Kangaroo Car ?

[entwistlea]

First couple of outings in the new toy (2.9 S2), bit of a shakedown to work out what needs doing...... seems to Kangaroo a little particularly when its been running just a few mins, noticeable on light throttle if come off slightly, car seems to realy buck then pick up. No rpoblem under acceleration... Also seems that the auto choke is playing up, seems to hold 2000rpm when warm. Tho turning off and on again helps....

Figuring its fueling. Possibly sensors or air flow meter, maybe ecu :-(... if its stopped slowing tomorrow i'm going to have a play and change points, plugs and leads.... before i head off and start taking things apart, is this common? Anyone had this issue and if so, any easy resolutions?

Ta all

Andy

[clarenceboddiger]

Throttle Pots seem to be a favourite, and your problem is exactly the one I had when mine started failing, then it just went worse and wouldnt tick over etc.Try unplugging the TP and see how it runs, apparently this puts the ECU into "limp" mode and should confirm your plugs and leads are OK and that the TP might be the problem (not definately as unplugging it overrides some other functions I beleive)

[entwistlea]

thanks - know where to start then !

[tvrgit]

Is this only when it's cold? Is it ok once the engine warms up?

[entwistlea]

happening mostly when the engine is warming up, once warm calms down, though yesterday it did happen after a failrly lengthy motorway run, was just trundling along the backroads, came off the gas then applied again ( gently, not full)kangaroo'd a bit, as soon as you put your fooy down it picks up just fine!

[spivvy]

try cleaning air flow meters also

do a search it will tell you how to do it

[entwistlea]

hmmm

Cleaned the airflow meters ( and boy did they need a clean), decided to drive it to work today (brave i know). Still problematic idling, still jumped a little when cold, but stalled twice, once warm was ok, but then idled at 2000 rpm... turned off, waited a mo and then on and it seemed to settle....

Any more idead, AF meters shot maybe???

[tvrgit]

Start it up, leave it idling until the fan cuts in, let the fan run until it goes off again.

Don't know why, but that seems to sort the problem of idling at 2000 revs, certainly on mine - I think it resets a temperature range for the cold start. I have to do that every time I disconnect and reconnect the battery.

[Mr Clifford]

entwistlea said:

hmmm

Cleaned the airflow meters ( and boy did they need a clean), decided to drive it to work today (brave i know). Still problematic idling, still jumped a little when cold, but stalled twice, once warm was ok, but then idled at 2000 rpm... turned off, waited a mo and then on and it seemed to settle....

Any more idead, AF meters shot maybe???

I had this problem for quite sometime.
Tried everything, cleaned everthing you have and in the end it was down to corroded wires on the injector wiring loom.
Took the guy 5 minutes to diagnose the problem and about one hour labour cleaning the wires.

Result = no more kangarooing down the road for the past year !
Worth a look perhaps.

Just added = Mechanic said that with this problem when the car is cold no problem.
Problem would get worse as the car wams up. Starts cutting out, jumping etc.

Edited by Mr Clifford on Wednesday 2nd April 11:07

[entwistlea]

ta all - will plow on with the ideas....

[entwistlea]

update..... cleaned air flow meters, new throttle pot, new leads, cap, sparks and rotor arm... decided a good service was in order....

An improvement for sure, but still can;t get it to idle correctly, idling very high when warm and a little fluffy when cold, someone suggested idle control valve, anyone heard of this ( where is it ???)

So, could be injectors maybe ? or maybe the AF meters are shot and cleaning didn;t help.... any more ideas.....

Andy

[kenpage]

hi the idle control vavle is that round object on the top front of the plenium chamber looks a bit like a microphone with 1 connector going to it,its held on with 2 small bolts.take it off undo the solonoid and clean the valve out with carb cleaner mine was very dirty the other thing suggested to me was the water temp sender to the ecu not the water gauge sender to the gauge its roughly underneath the idle valve in between the heads

[ketvrin]

looks like this...

http://cgi.ebay.co.uk/FORD-GRANADA-SCORPIO-COSWORT...

edited to say "LOOKS LIKE" ... this ones off a cossie

Edited by ketvrin on Friday 4th April 15:22

[entwistlea]

ahh right, took it off, pretty filthy, cleaned with carb cleaner though hasn;t helped. I did look at how it worked and have to say it wasn;t smooth in operation, though i noticed it was when i didn;t push it in directly straight, so could be user error, may be worth getting one if they are cheap !

[kenpage]

i wished i was clever like you kev but it does look like a microphone

[Gerald-TVR]

I might be being thick but find these 'modern' engines difficult to understand sometimes, (brought up with SU carbs and no ECUs) what is the relationship between control valve, throttle pot, air flow meters temperature sensor etc. Please does anyone have a simple guide.

And has anyone ditched the fuel injection and fitted carbs, Weber I guess, in place

[ketvrin]

kenpage said:

i wished i was clever like you kev but it does look like a microphone

Now if I WAS clever I could answer that last question for REAL clever ... read Tvrgits explanation which will be along in a minute... watch out for the fart though...

Norman, you are showing your age mate calling an 18 year old engine "modern"

Edited by ketvrin on Friday 4th April 17:08

[tvrgit]

Gerald-TVR said:

I might be being thick but find these 'modern' engines difficult to understand sometimes, (brought up with SU carbs and no ECUs) what is the relationship between control valve, throttle pot, air flow meters temperature sensor etc. Please does anyone have a simple guide.

And has anyone ditched the fuel injection and fitted carbs, Weber I guess, in place

It's not simple, unfortunately, so a simple guide is bleeding complicated!

The ECU tries to optimise the fuel/air mix at all revs and at all engine loads.

The Air Flow meters measure... well... the amount of air being sucked into the engine. The computer has to work out how much fuel to chuck through the injectors for that measured amount of air. The throttle pot measured the position of the throttle butterflies (and hence how far down the accelerator pedal has been pushed) If the driver has the accelerator depressed (ie he wants to go faster) then the TP tells the ECU to stoke up the boilers. If the foot is off the accelerator then less fuel is added (and less air is sucked in so the AFMs measure that too).

All of that information is fed into the ECU which has pre-programmed fuel maps for engine revs / load etc.

OK so far? Good. Hang on till I have a lie down...

Right... that's fine when the car is moving. When you stop and the car is idling, the throttle is shut. That means, in theory, no air going into the engine. Now engines need air to mix with the fuel kiddies (not much at idle, but it still needs some) and this is where we need... <plays fanfare> taraaa!! the idle speed control valve!!! It's basically a little tube that allows air to bypass the throttle butterfly. The vaccuum in the plenum chamber sucks that air in, it doesn't need any other help. The ECU mixes just enough fuel with that air to keep the engine going. If the engine speed starts to rise, the valve closes a teeny bit, to let less air in (and mix it with less fuel). If the engine starts to drop - well you can work that out now eh?

So the valve controls the idle speed (hence the name) by bleeding air past the bleeding throttle butterfly, except if the bleeding thing gets choked with bleeding carbon, it sticks and then the bleeding revs are all over the bleeding place.

I'm tired again and my head hurts...

Right... so that's ok when the engine is warm... but when the engine is cold, you need more fuel in the air to keep it going (the principle of the dear old choke cable which simple "choked" the air with a flap in the carb, so that there was less air mixed in the fuel, with the same effect).

So the engine temperature sensor tells the ECU when it's a bit chilly, and it adjusts the fuel map accordingly. Now if the temperature sensor is broke, it can't tell the ECU that, so it can't adjust the fuel so the engine then runs like a wet fart in a silent church.

Similarly, if the ISCV is broke it can't adjust the engine revs when the engine is cold (ie maintain a "fast idle" so the result is similar to the aforesaid digestive malfunction in a place of worship.

Is that simple enough?

And before any engine experts come on saying "ah but that's not quite right" let me say "I'm trying to explain the basic principles ok?"

I need another lie down...

[entwistlea]

excellent description... me thinks its either my temp sender or the iscv.... any idea of a part number for the temp sender anyone, only one i can see is the thermostat for the radiator....

[tvrgit]

entwistlea said:

excellent description... me thinks its either my temp sender or the iscv.... any idea of a part number for the temp sender anyone, only one i can see is the thermostat for the radiator....

Don't know the part number but IIRC it's under the plenum at the front right (ie behind the alternator)