Evening all,

Recently acquired a 52 plate ST170 after a 20 year break from Ford's! Despite a few issues, really enjoying it, totally bog standard. Have already rebuilt runner control box, new thermostat etc. Lambada sensors to do as I have EML light on and showing the codes for these.

A couple of questions: -

1) Idle cold is high (1500 rpm) but looking through the posts I see this is common but when it warms up fully, still a little high (about 1000 rpm). I suspect the idle speed is controlled by the ECU but if anybody knows different I'd be pleased to hear from you. Throttle body cleaned up in case of sticking butterfly so eliminated that.

2) When accelerating through the 2000 to 5000 rpm range it feels a little lumpy - almost like driving an old Ford with twin stage Webbers on!!! Not a show stopper but I like to try and get things right. A bit hesitant one moment then pulling like a train the next - I'm thinking fuel filter/fuel pump (it's got 87K on the clock). Reset all leads, checked plug gaps etc.

Any ideas welcome. Many thanks!

Julian

 

ST170 has a flat spot that comes in around 2200rpm that is caused by an issue with the standard map. Only way to get rid is to have a remap, Blufin wont fix it you need a dreamscience map or similar.
Fuel pumps are a common faliure, there is no inspection hole under the seats so to adress the pump its a bugger as you have to drop the tank.

 

You can manually adjust the idle speed by increasing or decreasing the tention of the throttle cable.

If you follow the cable back towards the bulk head on the driver's side you will see a small plastic sleeve. The sleeve opens up to reveal an adjuster. Turning it one way tightens the cable and turning it the other way loosens it.

Ideally you should adjust it so that once the accelerator is fully depressed the throttle body is fully open. If the cable is too tight the revs and subsequently the idle speed will be high. If it is too loose the throttle won't open fully when you press the accelerator to the floor.

Remember, you should only make small turns when moving the adjuster as it only takes a few turns to completely tighten or loosen the cable.

 

I have a 53 focus st170. Had similar problem with really bad lumpy idle on tickover after engine warm up & a slight juddering around 2000rpm. Diagnostic check, replace before cat lambada sensor. Still had problem. Replaced spark plugs, ht leads & coil pack, still had problem. Cleaned throttle body & butterfly, cleaned air box breather pipe, cleaned maf sensor & replaced air filter. Still had problem. Went through pages & pages of posted threads & came across a topic on crankcase breather pipe situated behind throttle body & other end going to engine block under coil pack. Sure enough this pipe had a small split in it common problem after time. Gk ford Ł15. Replaced pipe & runs like a dream now. So after going long way round as some of us do from time to time & emptying pockets of cash. A quick vacuum check would have done job. Where would we be without forum sites. Thanks

 

Thanks for the post, could help someone searching in future!

Trouble is, a lot of lambda sensor codes are only the sensor 'reporting' a fault. Not the actual casual part. Your air leak is a prime example.

 

having these issues atm will inspect the breather pipe today