Cossiestu123

iTrader: (1)

hi all i brought my moonstone 2wd sapphire cosworth about 3 months ago, almost immediatly after purchase it developed a fault that to date seems incurable!
when idling the car occasionally hunts between 600rpm and 1200rpm ocassionally cutting out when driving when applying the clutch to stop at a junction etc.. also and more concerningly when you apply full throttle when it hits boost it hesitates and misfires its head off! half throttle seems ok, it has +.50 mahle pistions, standard cams, ported head, bosh 803 injectors, stage 3 chip, ar63 turbo rs500 intercooler, 3" exhaust system. grp a coil, wrc head gasket and arp stud and nut kit

to date i have had the head refurbished, replaced plugs, new cambelt, tensioner and cometic wrc metal head gasket fitted new grp a coil but thus far problem still present!

please guys if you can spare some time to throw some suggestions at me as im running out of ideas (and money lol!)

cheers stu

J1mbo

iTrader: (1)

What plug gaps ?

BJAS

iTrader: (1)

The usual suspects for hunting are:

ISCV
Throttle Position sensor
Engine Coolant Temp Sensor
Intake manifold gasket.

Cossiestu123

iTrader: (1)

plug gaps set to .60 mm

ordered new coolant temp sensor, and a charge air temp sensor (should be with me tomorrow)
and intake mainfold gasket is new so fairly sure its not a vacum leak
is there tests i can carry out on the tps?
and excuse my newbyness but whats a ISCV?

BJAS

iTrader: (1)

ISCV = idle speed control valve

You can test the TPS electronically; or simply change it out and see if the problem goes. Eliminate the potential faults one at time by changing and retesting; that way you won't end up changing more than is necessary.

If the intake manifold has been off the car recently then the gasket would be my main suspect. Do a smoke test.

dazzle740

iTrader: (1)

The hunting when at idle is quite usually the idle speed control valve sat on top of the throttle body, which is usually fixed by giving it a good clean with something like brake cleaner solution.
In regards to your missing when on boost have you checked your plugs are they ok (condition wise) are they gapped right could be getting blown out when coming on boost.
Or failing that get it booked in with a specialist to give it the once over (if you have'nt already).
Hope this is of some help....

Miller 3

iTrader: (4)

have a quick flick through this thread regarding tps settings, there is also a bit more info that may be of use to you at some point.

https://passionford.com/forum/ford-s...g-idle-co.html

but i would suspect that you have an air leak somewhere.

J1mbo

iTrader: (1)

They're good then

You gapped them with a feeler blade at an angle yes and not flat across the top as the electrode dosnt sit on top of the plug on a 071c

I wouldn't advise changing throttle position switch as you have no way to tell if you have set it right, you need a engine monitor to do this, a Job for a specialist

Your idle problem, did it always do this or has it just come on ?

Cossiestu123

iTrader: (1)

Yes gapped with feeler gauges. Plugs look a nice healthy colour as well, it did hunt a bit when I got it, but it was running really rich at the time and I discovered the lambda wires had been snipped! Upon re connecting it ritchness problem dissapeared. Will try the smoke test but fairly certain there Is no leaks. Do you think the leads could be breaking down under load? Or a phase sensor fault causing missing and hesitation on boost?

martysmartie

iTrader: (1)

The only two things that can raise idle speed is throttle and ISCV (Idle Speed Control Valve) and it is located in front of the throttle body and has a white top to it, cylindrical in shape. Cleaning will not solve it as it is being told to do this.

To start with I presume the base idle is higher than 600RPM? If not this will will be the problem, it thinks it's going to stall and so the ISCV opens and lets air in hence the 1200RPM until the idle drops again and then the same happens again due to the base idle being to low and so on, you want around 950RPM as a base idle speed when at running temp.

Also you would not have a lambda sensor as standard so this has been added.

The ignition system needs to be 100% in perfect working order on these, so the leads need to be good plugs you have already changed, but also make sure the cap and rotor arm are good.

Martin

cossieDavedree

what ecu has it got? and can you definetely confirm the chip being used ?
It shouldn't have lambda conrol unless it's a 4x4 engine or l8 ecu.


One thing not been asked is what is your fuel pressure readings after the reg with vac on and vac off? could be fuel starvation, also what voltage is your fuel pump and ecu supply wires running at with ignition off and on.

as people have said you need to check all the sensors and base map settings etc and get the readings off of them using an multimeter,

it may be easier just to replace for bran new parts, but testing things before would have saved you lots of money and identify the fault rather than 2nd guessing.

I'd advise a specialist to look over the car and get it setup.

tabetha

Change to AGPR 12PP8 plugs first, or IK27, these will give a std ignition system it's best chance.
Hunting isn't caused by a iscv, as said iscv only raises rpm above base idle, check your fuel pressure, make sure the fuel filter is not more than 18 months old, then fit a new CTS and set the co to 2.5%, or whatever the chip maker says.
The main thing that raises the idle speed is the TEMPERATURE of the engine talking through the CTS to the ecu and this telling the iscv to open a bit more, it could just be a very low base idle and a sticky iscv giving the trouble, but the cts and fuel filter should really be service items, mine are changed every 2 years, most are not.
tabetha

dazzle740

iTrader: (1)

As stated before mine did the idle speed hunting thing two so wiped off the iscv and gave it a good clean with brake cleaner and re-fitted more hunting...

dazzle740

iTrader: (1)

oh bollocks should read my posts before submitting.........
after cleaning no more hunting.

Cossiestu123

iTrader: (1)

sorry for the delay in replying idle problem now sorted base idle was set too low! but still getting massive hesitation under boost any ideas on this its driving me mad!!

COLEYST200

iTrader: (3)

i had the miss fire all last year and it did my head in .i put new every thing in 2 times over and i gave up on it then by look i got a new coil from a tat yard /im running wasted spark any way i put it on the car with the leads just lying all over the motor and it ran 100% spot on so i fort spot on so i put the car all back togever then went for a drive and fuck me it was back . its was put to me wot have you done in the last 10 min that may of done this so all the covers came off again leads all over the place and the car ran spot on . It was the leads ford leads out of the bags we had even run the car in the dark and on arking on the leads but under load they let go . so have a look in to it mate

COLEYST200

iTrader: (3)

here is a link to my post about wot went on with my car . its about a 1/3 the way down the page i hope it helps you out with this problem

https://passionford.com/forum/restor...ml#post4844353

martysmartie

iTrader: (1)

As said from the start what plugs do you have and what are they gapped at? Inspect the leads etc as the ignition system needs to be 100% to start with.

Have you had the fuel pump checked/rewired and how long since the fuel filter was changed?

Martin

Cossiestu123

iTrader: (1)

YESSSSS i have sourced the problem! 3 bar boost solinoid had a dodgy earth and was practically hanging off! cleaned up contacts and woooooosh away it goes! many thanks for all the top advice guys

cheers stu

martysmartie

iTrader: (1)

Good stuff but it's actually the 3 BAR MAP sensor the boost solenoid is actually a Amal valve and is fixed to the top of the intercooler

Martin

Cossiestu123

iTrader: (1)

aww hell its still doing it, think the wet roads and wheelspin were giving me a duff result by not loading up the engine, put it in third and give it some and its really weird its like its hitting boost cut or something even though its barely getting to 1bar before it pops and farts i dont think im running a amal valve as i cant seem to find one just a manual boost controller

martysmartie

iTrader: (1)

What I said earlier about the plugs etc? Yes some remove and fit mechanical bleed valves.

Martin

COLEYST200

iTrader: (3)

phase sensor and the wiring and HT leads

Cossiestu123

iTrader: (1)

yea thats deffo the next step bloomin thing drives me mad! plugs are new ik27's gapped to .6mm look to be sparking ok but very sooted up

cheers stu

martysmartie

iTrader: (1)

Check the rest of the ignition system cap, leads and rotor arm, the ignition system on these has to be 100%, while your there make sure the phase sensor leads inside the car are in good condition as there prone to corroding and shorting.

Martin

Cossiestu123

iTrader: (1)

right just ordered new cap and rotor arm, phase sensor, leads and a cps for good measure lol might was well rule out as much as possible and be safe in the knowledge ignition side is tip top!

Cossiestu123

iTrader: (1)

ok so its had new plugs, leads, group a coil, CPS, engine to ecu temp sensor, phase sensor, charge air sensor, dizzy cap, and rotor arm and still it is being a bag of shit hesitating on boost! help please else the world is gonna be minus another moonstone blue cossie!

cheers stu

Char1ie

iTrader: (6)

Cossie woes are best diagnosed on a rolling road by a professional. A diagnostic run on a dyno isn't going to cost much at all and you'll have the problem identified in no time. Just find your local rolling road tuning centre and take it there and get it sorted.

This one is near you: http://www.sptuning.co.uk/#/rolling-road/4538672308

Charlie

COLEYST200

iTrader: (3)

just ring martin at reyland he is about 70 miles from you get it on the rollers and he will find it

Cossiestu123

iTrader: (1)

Think that's the plan now be nice to get it sorted properly! Cheers lads

martysmartie

iTrader: (1)

Do you know whose chip is in it, I.E a reputable author?

Martin