Thread: No more 'Whoosh' in 4th

I have just been reading a great thread which was in Technical Chatter "TD5 Inlet Manifold Pressure", back in 2010, it is providing me with great info on what is going on, I had tweaked the wastegate upwards in past few weeks, and problem has started since I have done this.

Atmospheric pressure is having an effect, hence it is better or worse depending on the weather on the day, going to wind back the boost a bit and hopefully will resolve the issue. Boost cut out for the ECU is 242Kpa and often can be hit when the wastegate has been tampered with.

TD5 Inlet Manifold pressure

Great thread, great forum as always.

Matt.

I'd guess the boost pressure reg.
You said 'no change, maybe a little bit quicker', so maybe there's a bit of a hint there for 'ya.

I don't get to tinker with Td5 much, but I remember this similar feeling on brother's Td5 about a year ago.

engine felt like it wanted to go harder, but something holding it back. His is auto, so in some cases the trans smothered the feeling a little.
Anyhow, on advice from the forumites, I changed it, and difference was quite large.
(his is also chipped).

Another thing to check is the 'smooth' operation of the wastegate.
From my experience: I checked this my manually moving the wastegate arm, and it moved pretty much OK. But using compressed air, it moved in fits and bursts .. ie. not smoothly.
Sprayed it with some WD, compressed air, moved it by hand, sprayed it again .. etc. finally got it to move more smoothly of it's own accord, which helped before the WGM was replaced.

Quick update, my EGT temp gauge has recently increased a great deal, now whilst driving up a small hill, I am hitting 500 degrees and any serious longish incline, I will get up to 650 and then driving by the gauge. Such a substantial change has never happened before, even though I tinker with the wastegate every now and then, but now having to drive very carefully and watch the gauge all the time. Usually I had to work the car really hard up a long hill near home to get to over 600, but at present I am pretty much getting there a third of the way up.

I thought I would throw it out there to see if there is any one specific reason which might cause this ? Not good.

Matt.

What's the max turbo pressure(or MAP) you get cos it seems a boost leak to me... eventually record an inputs fuelling log to SD card, save to PC, convert to excel and post it here.

btw, do you still have EGR ?, if yes that would be a good point to start with

Originally Posted by sierrafery

What's the max turbo pressure(or MAP) you get cos it seems a boost leak to me... eventually record an inputs fuelling log to SD card, save to PC, convert to excel and post it here.

btw, do you still have EGR ?, if yes that would be a good point to start with

Thanks Sierraferry, it turns out I had not tightened the wastegate nut sufficiently and it had wound itself back, and consequently EGT's went up sufficiently. I have no idea behind the Science why ?

I have downloaded a couple of saved files from the nanocom, and another member on the forum is already looking at them for me, so I do not want to steal his thunder until he has had a look and can see what is wrong. Thank you for the offer. Matt.

Quick update, we have finally narrowed it down to the MAP sensor, disconnected it and car ran better than ever had done before, stuttering all gone. Managed to get hold of a second-hand sensor yesterday from breakers, At first, no good at all, but after clean, car ran very well, albeit, differently. Not sure if with stage 2 tune and other mods, something is now telling the ECU to limit something, but still getting great help on it from another forum member.

So moral of story, is that MAP sensors are always worth a periodic clean with contact cleaner, will update when further progress is made.

Did you get your overheating resolved?
Nick

Originally Posted by surfingooner

So moral of story, is that MAP sensors are always worth a periodic clean with contact cleaner, will update when further progress is made.

Yes they need to be cleand if you still have EGR and only then... but if it's very old you need a new one cos it's a piezo electric crystal which gets ''tyred" in time, IMO you can't rule out the MAP sensor with some old sh*t from a brakeyard...show some respect for your vehicle and buy a branded new one not some cheap chinese aftermarket then you can say it's ruled out...disconecting the MAP is not like when you unplug the MAF cos it's a completely different default as the MAP is actually a double input sensor correctly named MAP/IAT so if you unplug it the ECU goes to IAT default too