Technical Power issue-no straight answer from garage!

[Cochyn1]

Hi , posting as really fed up at the moment! Our 2011 nexxo t660 amber engine light came on about 7 weeks ago now and had no power. Okish on the flat but any hills I needed to change down to 2nd! Took it to our local garage who did diagnostics and said it pointed to EGR issue. I had a warranty provided when i bought it so thought great go ahead. They checked the EGR and it was clean so wasn’t causing the issue apparently. The warranty wouldn’t cover this as wasn’t faulty. £250 down. The garage then said it would be best if I took it to a Fiat dealer who have a specific diagnostic machine. Took it to one 45 minutes away at £110 an hour . Couple of weeks later said they needed to take manifold off and they found it caked with carbon-see pics. Said they cleaned it and took it gor a test drive and sorted -£700. Also told me as van was 2011 the Fiat diagnostic machine didn’t work on ours so used snap on which I think my original garage use but only charge half the price per hour!
Picked it up Thursday after work as going away the weekend and no change-still no power on hills etc. had to take it home as going away the weekend
Subsequently took it back after the weekend and made the error of telling them no rush as going on a 10day cruise! Came back-hadn’t looked at it. Eventually did yesterday and now they say they think it’s a faulty EGR valve! Fiat one £800 non fiat £400.
Phoned warranty company again -told to email fella who i had dealt with previously. Had email back saying they had found one on europarts for
£24.99! Phoned garage and they said wasn’t a full egr valve but willing to try it. I don’t have much idea with vehicles so any advice is greatly appreciated. Think I found a full egr valve for our van for £280 but not certain? https://www.onlinecarparts.co.uk/partstec-18608180.html. I’m thinking of going for the £280 but not sure?
Any other owners had similar issues and could shed some light please? Many thanks. Daf

 

[Anthony489]

Hi

The warning light accompanied by the loss of power is likely to be the ECU deliberately running the engine in "restricted power" or "limp home" mode to protect the engine from damage. In this situation there will be one or more stored fault codes. Ask the garage what the codes were and post them here if you can.

Although some oil/carbon deposit in the inlet manifold is normal, yours looks to have rather a heavy buildup. This could be caused by an Exhaust Gas Recirculation (EGR) valve that is clogged, and therefore still partly open when it should be shut. EGR is supposed to occur only during light cruising, to reduce nitrogen oxide emissions. If you have EGR happening at other times, it will tend to reduce the percentage of oxygen fed to the engine which will increase the amount of soot it produces in the exhaust especially when the power demand is high. This in turn ends up recirculated to the inlet manifold, where it mixes with oil fumes from the crankcase breather and makes this black sooty and sometimes sticky deposit.

Your picture shows the EGR valve (the black blob on the left hand end) plus its associated cooler (the long silver bit) as a complete assembly. It's probably best to replace the whole lot rather than just the EGR valve, as the cooler can get blocked by carbon deposit. The idea of the cooler is to surround the EGR pipe with a jacket fed from the coolant circuit, as the exhaust gases would otherwise be too hot to mix with the intake air.

Once this is changed, I recommend that the engine is checked to make sure it is no longer producing excess carbon (soot). Note that the EGR is fed from upstream of the catalyst and DPF, so may be getting sooty exhaust gas even if what you see from the tailpipe has been cleaned up. Apart from EGR faults, excessively sooty exhaust may be caused by over-fuelling or a restriction in the ("fresh") intake air.

 

[Cochyn1]

Hi

The warning light accompanied by the loss of power is likely to be the ECU deliberately running the engine in "restricted power" or "limp home" mode to protect the engine from damage. In this situation there will be one or more stored fault codes. Ask the garage what the codes were and post them here if you can.

Although some oil/carbon deposit in the inlet manifold is normal, yours looks to have rather a heavy buildup. This could be caused by an Exhaust Gas Recirculation (EGR) valve that is clogged, and therefore still partly open when it should be shut. EGR is supposed to occur only during light cruising, to reduce nitrogen oxide emissions. If you have EGR happening at other times, it will tend to reduce the percentage of oxygen fed to the engine which will increase the amount of soot it produces in the exhaust especially when the power demand is high. This in turn ends up recirculated to the inlet manifold, where it mixes with oil fumes from the crankcase breather and makes this black sooty and sometimes sticky deposit.

Your picture shows the EGR valve (the black blob on the left hand end) plus its associated cooler (the long silver bit) as a complete assembly. It's probably best to replace the whole lot rather than just the EGR valve, as the cooler can get blocked by carbon deposit. The idea of the cooler is to surround the EGR pipe with a jacket fed from the coolant circuit, as the exhaust gases would otherwise be too hot to mix with the intake air.

Once this is changed, I recommend that the engine is checked to make sure it is no longer producing excess carbon (soot). Note that the EGR is fed from upstream of the catalyst and DPF, so may be getting sooty exhaust gas even if what you see from the tailpipe has been cleaned up. Apart from EGR faults, excessively sooty exhaust may be caused by over-fuelling or a restriction in the ("fresh") intake air.

Thanks for the detailed response. The first garage tool the egr out and said it was clear