Engine flat spot

[Anonymous]

I wonder if anyone can help or has experianced a similar problem. I've just bought a 2000 MRS import. It's a babe and I love it although, there is a flat spot when you push your foot hard on the accelerator the engine sort of stutters. Let me try and help.... Bru........Bruuuuooooom Bru...........broooooomm... it has had a full RAC inspection and has been given a diagnostic check with no fault found. The only other thing is, it's got a TRD exhaust and I don't know if this would alter anything... Heeelp.. thanks...  Also who is MrT..?? sorry i'm a newbie and all though.. thanks..

[GSB]

Sounds like an intake problem... Remove and carefully clean the Air flow sensor (MAF), and then check all the joints in the air intake for air tightness.

Next on the list would be the dreaded pre-cat problem, but if its just a stutter followed by a resumption of normal service I think we can discount that.

Mr. T is is man who can significantly improve your power to weight ratio.

He does this by removing significant quantities of cash from your wallet at any given oppertunity. He is more usually know as your local Toyota main dealer...

[darrenjuggins]

Hi,

I've been experiencing this problem, had to CEL's now for fuel mixture and he's now diganosed it as a MAF falure - parts on order, will hopefully sort the mixture and also flatspot problem....

Flat spot is worst at 4 to 5 k and above (i.e. VVT Zone)

I'll let you know friday after new part has been fitted.

Cheers

Darren J

[Anonymous]

I don't know if a flat spots the right way to describe it, maybe it's more of a stutter, if you accellerate more gently till your above 2000 revs it's not there at all, it's more if you push your foot hard down on the throttle then right at the bottom of the rev range it doesn't pick up cleanly. Bu.......brooooooom. Does seem like a fueling thing though so i'll check the air filter tonight and see if that makes a difference.
and as for MrT does he have a website I can peruse to see how I can most effeicently spend my money the fastest haha.

[Jap GT300]

The term you've described is bogging and I think it is most probably an air/fuel problem ie. the MAF, or a vaccum leak.

It could also be worth spraying some carb cleaner down the throttle body to clear any oil residue (I got that one from Mark   s:wink: :wink: s:wink:  )

[Darth Paul]

It could also be worth spraying some carb cleaner down the throttle body to clear any oil residue (I got that one from Mark   s:wink: :wink: s:wink:  )

Where exactly is this, and how do ya do it?

[markiii]

The best stuff to use is 10K Boost, spray it post maf into the intake, it will clean any oil residue off the TPS sensor, which can get very caked up, as we found with Seans when doing the turbo.

You will be amazed at teh black shit that will come out of your exhaust (and all over your trousers if your standuing in teh wrong place) as I found when doing Adams  :-) :-) :-)

However Wynns carb cleaner isn't bad and is safe to use pre-maf as well.

It's one of my biannual maintenance jobs, along with running a can of injector cleaner through.

[so.simple]

Good idea. Is the engine supposed to be running while you that? Also, where is the best place to spray the carb cleaner? Should I disconnet the pipe right after the air box?

[Slacey]

Good idea. Is the engine supposed to be running while you that? Also, where is the best place to spray the carb cleaner? Should I disconnet the pipe right after the air box?

Yep, engine running. If you are using the stock airbox, just remove the filter and spray into the intake in short bursts.

[so.simple]

Ok... But markiii said "spray it post maf into the intake"... Removing the filter means pre-maf. Which is the correct way?

[Slacey]

With the stock airbox there is no way to spray it in post MAF other than disconnecting the large rubber hose that goes into the throttle body - this wouldn't work as the car won't run without the MAF metering the airflow. If you are only using the carb cleaner then it is perfectly safe to use pre-MAF - it will even clean it to a certain degree!

[so.simple]

Great! I'll do it tonight! Thanks for the info.

On the same subject, if the TPS gets dirty with oil, that must coming from the breather pipes, right? Would you recommend an oil catch tank? Are they a good idea to keep the engine's inside nice and shiny?

[Slacey]

Catch tanks can only help, but aren't really necessary in an N/A application. The only reason I had oil trouble (and it was the idle control valve that was the most affected) was that I had initially allowed the crankcase and engine to pressirize under boost by leaving the breather hose attached to the throttle body, which drew quantities of oil through the hose, into the throttle body which when closed vented it all arounf the intake system and I/C via the recirculating BOV  s:roll: :roll: s:roll:

[markiii]

Ok... But markiii said "spray it post maf into the intake"... Removing the filter means pre-maf. Which is the correct way?

loosen the clamp that holds the airbox to the intake pipe (post maf) and insert a straw, spray through that.

10K boost is not MAF freindly according to teh can.

[Jap GT300]

Wynns is MAF friendly though   s:? :? s:?

[Slacey]

Wynns is MAF friendly though   s:? :? s:?

Yep, which is why I said you can spray that straight into the airbox and clean the MAF at the same time.

[heathstimpson]

Wynns is MAF friendly though   s:? :? s:?

And what I use anyway to clean the MAF  s:wink: :wink: s:wink:

[Anonymous]

Let me try and help.... Bru........Bruuuuooooom Bru...........broooooomm...

 Lol - this amused me greatly, thanks

[heathstimpson]

Let me try and help.... Bru........Bruuuuooooom Bru...........broooooomm...

 Lol - this amused me greatly, thanks

Ditto; have a listen down my mobile  s:lol: :lol: s:lol:    s:lol: :lol: s:lol:    s:lol: :lol: s:lol:

[Anonymous]

HI Darren,

How did you get on with the car did they solve the problem..?? I had  a quick look at the air filter on mine with no joy..
I've seen so much written about this precat thing now i'm worried about that, mines quite a high miliage car with 60,000 on the clock so if the cats havn't been gutted it sounds like that will be a problem anyway. Two questions,

1/ Has anyone ever written an explanation on here on how to gut the cats. ( I did search for it but there is so much on here).
2/ Does gutting the precats not put the sensor doobrey thingy out on MOT's..?

[GSB]

Q1/ Yes they have... I wrote a post detailing how I did it, quite a while ago, and then ended up gutting 4 or 5 manifolds at the first pre-cat meet. Others have since added there own interpretations to a few details, but essentially its done like this:

 m http://www.mr2roc.org/phpBB2/viewtopic. ... 4840#44840 m

Q2/ The gutting causes no issues whatsoever regarding ECU operation, Check Engine Lights, Sensor operation, or MOT emmisions testing.

[Anonymous]

I guess it's off to halfords again tomorrow then to get some carb cleaner. Yes bogging is the word I was looking for, it's bogging down when I accelerate. Mind you I think Bu.... Broooom works well too... I was thinking of recreating the sounds made by my car during my whole journey to work, using just my mouth, then making it into a ringtone. maybe i'll use a little caracture to advertise it on the TV, crazy toad or something... Baaaa baaa baa.....Broooooom. Who knows I could even release it to a film theme tune... Yeah right...!!  [/quote]

[heathstimpson]

I guess it's off to halfords again tomorrow then to get some carb cleaner. Yes bogging is the word I was looking for, it's bogging down when I accelerate. Mind you I think Bu.... Broooom works well too... I was thinking of recreating the sounds made by my car during my whole journey to work, using just my mouth, then making it into a ringtone. maybe i'll use a little caracture to advertise it on the TV, crazy toad or something... Baaaa baaa baa.....Broooooom. Who knows I could even release it to a film theme tune... Yeah right...!!  

[/quote]
That's what I was thinking; you've got that frog tune driving you mad in your head  s:wink: :wink: s:wink:

[Anonymous]

Darren, How did you get on with your MAF sensor did that cure the problem..?? Havn't had chance to clean mine, ran some carb cleaner through the air filter but that didn't make any diff... although running at some point with the air filter half on half off it seemed to be revving freely. So sounds like this could be the problem.

[Anonymous]

Hi just thought I would end this thread by sharing with the group the fault. It was as a few of you suggested the MAF sensor, the dealer I bought the car from bought the part for me and I fitted it in just a few mins. It cost around £95. So if anyone has these exact same symptoms i'd say this  is the cure. Thanks for all your help.