C5 power issue yet again or still

[skp]

You might also want to lookout the throttle position sensor... i am having a few similar dramas, tho' nowhere near as bad.
One computer interrogation stated that the throttle sensor was earthing out. This results in hijacking the throttle and no power for the first 50 metres or so... then releases control. Scary, when you are crossing traffic - you don't know if you are going to have power or just idle across the oncoming traffic.! Such fun.
skp

 

[shanadoo]

You might also want to lookout the throttle position sensor... i am having a few similar dramas, tho' nowhere near as bad.
One computer interrogation stated that the throttle sensor was earthing out. This results in hijacking the throttle and no power for the first 50 metres or so... then releases control. Scary, when you are crossing traffic - you don't know if you are going to have power or just idle across the oncoming traffic.! Such fun.
skp

Oh yes such fun, 3 months waiting for a new door from France as a result of some fool who thought I was going to move out of his way. Don't know why insurance didn't fit S/H one.


Anyway folks today is the day. Gonna remove the exhaust and cut the front section open for a look see. Don't know how I'm going to weld it back up, only got a stick welder. But cross that bridge later. Cheers.

 

[dcc236]

What engine is that? Doesn't look anything like the one in my C5, 2008 2L 16v Hdi SX.
Are you in some sort of limp home mode? Does Lexia tell you nothing or give you any ideas?
You are welcome to borrow mine if you do not have it, mine's still in its box, haven't installed it yet.

 

[dcc236]

Not sure it's the same issue but my previous c5 (2003 2l hid) had the same symptoms after I sold it to a mate and the fault was in the MAF sensor. Replaced it with one from a wreck and all was OK. It was on the forum some time ago.

To check if it is the MAF, unplug it. If it runs better, it is a faulty MAF. The ECU has default parameters it uses when there is no signal from the MAF, at least it does in VW spec cars.

 

[David S]

The exhaust has a catalytic converter just after the flexible joint, but it has no particle filter. It's possible it could be blocked.

Have you gone over the vacuum system and tested for leakage? These cars are now at least 11 years old and old rubber can let go, especially where vacuum is involved. Attached are relevant pages for checking some parts of the vacuum, fuel and EGR systems. It doesn't show the piping to the throttle butterfly, but it will be there too. The vacuum pump/tester is available for about $30 and is an invaluable tool for testing this sort of stuff.

 

[shanadoo]

Thanks David
I've vac tested this thing under many different conditions. The system will hold 25ins with motor off for a while so nothing of consequence there. But if necessary I can isolate each section using some non return valves I have, if a leak is suspected. Although even with an open vac line the system will still register 25/28ins at 1000 rpm.
Tested tank pump pressure before and after filter along with fuel quantity.
I replaced turbo solenoid due to Lexia reporting usual electrical short or open circuit as it does and, it was getting very hot.
Have run this car down the highway with Turbo gauge, vacuum gauge, primary fuel pressure gauge and volt meter all connected and in the cab alongside the Lexia reading engine parameters. Of course engine was running temp so I found nothing.

The trouble started with only loosing power for the first few minutes at cold start, lexia came up with codes P0110 inlet air temp and P0101 permanent fault, flow meter too low coherence. Can't seem to find anything wrong there and according to other sites I checked these readings are common, like the radio aerial cable and instrument fault.
Couple of days ago I removed the management ECU motherboard and under 15+ magnification checked for any dry joints or signs of overheating like deformed capacitors, chip discoloration, popped transistors etc anything would do. I'm desperate.
To day I removed exhaust and cut open the cat looking for possible blockage, and as usual I found nothing untoward.

Dare I say Cheers.
Tony.

 

[JohnW]

Phew. No one could accuse you of jumping to premature conclusions. Once fixed, or at least a problem found and addressed (or burned after checking the insurance carefully ), my worry would be how to trust it for the next long trip, i.e. out of the suburbs.

Good luck.

 

[shanadoo]

John W
Exactly.

 

[David S]

Increasing age is always a problem, so preventative maintenance becomes important. The good news is these engines can keep going for a very long time. A family member has one that's now at about 400K and still going OK. However, the fuel pump failed recently and now a low turbo boost fault making it belch black smoke and surge. Three problems now found, being a perished vacuum hose to the throttle butterfly, a leak in the throttle butterfly diaphragm and also a split in the bottom turbo to heat exchanger pipe. Those problems fixed and it's back to normal. The turbo boost pressure sensor is at the top of the cooler, so a split in the pipe before that made the measured boost seem low. In fact the turbo is fine an the boost loss due to the split goes a long way to explaining the black smoke and power loss. The leaky vacuum hose was probably not that important, but the leak at the throttle valve meant it would not have been closing as much as the car expected and probably goes a good way to explain the surging experienced. Seems OK now, but it's possible the catalytic converter and exhaust system may be sooty until it is given a decent drive.

The quoted test values for each component would tell you whether the component is suspect or maybe the electrovalve that controls each part. Looking at the vacuum test values, it becomes obvious that the EGR valve is closed off at high rpm and the throttle butterfly should be fully open, but the reverse is true at low rpm. I'm not entirely sure I can work out why disabling the EGR valve should magically restore boost (per dogboy's thread from a year or so back), unless disabling it took a leaky diaphragm out of the vacuum circuit or it forces more air through the throttle butterfly with a consequent response by the AFM/ECU to pile in a nit more fuel. Regardless, disabling the EGR valve vacuum connection had no useful effect on the 400K car with a bad throttle butterfly and split turbo pipe.

I don't know if any of this help you Tony, but I would say a good vacuum measurement at the pump would not by itself be evidence of no faults in the actuator diaphragms, which are themselves each downstream of an regulating electrovalve.

 

[shanadoo]

Thanks David and understood but this is a RHZ==DW10ATED so no throttle butterfly.

I always use tee pieces when testing a vac circuit so the solenoid, diaphragm or sensor can remain in situ and operating. I use the white nylon ones from fish tank air supply, cheap and plentiful and some are available as a small tap to control the vacuum to individual components if you wish. Easy as to test any component
As you know, the vac system on these engines is pretty basic. Vacuum pump has to supply only three units, Brake booster, turbo and EGR systems. My EGR valve has been blocked off for a long time using a plug in the line to fool the computer so that's Ok. Brake booster is holding vac ok and the turbo system is working correctly according to Lexia live parameter readouts. I have tested the solenoid supply and control voltages and that all seems normal unless, I'm missing something obvious. Which a lot of folk would agree with.

So nuts it's driving me.
Looking for a Lotto win so I can tell the wreckers to come and get it. Which is a damn shame, it's really a nice drive when it's behaving.
Tony.

 

[GreenBlood]

Frogs to the rescue. . .

Thanks George,
Sort of done that, I can't even get my hand to the suspect hose, looks like you would have to drop the subframe - I think I'm over it. . .

Cheers
Chris

We're back on the road thanks to much help from members here but particularly one very hands on member (who may wish to remain anonymous). The metal pipe that connects the thermostat housing to water outlet on the lower block via a few rubber hoses had developed a pinhole. Replaced with a new hose and seal requiring the sub-frame to be dropped for access. :crazy:

I'll get a pic of the offending pipe, apparently very corroded on the inside despite always running coolant. The part was off the shelf in Sydney so I guess a not uncommon problem.

I'll still keep a box of matches in the glovebox, but for now our C5 has a reprieve :burnboun:

Tony, hopefully by now you have my MIG at your disposal if you need a hand sing out :wink2:

Cheers
Chris

 

[JohnW]

So what is the offending pipe made of? Glad you're fixed, but metal pipes corroding despite coolant isn't too flash.

Cheers

John

 

[GreenBlood]

So what is the offending pipe made of? Glad you're fixed, but metal pipes corroding despite coolant isn't too flash.

Cheers

John

I'll let you know, but there was mention of dissimilar metals possibly contributing. 14 years is not a bad innings and the fix wasn't horribly expensive (though I know the job was done at mates rates).

The motor is common to several Citroen and Peugeot models so something to be aware of. Not a side of the road fix item. . .

Cheers
Chris

 

[cluso]

C5 2.2 diesel? You've got what I had. Continually went into limp mode after a while on road at maybe 90-100kph. No throttle response, or virtually none, having to use semi manual and hold in gear to get things happening. Sorted by having turbo electro valve replaced and actuator diaphragm. You won't recognise it once done. Parts $192, 2 hours labour.
Bon chance!

 

[shanadoo]

C5 2.2 diesel? You've got what I had. Continually went into limp mode after a while on road at maybe 90-100kph. No throttle response, or virtually none, having to use semi manual and hold in gear to get things happening. Sorted by having turbo electro valve replaced and actuator diaphragm. You won't recognise it once done. Parts $192, 2 hours labour.
Bon chance!

Sounds like I'm not the only one having fun driving a C5 when and if it's in the mood. The factory should supply a book of matches as part of the handbook from new, call it emergency sanity kit, to be used as soon as the wallet has been emptied.

Anyway cluso mine is a 2ltr single cam diesel, I've replaced the turbo solenoid and the actuator is working fine. Plenty of boost. But nice try. Thanks.

And I do so hate having what somebody else has got, it takes away my individuality and raises the dreaded fear of one becoming just another 'one of the mob'.

Cheers Tony.

 

[shanadoo]

I offer 2 cents worth of advice to anyone interested, Diesels require a heavier concentration of corrosion inhibitor, usually about one point up on the acidic side of the PH neutral mark. Premixed coolant, unless it's concentrate, is a waste of money in diesels. So always keep a check on the PH value of your cooling system with a litmus test at service time. Litmus paper can be bought at the chemist along with your next condom order.

Cheers Tony.

 

[shanadoo]

Got the mig thanks Chris. All in Hand now, weld complete, just need to refit the damn exhaust. Cripes I wish I had a hoist.

Cheers.

PS and what a wasted exercise this has been.

 

[GreenBlood]

Got the mig thanks Chris. All in Hand now, weld complete, just need to refit the damn exhaust. Cripes I wish I had a hoist.

Cheers.

I have a set of ramps, would that help?

Cheers
Chris

 

[David S]

A pair of jousting sticks might lift it ...


The car I was referring to has the RHZ engine. It has the black plastic vacuum operated throttle body bolted to the elbow of the inlet manifold. The turbo air pipe from the top of the heat exchanger slips over it. Here's the parts diagram and it's item 12.



EDIT: Seems the throttle butterfly valve was deleted from RP 9610, which means manufacture from March 2003. The elbow changed from #5 to #14.

 

[David S]

C5 2.2 diesel? You've got what I had. Continually went into limp mode after a while on road at maybe 90-100kph. No throttle response, or virtually none, having to use semi manual and hold in gear to get things happening. Sorted by having turbo electro valve replaced and actuator diaphragm. You won't recognise it once done. Parts $192, 2 hours labour.
Bon chance!

4 speed 2.2 HDi I assume. You mean that vacuum actuator with the long rod at the end of the head? It's part of the EGR system and the long rod snaps and then it runs like a dog. You also want to check your fuel filter is not leaking fuel into the engine harness via the plug on top. Remove the seal is it's still there. It's potentially very expensive to fix if it's affected all of the connected items. If commonly shows up as a dash Christmas tree, odd faults and maybe no start once the engine slave / fuse box is damaged. Also, you want to bypass the water side of the heat exchanger so it can't leak coolant into the engine intake and kill the engine via bent rods!

6 speed 2.2HDI. Different car and issues, but the mixer motor down the front can drown in oil residue and sometimes drops a tooth on the cog. You don't get a specific fault pointing to it.