TonyK
True Classic
On my car on an 80 degree day I am seeing 70 PSI. I think you are there.Rest pressure on the low side with system off is over 50psi.
TonyK.
Grimsby Ontario Canada.
On my car on an 80 degree day I am seeing 70 PSI. I think you are there.Rest pressure on the low side with system off is over 50psi.
Hussein, you are so close to the answer it will hit you in the face when I tell you the solution. Abarth swap has the same issue, solution, install the X1/9 idle up AC air valve. The ECU will see the change in MAP value and adjust the injectors accordingly. Feed the solenoid valve from the clutch wire of the AC compressor. On the Abarth it works so fast that you really have to pay attention to a very small hiccup in the idle.
TonyK.
Grimsby Ontario Canada.
Well you could make an emulator that clones the CAN packet and put that on the CAN bus when the AC switch is pushed to allow the ECU to bring the idle up for the AC load, but connecting 2 wires of a DC solenoid and a bit of hose routing seemed to be a simpler solution from my way of thinking. Now if you like messing around, then you could find the climate control module from the Honda and use it to put the CAN Packet on the bus as well.
TonyK.
Grimsby Ontario Canada
Well the way the switch is drawn it is normally closed which in electrical drawings means de-energized state or at rest, wheels straight. When turned it opens. ECU's normally put out + voltage and change in state applies a ground to bring the status to low. That being said, you now need an interposing relay to accomplish this.
TonyK
Grimsby Ontario Canada.
Well the way the switch is drawn it is normally closed which in electrical drawings means de-energized state or at rest, wheels straight. When turned it opens. ECU's normally put out + voltage and change in state applies a ground to bring the status to low. That being said, you now need an interposing relay to accomplish this.
TonyK
Grimsby Ontario Canada.
Looking at the diagram E16 on the left is showing a blocking diode and a resistor. I think if I am correct those componets are in the ECU. So applying a direct ground is all the switch does. But let's give this a bit of thought. I say that the input at rest must be grounded and when the switch goes open it provides a higher idle. You say you have a high idle without reason, possibly you have stumbled on the reason that the high idle is being produced because E16 is not grounded. I say ground E16 and see if idle goes to normal that would explain a lot of the issues you are having with the idle control valve. Possibly the idle control valve is doing it's job, the ECU is telling it that the power steering pump requires a higher idle because the circuit is open and not grounded.
TonyK.
Grimsby Ontario Canada.
Unfortunately I can't install a stock ECU - they all have an immobilizer feature that locks it to the chassis. I can try re-installing the Accord ECU with the K-Tuner board installed - of course if the problem is the K-Tuner user board the problem will just transfer over. I may have no other option though. It can't be from switching the IACV signal & ground wires. I also unplugged the IACV, so those wires are not even in an active circuit, and the symptom persists.
I've disconnected the battery, restarted the laptop & K-Tuner app, and reflashed the ECU without any change. I ended by leaving the batteyr disconnected & I'll see what's up tomorrow or Monday.
Hi Hussein,
I preface my comments by pointing out that I have absolutely no knowledge of the idle control system in a Honda, so my comments may not be relevant at all . With that said, all the idle control systems I have ever seen are not simply "on / off" systems where the ECU supplies a binary signal but rather PWM systems where the amount that the valve opens is proportional to the duty cycle of the PWM signal from the ECU. The valves I've used in the past are the 2 wire variants similar to these (BMW part):
There are also 3 wire valves. There is a small vane in the valve that will open proportionally to the input signal (or more specifically the duty cycle of the input signal). You could use an oscilloscope to check the signal that is coming out of the ECU to validate this and also validate the operation of the ECU concerning idle control. If the idle valve is indeed PWM controlled than you could (as a troubleshooting method) use something similar to this to drive the idle control valve independently of the ECU.
In any case, having an oscilloscope record the ECU output (for the idle control) and how it responds under various conditions would certainly provide you with some valuable additional information. You can get portable oscilloscopes pretty cheaply these days (e.g. SainSmart DSO211).
Cheers,
Dom.
PS: This is what you would expect the PWM signal to look like (where the width of the square wave will vary):
Always keep an open mind, if you change something and things go south change it back, but realize that it too may be hiding another problem.
TonyK.
Grimsby Ontario Canada.
If the ECU does not "see" the throttle position, that could cause problems both with idle and with the fuel injector cut-off. Do you know how the throttle position sensor works? I know simple pots (variable resistors) have been used in the past, but would assume something more sophisticated is used now (something that does not wear like a pot does).Rechecked my wiring again. Everything is as it should be, but it doesn't register throttle position - I can see it in the live data. So, I followed the above advice, and with the signal/ground back the way I had them, the engine starts & runs as it did before, in other words normal as it was. I don't now what to do next, as this is not as it should be.
I grounded the E16 wire, and I think the idle is more stabile, but I didn't drive it much. Still having the bucking off idle, so I need to investigate the Fuel Cut settings.
This is perplexing, as according to the wiring I definitely have the IACV wired backwards in terms of ground and signal I/O. I don't want to install the new Honda IACV when it arrives with the wiring backwards.
If the ECU does not "see" the throttle position, that could cause problems both with idle and with the fuel injector cut-off. Do you know how the throttle position sensor works? I know simple pots (variable resistors) have been used in the past, but would assume something more sophisticated is used now (something that does not wear like a pot does).
So, I looked again at my wiring diagrams, and of course I wired the TPS 5v and signal ground backwards also - I labelled them 1 2 3 in my sketch of the connector, but that's from the terminal side, not from the wire side. So, Both TPS & IACV are backwards.
I will reverse both sets of terminals ( 1 & 3 on TPS) (1 & 3 on IACV) & see if the TPS symptom I created by reversing the IACV wires is corrected. If so, then I know I can install the Honda IACV with the corrected wiring when it arrives later in the week
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