d14a4 idle problem

[saxophonias]

Back in the days I had bought some aftermarket wires called 5 star. I didn't used them for long. Do all d-series wear the same ignition cables?

[Dodo Bizar]

No, the D15B2/D15B7 type engines with the plugs on the other side have different dimensions. You can make them fit buts it is nasty.

[saxophonias]

Yeap I am aware of that! I was wondering about the non and the vtec versions!

[saxophonias]

I can't believe I am still writing here about the idle and hesitation issue...
Sudden loss of power and then it pulls again only in partial acceleration, not when you floor it. Also, what you had described, Joris, some posts before.
I have stable gas pedal and the car oscillates in surge with a period of like seconds, i push the gas pedal a little more and its ok. This is very irritating as you can't drive smoothly. This is not very intense but i hate it as it gives a nervous drive.
My mechanics can't give a solution all these years. They are not so skilled and motivated though..
So, I cleaned the injectors, and it has a better drive and faster acceleration.
Also, I convinced my mechanic to check and retune the TPS. It was off, not so much though. He told me he can't reach the ideal 0,5-4.5v but it was very close to it.
I think that gave a better feeling in gas pedal and response.
HOWEVER the oscillation remains. Less but it is there...
Next, change, the fuel pump. Could it be that? In little amount of acceleration (2-15%) not being responsive enough?

[Dodo Bizar]

Sorry if I am walking in circles... is your ECU still bonestock with some piggy-backing or properly tuned? Re-reading this I suddenly realize that this can happen (and probably has happened to me) when the fuel mapping is too far of or even so far of its doing the reversed of what should be needed since signal is not correctly interpreted by the lambda. Also when oil starts to come in the mixture (not accusing you of having a bad engine ) this might happen...

[saxophonias]

Well, guess what...The hesitation problem is still here.
The car runs great on full throttle, it is faster than ever. Still, when driving in low rpms, you can feel it is not so responsive some times and you can't drive easily in steady revs.
To describe it a bit better, when you accelerate very smoothly (5% throttle) in 1st or 2nd gear when you go past the revs slowly you experience some cuts and drops in power and then it continues accelerating. It is not always a smooth drive. Also, you cannot hold the revs high at neutral. For example you want to keep 3000rpms in neutral and despite you keep the throttle stable, the revs go up and down. This doesn't happen when the engine is cold. Maybe due to more timing advance? I mean you can hold the revs up steadily using the throttle when the engine is cold. As soon it gets warm you just can't. The revs will fluctuate. You go to 2500revs and then they drop to 2200-2100 and then they go 2500 again slowly.
Finally the consumption can't drop below 8lt, even with economical driving.
I continue changing parts without result.
So far I have replaced
Dizzy,
Power cables
Water Hoses
TPS
RACV
Map
Fuel Pump
Checked for air leaks
replaced the intake manifold gasket
the o2 sensor is relatively new
The only thing i haven't checked is the Fuel pressure regulator..Could it be that?


Also, another thing I am not sure about has to do with the 4-1 header option and the dislocation of the o2 sensor far behind comparing to its original position. When you go for a 4-1 header the place for the o2 sensor is on the collector. The oem header has a 2 cable non-heated o2 sensor (one for signal and one for ground). The oem o2 sensor wasn't heated and thus it didn't work right when the gas temperature dropped, and this happened very often since it was dislocated. So, ever since (for the last 15 years or so) we placed a heated o2 sensor. The heated sensor is always connected to power. This is not 100% right but it has worked. Could it be that? I mean the sensors be ruined after some time due to the fact that the power resistance they bear is destroyed since it is powered constantly, even if not needed?
I am familiar however with the symptoms of a slow o2 sensor and i think this is not that.

Every help will be much appreciated..

[Dodo Bizar]

Hmmm, the 4-1 header with a non central bung combined with a stock ecu map may be the issue indeed. I once had the same problem but can’t figure what I did that fixed it.

It may be the combination of header plus map being off.

The perma heated o2 is not my biggest concern. Well controlled o2 heaters do also die