See Post 22.

https://www.northamericanmotoring.co...93-post22.html


Here's a question for you guys...

When acceleration "normally" with your foot pressed on the gas just enough to hear that intake whistle; Acceleration between 2800 and 3200 rpm is jerky. Enough to jerk you around and feel foolish.

When Accelerating in a spirited fashion, jerkiness is not experienced.

A good way to reproduce this is to have your vehicle in 2 or 3 and quickly move your foot up and down on the gas only slightly. this will make the engine jump, and it will feel like what i am experiencing.

Any Ideas?



fyi:
I have a milltek cat back.
I have a ALTA intake.
I have NGK iridium plugs.
I have plasti-dip stripes(5/10hp increase)
I have tried different gas stations
I have Changed my oil with castrol syntec 5w-30

I have not replaced my fuel filter
I have not run seafoam through my intake/gas
I have not checked my bypass valve.

 

weyfey,

The following comes to mind:
1) Check your floor mat to see if it is under the gas petal, mine goes up there all the time and slows the accelleration.
2) Check the gas petal linkage, or electrical connections, I can't remember if the mini is gas by wire or not. This may apply if the jurking is at consistant RPMS.
3) Check fuel pump, again consistant problem
4) If the problem is not consistant it may be the gas, put in some dry gas (HEAT brand is cheap availabale at Autozone's) and keep fill up the tank with new gas from a different station than the last stop.
5) May be run some injection cleaner into the gas, Chevron makes the best brand.

Good luck, MiniGSport

 

I've felt the same thing with slight acceleration on my 06. It is a very very light bobble up and down a touch and goes away after 3200. Checked all the normal things but can't figure it out either..

 

It was more common on '03 and '04 MCS', but you may have a faulty bypass valve (BPV). Reference the infamous "yo-yo" forum postings in your searches.

 

That yo-yo is more when you are under boost/medium-hard acceleration. I have the DT bypass and my slight hesitation is only under light throttle

 

Twitchy foot. I have it too...

 

My 06 MCS has developed the hesitation over time, now at about 49,000 miles. Seems worse since the last visit to the dealer so I am not sure if they updated the ECU software. I just suspected that it was the BPV getting weaker but Jarid rules that out since he has already replaced the BPV with a DT unit and still has the hesitation.

 

I am also running a Unichip ECU FYI.

 

Thanks for the reply and suggestions.

I'm sure its not the floor mat. They have been in place since the car was new, and there are ruts in the carpet keeping it in place(lol)

The 2006 is def. drive by wire.

The HEET and dry gas is a good idea. i did not consider it.

BPV, ill investigate. Ive seen nothing but bad reviews/results from the DT BPV.

Also, MiniGSport, weyfey? i'm not insulted, its just strange to see that mis-spell.

Thanks again guys,. more tips are welcome.

-Wyefye

 

where? I put one on my GP at about 5k miles and the yoyo disappeared completely

 

Please don't make me quote something i found in casual reading and forgotten about :p

we all know what opinions are like, and everyone has one.

If the DTBPV works, i have no problem giving it a shot. I've been disproven so many times, I've learned that there are plenty of people that have more experience than me...

 

good luck in resolving your issue! Keep us posted if you figure it out!

 

well, i ran seafoam thru my vacuum line, it smoked like hell.

it fixed it in the sense that it is not as bad as it was.

ima try some other stuff

 

Perhaps the throttle plate is acting up? Maybe see about reseating the connector to it.

Also check to see what your fuel pressure is. Try connecting a gauge to the ?fuel rail? (I think that's where the connector is) to find out if it's correct.

 

You ever figured out what it was? Mine's doing the same thing...

 

Ok... so...

To fix this "Strangeness", here are the things i have done:

Replaced Fuel filter (Painful!)
Changed Oil
Replaced Bypass Valve
Tried different fuel
Installed Vacuum Gain System mod.

The thing that made it a lot less noticeable was the VGS mod. The issue though it that it still happens, quite a bit @ 3000 rpm @ half throttle.

I have found something else though. My AC compressor appears to be dying. Makes a nice whining noise, and adds about a 300 rpm drag to the engine when engaged. When i turn this off, the issue seems to disappear for the most part.

Any ideas?

 

A failing AC compressor can complicate the matter. Replace it and see what your throttle response is like afterward. I'm sure you have, but also do the basic check for vacuum leaks (especially the intercooler seals). Maybe do a smoke test.

Don't forget to see about verifying your fuel pressure. Others that have had issues with acceleration determined their HPFP was the culprit (though I think this is more common with R55/R56/R57s).

 

Ahhh...AC...mine's doing the same thing. funny noises...and I seem to remember it's a LOT better with it off (I'm in AZ, haven't had AC off in months) -> although I always put that down to the engine being down on power, so the AC just made it worse...I never thought that the AC could actually be the culprit.

I tested for vacuum leaks by idling the car and spraying carb cleaner all over the place - didn't change idle rpm...Is this still a good way of testing for leaks? Or is the control system so fast that I won't hear anything?

 

Not sure how carb spray cleaner would work. Maybe try spraying a water/soap solution on the intake hosing (this is also a good way to find a nail or other object in a tire that's losing pressure). Just look for bubbles.

The smoke test would mean placing something like a smoke bomb (i.e. fireworks) near the air filter housing and getting it to go into the engine. Look for leaks as it makes it's way through the intake hosing.

 

Everything I did:
Replaced coil&plug wires: Slightly better performance at low rpm - didn't change this issue though.
Seafoam: No smoke. Zero Difference
Cable-tie BPV: No Difference
Replaced Fuel filter: Problem solved. Still a slight "hole" at 2800 rpm that I know I can have tuned out.

The car only has 50,000 miles on it - and the filter didn't seem all that dirty...But replacing it made a HUGE difference across the entire range.

I need to learn to drive it all over again. It's a JCW and it seems now I can't pull off without spinning the wheels in 1st...need to feed clutch in at much lower rpm than previously.

Thanks NAM...!

 

I noticed you changed your coil and plug wires but not the plugs. You might want to replace the plugs, especially if you had a fuel delivery problem due to a clogged filter. If you were running too lean you could have fouled the plugs.

Just my 2 cents.

Chad

 

Ok... so i had a bit of time...

I had bought the 1500.00 kit from out-motoring with the milltek exhaust,
Alta pulley, belt, Beru Spark plugs and a few other things.

In November of 2009 i replaced my spark plugs with NGK Iridium spark
plugs from Auto zone. Torqued them till they felt "Right". I did not have a
Torque wrench at that point.

Fast forward to present time.

I have stumbling on cold start, and a strange acceleration issue that just
does not feel right. So i did a bit of googling.... and came across this:
http://www.mini2.com/forum/first-gen...park-plug.html

Lo-and-Behold... Number 2 spark plug was covered with soot and the tube
had some soot in it. As soon as i pulled the coil tube, i smelled Gas/Petrol.

AH-HA! i said to myself as i stood, feeling like a idiot. Darn thing was loose
by about a Turn and a half.

Replaced all spark plugs with the Beru Ultra-X plugs that came with the kit
from out-motoring, and torqued to 22ft/lbs. I read that it was supposed to
be 20ft/lbs, but i wanted to make sure that washer was crushed. In a few
weeks, ill tighten again to see if any are loose.

Lesson learned: Don't be a cheap ***. Get a torque wrench; 50.00 at
Pep-Boys. Follow directions or you may pay for it later as i did in misc.
parts that needed to be replaced anyways.

-Ryan

 

Good point - since I replaced them about 5,000 miles ago I didn't even consider that they might be part of the problem...I just assumed they would be good...I'll definitely follow your advice.

 

ok... came back.. back to the replacing game.... lolz.

wonder if my o2 sensors are about to kick it. I might also need a new belt.. this gives me a motivating reason to buy a pulley puller and do it.

Unless someone has one i could borrow?

-Ryan

 

I wish I could say this is a surprise. My issue is back too. It was gone after I replaced the filter...but it's back today. My car has more power, but the issue is still there.

I ordered some data logging software - I'm going to take some logs then post them on here and hope someone can tell me what's going on...I'm starting to have a strong suspicion it's just bad summer gas and high temperatures...