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Flat spot mid rev rance and POWERRRRR after about 4-4.5k rpm

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- Danny Boy -

Post subject: Flat spot mid rev rance and POWERRRRR after about 4-4.5k rpm

Posted: Thu Jun 02, 2011 9:37 am

FSI Supporter

Joined: Fri May 23, 2008 12:40 am
Posts: 7094
Location: Portsmouth
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Hey guys, I was wondering if anyone might have experienced something similar like this before?

Basically if I pull away with my foot planted, at first it seems good, then through the mid rev range say between 3k rpm and 4k rpm/4.5k rpm it just seems flat and gutless, but soon as i hit about 4-4.5k rpm it picks up and goes and, like properly goes.

I will check the rpm it does it later, and will also be checking sensors here and there too, but I just wanted to see if anyone had any opinions on what it could be just incase there is anything else I can check that I havent thought of.

Also just to put it out there, my engine is standard 1.6 zetec, only mods it has is a K&N filter and a banana-rama pipe, and a magnex cat back system.

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The Loumiester

Post subject: Re: Flat spot mid rev rance and POWERRRRR after about 4-4.5k

Posted: Thu Jun 02, 2011 10:05 am

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Joined: Sun Aug 03, 2008 11:20 am
Posts: 8463
Location: Rochdale
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Mine did exactly the same until I cleaned the MAF but I know you've already done that so god knows lol

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- Danny Boy -

Post subject: Re: Flat spot mid rev rance and POWERRRRR after about 4-4.5k

Posted: Thu Jun 02, 2011 11:16 am

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Joined: Fri May 23, 2008 12:40 am
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Location: Portsmouth
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Yeah maf is clean. I'll pop down to the garage when I get home and if the battery is still good ill let it warm up and start playing around with different sensors and see if one plays up or not. Neighbours will love me going up and down the road constantly :lol:

Might have to take a trip to the petrol station on the old push bike later :lol:

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elPaulio

Post subject: Re: Flat spot mid rev rance and POWERRRRR after about 4-4.5k

Posted: Thu Jun 02, 2011 1:22 pm

Elite FSI Poster

Joined: Wed Sep 10, 2008 1:21 pm
Posts: 1296
Location: Aberdeen, Scotland

No amount of sensor twaeking will fix it im afraid!!

The silver top zetec has a horrendous flat spot between 3kish to 4kish.

The only way to fix it I know of is to put in an FSE Power boost Valve or similar.
Both my car and my mates 1.6 Focus do it, he thought it had a twin cam his was so obvious LOL

Paul

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- Danny Boy -

Post subject: Flat spot mid rev rance and POWERRRRR after about 4-4.5k rpm

Posted: Thu Jun 02, 2011 1:35 pm

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Joined: Fri May 23, 2008 12:40 am
Posts: 7094
Location: Portsmouth
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I know they suffer around that rpm, but it annoys me because it's fine when the engine is cool/quarter the way up the temp gauge but soon as it's hot it's like nahhhhhh. And it's fine on just under full throttle too.

But other than that it goes fine. I think it's begging for some forced induction

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Post subject: Re: Flat spot mid rev rance and POWERRRRR after about 4-4.5k

Posted: Thu Jun 02, 2011 1:38 pm

Jap Crew

Joined: Tue Dec 21, 2004 6:24 pm
Posts: 11189
Location: In the Shires
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I'd say the cure would be to RR it.

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stuff n that

Post subject: Re: Flat spot mid rev rance and POWERRRRR after about 4-4.5k

Posted: Thu Jun 02, 2011 1:39 pm

Regular Poster

Joined: Wed Jul 01, 2009 1:25 am
Posts: 304
Location: barnsley
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try disconnectin the vacuum hose off the fuel reg, pressure goes to 2.9bar so makes it rev nicer

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andyleesy

Post subject: Re: Flat spot mid rev rance and POWERRRRR after about 4-4.5k

Posted: Thu Jun 02, 2011 10:11 pm

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Joined: Wed Feb 08, 2006 10:27 am
Posts: 1391
Location: Leicester
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I would have said MAF, I can remeber mine doing the same.
If it's slightly better with less throttle (i.e 75%) then i'd do plugs & ht's and check the loom around the coilpack.

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- Danny Boy -

Post subject: Re: Flat spot mid rev rance and POWERRRRR after about 4-4.5k

Posted: Thu Jun 02, 2011 10:15 pm

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andyleesy

Post subject: Re: Flat spot mid rev rance and POWERRRRR after about 4-4.5k

Posted: Fri Jun 03, 2011 9:33 am

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Joined: Wed Feb 08, 2006 10:27 am
Posts: 1391
Location: Leicester
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how about the coilpack itself?
other than that I'd do a compression test, does it idle ok?

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- Danny Boy -

Post subject: Re: Flat spot mid rev rance and POWERRRRR after about 4-4.5k

Posted: Fri Jun 03, 2011 9:44 am

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Joined: Fri May 23, 2008 12:40 am
Posts: 7094
Location: Portsmouth
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Yeah it idles fine. Nothing wrong with it apart from the flat spot. Ive seen some RR graphs on various zetecs - few standard 1.6's too and you can see the flat spot. So must just be me being anal.

Im going to leave it for now because other than that which is normal for the engines, its perfect and i shall be going down the 2 litre route soon anyway

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james_rs

Post subject: Re: Flat spot mid rev rance and POWERRRRR after about 4-4.5k

Posted: Sun Jun 05, 2011 9:43 pm

FSi Donator

Joined: Mon Jun 19, 2006 10:22 am
Posts: 1503
Location: Hertford, Hertfordshire
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Ive got a blacktop 2.0, (brand new) in my si and its does it. Its also running a aftermarket fuel reg.

My 1.6 engine done it, my bros rs1800 done it. I think its a zetec-e thing.

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vw_99_bmx

Post subject: Re: Flat spot mid rev rance and POWERRRRR after about 4-4.5k

Posted: Tue Jun 07, 2011 7:11 pm

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Joined: Sat May 22, 2010 10:36 am
Posts: 92
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mines doesnt idle when cold just cuts out but revs free all the way through the revs

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- Danny Boy -

Post subject: Re: Flat spot mid rev rance and POWERRRRR after about 4-4.5k

Posted: Tue Jun 07, 2011 7:17 pm

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Joined: Fri May 23, 2008 12:40 am
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