Hi all - I have an odd hesitation / sluggish response issue that I'm having trouble locating in my 04 MCS.
This started over a year ago and can be described as a sluggish response in first and second gears which gets better as the car accelerates.
I did install a boost gauge and made sure that all fittings are secure and zipped tied shut to prevent a vacuum leak under the intercooler horn....and my gauge reads steady with no fluctuations.
Next up thinking the bypass valve had gone soft I installed a Detroit tuned valve and it made the car feel a bit snappier but the sluggish response is still apparent.
Finally I did install a Sprint Booster and BAM now the car feels like it did before and when I turn the booster off we're back to that sluggish response.
Car has a 15% pulley, UCC exhaust and new spark plug wires but otherwise stock.
Any thoughts on what might be the real culprit?
Thanks,
Steve....

 

Is the line on the fuel pressure regulator still intact? Also do you know if your clutch might be slipping?

 

Turn off the DSC at startup each time.

 

Thanks for the replies.
Clutch was serviced 2 years ago and has a really nice positive feeling when it engages.
Re: fuel pressure regulator - I'll check that out this weekend and see what the hose looks like - Thanks for the lead.
Re: DSC off at startup - I can try that but why might that solve my issue?
Thanks!

I should also add that the Supercharger was serviced about 2 years ago and I did recently replace the PCV valve.

 

Yeah, my JCW was acting up yesterday. While sitting at a signal, the engine started to vary in RPM, almost to the point of stalling. I kept the RPM up while sitting, When the light turned green, no problem accelerating. When I got to where I was going, about 2 blocks away, I let the engine idle before I turned it off...no problem..! No problem since.

And yes, absolutely...I always turn off the DSC. The car is much more fun to drive with it off..!

No idea on yours or mine.

Mike

 

No idea why turning off the DSC works. My '04 was bogging down badly after first startup and I found a thread suggesting turning off the DSC. Instant cure. I've not been able to have anyone on this site provide a suitable explanation for why it works -- it just does. May not be your issue but it's worth trying. You just need to remember to manually flip it off every time you start the car. It can be programmed into the ECU (auto off) if you want to go that route and to that expense.

 

Hi all,
Had some time today so I tried starting the car with the DSC turned off and that did not seem to make any difference.
Next up, my son and I pulled the intercooler off and checked the vacuum line that I tapped into for the Boost gauge. Zipties are still there and all seems tight.
Next we removed the other vacuum lines and all seemed to be seated correctly but all were a bit loose. So for good measure we zip-tied them tight.
Also checked where the vacuum line attaches to the fuel regulator and added a zip-tie there as well.
Felt all along all the hard plastic lines and confirmed that there are no obvious cracks.
Put it all back together with high hopes that we found the issue..... and it made no difference
Any other ideas? Does any of this sounds like a bad throttle body or bad fuel pressure regulator?
thanks....

 

Try cleaning your map sensors...ones by the intake filter the other is rite under the intercooler in the intake manifold ..
thats fixed my issue. Another time too i had sluggishness was from a bad knock sensor..
car would run fine going slow but getting on it it just had no guts it would seem..the knock sensor being bad though was farrrrrr more prominent of an issue though so I say just try cleaning them with like mafs cleaner or something.

 

Ok - pulled both MAP sensors and cleaned them. Photos below are from before cleaning. Not very dirty at all and after a test drive made no difference to my issue.
While I was there I pulled off the air intake and had my son run the car. Have a look at the video below. The butterfly in the throttle body only opens wider when you press the gas pedal more than 1/2 way to the floor. I would think that its opening would be linear as you press the pedal. Is this my issue?

 

so, no codes ??

I'm leaning towards a Fuel supply ( fuel pump / filter ) issue.

I would even entertain the possibility of chunks of broken ceramic in the cat balling up but I think you would prob see a code on that ?

 

+1 what codes u have?

with inpa I think you can check throttle position values, responses...

 

Maybe start with the easy stuff and just DUMP a can of this into a tank of fuel....

 

Do you have to reset the ECU when add the Sprint Booster?

 

Thanks for all the replies.
No codes and no check engine lights. I can plug in my scanner and see if anything is there.
I did reset the ECU when I first installed the sprint booster but I could leave the booster off for a while and reset the ECU to see if it makes a difference.
@ssoliman - What is "inpa"?
@Eurothrasher - if you put a link in your post it was stripped out. What were you recommending?
Thanks...

 

.A can of seafoam added to fuel...(Walmart = $7.00 can ) maybe an injector issue....

 

Sounds silly but could a throttle reset help ? And for sure for sure no belt slip ???

 

Gone are the good old days where you had a solid link between the throttle peddle and the throttle body... sigh...

Could the OP's issue have anything to do with the adaptations I read about?

Fuel pressure regulator... we have a return-less system? Isn't there a schrader valve on the rail? If it is overfueling down low, wouldnt he be able to yank the plugs for a sniff test?

Edit: I see on a diagram provided in another post that it is a return system... If the regulator is leaking I would think that it would show up under higher load demand, which from a take-off event, 1st, 2nd gear, I could see it being a problem.

 

I believe the OP checked the vac line to the FPR...for cracks.

MINI doesn't sell many FPR's ( Fuel Pressure Regulators ) which are attached to the rail in a bell housing.....If rail parts related, I'd be more inclinded to think that the injector O-rings have hardened and become brittle with age....allowing air in, gets REAL hot there.....

 

Air cant get in while running... fuel pressure.

 

If Injectors O-rings are compromised then yes it will run crappy due to incorrect air fuel mix.

 

if injector orings are bad its going to be obviously leaking out fuel...

 

Hi all,
Using my Ultraguage - confirmed that there are no error codes in memory. I did check the vacuum lines for leaks and didn't find any.... doesn't mean that I didn't miss something.
This weekend I'm going to pull the plugs and see what i find there.
re- belt slipping - I'm not sure what that would feel like but when I had the supercharger serviced at the dealer 2 years ago I gave them the correct belt for my smaller pulley.... I assume they put it on because they say they did . If they didn't would it cause the issue I'm describing?

....and what did you guys think of the video at the bottom of my last post? From what I'm seeing the throttle is holding closed much longer than I would expect it to.

Thanks again...

 

it absolutely would cause what your describing...lack of boost would equal lack of power but yer the car would run perfect otherwise . You miiiiight hear an extra loud whine/squeal when you are at wide open throttle ..
whats your vacuum in idle once fully warmed up and whats your max psi ?? That could tell you ALOT of what could be going on.
and all of articles I found actually said running smaller pullies and belts the belts often need to be serviced yearly exp if its a daily driver.

 

Negative...

 

Care to explain your point of view?

The o-rings job is to seal the injector body to the manifold, if the injector to manifold seal is good then no leak, if it cant make that seal it will leak under pressure. I personally have only had 1 truly bad fuel injector over the years and I seem to recall having an o-ring leak on an injector. Cant pick out the car it was but I'm pretty sure it was one of the Hondas (mid 80's MY)