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Location:
Glossodia,NSW
Registered:
May 2002
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Mr2 Hesitating/Flatspot
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Sun, 04 January 2004 10:48
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My sw20 non-turbo mr2 is having some problems,it struggles to rev out freely.The car itself doesn't feel/seem to have much acceleration and it overall seems to be lacking in power somewhat.But the big problem is that will not rev out freely.The engine definately struggles when getting any higher than 4000rpm.It won't get anywhere near redline in the higher gears,but you can push it to redline in 1st and 2nd,however it doesn't really like it.It's been like this since i've bought it and i just can't figure it out.
It's puzzling,i had an ae82 with a 4age in it,and that went so much harder and overall seemed heaps quicker than my mr2.
Do you think i've got major problems??I was thinking that maybe my catalytic converter is broken/collapased.
Any thoughts??
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Location:
Sydney
Registered:
May 2002
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Re: Mr2 Hesitating/Flatspot
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Sun, 04 January 2004 11:54
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OK in your thread topic u say hesitatin
does it stutter as it it goes up the revs ?
or it revs normal but just wont get up there ?
Ta
Mani
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Location:
Glossodia,NSW
Registered:
May 2002
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Re: Mr2 Hesitating/Flatspot
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Sun, 04 January 2004 23:57
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Nope doesn't stutter or anything like that,it just wont get up there.For example,i tried a top speed run on the m2 ages ago when i first got it.I managed 160km/h,thats all it would do,it still had heaps left to go before it got to redline,but it just wouldnt keep going.And it didn't flutter or bounce back down a few hundred rpm,it just got upto 160km/h(it took awhile) and about 4500rpm/5000prm i think around there and it just stayed firm on that reading.
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Location:
Sydney
Registered:
May 2002
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Re: Mr2 Hesitating/Flatspot
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Mon, 05 January 2004 00:05
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hmm...that boggles me then
if it was me id check to see if it was blowing smoke
and do a compression test
does anyone know how the timing advances on those ? maybe a loose vacuum advance hose ?
im just taking punts here to be honest
Ta
Mani
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Location:
Glossodia,NSW
Registered:
May 2002
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Re: Mr2 Hesitating/Flatspot
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Mon, 05 January 2004 00:19
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Nope no smoke,it's crystal clear,i can't see any hoses not connected.The other thing that has got me pointing to a blocked cat is the amount of flow of exhaust gases coming out.I have the original front section/headers and cat,then i got a new mandrel bend cat back system with a big cannon.Now when i put my hand over the exhaust tip,there doesn't feel like much flow is coming out,and thats why i was leaning to a new cat.If the gases can't get out,wont they just travel back up the exhaust and cause extreme backpressure??
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Location:
Sydney
Registered:
May 2002
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Re: Mr2 Hesitating/Flatspot
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Mon, 05 January 2004 00:23
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yep then it could very possible be a broken down cat
an exhaust leak can cause of lack a power aswell but not to the point that your describing i wouldnt think
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Location:
Glossodia,NSW
Registered:
May 2002
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Re: Mr2 Hesitating/Flatspot
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Mon, 05 January 2004 00:26
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Yeah,thats what i was thinking.I'm going to get it looked at today.
Got any other ideas/suggestions
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Location:
Sydney
Registered:
May 2002
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Re: Mr2 Hesitating/Flatspot
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Mon, 05 January 2004 00:35
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without actually seeing it myself i cant break it down to certain things
could be many things
could be something as simple as a blocked airfilter
u say its been like that since u bought it ...how long ago was that ?
Ta
Mani
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Location:
Glossodia,NSW
Registered:
May 2002
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Re: Mr2 Hesitating/Flatspot
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Mon, 05 January 2004 00:45
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I bought it end of july last year.I got a new timing belt done,new water pump,major service including new top gun leads,bosch super 4 plugs etc etc.Removed the airbox around october,and replaced with a length of pvc plumbers pipe and a ram pod which sits right down into the left side air vent,i also tapped in the sensor that was in the airbox into the pvc.and i got the exhaust done just before xmas.Thats the only mechanical changes that have been done
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Location:
Sydney
Registered:
May 2002
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Location:
Glossodia,NSW
Registered:
May 2002
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Re: Mr2 Hesitating/Flatspot
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Mon, 05 January 2004 05:34
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No it was happening as soon as i got the car,thats why i got it checked out and got the service done.When my mechanic told me everything was fine i presumed my car was a-ok.It was only when i tried the top speed run,that i was concerned and i was then convinced that something was wrong.
I got the cat checked today and it's fine,so im back to the guessing game again.
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Location:
Brisbane
Registered:
February 2003
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Re: Mr2 Hesitating/Flatspot
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Mon, 05 January 2004 06:17
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jeez, could be lots of things...
timing too far advanced (fine at lower revs, but way to early at high speed)?
or air leak (engine copes at lower revs, but is way too lean to at higher speeds)?
also, have you tried it without a cat?
are the cams at correct timing (seeing as you had timing belt changed at purchase)?
or, if the TPS has a WOT switch, maybe the TPS is incorrectly set?
or, is the AFM working correctly?
or, if fuel pump up to scratch and fuel filter clean/new?
would also advise you do some more diagnosis like pulling the spark plugs to see if they're running too hot or too rich.
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Location:
The Eastwood MASSIVE !
Registered:
May 2003
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Re: Mr2 Hesitating/Flatspot
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Mon, 05 January 2004 09:22
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Might want to check things like the ECU fault codes if you have any.
Something like your 02 sensor might be on the wayout and causing in the car into limp mode.
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Location:
Glossodia,NSW
Registered:
May 2002
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Re: Mr2 Hesitating/Flatspot
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Mon, 05 January 2004 11:08
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Thanks for the tips guy.But with me being not very techno related when it comes to cars,it seems like i'm going to be spending a small fortune at the mechanics to get it fixed
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Location:
Sydney
Registered:
May 2002
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Re: Mr2 Hesitating/Flatspot
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Mon, 05 January 2004 11:57
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Nah extracting fault codes is something u can do yourself
i didnt think of that one cause ive never had a car with an ECU
extract the codes yoursefl ATLEAST....so u know whats wrong with it so u dont get rorted
Ta
Mani
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Location:
Sydney
Registered:
September 2003
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Re: Mr2 Hesitating/Flatspot
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Mon, 05 January 2004 13:26
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Check this site out  :
http://www.yorksoft.co.uk/mr2/index.asp?selection= viewprob&problemview=Engine
Similar Problem:
[QUESTION]
Toyota MR2 MK2 N/A - MR2 MkII running really rough?
Hi, I've recently bought a 1991 J standard MR2 (no spoiler), and its started to run very roughly. It feels almost like one of the spark plugs is out (which they arent) - ie lack of response, its hunting to the point where it lurches ahead constantly and wont drive smoothly until you get up to about 65mph. I recently changed the radiator due to a leak, and after bleeding the system noticed it had improved the situation a bit, but for only a few hours, then became rough again. A garage thought it might be an air leak, but wouldn't spend time investigating. Does anyone have any ideas? Could it be air getting into the system perhaps? If so, whats the most likely cause? Would a diagnostic check from Toyota pin point this - or would I be chucking money away!! Thanks everyone.
[ANSWER]
It sounds like there is air in the water system, this can cause hunting and rough running. The temp sensor senses changes in the water and then air temperature and tries to compensate, hence the engine hunting.
Are you getting any white smoke out of the exhausts or white deposits in you oil filler cap?
If yes, get your head gasket checked, this can throw air and oil into your water system.
Another trick is to reset the ecu so it has to learn its timing setup again (this is normally only for fine tuning though). Disconnect battery for a while, this should reset the ecu.
[Updated on: Mon, 05 January 2004 13:32]
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