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Rough idle @ startup, only 1-2 sec.

13K views 12 replies 11 participants last post by  ebv888 
#1 ·
Hi,

Forgive me if this has been covered bit I would like a professional opinion from you ppl.

Our BA XR6 N/A sedan has only done it twice last week but one you fire the engine, it was really rough for the 1st second or two, then went back to normal. I rang the service depo. and they said it was normal. "Oh it does it from time to time, nothing to worrry about". Well I am worried! :AAHHH: It's NEVER done it before so why now. Thet said it's with all the electronics: "Take a while to handshake"??? umm.....pfffft.

Another opinion was the fuel injectors need a clean. Don't think that's the case. The only fuel that sees the tank is BP Ultimate or Optimax. 25,500kms. It's a smooth as a baby's bum the rest of the time.

Oil? It's only 4 to 5,000 kms old. Castrol Formula R series 0W-40 (I know, haven't changed it yet, still trying to make up my mind).

Cheers...

NA Thunder.
 
#2 ·
I can't give you a professional opinion but I have a similar story...

Sometimes so that I can move in the garage I'll start my car only to back it out then it sits for however long then I start it up again to put it back in without actually driving it... in other words it runs for 20 seconds x 2 with a gap of up to 8 hours.

A few times now when I have gone to start it for say the third time, it's either run rough or a nice puff of SMOKE have come from the rear... when it smoked, the exhaust smelt fuelly so I assumed it may have been unburnt fuel from the previous half hearted attempts..

NA Thunder, is your car subjected to similar starts leading up to it running rough..?

Can anyone explain what's happening in either case..?

Thanks

Steve

PS mine's an BA XR8 with 7000 k's on it.
 
#3 ·
This is my post from another thread.....

Dunno if this helps any of you, but the reason why I asked if you had just filled up with fuel is as follows - bear in mind, this is just a guess... the fuel system is a closed system, so what this means is that the vapour at the top of the fuel tank has to be burned off - the tank is domed so the fuel vapours can accumulate there, and these vapours are sucked off through a hole and hose at the top of this done, into carbon cannisters which are somewhere in the engine bay and the vapours are burnt off.

If you overfill the fuel tank, then what happens is this domed part of the tank fills up and instead of vapour it is filled with fuel, which is then sucked through into the carbon cannisters (this sucks the whole time it is running). When the carbon cannisters become logged with fuel, they are sending way too much fuel to where it shouldnt be and it affects the fuel mixtures, effectively flooding it - I think....

So, if you refuel, overfill and then only drive a couple of km home (ie not enough to remove/empty any fuel from the domed part of the tank), then the cannisters are becoming soaked on the way from the petrol station to your home, and because the tank is still over filled, the cannisters remain soaked until you next start it. It is kinda like flooding it. And it will continue to do this until the carbon cannisters dry out and begin sucking air for a while, again - which is why it will run rough, not start or stall in strange areas. It happened to me and I sort of eliminated it by trial and error and found that when I didnt fill it fully for a few weeks (this was about 6 months ago) I never had the problem again - so basically fill it to one click and leave it. And if you have to over fill it, make sure you are driving a reasonable distance before you stop it again....

Anyway, this might not apply to all or any of you - could be many things, but this is just something that seems to be quite common and also something that people don't think of... and if I have any of the mechanical details wrong, please correct me - I don't really claim to know anything....
rom another thread - dunno if this helps....

Also, have you considered an oxygen sensor problem - when it runs in lean mode, sometimes they run too lean and surge and jump around a bit - this can only be fixed by Ford reprogramming the computer settings....
 
#4 ·
Hi NA thunder,

You need to do what i do, Take it to your ford dealer instead of calling them and tell you that you are not happy with the running you have paid alot of money for the car and you deserve to have to runing at it's best. I always take mine in when iv got problems they seem to take more notice of you then calling,
Try going in you may be suprised.

Christine
 
#5 ·
My experience is that this has nothing to do with fuel levels or unburnt fuel from the last start. If I don't start the car for 2-3 days + it runs poorly on startup.

I will be parking my car this afternoon and going away for a few days.
When I first start my car next week, it will run like a Wartburg.
Anyone game to put their money on the table?

XRchic said:
This is my post from another thread.....

Dunno if this helps any of you, but the reason why I asked if you had just filled up with fuel is as follows....
 
#6 ·
The fly by wire throttle is very fussy. If you touch the throttle or hold it down a little as you turn the key you upset the base TPS parameters and it can cause the problem you have encountered.
 
#7 ·
Hmm, interesting. I can see here you are going SteevO but I never over fill the tank...lol. E means Enough and F means Financial if you get my drift, usually have 1/2 to 3/4 tank at all times.

It's booked in on Tues so yeah, I'll be hitting them hard. Cheers guys.
 
#8 ·
Dont bother with the service dept - WASTE OF TIME, they wont fix it.

This is what you do (I've had to do it a couple of times myself so i know it works - got it off a ford tech.)

1). Turn ignition to ON
2). Hold foot all the way to floor on accelerator.
3). Turn key as if to start.
4). Dont worry car wont start as sensor on accelerator knows you are flooring it.
5). Hold key like this and count to ten. During this time the starter motor will be going - dont worry this is normal
6). Turn key back to OFF.
7). Take foot off accelerator.
8). Wait 30 seconds then start as normal

This resets the cam phasers - the cause of your rough idle. They seem to need reseting from time to time. It works a gem and you shouldnt have any more problems for quite a while.
 
#10 ·
Cool, Reset of cam phasers. Hmmm, worth a go.

Our N/A is a cruise car, mainly used on weekends only so oil would usually find its was back into the sump and starting would br dryer than usual. Although it's never done it until last week. Usually just fires up perfectly every time. Maybe I ned to run it mid weel for 5-10 mins or something.
 
#11 ·
WBT56 said:
The fly by wire throttle is very fussy. If you touch the throttle or hold it down a little as you turn the key you upset the base TPS parameters and it can cause the problem you have encountered.
I'll pay that. I'm far too used to having the throttle half down when I start - due to older cars I've owned.

Keep your feet clear of the accel and you'll be fine.

Any probs - ie - if you get limp home mode - pull over, turn it off. Restart and you're fine.
 
#13 ·
the fuel pressure regulator has a check valve in it to hold pressure at the injectors for start up.these p.o.s. things leak back slowly-sometimes overnight,sometimes if the engine hasnt run for a couple of days.the poor idle is caused by the fuel pressure stabilizing.tell ford to replace the reg and keep replacing it untill u get one that works.i am a ford techo and have replaced a shitload of these things and they as big a money maker for ford as xd doorhandles.
 
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