Assuming your Swift is a recent fuel injected model, disconnecting the battery causes the ECU to lose it's "learned" settings - in cases like this, it's not unusual for the vehicle to idle poorly and possibly stall for a day or two whilst the ECU "re-learns" the settings the engine needs to run properly.

I would expect any competent mechanic to be aware of this, and I'm quite surprised the garage didn't mention it.

Drive as normal for a day or two and see what happens...

 

Assuming your Swift is a recent fuel injected model, disconnecting the battery causes the ECU to lose it's "learned" settings - in cases like this, it's not unusual for the vehicle to idle poorly and possibly stall for a day or two whilst the ECU "re-learns" the settings the engine needs to run properly.

I would expect any competent mechanic to be aware of this, and I'm quite surprised the garage didn't mention it.

I completely agree - I have suggested this to the garage but they've said that's not the case or it would have shown up on the engine management system (I am not so sure) and they say they've had to remove valves and clear out corrosion from pipes..

 

Rather than start a novel, Fodem is correct, mechanic is wrong

 

How would this show up in the engine management? theres no faults to detect!

Fordem is correct, your mechanic is wrong and has created the issue.

As you haven't told us the year and engine use this generic procedure below.

Correct reset procedure is as follows. (More applicable to the electronic / motor controlled throttle bodies) but this resets the fuel trims, base idle and IAC on the Swifts

Disconnect battery.
after 10 minutes, reconnect
Turn key on
Do not touch any pedals
wait 30 seconds
Start
Idle (depending on model) will either be ok, or can fluctuate (cable ones will fluctuate as IAC sorts itself out)
Drive normally, expect bad economy for a few days as fuel trims reset.

Very common on battery replacement, if they just changed the battery and started it immediately then that will cause all sorts of issues.

 

Or just leave it to sort itself,

The garage would not see any abnormality as the ECU has been reset to factory by removing the +Bat power.

Reset also erases all pending, and freeze frame data. Any technician worth his salt would know this...

 

Or just leave it to sort itself,

The garage would not see any abnormality as the ECU has been reset to factory by removing the +Bat power.

Reset also erases all pending, and freeze frame data. Any technician worth his salt would know this...

I agree, absolutely correct, You can leave it to sort itself out but who wants to wait? and is that fair on the customer that sent a (we assume) perfectly running car in and got it back in a worse condition? (ok, ok, I'm impatient too but I also don't give a car back to a customer running worse than when it came into the shop.)

These guys sound like parts changers and code readers, not automotive techs.

 

Thanks all. Unfortunately I could not prove anything - they said that if there had been a gap in power the radio would have reset. I pointed out that the clock had reset but they said that wasn't relevant.
They have taken off and cleared soot.out of various bits which is what they said was causing the problem, and charged me two hours labour for doing so. Nothing I can do about it, as it is now running fine so to them that proves they were right.
At least I know from your responses that my hunch was probably right!

 

a "gap in the power"?? clock will reset as soon as power is lost, radio will lose its preset stations after about 30 seconds. Sounds like they used a back feed setup to keep things "alive" and got it wrong.

 

Yes, which is why they're claiming it couldn't have been the battery replacement that caused the issue. Frustrating.

 

if they back fed thru the OBD2 port that could very well have caused an issue. Very easy to upset some ECU's as the power supply to that port may not get all ECU's with the key off. Many cars even lose power to the OBD2 port when cranking.
Only safe backfeed way that keeps everything working is via the cig lighter socket with key in ACC position as that supplies the whole car apart from the "running" stuff like fuel pump etc. Sounds like they screwed up and got it wrong. I'd argue it came in running fine they returned it in a non fine running state and they pay for it as it was ok when you delivered it.

 

Hard to challenge as they say the EVAP valve and MAF sensor were clogged up and it wouldn't have run properly like that. But I know it was running fine before I took it in. Thanks for the help and advice.

 

If they said they cleaned "soot" out of things, then I'd like to know how it got on the MAF and the Purge valve as both are well away from any soot producing areas.

 

This is where I'm at a disadvantage and unable to challenge as I don't have the knowledge. All I can tell you is that they said the valve was unable to open and close properly as it was all sooted up. All they've written on the invoice is two hours labour. I could ask for what they've done in writing - is it worth it? I feel like I probably have to write this off now, and find a better mechanic! (My usual trusted mechanic has just retired)

 

I would find another mechanic.

 

Working on it ?

 

Eu tenho um suzuki swift 1.3 1992 o carro levou velas novas cabos de velas novos tampa distribuidor nova o carro esta andar bem e desligasse e dp nao pega sabes o que podera ser

 

Welcome to the forum Pedro, please be aware that the rules requires posts to be in English.

I suggest you start your own discussion as you have a different issue to the one being discussed here.