Focus 1.6 2003 - engine pinking/rattle

Focus 1.6 2003 - engine pinking/rattle

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William-lpxee

Original Poster:

25 posts

104 months

Tuesday 28th July 2015
quotequote all
Hello, I'm hoping someone can help me out here or at least give me some ideas of where to begin!

Brief background -
My engine in my car was burning oil, smoking quite badly and rattling/pinking on light acceleration etc.. so I decided to source a lower mileage (64k) engine and replace it.
Whilst the engine was out I replaced; cam belt & tensioner (also other unrelated items).
As the new engine was running perfectly in its orignial car i used all the sensor which came with it, inc MAP, cam, crank & cylinder head temp sensors.

Now the issue-
When I first drove the car after the engine swap it made the same bloody rattle but after lifting the bonnet I found one of the breathers on the inlet manifold split so I replaced all of them including the PCV valve i was so chuffed when i thought id found the cause but im now gutted as the noise is still very apparent. Now I know this engine did not do this in its previous vehicle so there must be something on my car that's causing this....but that's where i'm stuck!

The rattle seems to happen on light acceleration between 1500 - 2200 rpm
Also it doesn't happen when the engine is cold.

What i have tried -
Super unleaded, genuine coil pack, checked all pipes for damage or collapsing, tested the car on an MOT gas tester and its perfect, ive 'data logged' the car and the HEGO/lambda switches between lean and rich as it should, the map sensor reads correctely and the cylinder temp sensor is correct. Read fault codes, (none present) and re-set keep alive memory for the ECU.

HELP!

oakdale

1,786 posts

201 months

Thursday 30th July 2015
quotequote all
William-lpxee said:
Hello, I'm hoping someone can help me out here or at least give me some ideas of where to begin!

Brief background -
My engine in my car was burning oil, smoking quite badly and rattling/pinking on light acceleration etc.. so I decided to source a lower mileage (64k) engine and replace it.
Whilst the engine was out I replaced; cam belt & tensioner (also other unrelated items).
As the new engine was running perfectly in its orignial car i used all the sensor which came with it, inc MAP, cam, crank & cylinder head temp sensors.

Now the issue-
When I first drove the car after the engine swap it made the same bloody rattle but after lifting the bonnet I found one of the breathers on the inlet manifold split so I replaced all of them including the PCV valve i was so chuffed when i thought id found the cause but im now gutted as the noise is still very apparent. Now I know this engine did not do this in its previous vehicle so there must be something on my car that's causing this....but that's where i'm stuck!

The rattle seems to happen on light acceleration between 1500 - 2200 rpm
Also it doesn't happen when the engine is cold.

What i have tried -
Super unleaded, genuine coil pack, checked all pipes for damage or collapsing, tested the car on an MOT gas tester and its perfect, ive 'data logged' the car and the HEGO/lambda switches between lean and rich as it should, the map sensor reads correctely and the cylinder temp sensor is correct. Read fault codes, (none present) and re-set keep alive memory for the ECU.

HELP!
If it only does it on light throttle, it's most likely the noise is caused by internals of the catalyst being loose and rattling about.

The cat is likely to have been overheated and damaged by the previous oil burning.

Prickly_buzz

Original Poster:

25 posts

104 months

Thursday 30th July 2015
quotequote all
Thank you for your reply,

I have been underneath and banged the cat, can't hear anything also if the cat is breaking/broken up wouldn't it rattle when being revved at a stand still?

Prickly_buzz

Original Poster:

25 posts

104 months

Friday 31st July 2015
quotequote all
The other thing I considered is perhaps a slow switching HEGO/Lambda fault.
I'm not sure if this could be detected at idle or is there a chance this could only be apparent under load?

paolow

3,208 posts

257 months

Friday 31st July 2015
quotequote all
Have you considered that it may have been something in the fuel you are using?
Old eninge was pinking. New engine wasnt until put in the car - at which point it started using the fuel the old one was using and began pinking. A flush of the fuel system and different source of fuel maybe?

Pumaracing

2,089 posts

206 months

Friday 31st July 2015
quotequote all
Engines don't pink on light throttle. They do that at WOT. So it clearly isn't fuel or anything else engine related. There's a resonant vibration somewhere in the car.

Prickly_buzz

Original Poster:

25 posts

104 months

Friday 31st July 2015
quotequote all
Ok, that's interesting, I assumed it was pinking as it really does sound internal to the engine (although this is hard to tell for sure without having your head under the bonnet when it does it). It sounds similar to the 'knock/rattle' you get when pulling away and not accelerating enough...

I have tried different grades of fuel from different places and had no joy, I don't know if it makes a difference but I set the fuel grade in the PCM to 95.

It only seems to happen at around the 2,000 rpm area and only when the car is moving and as I said under 1/4 - 1/2 throttle, If im honest it has never happed on any heavy throttle.


P.S thanks for taking the time to help!

Prickly_buzz

Original Poster:

25 posts

104 months

Saturday 1st August 2015
quotequote all
Ok been out today in the car again.
I now feel it's got a lot to do with fueling reason being the exhaust tip is black & there where intermittent clouds of grey smoke coming out the back.

Pumaracing

2,089 posts

206 months

Saturday 1st August 2015
quotequote all
Have you retained the original ecu? Maybe it has a mapping fault - giving too much ignition advance.

oakdale

1,786 posts

201 months

Saturday 1st August 2015
quotequote all
Prickly_buzz said:
Ok been out today in the car again.
I now feel it's got a lot to do with fueling reason being the exhaust tip is black & there where intermittent clouds of grey smoke coming out the back.
Which would fit in with the cat internals being broken up and/or loose.

bearman68

4,644 posts

131 months

Saturday 1st August 2015
quotequote all
Sounds like an ECU issue to me too. Can you use your fault code reader to measure ignition advance on various throttle loadings. Having said that I would expect the knock sensor to limit this - you may need to scope some of the output from the ECU - most obvious is the knock sensor, ignition advance, and fuel injection timing / duration.
Whereabouts are you ?

Prickly_buzz

Original Poster:

25 posts

104 months

Saturday 1st August 2015
quotequote all
I have done a gas test on the car and all is bang on, not ruling out the cat but seems un-likely.

Im startiing to suspect the ECU to be fair as it is the orignial and was running the previous engine. Also im running out of things to replace!

Bill

Oh and im in Kent

Prickly_buzz

Original Poster:

25 posts

104 months

Sunday 2nd August 2015
quotequote all
I removed the ECU (to get the numbers from it) this morning and when i put it back on about 10 minutes later, i went for a drive so it could learn basic settings etc, the noise was no longer there, however im conviced this is not cured but it seems like the issue could well be with the ECU.

Prickly_buzz

Original Poster:

25 posts

104 months

Friday 7th August 2015
quotequote all
Update -

I have had to keep driving the car as its all I have got and I need to get to work!

I have not found there is intermittently puffs of grey smoke coming out the back.
Also it has now developed a lack of power/flat spot intermittently when pulling away from a junction or roundabout.


I am really getting fed up with this now I just don't know what to try next, any suggestions would be much appreciated.

Sardonicus

18,928 posts

220 months

Friday 7th August 2015
quotequote all
Try the PCV valve and hoses if the valve gets stuck open this will give you a flat spot (done these before on Zetec's) it may also be drawing in too much crankcase vapours causing the smoke ..... possibly, any problems with the above will also cause overly weak AFR's causing pinking, the O2 sensor cant add enough fueling to compensate for this massive unmetered air leak scratchchin just a thought

Prickly_buzz

Original Poster:

25 posts

104 months

Friday 7th August 2015
quotequote all
Cheers for your reply.

Unfortunately I have already replaced the PCV valve and the vac pipes and it didn't make any difference.

I have managed to get some data, not sure if its relevant....
The noise was heard at '1' on the graph (you can see that's where I touched the throttle)




1) Long term fuel trim
2) MAP sensor pressure
3) MAP sensor voltage
4) Pre-Cat Hego Voltage
5) Post-Cat Hego Voltage

Edited by Prickly_buzz on Friday 7th August 13:47

Pumaracing

2,089 posts

206 months

Friday 7th August 2015
quotequote all
I would have thought that if the closed loop system is working correctly the O2 sensor voltage should be bouncing up and down between about 0.1v and 0.9v on a fairly rapid frequency like every half second or less.

bearman68

4,644 posts

131 months

Sunday 9th August 2015
quotequote all
Agree with the above - that engine looks as if it is running lean as a stick insect.
I'm assuming the engine temperature is normal operating?

O2 sensor looks as if it's working OK, because you can see the blip in accleleration, but don't understand a consistent 0.15v reading

Pumaracing

2,089 posts

206 months

Monday 10th August 2015
quotequote all
I think we may have been somewhat misdirected in the first post that this noise is happening at light throttle rather than WOT. At such low rpm only a small amount of throttle opening is needed to fully supply the cylinders and the MAP trace is showing what appears to be about full atmospheric pressure of 100kPa as the throttle is opened. So this is really WOT not part throttle and the engine could well be pinking.

The mixture is very lean and closed loop does not seem to be working. It looks like the ecu is fried.

Pumaracing

2,089 posts

206 months

Monday 10th August 2015
quotequote all
bearman68 said:
O2 sensor looks as if it's working OK, because you can see the blip in accleleration, but don't understand a consistent 0.15v reading
This can only happen if the ecu is not responding to the low lambda voltage and injecting more fuel which should then bump the mixture above stoich, generate high lambda voltage which then immediately triggers a cut in fuel, repeat ad infinitum.