Technical 500 Diesel smokes with clanging

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Technical 500 Diesel smokes with clanging

gtv6capri

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Hi all, I have an 09 Fiat 500 turbo diesel manual tans. I bought it with issues, believed to be blocked DPF. The previous owner had replaced the fuel pump, the glow plugs and the injectors chasing a problem, and bailed out when it still gave trouble.

I removed the DPF and flushed it until high pressure water came out clean. I also removed the turbo and checked it-no movement in the shaft and no oil stains, and hardly any oil in the intercooler. I reassembled the car and ran it. perfect idle and no issues until it got to operating temperature and put under load.

A knocking (almost like a failed big end) noise came from the engine bay, maybe 6 or so knocks / clanks, then white smoke came pouring out of the tail pipe. No smoke in the engine bay, just out the pipe. I drove it back home smoking like James Bonds smoke screen car- no knocking just smoke.

I left it for a day, and tried again. Car drove perfectly for about a mile, no smoke, then some more knocking and smoke again, also felt like the engine was down on power - feeling like a miss.

Day 3 I sprayed a can of EGR cleaner into the air inge and went off for a drive. Went 10 miles at 3000-3500 RPM and all good. got a few little spurts of rattle and puff of smoke when it made noise but backing off stopped the noise and smoke. Loading up the car then made the noise come on faster, and the smoke quite profuse, I really had to limp it home to avoid the rattle and smoke.

Any ideas as to what this knocking / clanging is? When it happens then the smoke comes, I get the feeling its a solonoid or valve that opens and shuts and gets stuck causing the smoke. Could this be EGR? All help greatly appreciated
 
Yes, a compression test is a good idea. Do it when the engine is giving problems.

Compression testing on a diesel isn't so easy of course. Dunno if you can the tester connected to the glow pug holes, but other than that, you'll need to remove the injectors.

Good luck,
Mick.
 
OK so the smoke is actually light grey not white. noise sounding like an engine bearing but it is not there at idle. I have a scan tool coming so I can note the log then clear the fault code list, then retest.
 
When my 08 mjet does a dpf regen there's a fair amount of white/grey smoke out the back. The engine note also changes slightly. I can only describe it as a slightly more metallic ring sound. If the car has recently done a regen and i stop and turn the car off sometimes​ there's a rattle from underneath.

Maybe your car is constantly trying to force a dpf regen?
 
How does the cooling liquid looks just after the issue occurred (bubbles or loss of liquid)? Grey smoke might be cooling liquid / head gasket issue.
 
I had put a bottle of DPF cleaner in the tank, it is still in there. The battery has now decided to quit so Ill have to get another one and await my scan tool arrival to investigate further
 
OK so I got back into the Fiat 500 today, I took a look at the glow plugs, #1 plug had a bulging tip, the others were perfect. I bought a new plug and a glow plug relay and fitted both. I then went to start it and got a lot of cranking and tries to fire, but no joy.

Todays job is to have a look at the EGR system. VERY hard to get to. I removed the throttle body-or whatever it is where a petrol engine throttle body would be-no carbon build up just a bit of oily diesel.

I then removed the cover from the EGR valve which appears to be a solonoid to open and close the EGR valve. This was in very clean condition. The base of the vale is perfectly clean and operates just fine. I cannot see the other side of the valve of course, but I know it is operating.

I will next remove #1 injector and get it tested, I had discounted this as the previous owner said they had fitted new pump and injectors, but who knows it may have just been they were cleaned.

Ill get this damn thing running yet:bang:
 
Valves are operated via hydraulic tappets, if one of these is failing it might cause knocking.
I understand that the rockers are designed to fail if a chain breaks. As each cylinder has four valves, one of each failing to open might not be apparent until higher power is required.
As said above a compression test is a good idea.
Then pop the cam cover off and have a good look at all the valve gear.

Also, if injector no1 is faulty, excess fuel can cause knocking, so hopefully the scan tool will show injector openings. Grey or white smoke is unburnt fuel, usually not vapourised properly. This means either low compression, cool cylinder, poor injection causing droplets instead of mist, or too much fuel for the air available.
 
Good info Bill and Rallycinq, If plug #1 has a bulging end, does this point to a fuel problem? like glow plug heating up but not getting a combustable mix to fire? Also it did fire up yesterday, after a short time smoke started to billow out of the airbox coming from the MAF side
 
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OK so I got back into the Fiat 500 today, I took a look at the glow plugs, #1 plug had a bulging tip, the others were perfect. I bought a new plug and a glow plug relay and fitted both. I then went to start it and got a lot of cranking and tries to fire, but no joy.

Todays job is to have a look at the EGR system. VERY hard to get to. I removed the throttle body-or whatever it is where a petrol engine throttle body would be-no carbon build up just a bit of oily diesel.

I then removed the cover from the EGR valve which appears to be a solonoid to open and close the EGR valve. This was in very clean condition. The base of the vale is perfectly clean and operates just fine. I cannot see the other side of the valve of course, but I know it is operating.

I will next remove #1 injector and get it tested, I had discounted this as the previous owner said they had fitted new pump and injectors, but who knows it may have just been they were cleaned.

Ill get this damn thing running yet:bang:
I know you have been told injectors have been replaced with new ones , but worth checking for yourself. Symptoms could be from an injector sticking open slightly and so leaking into cylinder.
 
OK now I will take out the injectors, looks like I need a special tool to get them out, I will see if I can hire one anywhere.
 
OK now I will take out the injectors, looks like I need a special tool to get them out, I will see if I can hire one anywhere.
Don't mix up the injectors between cylinders , the ECU needs to be programmed with the build tolerances of each injector, that's the coding referred to in other posts.

I don't know if the following is a stupid idea but: can you disconnect one injector at a time and listen for change in noise? If disconnecting one injector significantly reduces the noise more than the others that could point to the problem.
Doing this will set fault codes so be aware of that.
 
Don't mix up the injectors between cylinders , the ECU needs to be programmed with the build tolerances of each injector, that's the coding referred to in other posts.

I don't know if the following is a stupid idea but: can you disconnect one injector at a time and listen for change in noise? If disconnecting one injector significantly reduces the noise more than the others that could point to the problem.
Doing this will set fault codes so be aware of that.

Not a bad idea, but do this with the electrical connection, not by releasing the fuel pressure connection. The fuel pressure is very high and can be dangerous.
 
The knocking and white smoke does sound like an injector issue.

Trouble is, what's wiped it/them out or causing the issue?

Someone has started the replacing parts in a hope to cure it, but that's usually a costly practise with a modern diesel and quite often fails to find the original problem.

Most fueling issues on a modern diesel will show at the injectors but can come from one or more problems further back in the fuel system, wiring or electronics.

Replacing the injectors with new may only be treating the symptoms and without find and sorting out what took it/them down in the first place is only likely to wipe out the new ones as well.

What makes me weary is that someone has replaced the pump and injectors already and if they did this because the pump broke up internally, there could be swarf in the fuel system.
 
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