Car will not idle, sometimes difficult to start.

[James23]

Hi guys, first post on here so be gentle with me!

My car is a renault scenic... dont laugh, read on...

It is the 2.0 16v engine which is the F4R. Standard figures from renault are 140bhp and 139lb/ft.

I have had a cylinder head, cams, throttle body, coil pack, inlet manifold, exhaust manifold and decat pipe from a 172. It also has a powerflow backbox and an induction kit. The inlet and throttle body are from a phase 1 as the scenic originally had a cable throttle.

The cylinder head and cams from the 172 went on first, a few months before the rest of the parts but since they went on the car will not idle. As soon as the car is not in gear and my foot is not on the accelerator it stalls. To make the car safe to be on the road I have adjusted the screw on the throttle body to keep the throttle open a little bit at all times, now though it ticks over at about 2k or just stalls. I tried for hours to adjust it to tick over at an acceptable level but had no joy.

I believe that the cams are timed properly. I have checked, double checked and triple checked for air leaks at the manifold and have even gone as far as putting silicone all over the inlet manifold gasket to make sure!

I have had the car on the dyno today (dyno dynamics) and it pulled 142.4 bhp and max torque was in the low 130's, but the torque curve is absolutely all over the place at 2800 it is at around 120lb/ft.. this then drops to just under 100 at 3600 when it rises sharply to 132 ish at 4300rpm then drops again to about 115 at 4750 rpm. Will upload images when i've scanned the graphs in on monday.

Something i'm not sure is right is all the breather/vaccum/idle hoses.
I would appreciate it very very very much if someone had pictures or could explain in detail of all the hoses and where they should go. So far from pictures all I can tell is that there is a small diameter hose connected to the air intake hose and I have connected this the idle control valve.
There is another hose that is connected to the underside of the throttle body, I cant remember from memory what the other end of this hose is connected to, though once i've found out hopefully from someone on here I will check (Its not a quick glance on my car as i have to remove wipers and a few bits of trim so I can see the back of the engine)

I cant remember if there are any more hoses?

My car first went into the garage just before christmas and I've took it to several places to try and get it to work and it's cost me a fortune and none of them seem to know what's wrong with it. I was convinced it was all in the map but the AFR seems fine (will post images as soon as i've scanned them). I know my car needs a remap but obviously I want it working properly before it gets done.

At my wits end with this now any help would be very much appreciated.


Cheers


James

 

[James23]

Above are the scans of the dyno run. As you can see the car also runs on LPG, the LPG is set up pretty well and is not the source of any of my problems as it behaves like that on petrol and LPG.

Today I have bought a new TDC sensor/crankshaft position sensor and replaced it and it make no difference.

Any Ideas?


cheers

 

[James23]

http://img641.imageshack.us/i/hpafr.jpg
http://img46.imageshack.us/i/hptor.jpg

cant get pics to work

 

[TimR26]

Probably running poorly because it needs a remap if everything is fitted correctly.

 

[Demi]

cant see the pictures!

 

[James23]

Petrol AFR is the lower one, not the higher one as described in my post earlier. Im red green colour blind and the lines are red & green so sorry about that!

Just had another attempt at the pics.
@atouba - That's what I thought but the dyno guy reckons there is something else fundamentally wrong but couldnt put his finger on what.

Im startin to suspect my Idle control valve is faulty, though I've tried both the scenic and clio one and it still doesnt idle correctly, I know for a fact the scenic one worked before but i suppose it could have broken. Don't have another one to test though, does anyone know how much they are?

 

[sideways danny]

that's running very rich which will lose you a fair chunk of power. I'd put it mostly down to the ECU having the wrong idle parameters for 172 cams tbh. You're going to need a full custom remap, it's not going to run nicely until you get it done

 

[James23]

Thanks for your reply danny, you reckon its all in the map then and that's why it will not idle at all?
Would just a custom map on my (scenic) ecu be enough as I've been told there may be things in the 172 ecu that are different to my scenic one that cant be got at? obviously I dont want to get a clio ecu if I dont have to cos i want a custom map anyway but if its the only way then i'll have to.

 

[sideways danny]

in theory it should all be programmable on your scenic ecu, if the place you chose to do the work has access to enough of the ecu code. I'd take a guess that it's a siemens sirius32 ecu, so all the info should be transferable

 

[James23]

Yeah its the sirius 32. That's good then, where would you recommend that would have enough access to the ecu code?
Would the place be better off putting the 172 code on and then tweaking it or just tweaking the scenic code?

 

[Manny86]

Hey pal. U shud fit a 182 mani on the car for extra grunt. They are flowed better according to loads of people so shud give more bhp and better torque.

Im with the above aswell. Custom map the car.

 

[James23]

Dont really wanna pay a few hundred quid for the 182 manifold for very small gains.
It always was (and is) my intention to have the car custom mapped, but it's not running properly and I think it's more than just the map thats at fault.
At the mo I'm thinking my vvt solenoid isnt working properly because i took it out and cleaned it (not that it was at all dirty) and put it back in and the car would (sort of) idle with the throttle closed and it ran a lot smoother. The next day it was back to how it was though so I think it could be that which is faulty. Phoned the stealers today and they want £98 for a new one but cant get me one until weds which is no good to me as the car is booked in at RS tuning to be sorted on weds morning ( 1.5 hour drive from me) so thats too late so i'll be hunting round the breakers tomorrow looking for one!

 

[James23]

Update - Car went to Paul @ RS tuning on weds and now works properly. Turns out the cam timings were both out... despite my mechanic guaranteeing that they werent, not a happy chappy!
Paul and Specky are absolute top chaps and diagnosed and sorted the problem very quickly! Would not hesitate to recommend them! Paul flashed the ECU with a standard 172 map and i've got to go back up for the remap as my car killed his OBD lead!
It's like driving a different car now! no longer have to sit revving it at traffic lights looking like a complete c**k!

has a nasty misfire under partial load @1500rpm though but im not worried about that for now.

Thanks for all your suggesions fellas.