Evening all,

have had the injector light coming on for the past couple off months now and AC Williams so far have replaced the Overboost valve and the MAF, but the engine is still reporting the overboost error.

I am presently awaiting a slot when i can get my car to grays in warwick for them to look at, in the mean time i thought if anyone here would have an idea what can cause the overboost problem - sticking turbo vanes have been mentioned to me (new turbo needed if so), so can go to grays with some ideas.

It comes on mainly going up a steep hill on the way to work in third @ about 3000+ revs, although twice it has come on overtaking @ about 4000 rpm.

also would a 1.9 jtd multipla turbo fit mine as there is one going cheap if mine needs a new one?

cheers

smtvlive
:bang:

I'd be looking at the turbo wastegate actuator circuit as this controls the boost. Any slight leak from the pipe and it'll act like a bleed valve causing over boost. The wastegate arm itself could be seized in the shut position

I don't think you'll have a variable geometery turbo in the Marea (ref sticking vanes) - I think they only came in for Euro 4 but I'm not 100% on that.

found this with regards to variable geo for the turbo

http://translate.google.com/transla...+marea+variable+turbo&start=20&hl=en&lr=&sa=N

which states

Feeding

Direct Iny.. Common conduit. -- compressing Turbo. of variable geometry. Intercooler.

also have just checked my marea serive cd and it is defo a variable geo turbo

so what you said above (is slightly greek to me) means that the turbo is knackered or are they seperate servicable parts??

but it also states that it has 2 valves by cylinder. a camshaft in the butt.

does that also mean a multipla 1.9 jtd turbo would fit??

thanks for your imput

its 2001 Marea JTD 110sx if that hepls any more

I didn't realise they were running VG Turbo's - you learn something new every day I must have a closer look at our 130JTD as I'm sure that was a standard unit.

Neither of my suggestions mean the turbo is knackered. The first is to look at the little pipe that runs to the cylinder (boost actuator) bolted to the turbo. Make sure it's on tightly and there are no cracks / leaks anywhere.

The actuator also has a rod coming off it which acts on an arm. The actuator causes the arm to rotate within the turbine housing when max designed boost is achieved, opening a wastegate to stop excessive boost to the engine. Take the rod off the arm and make sure it pivots easily.

Cheers matey,

Will try and have a look at the weekend weather permitting, i don’t want to rush it as i use the car every day.

From what you and others have said i think there is a good chance the actuator arm is the likely culprit.

Just as a footnote whenever i change gear in 3rd there is a whoosh/wisp noise, which i guess is the turbo letting off pressure. This happens really no matter how hard i am accelerating is this correct?

Also when i take my foot off the gas (accelerating & constant speed) there is a clicking from the passengers glove box, from a small black relay. The more clicking the more likely the light will come on, and when the light is on there is no clicking. Does anyone else have this clicking from a JTD

cheers

smtvlive

The whooshing noise is a circulating type of dump valve letting off boost pressure between the turbo and the inlet manifold and putting it back in again between the air cleaner and the turbo. You should hear this between all gear changes.

These are similar to what you hear on boy racer Renault 5 & Uno turbo's (when they sound like a buses brake compressor letting off pressure) except that the boy racer versions dump to atmosphere just for the noise effect. The boy racer versions cause all sorts of problems as the ECU doesn't know you've just dumped all the air back to the atmosphere and usually stall at junctions

Regarding the clicking, can't say I've even noticed on our 130, I need to see which relay that would be.

The relay is a small black one in location 'D' as specified in the Marea handbook, very very top left corner, it is a tight fit to get in and out (no bigger than a matchbox).

I pulled this out and tried to start the car and it just turned over so it is a relay for fuel or ignition etc. In the handbook there is a fuse for the injection system as well in there.

I have tried to get AC Williams to tell me what it is but there seemed less than interested in helping out, Quote 'so what do you expect me to do', bloke on front desk when preseneted with relay, relay number, relay location after guy from parts had gone home despite telling me he would be there ot help me.:bang:

Finally managed to get it into grays in warwicksire next week as they seemed very highly commended, round trip of about 170 miles.

cheers

smtvlive

Grays just phoned, they said problem is the egr valve, i thought these just dumped some exhaust gases back into the engine to lower emissions??

anyway in for a penny in for a pound, only 160 quid or so we will see what happens.

smtvlive

Although it's not strictly legal, I would do away with the EGR at the first possible opportunity rather than replace it with a new one.

doesnt it also lower the temp in the chambers, stopping no2 forming or something, so if you disable it the temp increases and can cause damage?

dont quote me, just something i have read.

cheers

EGR is one of the methods used to reduce Nox but it does affect the engines efficiency. I'm not sure about the increased combustion temperatures.

Another method to reduce the emissions is using sheep **** (urea) which is going to be being used extensively in the truck industry. No EGR required with this method.

had the egr valve replaced, but only got as far as the slip road onto the A46 when i managed to get the light to come on again, booted it in 3rd, over 3500rpm:bang:

so i have had the egr valve, MAF and overboost valve replaced, and i have a reconditioned Garret jtd turbo sitting in a box next to me, which i think i will have fitted next.

Can i do this myself ( am pretty handy with a spanner and a tub of swarfega) or is it a job for the professionals. Have looked in the porter manual and it doesnt seem to hard. will i need to get some gaskets?

cheers

I've been listening out for that clicking sound and have now noticed it. It was usually after backing off after a heavy right foot. In any journey I would only hear it click a couple of times.

If you have a turbo, you might as well go for it as replacing them is very straight forward.

I would expect there to be a couple of gaskets (manifold to turbo, turbo to down pipe) and also find out if you can get new seals/gaskets for the oil feed and oil drain pipes. (I think the oil feed is a taper thread but not 100% with garrets) .

Use lots of penetrating oil every day for a week to try and free off the nuts holding the turbo in place so you don't end up having to drill and tap the exhaust manifold.

When you have the turbo physcally fitted, pour some oil into the oil feed and give it a little spin to circulate it onto the bearing before fitting the oil feed pipe.

The first time the engine is started, just let it idle for at least 15 seconds allowing the oil to circulate before making the turbo work.

Thanks for that, as you said it seems fairly straight forward, probably a good weekends work, just need to order the parts then.

We shall seee in a couple of weeks if this works

regards

smtvlive