Over and under boost (p0299,p0234)

[Tizer]

If the car now drives ok and there are no further fault codes then I would follow Tom's advice and keep a record of the live data for comparison purposes in case that or another problem comes back again. It is very easy to go off on a tangent and convince yourself that something is faulty or needs replacing. 

I used to do screen records at different operating states when using my phone app for data logging but unfortunately I have since deleted the ones for that car.

[Dread91]

So unfortunately the dongle I borrowed wouldn't connect to my car so I'm going to have to order a new laptop battery or a wireless forscan lead.

However I did manage to take the car up and down the motorway but I just couldn't get it to throw a fault code.

If I create a bit of noise whilst driving like with the window slightly open, then you wouldn't think there was anything wrong with the car. It's just that horrid whine which makes me nervous because it sounds like something is just gonna blow up at any moment.

 

[Tizer]

The next obvious thing to check is that the noise is definitely coming from the Turbo.  

[Dread91]

I guess I could take some video recordings if that would help?

[Dread91]

So took some recordings, and tbh they don't do the sound justice but you can hear it.

Drive to the shops from cold start...

After the shop visit, just on an open stretch...

And stand still revving at the end of journey... (sorry misses had to film just over my leaking injector seal... cant get the staff)

If I'm being honest it only sounds worrying to me when doing 70+ on the motorway, the whine is just constant.

[Tizer]

It doesn't sound too bad to me. With noises it is a case of keeping an eye on things and doing something if they start to get worse or if the original problem comes back.

[TomsFocus]

I'd be more worried about the blowing injector than the turbo in all honesty.  Turbo's do make a bit of noise, as above, it doesn't sound particularly bad.

[Dread91]

Yeah I planned on getting the injector seal done once I was happy the turbo wasn't in dire need of changing because I don't want to put money I to the car if it needs over a grands worth of work for a new turbo.

So where to go from here? Just drive as normal and wait for a fault code to show up one day, whilst making sure that whine doesnt get worse?

If so I'll get the car booked in for the injector seal asap

 

Thanks

[TomsFocus]

I'd probably sell it and get something else if you can't trust it any more.

If not, it does look the best option currently would be to fix the injector leak and change the oil then just keep driving and hope for the best!

[Dread91]

The car is a shed exterior wise so I wouldn't get much for it, even part exchange. I'll get more money out of it just running it into the ground I think, plus gives me an excuse to get my old mx5 back out of storage.

Do the injectors need re-coding when taken out and put back in again? If not I'll replace the seals myself.

Also Iv got hold of a laptop now so will record a commute to work tomorrow, just to get some data

[TomsFocus]

If you keep the injector in the same cylinder it won't need recoding.

[Dread91]

Looked up a video of how to change the seals and it looks easy enough. However I read that the bolts that hold the injectors down can loosen over time due to vibration. Checked mine and indeed they were just a bit more than hand tight, so iv nipped them up a bit and the spitting stopped... just want to check that it's okay to do that?

Next step, oil change. I know its 5w-30 but does it matter if its fully or part synthetic?

[Dread91]

Unfortunately my EML has came back on today on the way to work, but maybe some good news with it?

Plugged the car back into forscan to read the error code and P0234 overboost has returned. However I now have two new faulty codes, being P0100 mass or volume airflow a circuit and P0113 IAT sensor circuit high input. Could this be pointing me in the right direction?

Thanks

Dread

[Tizer]

The IAT is part of the MAF sensor. Could just be bad wiring or connection.

The logical thing to do would be to monitor the MAP and MAF together on the road and take things from there. There is a wiring diagram somewhere in this forum and I think it is for the MK2 Focus.

Another forum member had a problem with something else that was caused by battery acid leaking and damaging the loom that runs underneath the battery tray, which was not obvious until he stripped the loom after exhausting all other possibilities.

 

[Dread91]

Was thinking about these new codes last night and I remember disconnecting the maf sensor at some point. Would that have stored that code from then with the IAT code with it, if they go hand in hand? And that the overboost code is unrelated but was the code to set the EML off possibly?

Will still run a maf and map test when I next go out 

Thanks

[Dread91]

tracked my maf and map sensors on a short journey, I couldn't see anything obvious but here is a print screen

(I did save the forscan file just for reference)

 

[TomsFocus]

Forscan tells you which codes have triggered the EML.  It also tells you which are present and which were previously set, but sadly doesn't give dates so faults can be stored for years.

It's almost certainly the overboost code triggering the EML out of those codes.

 

Regarding the oil, it should be fully synthetic and low SAPS (low ash) being a DPF model.

[TomsFocus]

18 minutes ago, Dread91 said:

tracked my maf and map sensors on a short journey, I couldn't see anything obvious but here is a print screen

(I did save the forscan file just for reference)

 

That flat line at the top of the MAP limits is the issue...it's out of MAP range so will trigger overboost if it stays above that for roughly 5 seconds.  The MAP maxes out at 2.5bar (35psi) as standard.

So, either the MAP readings are wrong (but they don't look it!), or there is genuine overboost occurring.  Has it been remapped out of interest?  A bad map could cause this.

[Dread91]

I haven't had it remapped myself, maybe the previous owner could have had it done but I didn't buy the car privately. I'm assuming the only way if finding out is to get it booked in for another remap?