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Teach me about hesitation!

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Old 14 January 2003 | 10:51 AM
  #1  
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OK here goes. I think i know what it is, or the symptoms anyway. I don't think that my car suffers from it, but here is my take on it. As you all know, i'm no expert but i do like laymans explainations.

Most common in MY99-00 models
When depressing the accelerator, the car actually feels like it looses power for a moment before picking up
Not to be confused with turbo lag because with hesitation, the engine revs do not rise in proportion to throttle movement.
About right?

I've had a "strange" thing with my car (MY00) about a year ago. I held the car at about 4,000 revs in 2nd round a large roundabout because I knew the exit road i was due to take was wide and had a "novelty" camber in it. As i was applying the power and straightening up for the yump, the power just stopped increasing. It didnt stop totally and it wasn't the rev limiter, it was almost as if the car had got comfy at 4k revs in second and didn't want to do anything else. I changed to 3rd all was well, at the next island, tried it again, this time it was a much smaller island so probably 4k in 2nd for about 2-3- secs. No problems since.
For the benefit of Saxoboy, the tank was full cos it was the island straight after a petrol station.
Was that hestitation?
So what is it, anyone know for sure or is it one of those "feeling" things?

Mikey
Old 14 January 2003 | 01:21 PM
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Dunno Mikey... but my my99 likes to this on occasions too [img]images/smilies/mad.gif[/img] .....

Just one of it's many habits IMO
Old 14 January 2003 | 01:38 PM
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The ECU goes into an "emmisons mode" when held at constant revs for a short while. This is to help the car get through the various EU tests. What has happened is that the ECU went into this mode which involves running low boost. When you hit the accelerator the boost would not have kicked in as expected and this is what you experianced.

That's my understanding anyway
Old 14 January 2003 | 02:35 PM
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thats sounds more like the emmisions thingy...

the hesitation on my MY00, is around 2500 -3200rpm, on part/light throttle only, it feels like quviver/stumble and makes holding the car ina cruise at does rpm 'uncomfortable' but not a severe as kangarooing...

it feels like a slight misfire, one plug maybe, but on WOT thru gears or even pressing on with 3/4 throttle its not there at all...

Cheers
Old 14 January 2003 | 02:36 PM
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thats sounds more like the emmisions thingy...

the hesitation on my MY00, is around 2500 -3200rpm, on part/light throttle only, it feels like quviver/stumble and makes holding the car in a cruise at those rpm 'uncomfortable' but not a severe as kangarooing...

it feels like a slight misfire, one plug maybe, but on WOT thru gears or even pressing on with 3/4 throttle its not there at all...

BTW I have changed plugs with no change, ive yet to tyr an MY98/99 ecu... any volunteers in the Dublin area?

Cheers
Old 14 January 2003 | 03:59 PM
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...my hesitation disapperared when I had the downpipe replaced for a Hayward and Scott Decat unit..

HTH

R
Old 14 January 2003 | 04:16 PM
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The emissions thingy needs the revs to be held at a constant 3krpm for @ 30secs at least and as yet I have been unable to ever replicate this ever since

I asked the same question as Gridlock about a year ago when I suffered complete lack of power when overtaking and it ain't done it as severely ever since. However the hesitation is still there (after new downpipe fitted) but I'm hoping that new plugs this week is going to fix it

Otherwise it's delta dash time or I know ........, I'll just go and buy another 4 MAF's [img]images/smilies/mad.gif[/img]
Old 14 January 2003 | 05:44 PM
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Mikey,

hesitation - could be your ecu. there are 2 types. AE800 & AE801 on those cars (as I remember!) and one does do bad things! think it's the 800. ECUTEK doing the TEK1 for this problem. or you can swap the ecu for the good one. (801 ??).

2nd problem . that is DEFINATLY DEFINATLY DEFINATLY the emmisions thing! Only happends in second gear. hold it around/above 2.5k for about 5 sec, then boot it. it only produces 0.5bar (instead of about 0.8/0.9) and will only resume normal boost until a) you let off & re-apply the gas b) change gear (basicly doing a) again!)

I can make this happen EVERY time in my car. it can get anoying until you learn to drive around it (leave it in 3rd and only change down when you are just going to overtake etc etc)

only way to get rid of it, is a remap! (does the ECUTEK maps get rid of this??)

cheers
Steve
Old 14 January 2003 | 07:02 PM
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No Ecutek does not get rid of it.

An engine with a compression ratio of only 8:1 will feel hesitant when snapping open the throttle compared with a good high compression NA engine.

All the MY99/00 ECUs hesitate when cold because they go into closed loop lambda control very early to satisfy emissions requirements. 14.7:1 is a bit lean when the engine is cold so it hesitates.
Old 14 January 2003 | 10:21 PM
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Thinking about it, my hesitation dissapeared when i had my downpipe fitted.
Old 14 January 2003 | 11:43 PM
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When you said "hesitation" I thought you were talking about you going to the bar to buy us all a drink

Andy
Old 15 January 2003 | 08:11 AM
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Thanks for the replies folks,

Attu, get ya coat

Mikey
Old 15 January 2003 | 12:23 PM
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I posted the same thing last year.
Have a read of thread id 137295 (car seems flat in second)
It may give you some ideas
Old 15 January 2003 | 12:44 PM
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Sounds to me like your engines about to blow up. That'll teach you for not bothering to monitor it
Old 15 January 2003 | 05:06 PM
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Cheers Ozzy I presumed that's what it was

Mikey
Old 15 January 2003 | 07:59 PM
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My hesitation on my MY00 didn't disappear after I had the H + S decat DP fitted!! I know that for a fact!!! It did after I had a AE801 ECU fitted. The AE802 seemed to cause the problems!!

Cheers Phill C
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