Just wondering if anybody has any/had any flat spots through the rev range and what might cause it??

I was just at a red light going into a 100 zone so I thought I'd give it a bit...noticed a very bad flat spot at around 65 in 2nd gear

Just thought it might be something worth worrying about or just something that happens as the kays rack up

Cheers,
Mikey

Mine just runs out of puff after 5.5k it is not so much a flat spot more they way it if geared I think

I think thats fairly normal Mecha...considering max power is qouted at 5250rpm iirc .Mine will hold gears out to 5900 compared to 5500 when i bought it but theres nothing up there!

This was more of a noticeable pause in power delivery..

Bad fuel. I saw you driving out of Matilda the other day (I work across the road, and those LED sand out :P), that would be your problem.
Nothing a fill of 98 ron and some injector cleaner / octane booster wont help :)

65km/h in 2nd gear in an auto is I guess around 3,800 rpm, so nowhere near the 'run out out of puff near the rev limiter' zone.

Even with plenty of ks on board such a loss of power shouldn't be normal.

Maybe a bad batch of fuel.

Maybe a dodgy injector.

Maybe a dodgy spark plug.

Maybe (but I doubt it) you have over-oiled your K&N filter, which stuffs up the MAF.

I gather you weren't turning sharply at the time with a lowish tank of fuel, this is a common problem with Magnas (fuel slopping away from the fuel pick up = sudden loss of power), haven't heard of the same problem in a 380.

Best bet is to give it a proper test. Try some WOT applications in each gear (using the tippy to hold it), and see if it happens again at the same or different revs.

If it happens again try resetting the ECU by disconnecting the negative battery terminal for a minute or so, and see if that fixes it.

KJ.

Edit - FFEEkY beat me to it about bad fuel, gotta learn to type faster!

Cheers fellas i'll get onto it tomorrow. I only just fueled up the other day as Keith pointed out, so it wasn't fuel delivery problems. I don't think the filter is over oiled, although it wouldn't hurt to check I guess.

Just a quick question though, and please no bias. I did fill up with E10 without realising....is it really a lesser grade fuel than standard 91 before the ethanol is added? Can I still add octane booster to E10 fuel?

Assuming it isn't dirty fuel could just putting E10 in really have an effect like that?

Oh and Keith, where abouts do you work mate?

Just to give you an idea.

I had a bad batch of E10 when I owned my Hyundai Accent and I noticed the exact same issue you were experiencing with flat spots in the rev range.

As soon as I filled up with 98 octane, the flat spots went away. I haven't used E10 since...

Run it with no air cleaner at all....then see if there are flat spots.

I had a bad batch of e10 from there a couple months back in the lancer, the flat spots were horrible. I just suffered it for that tank, then went to caltex and put in 98 ron with a full bottle of some octane boot/ injector cleaner from supercheap. That was like an instant fix.

I work at Retravision directly across from matilda. We have a full window front and the weekend is great for watching all the good cars driving in and out of town all day :)

I had a bad batch of e10 from there a couple months back in the lancer, the flat spots were horrible. I just suffered it for that tank, then went to caltex and put in 98 ron with a full bottle of some octane boot/ injector cleaner from supercheap. That was like an instant fix.

I work at Retravision directly across from matilda. We have a full window front and the weekend is great for watching all the good cars driving in and out of town all day :)

Ahh i see, well thats where I usually fill up so I might try premium tomorrow. Oh you work at retravision....well explain why my toaster is broken! haha

Just to give you an idea.

I had a bad batch of E10 when I owned my Hyundai Accent and I noticed the exact same issue you were experiencing with flat spots in the rev range.

As soon as I filled up with 98 octane, the flat spots went away. I haven't used E10 since...

Must be pretty shitty fuel as most people say the same thing!


Run it with no air cleaner at all....then see if there are flat spots.

How temperamental are the maf sensors...is there any way i can check if it has oil from the filter on it? Don't want to risk driving without the filter considering the amount of dirt around my area with the crazy amount of road works...

How temperamental are the maf sensors...is there any way i can check if it has oil from the filter on it? Don't want to risk driving without the filter considering the amount of dirt around my area with the crazy amount of road works...


The active component in a MAF sensor is a small signal silicon diode.
It usually has 0.6 volts forward voltage drop across it in normal forward biased opertation.
However being a semiconductor it has a negative temperature coefficient, meaning that the hotter it gets the lower the resistance and hence more current and lower voltage.
It is usually housed in the presence of a heating element which provides a known reference temperature for a baseline reference voltage on the diode which acts as a sensor to the ECU.
As air passes across the heating element it makes the PN junction of the diode cool and hence the diode gets a higher voltage across it's PN junction.

If you get dirt on it then it will think it is colder than it actually is....and think it is getting more air than it actually is.

If you get oil on it it will get a parallel resistance across the diode and with air passing across it the results can be unpredictable.

They say to never wash/clean it with petrol.

i have a faulty one here that makes the ECU think it is getting a mountain of air so switches on the fuel injectors to the point of leaking fuel all over the road.

Hey Mikey,
Just a thought, I had a similar problem with mine, I only got it about 6 weeks ago.
I got them to do a transmission power flush and the difference was remarkeable, no more flat spot and a considerable improvement through all gears

i've noticed that when ever i come out of a driveway thats a little steep and i have to go sideways causing the suspension to travel not to the point where a wheel is off the ground but as soon as i have both wheels on the road and plant my foot down to the floor to blend into the traffic i've noticed that the traction light flashes like a disco and the car acts like its coughing or something with my foot to the floor and no power being delivered then it takes a moment to realise what i want then responds accordingly. My black vrx did the same thing. Its like a delay or something. Has anyone else experienced this or could it be similar to what Mikey is experiencing.

All the time I turn TC off at a certain servo driveway as I have pulled out and had nothing before due to TC not happy with a wheel in the air only happens at this one servo though

well this is usually out of the driveway at the car wash in liverpool. Hmmm WARRANTY

Mine does the same Kiffy.
Ive always just taken it as the useless traction control system trying to battle wheelspin.

It cuts the power when it senses wheelspin, then slowly allows the power back to the wheels when your getting slowly underway.
Im just guessing yours is getting a bit of axel hop, Kif. The feeling like it wants to spin the wheels but there's that bit of grip and TC stopping it, feels like it want to jump jump jump.

Unless ive miss read what you were saying and then yeh..

yer Anthony thats what it seems like.