Focus 1.6 2003 - engine pinking/rattle

[Prickly_buzz]

Hello guys, cheers for the help thus far.

This noise is 100% only happing on light throttle i hardly ever go WOT to be fair but if anything this improves the issue.

I actually managed to source an ECU and programmed it today, i drove 15 miles with no noises what so ever unfortunately it would seem the problem is still there however as i can still hear the rattle but no way near as loud, it so weird that changing the suspected 'fried' ECU has only helped where as i thought it would either have zero effect or cure it completely?!


Does the 2nd lambda actually adjust the mixture in anyway, my understanding is that it does not?

Edited by Prickly_buzz on Monday 10th August 20:43

Not sure if these gas readings shead any light...


Idle -



~2500 RPM

Edited by Prickly_buzz on Monday 10th August 21:46

[bearman68]

Pumaracing said:

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.

Yes, agree with you Puma, and would comment the ECU reading is unusual since the LTFT is 0% too. However, the O2 sensor has some imput, but is not always the limiting factor, and I'm looking at this thinking there is some fundemental underlying mechanical reason for the lean running. I would defo be tempted to run a smoke test on the inlet side of things, check fuel pressure that type of thing.

[Prickly_buzz]

bearman68 said:

Pumaracing said:

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.

Yes, agree with you Puma, and would comment the ECU reading is unusual since the LTFT is 0% too. However, the O2 sensor has some imput, but is not always the limiting factor, and I'm looking at this thinking there is some fundemental underlying mechanical reason for the lean running. I would defo be tempted to run a smoke test on the inlet side of things, check fuel pressure that type of thing.

Im starting to think there is something mechanical causing this especially as im running out of things to replace!
I have cirtainly removed, checked and checked again all the vac pipes and i replaced the PCV valve. I have removed the idle valve and made sure the gasket is sealing correctly.
How would i go about checking the fuel pressure and any idea what its supposed to be? I know these focuss can suffer with fuel pumps, its never given me grief but it is the original and done 117,000 same with the CAT.

Edited by Prickly_buzz on Monday 10th August 22:03

[Pumaracing]

The idle readings are normal. At 2500 the mixture is going so weak it's ceasing to ignite properly, Lambda value off scale weak. The fuel is coming through unburned as a high HC reading. The oxygen similarly is not being used up during combustion leading to massive O2 readings which should be nearly zero at stoichiometric. The CO2 reading is always a maximum at stoichiometric and falls if mixture is either rich or weak as is the case here.

CO drops to about zero at stoich and then obviously can't go any lower, again as we see here.

The noise you are hearing is misfiring.

[Pumaracing]

I'm puzzled by some of the information we'd been working with. At the start you said the lambda voltage was oscillating normally which it clearly isn't from the trace supplied and you also said that exhaust gas readings were normal when they are massively abnormal at 2500 rpm. However we shall soldier on.

Let's now be very clear. Does this problem go away and the car accelerate normally at higher rpm and/or higher throttle openings i.e. with much higher fuel demand? If so then it can't be fuel pump or filter. However something is apparently not supplying fuel properly in this brief rpm band at light throttle. I will have to sleep on it.

[Prickly_buzz]

Pumaracing said:

I'm puzzled by some of the information we'd been working with. At the start you said the lambda voltage was oscillating normally which it clearly isn't from the trace supplied and you also said that exhaust gas readings were normal when they are massively abnormal at 2500 rpm. However we shall soldier on.

Let's now be very clear. Does this problem go away and the car accelerate normally at higher rpm and/or higher throttle openings i.e. with much higher fuel demand? If so then it can't be fuel pump or filter. However something is apparently not supplying fuel properly in this brief rpm band at light throttle. I will have to sleep on it.

I'm really sorry if I've supplied incorrect or conflicting information, I'm just trying to give as much detail as possible but I'm no expert! I am really grateful for your help as I am at my wits end and have spent a lot of time and money on trying to get a reliable straight car.

I tested the car this morning and can confirm that if I accelerate from a standstill I will hear the 'rattle' roughly 3-4 times through the rev range.
If I cruise along at say 40mph for a few minutes and then come off the throttle for a few seconds then reapply it I get the rattle nearly every time. (again sorry if this wasn't clear to start with but it can be hard to replicate the rattle however I think I've got used to when it does it now.

If its not the ECU causing it to run lean what else on the management side would have an impact on this?

Edited by Prickly_buzz on Tuesday 11th August 09:51

[Pumaracing]

Have you checked/replaced the throttle position sensor?

[227bhp]

Is it worth trying to record the sound so we can hear it?

[Prickly_buzz]

Pumaracing said:

Have you checked/replaced the throttle position sensor?

I have not checked the TPS, the replacement engine had one fitted already so I left it on, small chance that both are faulty (not impossible). Suppose it could be wiring issue but would I not get a fault code?

[Prickly_buzz]

227bhp said:

Is it worth trying to record the sound so we can hear it?

I did give this a go but it wasn't easy to pick up over engine and road noise with a microphone, I will attempt it again tonight.

[Prickly_buzz]

does the post cat lambda sensor just 'sniff' to make sure the CAT is efficiently working or does it actually have any control of fueling?

[Prickly_buzz]

Ok this gets more complicated and irritating....

It would seem the 'grey' smoke was in fact 'blue' smoke I was unsure to start with however I have since checked my oil and I seem to have lost 1.0litre in around 2000 miles.

Still getting the rattle and still only when warm....

I'm starting to think this is like a crankcase issue, maybe higher crankcase pressure not venting somehow? Unfortunately that's where my technical knowledge ends!

Edited by Prickly_buzz on Monday 17th August 19:34

[Prickly_buzz]

I have driven the car this morning for around 15 miles and there was no noises or smoke at all.

The ONLY thing that changed is the weather, it was damp, cooler and lightly raining....

Does this give any clue as to what it might be?

[steveo3002]

sounds a bit like a temp sender if the cold weather has cured it

so the old engine did it , new one was fine until its in your car , what parts havent you swapped over from the good engine?

[Prickly_buzz]

The only thing I haven't changed from the original set-up is the Cat. Its got the sensors which the working replacement engine came with, ive also changed the coil pack, plugs, leads, 1st lambda sensor even the ECU for a know good one!

[Prickly_buzz]

Right I've now changed the CAT and fitted a genuine fuel filter and I've still got the noise.

I'm thinking possibly fuel pump weak maybe? But I'm just guessing

[djfocusep]

Did you ever get to bottom of this problem as I have same issue with using oil, pinking when hot!
Cmax 1.8 2004

Regards paul

[JONATHAN_11_80]

Hi,

I used to have a 2004 ford focus 1.6 this also pinked lightly under load, this started at around 60,000 miles and continued right up until I part ex'd the car at 110,000 miles. The car always performed fine and drove nicely although Shell V Power helped a lot. A ford dealer did an update on the ecu which should have corrected this issue however it didnt have any effect. The car was never quite as lively, so I am assuming the update changed the ignition advance/timing etc. To be honest if the pinking is light I wouldnt worry about it and just drive the car. I did and the last i heard my old foci was still going at 150k. I have a younger focus now which also pinks occassionally.

Edited by JONATHAN_11_80 on Wednesday 20th July 21:34

[JONATHAN_11_80]

Hi,

I used to have a 2004 ford focus 1.6 this also pinked lightly under load, this started at around 60,000 miles and continued right up until I part ex'd the car at 110,000 miles. The car always performed fine and drove nicely although Shell V Power helped a lot. A ford dealer did an update on the ecu which should have corrected this issue however it didnt have any effect. The car was never quite as lively, so I am assuming the update changed the ignition advance/timing etc. To be honest if the pinking is light I wouldnt worry about it and just drive the car. I did and the last i heard my old foci was still going at 150k. I have a younger focus now which also pinks occassionally.

Edited by JONATHAN_11_80 on Wednesday 20th July 21:57