Been advised to SCRAP C5 2 litre 110hpdi LX

Citroenmad · Post by **Citroenmad** » 29 Nov 2010, 22:36

Since you have a code for the airflow metr (MAF) then id be changing that and see how you get on. Sometimes even cleaning the original has an effect, but they dont last forever.

Surely your car is worth more than a few hundred pounds? I would be very very doubtful if it is the onboard computer which is causing that fault, though i dont have expereience of its failure - its rare.

Dommo · Post by **Dommo** » 29 Nov 2010, 23:55

As said, the MAF = the air flow meter, so get that changed, or at least borrow a known good one off another car to see if that fixes the problem.

Old-Guy · Post by **Old-Guy** » 30 Nov 2010, 13:00

Back to basics. Lack of power on a turbo-diesel that otherwise runs well (not smoking?) has to be lack of air or lack of fuel.

Lack of air could be from:
- blocked air filter (or other obstruction)
- turbo not working properly (unlikely)
- big air leak between turbo and inlet manifold (split or loose pipe)
- obstructed exhaust.

Lack of fuel:
- the MAF data is wrong (or missing) so the ECU software controls the injected fuel level either to match the MAF data or to a safe (limp mode) level.
- insufficient flow to HP pump
- lack of fuel pressure at the injectors and/or
- excessive leakage from the injectors (but then I'd expect a dirty exhaust as the injectors wouldn't be injecting a fine even mist.

Since the only relevant fault code is for the MAF (Mass Air Flow) sensor then that's the first thing to do (and the one lying around the workshop is probably a dud - why else is it kicking around?

boristhespie · Post by **boristhespie** » 30 Nov 2010, 15:18

Okay the guys said they had tried the new MAF and the code still came up and the power remained low.

His ascertain is that it would cost a lot to try and locate a problem which he says could be simple eg could be a vacumn leak (All without my prompting).

He added that as there needed work to replace door handle, weld a leak in exhaust and new brake pads and possible corrosion would mean I would be better off trying to get money for the engine which would be worth something.

The guy HAS done a lot and he had the car and charged bugger all really for the 5 weeks of looking (he did it when he had spare time to avoid high costs).

Don;t like scrapping cars on basis of don't knows, however and and keen just to get to the bottom of it. HOw can one check vacumns etc on your own without any real kit?

RE the LIMP MODE: The car drives okay. IT has a lack of power when you put ffot down and when going up prolongued but shallow hill the speed will just fall further and further. It is not like the car cannot do 70, it can so I assume that this rules out LIMP MODE????

PS. Re reading, you say - obstructed exhaust. can cause problem. He says there is an exhaust leak? Could this be a factor (jncidentally the exhaust is only a couple of years old as I had the entire unit replaced a la dealer £400)

Citroenmad · Post by **Citroenmad** » 30 Nov 2010, 15:41

Some garage have smoke testers for testing vacuum pipes, they pump smoke through, if it comes out of somewhere it shouldn't, then there is a leak.

To test it on your own is more difficult, listen for air noises and check pipes visually. You could take some pipework off and inspect it.

You mention corrosion, is that bodywork, chassis or mechanical? C5s dont usually corrode.

This fault is permanent? Doesnt come and go? Will the car rev through the rev range? Did the fault start progressively or suddenly?

There seems to be a couple of people on here with 2.0HDis running slowly, i wonder if one found the cause it might be similar for the rest.

Often when fitting a MAF it can take the car a while to get used to the new one and its new perammeters.

It seems an awful shame to scrap a C5, the oldest is only 9 years old! But there are some being broken for parts. Brake pads are cheap to buy and fit (free if your doing them), a weld in an exhausts can costs as little as £20 if you know someone who will do it and a door handle from a breakers. All minor points, its just your main problem with its running.

Id hate to give up on a car, I couldn't scrap a car, especially if it has given me may miles and reliable service. Though i do get attatched to my cars, and dont really like selling them either

Unless you get a new car, there is usually always something which needs fixing on any used car. So your C5s replacement could well need things doing too. Often its not to do with what the car is worth, but how much you want to keep it going for.

If we give up on cars which are worth little, a fault or even day to day wear and tear items could be enough to see them off. A set of tyres for an Xm could be £400+ for Michelins, that could buy you an Xm!

I hope you go get it sorted out, good luck with it.

Citroenmad · Post by **Citroenmad** » 30 Nov 2010, 15:45

boristhespie wrote:
PS. Re reading, you say - obstructed exhaust. can cause problem. He says there is an exhaust leak? Could this be a factor (jncidentally the exhaust is only a couple of years old as I had the entire unit replaced a la dealer £400)

Did the problem start after the exhaust leak appeared?

Two years is not long for an exhaust to last at all. Mine is still on its original full system and there is no sign of it blowing any time soon. As is our C5 SX, which is a 52 reg with 127K.

An exhaust leak, depending on its place and size, can effect the cars running.

Was it you who had two C5s? I might be thinking of someone else, but if you do you could always try swapping bits over ...

boristhespie · Post by **boristhespie** » 30 Nov 2010, 16:21

YEah problem started years agao. Kept running . Before engine management light was not on, then it was on off now it is on permanently.

So I guess leak is not the problem.

The car has also been serviced since then so new air filter etc.

Citroenmad · Post by **Citroenmad** » 30 Nov 2010, 16:45

You see, a progressive problem would lead me away from thinking its anything to do with the ECU or BSI. I would think they would either work or not, not get progressively worse.

A sensor could do that though, or a failing with the EGR or Turbo.

A hole in air pipework could get worse and have that effect, but id expect that to happen sooner than over a few years.

JamesQB · Post by **JamesQB** » 30 Nov 2010, 20:45

When the turbo seized in our evil C3 HDi, the Lexia showed a fault code for the MAF. I suppose it didn't know the turbo was seized and just saw airflow was not what it should be, and pointed to the MAF for not reading it right. It did also flag a turbo issue though, so must be another sensor that detects pressure from turbo.

Are you able to get to the turbo, pop off the intake pipe and spin the compressor wheel? Could the intercooler be patrially clogged with crud or oil?

dieselnutjob · Post by **dieselnutjob** » 01 Dec 2010, 16:43

Personally there is no way that I could fix this without getting live data up on a diagnostic tool and seeing what the turbo boost is whilst the car is driven.
You should see 1 bar of boost.
Also if you have access to a good car you can compare the air flow figures with yours in live data.
You could try swapping the boost control solenoid with the EGR control solenoid as they are identical (at least on my 806 they are)
Normally the 110bhp turbos are extremely reliable as they are a simple wastegate turbo, but the wastegate is electronically controlled via a solenoid that controls a vacuum. Normally problems are related to
vacuum leaks
worn solenoid
boost leaking (such as from the intercooler or a hose to/from the intercooler)

If the EGR valve is stuck open you can get low power as well but I think normally clouds of smoke too.
One quick thing you can do to disable/eliminate EGR is to find where the EGR hose screws onto the inlect manifold and slip a piece of plate in there and do the screws up so that it's blocked. No more EGR.

HDI · Post by **HDI** » 01 Dec 2010, 17:05

Turbo pressure is the first thing I asked about the first reply to this thread !

dieselnutjob · Post by **dieselnutjob** » 01 Dec 2010, 17:15

he said that the mechanic has a bosch kts
with that tool you can get a lot of live data like
boost pressure
fuel rail pressure
air flow

at full power at 2000rpm you should see 1350 bar rail pressure and 1 bar of boost
I'm afraid I have no idea what a normal airflow figure it

It's a two man job because one has to drive and the other hold the kts and read the numbers

HDI · Post by **HDI** » 01 Dec 2010, 17:34

Live data is very well, as long as the sensors are ok.
Personally I always use a stand alone boost gauge so the sensor is not being relied upon for the reading.
Anyway, I was agreeing with you that a problem like this should be approached from first principals.

dieselnutjob · Post by **dieselnutjob** » 01 Dec 2010, 19:36

I agree that your method is probably more complete, but personally I find plumbing in a boost guage a paid in the @@se compared with plugging in a diagnostic machine

if the boost sensor isn't seeing any boost or is faulty the engine would go into limp home mode to protect the turbo anyway

boristhespie · Post by **boristhespie** » 01 Dec 2010, 19:55

If the EGR valve is stuck open you can get low power as well but I think normally clouds of smoke too.
One quick thing you can do to disable/eliminate EGR is to find where the EGR hose screws onto the inlect manifold and slip a piece of plate in there and do the screws up so that it's blocked. No more EGR.

HE blocked off the EGR to see if this would reduce error. It did not.

The guy charged 52 quid for 5 weeks worth of checking so am NOT unhappy at all. Just would love it sorted.

If I bought a Cheap Lexia off Ebay for a hundred odd quid and plugged it in would it be helpful and worth ?