C4P engine turns but won't fire after Cat and O2 sensor change - help please?

[Arpleyfields]

The saga of Mater the cake wagon
'Mater' is our 2009 C4 Picasso 1.6VTR+, inherited from my father in law after he died. Many Cakes arrived with Grandma in it, hence the moniker; we have had it for eight years now.This is my first post here, reading the various threads has been highly entertaining - thank you all for your time.

Last year, it had a new clutch fitted in September and was submitted for MOT in late November, which it failed with welding work, oil leak and emissions that were too high. As Christmas was on top of us and we had another car, it was laid aside, but not before an attempt to have a pair of new tyres fitted; that was defeated because the lock nuts had been chewed up by air tools, and had to be removed by drilling out and using a removal tool.
As I had to undergo cancer treatment for a month, further work was put off, but I duly sorted the oil leak from the rocker cover and oil pressure switches and cleaned the engine up (a 1.6vti Prince engine) followed by reprising an old welding skill and patching the cills.
After a discussion with my garage (satisfied customers for the last 27 years), I decided to change the Catalytic converter and the O2 sensors. These were duly sourced and fitted, and the engine was run up to check for gas leakage around the manifold and flexible joint. After a few minutes it stalled and would not restart, turning over but not firing.

First thought was that it needed fuel, as it had been showing a low fuel message for a while. That was added - no joy. The fuel rail was bled - the pump checked - pressure fine. The spark plugs were checked and changed (I had intended to do this anyway); the earth to the coils checked (OK); one was withdrawn and checked for a spark - none present.

My son and his friends lent an Autel computer to read the fault codes. One (P0011) suggested that the VTi system had malfunctioned, so the solenoids were withdrawn, cleaned and tested, and the alignment of crankshaft and camshafts checked with a clamp kit - all were OK. While we were at it, the timing chain and guides were examined - no cogs jumped, very little slack, guides intact - at the moment..
The crank and camshaft sensors were checked over, as were the wiring looms to them; MFI sensor checked, too.. Seemed OK.
Back to the Autel..
BSI fault codes -
F564 - service parameter configured incorrectly
F5FF - unexpected reinitialization fault coming from BSI.
Clearing faults only removed the F5FF code. Interrogating the live mode of the BSI produced the following; 'Faults detected during transmission of unlocking code?' Value, 'Awaiting response' then 'No Problem detected' followed immediately by 'invalid value'. At random intervals it would flick back momentarily to 'No Problem detected' and then 'Value invalid'. Checking the live mode of the ECU showed a similar Locked / momentarily Unlocked behaviour. In locked mode, it won't clear any faults.
ECU fault codes - some seem to have been provoked by the work on the Cat and sensors. Clearing and rescanning would point to where to focus, but of course, it wont if it is locked. For the record, here are the codes;
P0171 - intermittent - Fault in richness regulation - mix too lean
P0053 - permanent - Upstream Oxygen sensor resistance too high ...(voltage shown as 148931 mV !)
P2231 - permanent - Fault - Upstream Oxygen sensor signal - consistency
P0202 - permanent - Injector No2 control fault - open circuit ...(connection secure)
P0343 - intermittent - Intake cylinder reference sensor signal - consistency
P0368 - Intermittent - Exhaust cylinder reference sensor signal - consistency
P0011 - permanent - Intake camshaft dephasing fault - consistency
P0132 - Intermittent -Fault Upstream Oxygen sensor signal - short circuit to positive
P2177 - intermittent -Fault in richness regulation - mixture too lean
Other live data..
Downstream sensor value, weak
Downstream Oxygen sensor voltage - 465mV
Upstream Oxygen sensor voltage - 148931mV
Upstream sensor regulation status - open loop
Regulation of downstream sensor - open loop
Engine status - Invalid
Oil pressure switch status - pressurised detected
Engine operation - excessive engine speed
ECU wakeup status - Main triggering
ECU and Immobiliser programming matched
Power Relay control status - not controlled.

Wiring examination
Apparently, there have been issues with corrosion and failures in the fuse box and covers around the ECU; nothing disturbed and all seemed in good order, just a little dusty.

Replacement part learning;
I understood that certain new parts including O2 sensors would need to be introduced to the ECU and a learning of their parameters carried out - I assumed that would happen automatically. I have since found that there is a function in the Autel to do this, and I carried it out for the O2 sensors and Catalytic converter, as far as I could - but could not complete the process because the engine will not run. It underwent a similar process, I suspect, when it had the new clutch - it would go into default mode with the radiator fans running constantly until either the battery went dead or I disconnected it. That time connecting the Autel cleared the faults and it behaved.

Other relevant stuff
The battery has been kept topped up with regular charging - anything below 12.45 volts provokes Economy mode. Several BSI resets have been carried out to no avail. The key battery voltage is 2.93v, surely enough to ensure the immobiliser gets its signal. I have watched more You-Tube videos than soft mick (he is actually very clever - it's just a front) and perused several forums including this one in my quest to get Mater to run..

Now what?
When fault-finding, one thing holds true; what were you doing last when the fault occurred? I lack the underpinning knowledge to understand the start up logic and sequence, and have no wiring diagrams, but my guess is that the ECU has locked itself up after attempting to compensate for the change - and what looks like a duff new upstream O2 sensor. I have changed it for the old one, but until I can clear the faults and tried another start, will never know if that is the case. Certainly, if it was running up to the fitting of the new bits, it is unlikely that there has been sudden failure of other sensors. I suspect that the logical thing to do is to send off the ECU or / and BSI for decoding, but I run the risk of the same thing happening again. I have had a recommendation to obtain a second-hand full lock set ECU, BSI, Locks, Keys matched), but there is none available at the moment and would need full recoding and programming; is the car worth it given its age, notwithstanding the money spent on it?.

ANY HELP very gratefully received, many thanks.

PS..now the Renault has failed with a blown clutch operation cylinder.. I am having to borrow my son's Mercedes..

[mickthemaverick]

That is quite a tale, Is it feasible that the old cat and downstream sensor could be put back in?

[xantia_v6]

The work that you have (intentionally) done should not cause the engine to not start. I would be looking for the cause of lost spark, which should be simpler to diagnose. You should check that. a diagnostic tool detects sensible engine RPM when cranking, to ensure that the crank sensor and wiring are OK.

[Paul-R]

I suspect that when the cat was being changed that something in the engine bay was disconnected or just disturbed and this caused a new problem. I would go back to everything that was disconnected or moved in the engine bay looking for a faulty connection.

[PaulC5]

How many miles has it done ? The vti engines are known for timing chain wear, our 1.4 C3 needed one at about 50k miles and this might be suggesting the P0011 fault but you could have a read of this viewtopic.php?t=75944

What made you change the cat and O2 sensors - did you do a diagnostic first to see if they needed changing or was it just a guess ?

Have you tried easy start to see if it runs a bit which might point to a fuel problem and not ignition ? I note though you do not seem to have a spark on a plug.

A failed crank shaft sensor or its wiring/connection would prevent it running. These do not cost much so can be worth replacing.

The battery in the remote is just for the door locking so if its voltage is low (as it appears to be since not 3 volts) it would just need to be held nearer the car to unlock the doors. There should be a chip in the remote that is for the immobiliser - this can be checked by leaving the key in the ignition and opening the driver's door and there should be a warning - if not then the chip might not be working.

[Arpleyfields]

Hi Gents,
Firstly, thank you for reading and taking the trouble to reply, I'm very grateful.
Some comments on your questions;

Mileage; 93K, and yearly usage down to between 4 and 5K, it should have another couple of years left in it; it's not worn out by a long chalk, unlike our Renault which sits on decision at 153K with an original cambelt and broken clutch cylinder and an MOT about to run out.

The cranking speed was shown as about 200rpm but was also checked while the battery was jumpered to another running vehicle to maintain voltage. Unfortunately, it didn't help.

The possibility of disturbed wiring certainly crossed my mind and checking continuity would be my next step, but I need a wiring diagram so will look into that.

The Crankshaft sensor is not easy to access but after removing a little plastic cover and removing the connection, it is accessible - but I lacked a T-25 bit that was in good enough condition to break the seal on the securing screw. Now rectified and another attempt will be made - perhaps changing the crankshaft sensors would also help but the ECU needs to 'learn' their characteristics, too. Really, one thing at a time should be changed and then tried. There was a little oil on the wiring, but below the connector and that was dry and uncontaminated.

The cat and O2 sensors were changed as it had failed the MOT emissions test with levels too high at both idle and hot under load. Talking to the owner of the garage I use about possible fixes (he had a C4 himself at some point and said that he regarded them highly) he said that doing so would be the best fix. I didn't want to submit it again only for it to fail on the same thing. On removing the plugs and exhaust manifold, it is clear that the engine suffers from carbon fouling, as it has spent a lot of its life just pottering about town.
Once I locate the old downstream sensor, that will be reinstated...

The recommendation for the locking set came from another garage recommended by a friend who always used them for his own C4 maintenance.

Another battery for the key will be sourced and tried. Both keys underwent a recoding procedure using the Autel and will remotely lock and unlock the car.

Got to rush off now, but once again, thanks for your input and I will keep you posted.

[PaulC5]

A look at live data from the O2 sensors on a code reader before replacing the cat would have told you if it needed replacing and if it did it is likely a fault code would have come up and the engine light would have come on. When checking these sensors I think it might have to be done once they are hot so they are then in closed loop.

Was the replacement O2 sensor a cheap one or from a dealer, just asking in case the replacement is not good enough.

[Arpleyfields]

PaulC5 - many thanks for the further reply
As a an old stager brought up with Dad's Standard 10 and a succession of Cortinas and Capris (They were mine!), connecting a computer to diagnose first is a hard learned lesson, especially after consigning car maintenance to garages while I brought up a family, only now in early retirement have I returned to working under the bonnet and the car. So, yes, I should have borrowed the Autel and thought about doing a scan before lifting a spanner, but, here we are. I think there was an engine light lit and messages about exhaust emission faults popping up, but it is now a year ago.

The O2 sensors were sourced from good old e-bay, and yes, quite possibly not up to the job, although they were new and certainly not used. That is why I will put the old ones back - they will have to come off again anyway to enable the heat shielding to be replaced around the cat.

I think the key to this is that the ECU remains locked and will have to be sent to a specialist. (unless a high-end scanner can do the business - but I only have access to an Autel) More research and phone calls, then.

Once again, thank you all for your interest..BTW, we also had Peugeots ( A 205 and a 306D). No electronics and lovely cars.

[xantia_v6]

I haven't quite understood why you think that the ECU is locked. That should only happen if one of the ECUs has been changed, or if the transponder in the ignition key is wrong or not detected.

Is the immobilizer key symbol showing on the dashboard?

[Arpleyfields]

Hi Xantia_v6..
The Autel Maxiscanner has shown the ECU as locked with momentary unlocking before reverting to locked. If I can work out how, I will post an image.
There is no immobiliser key symbol on the dashboard.
A bit of research on a reputable company's website suggests that the ECU is failing or has been corrupted - it mentions failure symptoms for this particular type of ECU (an MV14.4, more usually fitted to Peugeots with the same engine) that Mater has suffered in the past including radiator fans running constantly. I have contacted them for an opinion and a quote.

Many thanks again.