iancshay

Hi there,
I would like to reprogram the ECU idle rpm target from 750 to about 1000 rpm.
My question is, which tool can I use to do this?
Why do I want to do this? After a clutch replacement, the car would shake unpleasantly at idle unless I press down the accelerator to bring the RPM up. This is really annoying to the point of wanting to get rid of the car, but I'm looking for a cheaper solution. The mechanics couldn't explain why this happened in the first place and this is an expensive enough procedure that I don't want to repeat.
My solution was to tweak the screw on the throttle that determines where the accelerator cable bottoms out and this works great - for about two weeks, at which point the ECU compensates and adjusts the rpm back down. I did this four times and will keep doing it until I reach a point beyond the ECU's ability to compensate, if such point exists. So, the cleanest way seems to be to reflash the ECU with an adjusted parameter, but after much research I'm still not sure what the appropriate tool/software would be to do this.
I suppose that another way to do this is to somehow erase the ECU's memory every two weeks. Just disconnecting the battery for 10 minutes isn't doing it so again there may be a tool to do this.
The car is Honda Civic 2004 LX 4 door.
Thanks in advance,
Yanko

BrotatoChip

You could get Kpro and manually set the idle, but you'd need a donor ECU and then Kpro on top of that. We're talking like $1k.

Colin42

find a different mechanic and fix the car properly

iancshay

The original mechanic said there is nothing wrong with the car now; when I demonstrate the shaking and how a cup of coffee will splash around because of the shaking, he still says that's normal.
The two other mechanics I talked to said they didn't know how to fix it.
I could do a clutch replacement again but that's wicked expensive and there is no guarantee...

iancshay

I was hoping for a tool that for a couple hundred $ would allow me to reflash the EEPROM with different settings but this seems not to be an option.

How does the ECU control the idle? I read something about a "programmable throttle stop" that is controlled by a stepper motor. If that's the case, then resetting the ECU won't remove the action the ECU took to compensate for my tweak, correct? I wonder ho many times I can tweak the screw before something falls apart.

sdaidoji

iTrader: (1)

7th gen ECU are not programmable. They are ROM (read only memory)

ezone

The coffee cup is too full. Duh.




Some vibration is normal and expected.
How much is too much? Compare against another identical car that has no complaints.

sdaidoji

iTrader: (1)

your engine is losing power.
Tune it up. that's why it shakes in low RPM. Event he AC will rob power enough that it will feel it.
Small engines does that. That's why they can get marvelous MPG.

Slumpertcivic

Would not surprise me if your running on just 3 cylinders.

Consider unpluggging / replugging each coil one by one and observing the idle.

I miss the days of pouring a bit of beer on the headers to identify which exhaust ports were cold on a bad running V8..

iancshay

The comparison was between before the clutch replacement and after. It went from smooth to my teeth chattering within one day. I guess they may have done some damage to the coils or cables or whatever to make the engine lose power, but my guess is that they installed something that is out of balance, like the clutch plate (or whatever it's called).

iancshay

I'll give this a try, but wouldn't running on only three cylinders trigger an error code and the check engine light?

iancshay

ugh I was afraid of that. I can dump the ROM contents, tweak them, and replace the IC although this may be more work than I feel like doing. Is there a map of what parameters are stored at which address in the ROM?

sdaidoji

iTrader: (1)

take it back to them.
finding the root cause is the solution, nothing else...

Slumpertcivic

Shockingly no...

if if it was a “out of balance” issue transmission , while it may subside at certain rpm ranges it would reappear at others.
if it’s barely able to hold a idle it will shake a lot then smooth out when faster due to the flywheel effect.
Also possible and even probable to rupture the factory hydrolic transmission mount and or mis-install a mount when they reassembled the car.

Those mounts hold back a lot of shaking when working properly..

iancshay

Agreed. But I tried that and they are like "there is nothing wrong" and I'm like "yes there is" so didn't get anywhere.
Got suggestions about what to tell them to get them to fix it?

mcnoople

Sounds like you need another mechanic that will stand by their work instead of collecting money and then running away.