duratec woes [hot start & idle]
shirt - 20/3/12 at 07:18 AM
hello all,
first time poster here, mainly as i bought my car [gts clubman] fully built. i do recognise the wealth of experience with the duratec and spannering
in general on these forums so thought it'd be an ideal place to start.
my car was imported as a kit to dubai and built by the autodrome for tuition purposes. they were too lairy for this [kept spinning] so were sold off
practically as new. the previous owner kept it for 6mths and under his direction it had a quaife lsd put in, new shocks and springs, a water rail and
electric coolant pump, quick rack and short shift kit. engine is a 2.0l duratec of unknown output mated to a 5 speed box [again, i have no idea
which].
i have tracked it a handful of times [it is a not road legal, so a pure track toy] and the car has difficulty starting when hot. i have resorted to
just idling it when in the pits or refuelling. last time i switched off and let it cool whilst i had a go in a mate's car. mine then started ok
but when i hit the throttle the revs would die and the engine went into a very lumpy/stuggling idle with pops and bangs from the exhaust. i got it on
the trailer and it has been laid up for 2 weeks whilst i was abroad.
last night i fired her up. caught second time of asking and idled fine. again, with a sharp throttle input the revs die, engine struggles and the
exhaust goes into a staccato popping. it only seems to rev with a slow smooth input to 3-4k rpm and will then allow the pedal to be mashed. hardly
ideal for a track car!
any ideas what i can check??
the car has the std. fuel rail with the damper halfway along. when the return from this is removed there is no flow on cranking. i believe it is
therefore still possible i could be boiling fuel in the rail and getting vapour lock.
the idle issue is stumping me. i have a new fuel filter i will fit this week and then do a flow/pressure test. i am fine with spannering, but
diagnosis is not my forte. all help greatly appreciated!
i was given a set of jenvey TB's with the car which are going on over summer. then i may fot a new rail with a regulator and proper return to
tank. however i'd like to get past these issues quickly and cheaply as we only have 8 weeks or so beofr the summer heat kicks in and the circuits
shut down. i'd like to do a few sessions at yas island before then!
MkIndy7 - 20/3/12 at 08:26 AM
Welcome, you've managed to cover a fair few bases and provide plenty of information but what ECU is it running? And inlet? I presume standard
Duratec?.
Also does the Electronic water pump 'over run' when the engine is switched or have the facility to?
That might be a quick work around if your changing to the Jenvys soon anyway. If the pump over runs and the fan can still come on if needed it should
cool itself down nicely to below the 'hot start' problems level.
Does it have the ECU controlled electronic thermostat on or has that been replaced with mechanical one (or even removed completely for the electronic
setup)?
FASTdan - 20/3/12 at 09:11 AM
If its all standard inlet stuff is it possible one of the throttle butterflies has failed - didnt the mondeo's suffer from this? Apologies for
the vagueness I cant remember specifics.
shirt - 20/3/12 at 09:18 AM
i have no idea regarding the ecu and thermostat. i will have a dig this evening and post pictures.
the inlet is non standard and is basic. there's a large cone filter going into a large diameter cylindrical collector with branches off to each
cylinder. there is what i presume to be a MAF sensor located on to the filter. the engine breather is currently missing but i mention that only as an
aside.
the electric pump can be turned on/off as long as the battery is connected. i always keep it on until long after the car has been shut off. i was told
by the previous owner only to worry if the water temp. rose above 80deg, which it never has. i did check that the pump was plumbed in correctly as
another owner found his was acting against the mechanical pump which was still in place and functioning!
i will take a load of pics tonight. still very much getting to know the car as i had hoped not to need to look underneath until summer!
jamesbond007ltk - 20/3/12 at 09:59 AM
quote:
Originally posted by FASTdan
If its all standard inlet stuff is it possible one of the throttle butterflies has failed - didnt the mondeo's suffer from this? Apologies for
the vagueness I cant remember specifics.
Yes, the first three or so revisions of the inlet manifold (think they made about 8 revisions in the end!) suffered from failure of the secondary
butterflies. Either the bar they were mounted on failed, the plastic butterflies themselves failed or a combination of both.
Sounds like this setup doesn't make use of secondary butterflies anyhow. In standard form the duratec mondeos were known for hot start problems,
or in fact any restart whatsoever from anything but completely cold. I never found a reasonable explanation or fix for mine but there was one widely
used workaround. Immediately after turning the key to off (so the engine is still just turning) you plant the throttle and will hear air sucking under
the bonnet. The theory is that fuel remains in the cylinders or inlet tract and effectively floods the engine so prevents restart. Planting the
throttle draws clean air in, but no fuel as the injectors are off by this point, and blows through to clean the fuel out.
I have no idea if the theory is correct but it is the most common exmplanation I've seen and I know first hand that it works in practice. Of
course as you do not appear to be using the standard inlet the above may well be irrelevant. Worth a try though I'd say.
I had an idle problem on my duratec but it was more a hunt that what you describe. I can't remember ever getting to the bottom of it TBH, but it
was improved by soaking MAF in a tray full of brake cleaner and cleaning every other sensor I could get my hands on.
HTH
Rich
FuryRebuild - 20/3/12 at 11:06 AM
I'm fairly sure I have an intact manifold, butterfly, throttle body, etc from my current duratec i'm stripping.
shout if you need it.
shirt - 26/3/12 at 11:19 AM
very kind offer and one i may take up, thanks very much!
sorry for the delay, only had chance to go down to the car last night [at 3am!].
a couple of pics:
first two show the manifold and butterfly. this looks homebrewed to me and basic with it. i have inspected the butterfly and it's working
fine.
this third one shows another view of the block. i'm quite keen to know what the large tapped hole is for to the right of the picture next to the
right hand inlet tract. this has no plug or bolt in it, hence my curiousity!
i removed, drained and cleaned the fuel rail. on refitting/restarting, it is weeping fuel from [i believe] the weld where the right hand bracket would
attach. it is very slight so i do not think it is the cause of my problem, just another thing to fix!
car was difficult to start, but then it has been lain up for a couple of weeks now. the problem is easily replicated - basically just floor the
throttle and the engine strangles and dies. strangely, when warm it isn't quite so bad. the revs drop but it doesn't die, then it stutters
and barks before revving away.
i will have a go at taking a vid and posting to youtube later. i am stumped. trackday friday so i'm getting short on time :s
MkIndy7 - 26/3/12 at 11:28 AM
The big tapped hole is part of the EGR exhaust gas recirculation system on the standard car and is likely to be blocked off on the exhaust side.
Definately a home brew system is that, but it looks like it retains the standard Ford throttle body.
Can't help but notice there is no wires connected to the throttle position sensor in the pic.. Is it just missing in pic, or has that been
unplugged and is causing the problem, I'd have thought whatever management it's has is likely to need it unless its working off Vaccume MAP
alone.
shirt - 26/3/12 at 11:42 AM
yeah, i took the sensor off to clean it. if you look the butterfly housing also has 2 bolts removed as i was halfway through the job.
also, when coming off the accelerator, it seems to take a breath [revs drop, almost like a pause] before idling. idle is smooth as silk.
i'll post a vid in an hour or so when i knock off, should give you guys much more to work with. playing bloody football weds, so i need to end
the week with some track action to make up for this indescretion!
MkIndy7 - 26/3/12 at 01:13 PM
quote:
Originally posted by shirt
also, when coming off the accelerator, it seems to take a breath [revs drop, almost like a pause] before idling. idle is smooth as silk.
Would be interesting to find out what engine management it has as that sounds alittle like 'fuel cut' on Overrun that some ECU's do.
Back to the original Fault of be being hard to hot start, running rough and popping down the exhaust I wonder if that's an ignition issue like
part of the coil pack breaks down after heat soak migh be something to try, check you have sparks on all cylinders when it's misbehaving.
shirt - 27/3/12 at 04:48 AM
heat soak could indeed be an issue, especially given my location.
i took a vid last night but the quality is appalling, i wanted to be able to show throttle position as the problem occurs, but i need something better
than my phone camera!
again, problem easy to replicate until the engine got warm. i did then find that if i turned off the electric water pump it could be replicated again
and the engine would infact die of its own accord if left to idle. temp. gauge was showing about 40-50deg at this point so well within range.
have decided to take tomorrow off work and whip it down to a garage as i am stumped.