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-   -   1st Gen Honda City Owners - Problems Areas, Fuel Efficiency and more (https://www.team-bhp.com/forum/technical-stuff/26232-1st-gen-honda-city-owners-problems-areas-fuel-efficiency-more-12.html)

Oh Xenrocron- have heard a lot of good things about them on Honda forums but never bothered to check their stuff in details. Seems like a good package. Whenever you're selling the wideband let me knowstupid:

Just kidding.

That's how it should be. Only thing I wanted to clear was the fact that this route isn't gonna be dirt-cheap when compared to the RD standalone. If you wanna learn that's fine, and I hope you have someone who knows his way around the electrical bit by your side.

Not sure how much it costs for later tune-ups but if you are well-versed with tuning they should be able to provide you the software which will enable you to tune yourself. You'll still need to invest in the wideband though I guess.

Edit: Hope you have thought of a way to get around duties, otherwise this DIY attempt can turn into an expensive proposition.

Hi Pranavt,

if you're planning to do that, be prepared to loose out on low end power. (Translates to better economy, as the primary lobes of the D16 cam are smaller than our indian vtec's) But the switch to vtec is something you will enjoy, the change in sound is like you suddenly hit boost!!! And the car actually takes off!!:D

Once you are done with this mod!! Please share your experience.

Cheers
Shrey

I really dont get this ecu launch control funda. How exactly does it work on cars that dont come with LC?

Atleast from what ive seen, it looked like the ecu holds a pre-determined rpm at launch and gradually increases rpm when the car takes off.

I wonder what would happen if i launched this car on ice, wet grass, slush etc.

Shan2nu

Keeping Electrical & electronics part on side, i will also recommend first you go more deep in to engine mechanical, like understanding air flow basic, manifold design (int/exh), compression ratio, flame front,octane rating of fuel, knock,air fuel ratio, the role camshaft plays in performance of an engine & how camshaft timing influence performance, plus lots more.

Once you know that, then you will know how to play with the AFRs & Ignition without that it will be like you are running blind folded, cause you can even damage your N.A engine with a wrong tune.

Trust me, it might take you years not months to learn all that, its never ending, you will need to keep up learning always to keep pace with technology.

It just fiddles with the rev limiter. You'd have no traction if you launch the car at ~4k rpm on anything other than a road lol. Another feature is the Engine Check light acting as a shift light.

@Jitu bhai: Yes, absolutely. The "couple of months" timeframe was for a safe map without any real optimisation. I understand that once you get into it, you can keep learning for years without knowing everything. There is so much to read and so much documentation about tuning Hondas, so I'm not going to whip out a map in a day. You read and learn new things everyday :)

@Shrey: Not sure if I'm going with OEM cams or aftermarket ones. Let's see how it goes :)

I posted this on the other thread but having received no responses yet am tempted to post it here:

About 3 weeks back I got the engine and gearbox mountings of my OHC II 1.5 Exi changed in a local garage in NOIDA. Since then whenever the AC is switched on the car vibrates a lot. The vibrations are more pronouced when the car is idling or at low RPMs. The vibrations persist regardless of the AC fan speed (1 or 4). Last weekend, when I showed it to the mechanic who replaced the engine and the gearbox mountings he advised that whenever the AC is switched on the engine RPM should increase which is not happening.

• I have observed that when the engine is idling at traffic points (neutral or in gear with clutch engaged) the RPM falls & stays at ~0.8 for a few seconds. During this vibrations start kicking in.
• If i let the engine idle for about 15-20 seconds or more the RPM falls further to ~0.6 & this is when the vibrations are most significant
• If I press the accelerator pedal a little to boost the RPM to 1.5k rev/min & above the vibrations gradually start to fade away.

Any clues/obvious culprits?

I had the exact same problem after changing my engine mountings. The problem turned out to be the AC compressor which had conked. Replaced the entire assembly, valves and refilled the gas for 16k. Problem was solved.

Now that you mention it though, is there a link between changing the engine mounts and the compressor going kaput? This happened to me and abk... Anyone else?

abk
1) do you have a FFE in your car ? i think that has a bearing on the vibration at idle
2) OHC idle is at 800 rpm and at that rpm there is bound to be very mild vibrations depending on the age of the car. for e.g i sometimes get a whining sound from the center of the dash board. but if i tap it a few times, it goes off
3) what is more worrying is the rpm drop to 600 and in general when rpm goes to too low levels, the engine judders. and this automatically disappears when u give gentle throttle. So pls get to the cause of the rpm dropping FIRST. fix that and then analyse why vibrations are happening.


i had a brief period when sometimes, when i used to crawl in neutral in my parking lot ( till i reach my exact slot ) and then when the car becomes stationary, the rpm suddenly used to drop below 600 and u get the sense that the car may stall any moment. but after some throttle input, the car automatically settles at the 800 rpm level. dont think, u face the same problem, but just thot of mentioning

How is the idling without A.C ?

You can do 1 simple test, at idle put a slight pressure on accelarator pedal till rpm comes to 1100-1300 RPm, keep engine running at that rpm & then switch ON the A.C , imo there should be no vibrations with slight load on engine with A.C ON. if there is still vibration there is some mechanical problem which can be anything, improper mounts or not installed correctly,
Ask your mechanic to do the following
1) check your IAC valve & throttle body, get it cleaned thoroughly.
2) check A.C Belt Tension it should not be overtightened from OEM Specs.
3) check your plug wires.
4) Recheck mounts installed.

@ Tejas I think you got con. there is no link between changing the engine mounts and the compressor going kaput.

Dear Narayan,

1. No, I do not have Free Flowing Exhaust. In fact all stuff in the car's engine bay (& much of the car itself other than repairs :Frustrati) is stock.
2. Agree. Prior to changing the mountings there were mild vibrations on turning on the AC which was acceptable & had always been there since I bought the car (was 4 yr old when I bought it). Just to add a point here - 2 weeks back on an emergency day trip to Rishikesh my car's AC fan motor went kaput. Upon opening the motor I was shown a lot of carbon deposit. The deposit was cleared and the copper plates rubbed with sandpaper since then the fan motor is working fine.
3. I agree. Somehow, here is where i smell a fish. In fact yesterday while driving to the office at the traffic stop looked hard at the Rev meter and found the RPM to be between 0.4 & 0.6k. So the RPM must have dropped to 0.5k levels whilst it should be ~0.8k. I suspect at such low RPMs the car will start juddering regardless of the AC. When I give it a gentle throttle the judder disappears gradually as the revs go beyond 1.2-1.5k. However, if I let go off the accelerator pedal (in neutral / clutch engaged in gear) the RPM level drops gradually & settles between 0.4 - 0.6k mark & thus juddering creeps in.

Please advise if I can then conclude:

• Engine idling RPM at ~0.8k without AC: Correct behaviour?
• Engine idling RPM at ~0.8k despite turning the AC ON: Incorrect behaviour?
• Engine idling RPM dropping to 0.4 - 0.6k range (only happens when the AC is ON): Incorrect behaviour and needs to be diagnosed and corrected first?

Dear Tejas@perioimpl,

I got my AC overhauled at Honda but quite a while back (~1.5-2 yrs). Until the engine & the gearbox mountings were replaced the AC was working fine without any noticeable deterioration of vibrations. All of these changed once the mountings were replaced!

Dear Ford_Rocam,

The vibrations almost disappear around ~1.5k & above but the problem is during idling the RPM drops drastically ONLY if the AC is ON. Nevertheless, I will switch on the AC keeping the RPM above 1.2k today and observe how the revs behave during idling and let you know.

It's the exact problem that I have been crying over all the OHC threads. RPM used to fall and fluctuate and obviously, cause engine judder (no vibrations since the foundations are rock solid). The IAC valve was the problem, changed it and the behavior turned normal.

Still there is a lot more to see in the Throttle Body since the TP sensor and the other once cause such trouble as well. If the air sensor wire thing (don't remember the exact name, the one that goes into your intake pipe if you have a conical filter) also controls the behavior of the RPM to a good extent.

There are still one off times when a tap to the accelerator is like a necessity to bring the the RPM needle back to 750 (in my case).

I know there is no link. I just got freaky when 2 incidents like this happened. But I wasn't conned, I got the state of the AC compressor verified by Honda and two outside agencies and they all said replace. Just a coincidence that it failed after changing the mounts I guess.

By any chance, Will ECU reset(disconnect the battery terminals overnight) help here to a certain extent?Bad fuel ?? (if yes then get your tank cleaned )

Guys needed some help

Over the past few days, whenever I switch on the AC, the car starts idling at a lower RPM when usually the car has to idle at a higher RPM. When I switch the AC off the RPM goes up. Its happening the other way around in this case. Also the thermostat cuts off and on 2 to 3 times in quick succession and becomes normal when I rev a bit and then stays that way. There is no problem in the cooling and the AC is working perfectly otherwise.

Any pointers to what could be the issue here?

That's a simple one. There is usually an idle control stepper motor near the TB opening. It varies the idling with and without AC.

If there is too much kachra stuck it stops working and does not increase the rpm. It just needs a bit of cleaning a 5 min job. When you turn on the ac the load causes the rpm to drop which is usually compensated by this stepper motor.