There’s an issue with my car — it's a 2005 Honda Civic Prosmatec (Automatic)

[fycel_khan]

There’s an issue with my car — it's a 2005 Honda Civic Prosmatec (Automatic).

When the AC is turned on, and the car shifts from 1st to 2nd gear, it gives a strong jerk. However, if I drive the car without the AC, this issue doesn’t occur.

Even if the AC is later turned off, the jerk while shifting from 1st to 2nd gear continues — it only stops after turning off the engine and restarting the car.

It is making me frustrated now

[hash4u]

Before touching mechanical things
I would suggest examining compressor

[Xulfiqar]

Is the ac wiring factory original?
Any other jugaarbazi like missing thermostat or manually adjusted throttle body?

[fycel_khan]

there is no jugar in wirring, Yes thermostat is missing and throttle is not adjusted manually.

[fycel_khan]

but issue is that once i turned off the ac car still give that same jerk. when shifting from 1st to 2nd until didn't put ignition off and start again.

[mehboobabubaker7]

hmm

[Xulfiqar]

Install the thermostat, make sure the engine gets to temperature, it also ensures the transmission oil comes up to temperature,

What is the transmission oil temperature when this happens?

[fycel_khan]

It usually happens when car hot like today after driven 16 km car give same jerks even without ac when shifting 2nd gear..

How to check transmission temperature

[fycel_khan]

This is not happening on cold car. When car is hot and temperature is at optimum in middle after driven much km.

Change gear oil, solenoid, plugs, fuel filter and pump.

I think it may be bad ignition coil as car jerks like coughing one shutter. Rest of time work fine with no issues just jerks when 2nd gear change.

[Xulfiqar]

A bad ignition coil doesnt affect shifting for one sequence only.

[fycel_khan]

Then you can advise what it can be. As iam reallt frustrated

[fycel_khan]

This happens when i service AC and after that car give jerk on sifting from 2nd gear on ac and without ac.

Should i need to calibrate gear again or what

[fycel_khan]

Should i change fuel pump . As tomorrow i will be checking the pressure of it. As last time same thing happened 2 years back changed pump and coil Issue was solved hard jerk was gone just minor jerk i feel when gear shift from 2nd.

But this time need to knew why this happened to get permanent solution

[fycel_khan]

Any one help me out.

Either is gear or fuel pump or another issue.

[pwuser174403931723]

Salam. I would suggest change gear oil. If that is already done then 2nd thing would be to check the gear mounting (kursi). Most cars usually have 3 or 4 mountings and often the harsh shift felt thru the car isn't anything to do with transmission but that the gear mounting has gone bad and needs to be replaced so that it can once again cushion the normal gear change vibration.

[fycel_khan]

But why it jerks harsh like when car is driven 15km without ac and jerks when changing to 1st gear only.
Same on ac as well but early then without car.

Im guessing fuel pump issues. As when it get hot pressure get less.

[Xulfiqar]

First gear jerk is a classic sticky situation in any oldschool honda autobox, the linear solenoid is not exhausting pressure correctly.

Connect a decent scanner and see if you can plot the fault timeline.

Dont guess, pay a real workshop to do proper diagnosis,

[pwuser153796752163]

I'm 40 years old now, owned my first car when I was 16, I am yet to find a "real" workshop in Karachi.

[fycel_khan]

linear solenoid

Sure let me check this tomorrow and update on this. As if you any knew any one from Karachi do let me knew too in north or gulshan area.

[pwuser174403931723]

True. I'm 43 and lived most of my life in Sharjah UAE. Compared to Sharjah, a big city like Lahore with a much bigger population has sadly a very low number of reputable garages.