Blacktop problem

[domi]

All 4-wire Zircinium based O2s are the same. Check the voltage it outputs on it's signal wire - if it fluctuates properly - it's not that. It has to fluctuate between rich and lean constantly.
If you still see a drop as you're opening the TPS - it deserves a change.

I didn't understand what you meant by working absolutely fine when you put your hand on the plenum hole or press the fuel return. What do you mean?

[Akis308]

I mean that the engine rev smooth, when I cut the air from it, or strangle the fuel.
Doesn't lag or anything.
It seems to me, that the ECU is seeing lean mixture and tryies to give more fuel and there's the whole problem.
I've made a research about the ox sensor and, yes their core is the same, but the holes around it are totally different.
The cost for it is 200 euros, and I don't know if to take it or not.
The TPS is already "traveling" towards me and it is going to be changed.
I'm going to measure the Ox sensor signal and see what it is giving to the ECU.

[domi]

If the O2 sensor is continuously sending 'lean' signal to the ECU - there's an error code for it.
It's one of the Two-Trip Logic codes, #25:

[Akis308]

Aha...
But it has to be on "test mode"....
Ok...
The only error I get for now is the speedo connection.

Domi, I have the FSM, so in the future (which I hope it won't be needed again), just tell me the page.
Thanks a lot man!


Something else, is as the engine gets hotter (let's say after an hour of operation) the things gets better...

[Akis308]

Something else which I've notice yesterday is that the distributor cap has a small crack, enough for a spark to escape on the base of the 2nd cylinder lead.
Could be this the cause, is very very unlikely to me.
I've seen bigger cracks and everything was working perfectly.

[domi]

Yeah, i've had my share of improvement when the engine heats up, most of which not entirely logical. The distributor might be worth looking into, but doesn't sound like it could be the source of the issue - if it exhibits itself only on partial throttle, it sounds like a hole in the air-fuel mixture maps.
Your statement on closing the fuel or intake, kinda makes me wonder: what is your fuel pressure? If it's not at service specifications [page FI-32 ], you should look into it. That might explain a few things...

[Akis308]

Τhe fuel pump is easily rises to 5 bar with an external fuel regulator, so, I'm guesting it's Ok.
I've talk 5 minutes ago with an electrician, expert on 4AGE here at Greece, and is absolutely sure that the cause is the combination of Ox sensor and speed sensor.
He told me that, beside the analog part on the transmition , on the Km meter, there is a purple wire, which MUST be connected to the speed sensor plug.
Otherwise the ECU think that you are just playing around with the throttle on neutral, so it doesn't sent much fuel at the injector.
Going to try this and hope will be Ok.
I've already purchase the Ox sensor and will have on Monday...

[Michel H]

That would be very weird because I'm driving for more then a year now with speed sensor disabled and on top of that my o2 sensor is screwed for at least 4 months and I have no problems. The only thing that tells me that there is something different is when my speedo is reaching more then 190km/u and that "check engine" light lits up.. nothing else. No power problems, no hesitating..nothing.

[Akis308]

My check engine lights really often.
Code 42 (no speed sensor while engine has load for more than 8 sec.).
Wait till Monday....
The Ox is going to be replaced and the speed sensor is going to be fixed.

[Akis308]

If the "check engine", lights after 190Km/h, then it is obviously that the ECU is receiving signal about the vehicle speed.