Acceleration

[Anonymous]

Hi, I'm pretty new to the forum but have found the site very informative and helpful.  Hopefully some of you may be able to advise on the following, you've all been very helpful with other Q's I have posted, thanks!!

I bought my 2 privately three weeks ago on an '00 plate with 35k miles and I have been very, very happy with it (actually I LOVE the little thing, it rocks!)    s:D s:D  .    

However there is one little thing that is starting to worry me...When I accelerate up through the gears the car is pretty smooth but as soon as it reaches 5000 rpm it judders and then continues smoothly up 6000rpm when I then shift up a gear.

I never really noticed this before as I've been driving it like Miss Daisy when I first got her but over the last week or so I've been winding her up a little and have come across this little issue.

Has anyone else experienced this or is this normal (although I don't think its normal)?  

HELP pls!?   s:? :? s:?

[leon_in_uk]

have a look at the pre cat removal. and pre cat issues stuff on here... its at the top of maintenance....

[markiii]

search fro Precats and get reading quickly

[SimonC_Here]

If it was the precats, would it continue to pull past the judder? Most with precat failure, mine included, wouldn't increase power at all past about 5000 rpm.

Does it rev freely all the way up to 7000 after the 5000rpm judder?

Simon

[darrenjuggins]

Hi,

Consider a dirty MAF - you notice a dirty MAF around 4 - 6 (000) RPM, it will make the car feel really flat and may also end up throwing a CEL (error code) as the mixture will normally be too lean for the REV's.

do a search on what you need to do to clean this.

Cheers

Darren J

[Anonymous]

Yeh, the car powers on up to the 6000 rpm/red line without any further judders.

[markiii]

If it was the precats, would it continue to pull past the judder? Most with precat failure, mine included, wouldn't increase power at all past about 5000 rpm.

Does it rev freely all the way up to 7000 after the 5000rpm judder?

Simon

fair point however most probs won't kill yur engine, this one could.

I'd be checking it first every time. Pull those 02 sensor and have alook

[leon_in_uk]

yea people say take the o2 sensors out etc. and thats just the top half of the pre cat... the most common cause is 1 pre cat missing from the bottom of the manifold - joining to the cat.....

you cant go by just checking the top part..... me and dimwit did that until later found i had the lower end missing....

if you dont know what you are doing take it to a garage or a friend that knows about cars to take the manifold off and have a good look. otherwise check the MAF.. and with that many miles you defo need to gut your pre cats anyway.

otherwise like me you will be sorry..

[Anonymous]

But it's only the top of the pre-cats that will toast your engine. The bottom isn't such a problem.

[markiii]

But it's only the top of the pre-cats that will toast your engine. The bottom isn't such a problem.

true, but the bottom will block teh main cat causing excess pressure which can equally toast your engine

[Anonymous]

Hi, I'm pretty new to the forum but have found the site very informative and helpful.  Hopefully some of you may be able to advise on the following, you've all been very helpful with other Q's I have posted, thanks!!

I bought my 2 privately three weeks ago on an '00 plate with 35k miles and I have been very, very happy with it (actually I LOVE the little thing, it rocks!)    s:D s:D  .    

However there is one little thing that is starting to worry me...When I accelerate up through the gears the car is pretty smooth but as soon as it reaches 5000 rpm it judders and then continues smoothly up 6000rpm when I then shift up a gear.

I never really noticed this before as I've been driving it like Miss Daisy when I first got her but over the last week or so I've been winding her up a little and have come across this little issue.

Has anyone else experienced this or is this normal (although I don't think its normal)?  

HELP pls!?   s:? :? s:?

MAF 80% sure  s:D s:D

[Anonymous]

apologies for going ever so slightly OT, but I had a similar thing, although it wasn't so much a judder, more of a slight hesitance. between 4500-5000

I cleaned the MAF, disconnected the battery for 20mins, and now my aerial stays up whether I've got the radio on or a CD playing, it used to retract when playing a CD...? any ideas?? (it's not a stock HU but a rather nice Sony, but it was working fine!)   s:? :? s:?

**Edit - Oh, and cleaning the MAF didn't sort out the hesitance! it seems to be when i've got the throttle about 85-90% open, doesn't seem to do it when throttle's all the way down???

[Anonymous]

not sure, but i think you've got to turn TA or AF off, with it on the aerial will stay up

As for your flat spot, will it continue to rev past 6000?

[Anonymous]

oh yes, it goes fine after about 5200, it's just between about 4500-5000, and it's just a slight hesitance, like it can't make it's mind up if I want to accelerate, or accelerate!! although having said that, it has seemed slightly 'breathless' at the higher end of the rev range, which is why I cleaned the MAF in the first place, but it's not really made any difference. This perceived breathlesness may be entirely in my mind though! (with the weather getting increasingly warmer now as well, I guess it could be put down to that?)

like i said, it seems fine with the throttle wide open, it's just when my foot isn't quite 'to the floor'...

I'll try that with the TA/AF, thanks! Car's in the garage at the mo havin a new set ot toyo's fitted! last ones lasted 16500miles, which took me by surprise, everyone at work is saying i must be a lunatic now!!!   s:twisted: :twisted: s:twisted:   I would've thought that once the CD player was on, and the radio off, that this setting wouldn't make a difference? I'll try it anyway though, certainly can't hurt! thanks.   s:) s:)

[Anonymous]

not sure, but i think you've got to turn TA or AF off, with it on the aerial will stay up

You're a god! an absolute genius! thankyou!   s:D s:D  


(funny how it's the little things that matter!!!   s:lol: :lol: s:lol:  )

[Anonymous]

it's true, i am amazing.  s8) s8)    s8) s8)    s:lol: :lol: s:lol:  

does it hesitate in every gear at that point?

My previous car had ther same trouble, i put some redex in the fuel and gunned it, seemed to clear it's self after a couple of drives

[Anonymous]

yes, it seems to be in every gear. I heard that those engine cleaning additives can damage newer engines in some way, is that right? or would it be worth a shot?

Also, I was just browsing older topics and read that I ought to be able to hear a vacuum-releasing-hissing sound when I open the petrol cap after a good old blat, but I very very rarely hear this... In those older topics I mentioned though, I couldn't find out what may be causing this, or how to fix it, could this be related? would it affect performance anyway?

(no doubt someone will post a link explaining all the above and if so, sorry, i did look! really i did!   s:oops: :oops: s:oops:  )

[Maxx]

Hi,

I've had something similar and a 2nd clean of the MAF has certainly made a difference, see this thread :  m http://www.mr2roc.org/phpBB2/viewtopic.php?t=11519 m

M.

[Anonymous]

ok, i'll try it again, think i'll also try some of that redex stuff seeing as a couple of people have now mentioned it on here... thanks!

[Maxx]

Just thought i'd update this thread as I still had a flat spot/hesitation problem, even after 2nd MAF clean, Redex, new plugs etc. etc. In the end I thought it must be the MAF itself. Replaced it with a new one, problem sorted. No flat spot, hesitation or anything. Much more lively 4k and beyond.

Maxx

[Anonymous]

It does amuse me slightly that whenever anyone posts a problem which involves anything resembling a drop in power people suddenly go crazy about precats - sure they have caused some serious problems for some people but it's still a very rare problem.

Look out the window - you'll see a sparrow , not an eagle.

I just think that anyone looking to buy a mr2 could read through the forum and blow the issue out of proportion.

[roger]

I just think that anyone looking to buy a mr2 could read through the forum and blow the issue out of proportion.

I agree with you Simon, but "unfortunately" it is about the only thing that goes wrong, so it does get picked on. We've got nothing else to talk about!   s:) s:)

[Anonymous]

About the only thing that goes wrong!!!

Tell that to my power steering pump! Or to hole in my soft top!

[roger]

About the only thing that goes wrong!!!

Tell that to my power steering pump! Or to hole in my soft top!

Ok   s:oops: :oops: s:oops:  , ...I meant on a regular and car specific basis. Like an MGF engine gasket.

We all have problems (well you all do...I haven't yet - touch wood), but none that can be classified as regular and specific to the MR2, like the pre-cats can.

[Burning rubber]

I bought my 2000 MR2 about a month ago and my car juddered and flat spotted at around 5000 rpm. I removed the precats and the car is now a totally different drive, more responsive and free revving. I very worthwhile job