Revs drop on cold run with A/C on ( faulty engine mounts?)

Hi All,

My 1.5 CVT jazz has started to do something strange over the last 10 months when the A/C is on. What happens is if I start my car after work (after it has been parked for 8 hours) and put the a/c on, when i stop at the first and sometimes the second set of traffic lights (within the first 2-5 mins of starting) the revs will drop down from about 1,050 to about 700 and the idle gets very rough (it feels like it may stall, even though the revs don’t drop down to stall level).....it will then very quickly go back up to 1000 (like some anti-stall system cuts in), and then do it again once more (it is not correlated to the compressor cutting in though).

If you go to accelerate softly during this time, the car won’t go for a sec (again idles very hard before it decides to go). The strange thing is it won’t do it again at the next set of lights if it has been about 5 mins since start.

I did a bit of research on the web and found that people who have had hard idel have had to replace their engine mounts on their Jazz’s at about 80k. My car has done 82,000. But i find it hard to believe that such a new car will need engine mounts....?


Any ideas about cause / engine mount theory would be greatly appreciated!

my jazz is abit like that...but i think its coz of the turbo i put in... hmmmmmm

I also have the delay when accelerating from start with the air-conditioning on.

Though, I've always had this issue with all cars I've had...I've only had 1.6L and below cars. When I drive my dad's civic 1.8L, I don't feel any hesitation.

Driving an automatic, 1.5L with Air-conditioning on, I'm not really surprised. Air-conditioning really sucks power from small engines.

i have a 06' vtsi manual jazz and i too have recently got this problem, with the air con on and starting the car from idle it appears its lacking response it would take take off abit rough as if its in 2nd gear i've recently got the car serviced but havent gotten the guys to check the air con although it will need to be regassed soon.

also i've noticed some knocking clunking noise from under the car from time to time this only happens with the air con on.

there is only 1 variable here which is the air con causing these issues..
i am taking my car in soon to get the air con serviced and regassed hope this fixes the problem.

Thanks for everyone’s replies!

Hiko, mine sounds to be doing exactly the same and will do the thing with the revs occasionally when sitting at the lights at idle... though mine is an Auto.

I know its a small engine car and will suffer with the A/C, but having owned it for the last 3 years, it has only recently started being rough with the A/C on. From what i have found, I somehow think it is related to the engine mounts...

The company that i work at has a 1.3 06 Jazz Gli Auto and goes much better with the A/C on even when taking off than my 03 1.5 VTI-S.

Hiko if u find an answer for your car, please let me know. BTW what makes u think u need to re-gassed your A/C? Is it not cooling that well?

yeh its not cooling that well at all, i reckon a pipe is loose or needs servicing the air con units also noticed in the foot space its also blowing out warm/hot air even with no aircon or anything turned on. something must be directing that in there too.

the car feels like its about to fall apart especially if i try to push the revs over 3k it will just jerk back and forth a few times with the occasional clunking noise from the bottom of the car.

unfortunately i wont be taking my car to my mechanic til i get paid in 2 weeks time :(

Why would the engine mount having anything to do with the a/c?

They just merely hold down your engine to the chassis as far as I know.

When they fail you will feel more vibration. But by no means should they cause your revs to drop.

It is also possible that your battery is near its end of life.

yeah a shagged engine mount sounds unlikely to be related to low idle when the A/C is on

first guess is that your idle control valve is sticking as it is gunked up with carbon. clean it and while you're at it, clean the throttle body too. it's easy enough to do yourself - or ask your mechanic to do it for you next service :)

Quote:

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Originally Posted by lithium

yeah a shagged engine mount sounds unlikely to be related to low idle when the A/C is on

first guess is that your idle control valve is sticking as it is gunked up with carbon. clean it and while you're at it, clean the throttle body too. it's easy enough to do yourself - or ask your mechanic to do it for you next service :)

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Interesting...Where is the idle control value located?

Quote:

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Originally Posted by Poeter

Interesting...Where is the idle control value located?

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i've never worked on a Jazz before, however the ICV is always connected to and near the throttle body. is there a pic somewhere of a Jazz engine? i could point it out :)

i have this in my subaru. drops and sometimes even stalls.

Quote:

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Originally Posted by hisoka

i have this in my subaru. drops and sometimes even stalls.

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try cleaning the throttle body/ICV :)
also do you have your Subaru serviced at a Subaru dealer? if not remember to run Subie upper engine cleaner through your engine every service or second service. the boxer design tends to gunk up the intake manifold quickly :)

nah i dont take to subaru, i actually done most of work myself, or performance worskhop . and yeah i clean out pcv and catch cans and i used upper engine cleaner

. it is blowing back a shit load of oil in summer. but its okay right now. have to go retune for this summer but its so hot the cabin gets dryer then dogshit.

your subaru does this too ?

no, i actually don't own one but my brother does (and doesn't have problems with his A/C)

it's just something that applies to all cars. some cars (especially euros like Astras) tend to carbon up the throttle body which cause low idle and occasional stalling at lights. with A/C, all cars use a bypass valve of sorts to increase the idle when the A/C is running - if your idle is not increasing correctly, chances are the valve isn't working. and first thing to do before running out and buying a new ICV is to clean the old one and see if it helps :)

oh yep. well ive been cleaning it and cleaning out my catch can. just shit loads of oil . found some oil in the intercooler too lol~

think because hasnt had a tune for this summer

I think the OP's problem is the battery like Poeter said.

How old is your battery hisoka? is the timing set right? and do this!

I would also do the tappets if they need it.

my battery is quite old, i dont even know how old, just dont ever remember replacing it.

might take it to get tuned first before i replace things

For sure,I had so many electrical problems and after FINIALLY replacing the battery I understood that was the reason,although I was charging it to 100% that was only 50% maximum capacity cause it was old,my auto electrican hook up a tester that said the 50% reading.

Thanks everyone for your replies!

An update on what happened with my car....

My engine mount on the passenger side was broken. The way i knew was after i washed my car on Monday i popped the bonnet to clean the engine bay and found a trail of black fluid partly dry and a bit damp coming from below the battery plate on the same level as where the engine mount bolts onto the body. I had an appointment with the foreman at a Honda dealership to correct an issue with the brakes, and after showing him the fluid he confirmed that it was the engine mount that was leaking.... apparently the Jazz has fluid filled engine mounts. It cost $215 to replace (parts were $115). Apparently this is a sort of common problem from what I have read on the net: http://www.caradvice.com.au/3841/hon...st-satisfying/

I also explained to him that i felt that the car’s power was a fair bit down (it was really struggling over the past few months). I know it’s got hotter in Brisbane, but having driven the car for 3 years, it was the slowest it has ever been. He said that they can perform (can’t exactly remember what it was called) but basically it was a top engine and throttle body clean.... despite being a bit sceptical i agreed.

After picking up the car i must say that it now drives better than it ever has. It accelerates soooo much better and just feels livelier. I also haven’t had the A/C issue since that was done so that hopefully has been the fix.

Lithium – you were 100% right, it must have been the carbon build-up causing the AC issue and the drop in performance. Thanks!

Poeter & beeza – My battery was changed in July this year and was checked by Honda and was found to be ok..

I’m soo happy the car is back, if not better than it was. I know it may have cost more taking it to Honda, but the service department was super! The foreman was really obliging and knew his stuff. Compared to other Honda dealers i have been to, this one on the Southside was by far the best!

Thanks again for everyone’s help! Hiko – maybe think about getting the same thing done on your car. From memory it cost about $80-$90. Hopefully it will help resolve your issues.

Wow,nice,fluid filled engine mounts but obviously a great idea..

Sounds like they put 'Suburu Upper Engine Cleaner' through her.

Jazz's must be prone to large carbon build up,more than likely around the top of the valve's.It would be worth your while spraying a bottle through every 2nd oil change,the car will perfrom much better,much smoother.

glad to see you came back with the sollution~