a visit the Toyota dealer and ask them about the problem. Hope they can give a correct answer.

What do you guys think it would be?

[DJexor]

b.t.w.:

Ignition timing is good and it's got brand new NGK R spark plugs.

[Ivan141]

You probably dont have an EGR system, so you can take that one off the list.
The manuals usually dont have the answers you are looking for anyway.
Have you already checked if all the pulleys on the timing belt are properly aligned? Are your sensors correctly wired? Is your ECU throwing codes?

Find out the simple things before continuing to the complicated stuff.
You checked your ignition timing, so I assume you already bridged the diagnosis connector once to be able to check timing. Was the ECU giving any error codes?

[DJexor]

ECU wasn't connected to some kind of testing device. They checked te timing with a stroboscoop look a like gun I don't know if they did something else.

[DJexor]

It looks like the vacuum circuit is good.

Do you guys know what the yellow connector thing does on the T-VIS. Look at the pic i don't know how to explane it

[Ivan141]

Ermmm...cold start injector maybe?
About the ECU codes and timing:
You can get the ECU to give error codes by putting a wire (shortcircuit) in the yellow connector with rubber cap that dangles on the firewall somewhere around the intake manifold. Late model ae86's have a diagnosis box where you need to short 2 terminals or something.
Anyway, when you do this, the ECU gives you error codes through the
orange check engine light in your dash. It makes patterns of flashes (you need to count how many flashes it puts out), the description of the codes is in the manual. Also make sure that your timing was checked when the diagnosis connector was bridged, because it stops the ECU dynamically changing the timing (which is the only way you can set the timing properly).