4age 16v blueport issues

[tottacrolla]

" whereas at any other BTDC`s she lights up like a christmas tree."
Are you getting other BTDC's because of increased engine speed or are you just moving the distributor ?

Are you absolutely, definately sure you are getting diagnostic mode ? You can check this by running the engine with a sensor disconnected and then doing a diagnostic check to see if the code is there.

[Tore]

At around 1000rpm I can see the BTDC`s 20 and 0, but not 10 or 15-17.
As you already know she will light up at other cyls and other times not etc, it`s just a mess.


I read up on what little I`ve been missing and according to some people and some FSM`s (Right now I`m not sure there are any FSM`s available for this specific engine/setup), if there are no error codes I should be getting 1 blink every 4th second, which I`m not getting, but seeing as this is among the earliest with not even a O2 sensor even that might not be the case here.

As I mentioned earlier when I bridge her and check for error codes it shows nothing.

Checked compression once more as well, I dont have a compression tester with me right now but that hasnt stopped me from testing each cylinder with a plug installed and rotating the pulley bolt with a smaller tool and they all give the same resistance for my little finger, maybe next time I`ll use a torque wrench and find how much each cylinder makes the wrench click at which nM (more bothersome but should be tons more accurate).

When she runs, there are no bad mechanic sounds either, just the typical slight ticking sound that makes the 4AGE so adorable, re-checking water for miscolored (there are none) and oil for any water etc shows all seems well.

I`ve been giving the ECU a fair bit of thought today, I can`t open it because screws are apparently torqued on for life, but from the reading I did today, this non-VAST ignition system works by sending specific pulses somewheres in the lines of dizzy>igniter (which transforms the pulses for the ECU to ""understand"")>ECU and then ECU>igniter>coil/or/dizzy (Correct me if I`m wrong here) to make the ignition advance work as it should, maybe the ECU is dead and makes the Igniter seem faulty?

I suppose the only way to be sure the ECU isnt crapped out here would be to get another ECU, but these non-O2 sensor Blueport AE86 ecu`s are pretty hard to find and I dont have a hidden fortune

[tottacrolla]

I'm in the U.K, every U.K car is the same as yours. No O2 sensor but it does have diagnostics. In an earlier post I linked to an article and at the bottom of that article was a piece about a mixture screw, this is what your car has instead of an O2 sensor.
Before you do anything else you need to get the diagnostic working. If fixing the TPS idle switch solves the problem it will give you a diagnostic mode but more importantly the engine will run on its idle map setting when its idling, it could well be trying to idle on its normal running map right now.
Download a copy of "AE86 4age dianosis" for more info.

The following was copied from a genius on clug 4age and all credit should go to Jondee:

"The AE86 ECU has some basic OBD1 diagnostic ability, and can
output codes to signal fault conditions on a number of the engines
sensor systems. The codes can be extracted by putting the ECU
into "Diagnostic Mode" and reading the flashing codes that are
displayed on the Check Engine light. A full list of the codes is
contained in the Factory Service Manual.

Fault codes are displayed when two pins (T and E1) on the
"Diagnostic Plug" are shorted, and the ignition switched ON.
The engine will go into diagnostic mode providing certain
conditions are met. These are...

1. Battery voltage 11 volts or better.
2. Throttle fully closed (TPS IDL switch closed).
3. Transmission in neutral.
4. All accessories switched OFF.
5. Engine at normal operating temperature.

One other use for the diagnostic plug is to put the running engine
into diagnostic mode for setting the base ignition timing. You will
know that the engine is in diagnostic mode if the engine speed
drops by about 100 rpm, and the timing drops back from 16-17 deg
(typically) to 10 deg base timing. If this does not happen, then the
engine has not gone into diagnostic mode."

The ecu's are super reliable.
Another point to consider are the VR sensors in the distributor, these need to be set to very fine tolerances and a little research will reveal that at slow engine speeds the settings become even more critical.

Just remembered that there is a way to check the TPS operation:
Short the diagnostic
Ignition on - engine NOT running
press throttle more than half way down
watch the diagnostic light

Post up here the result

[Tore]

Ahoy again!

I remember glimpsing past this one, Jondee is indeed quite the crafty man!

The result:
I realize this was a bit of a stupid thing to do but I asked around on some forum+FB group without getting any answer, I didnt know how to connect the makeshift CEL (small as heck test lamp), then again I only did this when all other means were exhausted, so I tried both one end to W and the other to earth, still no light, so I tried one to W and one to interior light circuit, again, no light.

As I mentioned, engine does not seem to alter timing when I short T and E1 (Or in my case, that 2 pin plug next to the firewall) so this is probably the final nail in the coffin.
In fact there is very little alteration to engine characteristics even when I loosen up the distributor bolts and twist it all the way to one side or another.

Distributor internals wouldnt go out of whack just because the car had been sitting still for a month (And prior to that, worked just flawlessly).

I think I`m at the end of a road here, I`m pretty sure next up is somehow finding a non-o2 zenki ECU (the one that uses the 2-pin diagnostics plug).

Still, could be worse, at least the engine is okay!

[tottacrolla]

Ok I read it all again.
It certainly sound like too much fuel is being injected and as the car stood around for a while.
Stale fuel ? You need to drain the tank, adding new fuel to stale fuel will not work.
Have you checked the FPR return line is clear all the way to the tank ?
Leaking injectors ?
Include checking the cold start injector. The cold start injector only works when the engine is cranking but it is subjected to normal fuel rail pressure all of the time.

[Tore]

I`ve checked the cold start injector by pulling out the connector when the engine is running, engine behaviour does not change.
Before I parked the car, the fuel was pretty fresh, in comparison the 20v AE86 has had the same fuel for 2 years and still starts and behaves fine.

[tottacrolla]

The cold start injector may be leaking fuel regardless of the electrical connector.
Fuel quality is crucial and should not be overlooked. A comparison to your comparison, I have seen 3 month old unleaded cause engine running problems. Lots of factors at play here not least of all how much fuel is in the tank.

[Tore]

Swapped in with another 2 cold start injectors that I also know works, still no change.
Drained the system and filled the catch can with new fuel, still no change.

[tottacrolla]

Did the car originally come with a factory fitted 4age ?

[Tore]

Nah, its a frontyard 4age swapped ta40, nothing unusual about it though.
Instead of a COR, it has a couple of relays for ignition switched fuel pumps and ECU power.
Coil+Injectors gets power from the old coil circuit.
Normal 2.5L M-Tech catch tank setup with Bosch high pressure pump (For what its worth I tried with another one, no go) & generic lift pump, brand new 8mm fuel line (not clogged), old fuel line for return.
I`ve done it all according to what everyone else does to KE70`s etc since these are all the same cars underneath.
Did nothing but follow the full recipè to the T, without any trouble, until now anyway