Hesitation when engine cold

[chicaboo]

Hi all,

Ever since I got my 60k service done about 6 weeks ago (the best I can place it), the car has had a really bad hesitation when trying to drive off on a cold engine. When I'm at home I give the car a minute or so to warm up, and then I need to back down a long driveway, and then drive off down a hill, so I never feel the car do this when at home. But after it's been parked somewhere for a few hours or more, and has returned to stone cold, it's a real problem as I generally don't sit around waiting for the car to warm up. It doesn't matter if I have the aircon on or not, although it seems worse when it is on. And the problem only lasts for about a minute, and the hesitation stops after the car gets over ~2000rpm or so (it could be a bit more than that). It also doesn't seem to matter how hot a day it is, apart from the aircon running on a hot day.

I had these sort of symptoms once with my Mazda, and it turned out to be an earth leak on one of the ignition leads. However, this wouldn't make sense here given the problem lasts for only a short time and then fixes itself. Someone suggested that it sounds like a fuel delivery problem, but I can't see how this would fit in given it's fine after a minute and holds a smooth idle in any case. One thing I can say it's not is modifications, so I don't need to worry about that atleast.

I will check my leads, coilpacks and plugs tomorrow to see if everything looks alright. But I thought I would ask if anyone knows of this problem first. If it is just a symptom of owning a Sportivo, I guess I will just have to live with it (along with grainy shift and groaning front brakes). But it's strange I didn't notice it doing this for the first 4 weeks or so that I owned the car prior to the service...

Cheers, Gav.

[SuperDave]

How long ago did you modify your air box? Have you tried resetting the ECU to see if it goes away?

[chicaboo]

Hi Dave,

I removed the snorkle off the airbox 3 weeks ago, in the hope that it would fix the problem. But it didn't make any difference.

I've had 2 ECU resets aswell, and these don't make any difference either. So that's why mods don't seem to enter into the arguement.

So I made a trip to a certain custom fabricator in Logan 2 weeks ago (), in the hope that would help, but that's made no difference either.

It's not a huge problem as it only lasts for a minute, but I am worried it is a sign of worse things to come. I suspect fueling and ignition as culprits.

What reassures me is the car has a good service history. And I do 10k dealer servicing and do my own 5k oil/filter changes (check over) in between aswell.

Cheers, Gav.

[whitestivo]

Gav

As soon as I got the CAI, my stivo always hesitates when cold.

You know how steep my hill is (not that steep), well when I reverse out and then drive up, I give it normal throttle, and it just sits at 1500rpm, then a couple of seconds later, it just picks up and revs to 3000rpm, and i change gear.

No worries, just reminder drive slow when cold

whitestivo

[chicaboo]

That's exactly what mine does Phil, but I don't recall it doing it for the first month I owned the car. But I definately started to notice it after the service.

If nothing's wrong with the car, I won't worry about it, but I want to be sure. I am very fussy when it comes to mechanical items on my cars. :P

Gav.

[whitestivo]

that's cause you only got the cai recently.

i think after our conversation yesterday, its taking in too much air or something early on, and it just needs to warm up.

i also notice the revs when cold with the cai where higher than before, and that it took about a month for the fuel economy to return, it was down around 520 for a while, but is back above 600 again now.

whitestivo

[chicaboo]

Nah, it's got nothing to do with the CAI or the de-snorkling. I thought each of those mods would make a fair change better or worse, but neither made a difference.

I've had the hesitation issue for 6 weeks now, and only had the CAI on for the last 2 weeks, and de-snorkling for a week before that, so it's neither of those things.

I wonder if the catalytic convertor and/or EGO needs a bit of time to warm up before it will allow a certain amount of fuel to flow beyond idle conditions? Hmmm...

Bosch suggest EGOs needs to be replaced every 2 years, and I'm willing to bet Toyota has never touched mine in 5 years. Lucky I know how to score Bosch EGO's cheap. ;)

Cheers, Gav.

[Smithy]

Sorry...EGO ?

[Hiro]

Sorry...EGO ?

Exhaust Gas Oxygen, aka oxygen sensor.

[Guni]

It happens to me too sometimes.........

Give it more gas but not ridiculously more till it redlines.

;)

[chicaboo]

I may have even subconciously tried that. Will do so conciously next time. :P

Gav.

[Madrox]

same thing happens to mine.

i went over it in the echo cold start thread.

still dont know what the problem is.

[taragasaurus]

I have the same problem after i put the CAI in when the car is cold, if i start it and go straight away its a bit of a struggle just to get it moving. 20 seconds later (or more throttle) and the car is fine.

one thing that did make a NOTICABLE differecence was taking out and spraying the MAF with jaycar electrical circuit board cleaner (green can) car is a lot better cold.

[chicaboo]

I don't think the MAF has ever been cleaned in my car. Is that the only way to clean it, by getting this electrical circuit board cleaner stuff?

Cheers, Gav.

[CHA54]

The metho dunking method works better for cleaning the MAF, but isn't quite as safe as spraying with contact cleaner.

Get a cup of metho, remove maf with the loom plug still connected, drop the maf in the cup of metho, switch ignition on for 10 seconds and then off again, remove MAF from metho and let it dry.

The maf element is a "Hotwire" filament, it heats up in the metho and all the crap is cleaned off.

[Guni]

The metho dunking method works better for cleaning the MAF, but isn't quite as safe as spraying with contact cleaner.

Get a cup of metho, remove maf with the loom plug still connected, drop the maf in the cup of metho, switch ignition on for 10 seconds and then off again, remove MAF from metho and let it dry.

The maf element is a "Hotwire" filament, it heats up in the metho and all the crap is cleaned off.

Oh cool!

I'm gonna try that.

:D

[sinan]

my car has been doing the same thing for the last few months. only on 40,000kms and have a cold air intake. so i take it its normal

[Spirited]

Check plugs and as a preliminary measure, run a little bit of injector cleaner through.

This symptom sounds closely related to the air flow allowed during idle (altered with CAI) and diagnostic sensors, eg. O2, coolant temp, etc.

Always warm your car up though.

By hesitation, do you mean the idle is dropping really low like the car is about to stall? eg. like after resetting ECU? or lack of power delivery? Never the less, check all of your connectors to sensors and such, otherwise you may have to take your car into your mechanic.

Goodluck mate.

[chicaboo]

Hi Spirited,

It's not the CAI, I have tried various setups with the intake, and nothing makes any difference.

When I say hesitation, I mean the car just sits on 1000-1500rpm and won't accelerate for a few seconds.

But the problem goes away after a minute of warming up when stone cold, so that is the fix for now.

I went to check the plugs, and then noticed it has Iridium plugs, so I didn't bother going any further since they are supposed to last 100k. Strut brace is in the way too.

Not that I could tell a worn one from a good one anyway. The only thing I know to look for in a good plug is a light tan colour on the ceramic around the electrode...

But like I said, I only noticed it start doing it after my 60k service. <_<

Cheers, Gav.

[Spirited]

So the car won't accelerate for a couple of seconds? - like a delay in engine response or some sort of misfire?

- Is the response from the engine rough as it begins to rev up after idle, like it is spitting/ missing ignition - the nature of a misfire perhaps?

You can tell when the plugs are dirty when they are covered in a dark layer of carbon. Rich fuel mixtures increase the likelihood of misfire and improper ignition so it is always a good idea to check the plugs.

Check the contacts between the electrode, which is the little metal stud protruding from the centre of the plug core and the surface of the conductor facing the electrode which carries the spark.

Give them a good clean using a scourer (green scotch-brite) and metho, cleaning the surfaces where the spark carries between both surfaces on and around the conductor and electrode. Clean off any residue left behind from the green scourer using metho and a clean cloth. Blow any excess metho left down the inner cylinder of the plug and you are good to go. This method works well for standard plugs from NGK, but have never tried them on the iridiums, so I will give it a go to see what my advice is like :P Never the less, be careful anyway, iridiums are delicate in the way that the core element is much smaller and thinner than the usual type of plug with a copper core and electrode.

You can also check the gap on the plugs, where 1.1mm is industry standard for NA engines, 0.8 usually for turbo.

Following that, check your sensors for any defects, like cracked wiring, improper connections. etc. although I think the coolant temp, idle control (solenoid?) may have something to do with it because it is related to cold starts.

Goodluck mate.

Hope this helps.

[chicaboo]

Hi Spirited,

Thanks for all the tips. The hesitation is somewhat similar to a very very rich carby engine thats flooding on take off. It sort of bogs down, but I wouldn't call it a miss. It's smooth but is not willing until after a few seconds. The duration of the hesitation shortens as the engine warms up, to the point it is gone after a minute or so.

My 88 TX3 Turbo does the same thing when it's cold because it doesn't have a cold fuel/ignition map on it's primitive ECU. The solution on that car is to use less accelerator pedal.

Do you think it could be the EGO, as I mentioned earlier? I don't think my EGO has been changed by Toyota at services, and I know Bosch recommend to change them every 2 years (but of course they would ;)).

Cheers, Gav.

[robie]

dont wanna sound like a twit but could your have got a bad batch of fuel maybe it happens if it is the only way u will know is to change the fuel filter goto a different station to get ur fuel and if you can go with out your car for a day send your injectors off to get bench flow tested (i know it sounds far fetched but i know it happens 1 other way of finding out see if you can get your hands on an IT2 tester and look in engine a data list im sure it will give you an engine missfire reading for cyl 1 2 3&4 although some toyota vehicle dont have this feature

[Madrox]

same thing happens with chika's car that happens with mine.

highly improbable that we both got a bad batch of fuel.

the problem doesn't get worse.

ill explain mine.

i start on a flat road at 7am in thhe morning in sydney.

not too cold. turn the car on and 10 seconds later i am in first accelerating normal and easing out the clutch.

the car starts to splutter a bit and the revs drop down low. it continues doing this moving at about 8k's an hour for about five seconds.

i put my foot down a bit harder and absolutly nothing changes.

push the clutch in a little more rev up 2500 and let out the cluch while increasing the revs and off she goes.

drive 500 meters to a give way sign. stop and start in first again just like normal and she runs how shhe should.

no problem after 1 min of driving.

even today on a 38 degree day when the car temperature dial was just about to bounce upto 40 it still happened after sitting still for 6 hours.

didn't happen when i bought the car off mark and mish 4 months ago. but it is now.

i have changed nothing to the engine and it has only done 8000 more k's with a service chucked in there.

[Blind Kid Seeks]

sounds like this is a common thing... mine does it as well... would be interesting ifanyone with a PFC instaled as the same problems.

[theDefiant1]

Mine too - I have removed the snorkel.

Just add a bit more fuel to the mix and all is right with mine. Might require a little more clutch work, but it settles down quickly.