T4 Boost cut off!

[Alex121]

Update on this.

Happened again this morning.

Took it back to Volvo after work and did a code test. Apparently my battery needs replacing ASAP so £49 later for a gen Volvo one that's sorted. Also found faulty signal on camshaft reset valve.

Not sure if that would put it into limp mode but it's something so guess I'll start looking for those lol.

[Alex121]

Update on this....

Well, no update really - More money spent, problem still persists

Put my brand new MAF in last night, got limp mode twice this morning, same as yesterday.

Parts replaced in last 6 months, all brand new, all Volvo.

Turbo
Coil packs
HT leads
Spark plugs
TCV
MAF sensor
MAP sensor
VVT solonoid
Thermostat

I even took boost down to stock for a week and still had the same problem so it's not an over boost issue.

I'm now a bit stuck, as mechanically, I can't think of anything else that can cause this! It's at the stage where I would just be replacing parts for the sake of it and even then, I'm unsure of what I would even replace next!

Any ideas anyone? I'm desperate now lol.

[960kg]

I see in your list no O2 sensors replaced and the motor has done 166,000 !!

I don`t know how long you have had the car miles wise but all the fuel system major parts should of been replaced including the O2 sensor at around the 100,000 mark for Preventative Maintenance and especially for reliability........but of course if one just waits for problems then so be it!

Having said all the above i never always agree with Mitch but this time even as early as post number 2 he states actuator adjustment...

Although you say it was set by Volvo the proper way...ok, the proper way but i believe that the actuator is set too tight and as Mitch says it will give Limp Mode for a time until you use lower boost for a while to give the ECU chance to reset itself...

1.35bar = 19psi........1.4bar = 20.31psi which is too much for a P2 2litre motor unless more modified to overcome problems...these motors have 2 boost sensors to keep the motor safe and you turn it up so it complains and gives you Limp Mode.........On a P1 motor it is ok as most is forged so safe up to 26 / 27psi i believe Tommy blew his T4 up at that......

The map you have should be set around 16psi and also will delete the boost limit but then you have over ridden that by too much adjustment.

Why don`t you just turn it down to standard setting and then find out what the problem is, at least then all is set how it should be!

The chart tells you what settings ...

Good Luck!

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Just read down to stock boost bit......but keep it there until you find what is what!...

What Turbo did you replace the old one with?...and are the compressor wheels inside the standard size or was it an upgrade?

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You are really getting down to the nitty gritty, and things which should be ok may not be so you have to check everything sensor wise!

Have you checked the Knock sensors on the front of the engine under the manifold ...they are bolted on and have to be torqued to the exact amount and at the correct angle on the block otherwise when the engine knocks or detonates the knock sensor may just to easily put the ECU into limp mode...

[Alex121]

Hi Keith,

I've had the car since it was on 129k, the O2 sensors were replaced at around 115k IIRC by Volvo, I've no reason to doubt the service history since it's got a lot of it! The fuel pressures been tested and come back fine so I would assume the pumps OK. Injectors are fine. Fuel pressure regulator has been replaced since I took ownership of the car.

IIRC Ashoks map is set for 1.2 bar and is expected to reach 1.3/1.35 bar with an exhaust system, which mine has and the torques progressive. I think the whole P1 is stronger thing is massively over exaggerated so I'm not too worried about it going pop, it's not an off the shelf map. Compression is near enough spot on so I would say it's a healthy engine - However, due to the mileage now I have a complete rebuild planned for this year.

I've no reason to doubt the actuator wasn't set-up correctly since my uncle only gives it to the master techs, he doesn't let the others work on mine.

Also forgot to add, when I first got the car back with the new turbo fitted I kept it on standard boost for around two weeks whilst giving the turbo a chance to bed in before cranking it up to suit the map. During that time this problem was still happening. About a month back I also wound it back to standard and it continued to happen....

EDIT: Turbo was replaced with a new, genuine Mitsubishi 14T, supplied from Volvo over in Sweden and fitted at Volvo.

[960kg]

So your all ok O2 sensor wise and fuel wise......

The P1 thingy is not really over exaggerated unless one has owned one and you see how much a thrashing they do take everyday and i mean thrashing only then can one form an opinion.

Yes, the P2 can be ok....but not as standard...this is the important thing that i get pulled over about.

Did it do limp mode before the new turbo?

Is the turbo exactly as what you had ....maybe the actuator diaphragm and spring are not right for the turbo!

I still think as you have a map set to 1.2 then the turbo at std settings it is too much boost.....try it at the minimum on the actuator arm, go as low as you can to try it.....

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Nothing to do with your motor but i am down your way Horndean to get a remap for my Merc in a couple of weeks.... bit of a way from Dover for me so i hope it`s worth the effort...Lol

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Strange everytime i ask you a question when i read your post then the answer is there .....i think you must get all things correct first ....so try the Knock Sensors...they do go wrong!

If i told you i was driving my first Volvo for 5 yrs until i knew the pinking was those sensors you would never believe me...i was then 1986 learning Volvos and never knew what a knock sensor was....

[Alex121]

Originally Posted by 960kg

So your all ok O2 sensor wise and fuel wise......

The P1 thingy is not really over exaggerated unless one has owned one and you see how much a thrashing they do take everyday and i mean thrashing only then can one form an opinion.

Yes, the P2 can be ok....but not as standard...this is the important thing that i get pulled over about.

Did it do limp mode before the new turbo?

Is the turbo exactly as what you had ....maybe the actuator diaphragm and spring are not right for the turbo!

I still think as you have a map set to 1.2 then the turbo at std settings it is too much boost.....try it at the minimum on the actuator arm, go as low as you can to try it.....

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Nothing to do with your motor but i am down your way Horndean to get a remap for my Merc in a couple of weeks.... bit of a way from Dover for me so i hope it`s worth the effort...Lol

Yep, it went into limp mode before the turbo got replaced and even on the old TCV. The turbo was a part for part replacement, the waste gate comes as apart of the turbo assembly so that's brand new. I'm not sure if it's the same or not. I would be surprised if they fitted anything different.



EDIT: Nice, Horndean is the next village so only about a mile away. Where are you getting it mapped?

[960kg]

Getting it mapped at PCS ...Prestige Car Services

113A London Road
Horndean
Waterlooville
Hampshire
PO8 0BJ

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Nice turbo.

Am i right in remembering you had a new engine or another engine put in some time back....all the more reason to check the knock sensors even if for piece of mind...

[Alex121]

Originally Posted by 960kg

Getting it mapped at PCS ...Prestige Car Services

113A London Road
Horndean
Waterlooville
Hampshire
PO8 0BJ

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Nice turbo.

Am i right in remembering you had a new engine or another engine put in some time back....all the more reason to check the knock sensors even if for piece of mind...

Ah, that's still technically Clanfield, just up the road. I do my 0-60 tests up there, you'll see why when you get there lol.

Nope, original engine here.

[Matt86]

I'm probably talking nonsense but Was the waste gate replaced?

Also does the t4 have a n75 valve? Could be that?

[Alex121]

Originally Posted by Matt86

I'm probably talking nonsense but Was the waste gate replaced?

Also does the t4 have a n75 valve? Could be that?

Waste gate is apart of the turbo unit. All got replaced.

T4's have a TCV (turbo control valve/solenoid) rather than a N75