My car revs take ages to fall. Help.

Fuzzy GT

Fuzzy GT

Wrench Pro
Points
21
Location
Scotland
Car
Reanult Clio GT
Hi guys I'm looking for some help and advice.

A few months ago i got a backbox fitted to my brand new Clio GT. Since then, when i rev in neutral it takes a while for the revs to fall again and It's really starting to ge to me now.

The exhaust place said that bigger pipes would be of benefit but I'm not sure if the current backbox with bigger pipes would sort the problem? Or if It's something totally diffirent which is maybe serious?

Thanks, Fraser.
 
HDi fun said:
Clean or replace MAF is an obvious place to start. Also clean the throttle body with some carburettor cleaner. Any warning lights?
Click to expand...

Hi.

I'm pretty useless when it comes to the mechanical side of cars so forgive me for the probably silly questions.

The MAF is a sensor right? Also where is it to be found? and how do i clean both the throttle body and MAF?

Also, There are no warning lights no.

Thanks, Fraser.
 
Fuzzy GT said:
Hi.

I'm pretty useless when it comes to the mechanical side of cars so forgive me for the probably silly questions.

The MAF is a sensor right? Also where is it to be found? and how do i clean both the throttle body and MAF?

Also, There are no warning lights no.

Thanks, Fraser.
Click to expand...

The MAF will be upstream of the air filter enclosure. The throttle body will be further upstream still.

Send a photo of the engine bay, someone here will be able to assist directly.

If it's brand new though it should be under dealer warranty.

Rgds,

P.
 
HDi fun said:
The MAF will be upstream of the air filter enclosure. The throttle body will be further upstream still.

Send a photo of the engine bay, someone here will be able to assist directly.

If it's brand new though it should be under dealer warranty.

Rgds,

P.
Click to expand...

Hi.

Yes it is brand new which is why I'm wondering if It's something serious or not.

I have a pic here of my engine bay but not too clear wil try get another soon. Also i fitted an induction kit so not sure if that affects anything. -

P1020961.jpg


Thanks, Fraser.
 
OK , I'll download the pic later and show you the items. Trouble is with a brand new car they won't have had enough time to get dirty or fouled up.

I'd consider removing the induction kit first and see if things return to normal.

Modern petrol engines do use a lot of throttle lift off damping to stop revs dropping too fast as this leads to sudden increases in CO emissions when changing up/down etc. It might just be acclimatisation time for you.
 
HDi fun said:
OK , I'll download the pic later and show you the items. Trouble is with a brand new car they won't have had enough time to get dirty or fouled up.

I'd consider removing the induction kit first and see if things return to normal.

Modern petrol engines do use a lot of throttle lift off damping to stop revs dropping too fast as this leads to sudden increases in CO emissions when changing up/down etc. It might just be acclimatisation time for you.
Click to expand...

Ok thanks.

I only started to notice the rev problem when the backbox was fitted. Could it have anything to do with this?

Also, Theres a boy at the garage i had it fitted at who doesn't seem to like me haha. He had his nose right in about the car I'm not sure if he could have messed with something?? I wasn't aloud in the workshop so I couldn't see.

The induction was installed only a few weeks ago but the problem was already there.

Thanks again, Fraser.
 
Fuzzy GT said:
Hi.

Yes it is brand new which is why I'm wondering if It's something serious or not.

I have a pic here of my engine bay but not too clear wil try get another soon. Also i fitted an induction kit so not sure if that affects anything. -

P1020961.jpg


Thanks, Fraser.
Click to expand...
i cant tell 100% from the pic but it looks like the maf has been removed:blink:
has the joiner for the filter got any wires going to it????
 
herb said:
i cant tell 100% from the pic but it looks like the maf has been removed:blink:
has the joiner for the filter got any wires going to it????
Click to expand...

Hi.

I have attached a picture of the almost standard induction before this viper, the only thing removed is the large ish sized plastic tube comeing from the throttle body. The new viper kit goes direct to the throttle body.

P1020957.jpg


The pipe attached to this plastic tube is the breather hose. The new pipercross has a seperate filter fitment installed.

Thanks, Fraser.
 
I had a look a tsome pictures i took when i was installing the pipercross viper kit and came across this one -

P1020960-1.jpg


It shows the throttle body and 2 what i think look like sensors? Could 1 of these be the MAF sensor?

Thanks again, Fraser.
 
HDi fun said:
It does look indeed that the MAF has been removed. But surely this would throw up an engine check light?
Click to expand...

I was out looking at everything that came of the standard filter system and all i see are plastic tubes, the pannel filter and caseing. No sensors or wires.

Could it be located elsewhere?

Thanks, Fraser.
 
MasterAuron said:
MAF will be there. It probably wouldn't run without one. Sticky butterfly first port of call imo.
Click to expand...

It would run in limp home mode but very badly. And with the engine check light on. That's why I'm puzzled.

Sticking throttle is unlikely as it's a brand new car (and not a Toyota :) ).

How slowly is slowly. Rev up to 3000rpm and then let go, how many seconds to stabilise at idle speed?
 
You're right it's too new, ignore that and don't spend the 5 minutes it takes looking to see. Instead spend hundreds changing sensors that are fine ;)
 
HDi fun said:
It would run in limp home mode but very badly. And with the engine check light on. That's why I'm puzzled.

Sticking throttle is unlikely as it's a brand new car (and not a Toyota :) ).

How slowly is slowly. Rev up to 3000rpm and then let go, how many seconds to stabilise at idle speed?
Click to expand...

From 3k revs it drops fast but as soon as it hits 4 and above it takes far too long.

I wil try get a video of the rev guage as i rev up. That's maybe the easiest way to show u guys.

Fraser.
 
Fuzzy GT said:
From 3k revs it drops fast but as soon as it hits 4 and above it takes far too long.

I wil try get a video of the rev guage as i rev up. That's maybe the easiest way to show u guys.

Fraser.
Click to expand...

Modern petrol engines do have the throttle heavily damped on lift off. Whether mechanically or electronically if it's a fly-by-wire arrangement.

I know what you mean though - it is annoying when you're just driving through town - lifting off gives very little engine braking initially.
 
pgarner said:
black thing in front of the throttle body. does it go into the throttle body

also what is the red thing?
Click to expand...

Hi.

The black piece goes around the throttle body. It's a siliocne section which the induction fits onto.

Th red thing is the positive terminal for the battery, it's just not connect in this picture.

Fraser.
 
pgarner said:
no sorry i meant the other black thing but have thought it could be the MAF but a second look would suggest it is the stepper motor for the TB
Click to expand...

Oh i see. Do you mean the large sort of circular black piece? Like above the red terminal?

I'm not sure what it is sorry.

Fraser.
 
Truly, it might be better to return the car to standard and leave well alone. Even if you were of a mechanical disposition modern cars are outrageously complex and can confuse even the finest mechanic.
 
Hi ive got a 197 as youve probably gathered from my name, errrm the MAF should be to the right of the battery and even in the pic with the cone filter, the MAF seems to have been removed along with the original airbox.........quite puzzling really, i would imagine your engine will be misfuelling, cant understand why there isnt a warning light on....... head scratching time for me.......
 
clio197MJB said:
Hi ive got a 197 as youve probably gathered from my name, errrm the MAF should be to the right of the battery and even in the pic with the cone filter, the MAF seems to have been removed along with the original airbox.........quite puzzling really, i would imagine your engine will be misfuelling, cant understand why there isnt a warning light on....... head scratching time for me.......
Click to expand...

That's where I was looking, too. What's really odd is that there's no warning light.

Soes the car drive properly? Ie. proper power and torque delivery, no mis-firing?
 
i have a theory, the MAF analyses the air coming into the airbox. so i think im right in saying that if the MAF was to be removed all together then the ECU would run the car on a 'default' setting, with regards to air intake and fuel mixture etc etc, FuzzyGT, if this is in fact the case, and i may be wrong, you may be down on power your MPG will be off and all sorts. As suggested in previous posts, if i were you, i would bite the dreaded bullet and go and plead with the dealer to get you back to standard intake wise, and then if you wanted to get a professional to encorporate a new intake system with the MAF in line.
 
But when a car gets old, do these throttle bodies start giving trouble of slow rpm droping.
Supposing you drive at 50 kph, clutch in and brake. Now the rpm sticks to say 1500
na dthen drops after 3 - 4 sec. later to 900.
 
davevm said:
But when a car gets old, do these throttle bodies start giving trouble of slow rpm droping.
Supposing you drive at 50 kph, clutch in and brake. Now the rpm sticks to say 1500
na dthen drops after 3 - 4 sec. later to 900.
Click to expand...

There car be some wear. But what you're reporting, ie 3-4 seconds to fall from 1500rpm-900rpm is not uncommon. Sudden throttle closing is damped (either electronically or hydraulically) to reduce a spike in HC emissions when the throttle is closed.

It is annoying when changing up.
 
I'm guessing lack of back-pressure is what's causing it and now you have yinkered with it i don't think it's warranty is valid
 
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