Technical Annoying Problems with my Punto 1.9 JTD, sometimes starts sometimes doesn't!

[Pigpig]

Punto Problems! I've been browsing this site for the passed few months trying to debunk and figure out what's wrong my old car. Thought I'd finally sign up and see if anyone knew what's up with it as there doesn't seem to be any thing else similar on here!

My poor old car (02 mk2 Punto 1.9 JTD) has been very unreliable for the passed 3 or so months, sometimes it'll start like new, sometimes It'll crank over and sound like it's about to start then no and then it'll run the battery flat trying...

I'll charge the battery up and usually with a small struggle it'll go. Doesn't seem to matter if it's cold/hot on a slope/level ground or even if it's been sat for the weekend. It just goes sometimes and sometimes doesn't. It's done a good 187k now and to be fair it's very rough but I don't really want another car!

So we've done, Oil/filter change very recently, spark plugs all changed and tested battery/glow plug relay - all fine to do with this problem, and additionally changed the clutch/heater fan/pulley etc to do with other problems in it's lifetime.

I've tested the glow plugs when we changed them, old ones were charging up red fine but changed them anyway as we had them out already. There's visually nothing wrong with the CODE on the key as there's no warning lights (maybe it's still the culprit?). after scouring this forum for the passed few weeks, I've heard somewhere that it could be a faulty fuel injector? But

So I'm really not sure why it won't start, starter motor and battery are clearly pretty healthy, they seem to crank the engine over without any horrible noises and the battery manages to do it for a while without trouble?
I'm stuck for things to try myself with limited mechanical knowledge and experience!

Massively appreciate any responses/help given! Thanks! Ben

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[digger58]

"So we've done, Oil/filter change very recently, spark plugs all changed and tested battery/glow plug relay. You say 1.9JTD, "Spark Plugs" ? Did you change fuel filter/ I would suspect either air in system or you have a fueling problem, ie pressure at rail insufficient. A Plug in seems appropriate to see if there are any faults logged.

 

[Pigpig]

Haha Whoops, It's late I meant Glow plugs obviously. Ok cool, I need to bring it to my mate's garage for a plug in, just haven't had the chance. Should be up there this Monday and I'll post results if I can. I've tried starting without the air filter connected but didn't seem to help at all. Thanks for replying!

 

[jazz452]

You checked the earth wire to the bell housing? Needs to be good contact,they come loose although look like there still good. Good for at least anther 100,000

 

[digger58]

Haha Whoops, It's late I meant Glow plugs obviously. Ok cool, I need to bring it to my mate's garage for a plug in, just haven't had the chance. Should be up there this Monday and I'll post results if I can. I've tried starting without the air filter connected but didn't seem to help at all. Thanks for replying!

I meant air in the fuel system

 

[Akystilo]

Check the crank sensor mate the magnet could be getting weak

 

[Brendan W]

Most points covered already but anyway............
Diesel starting problems in modern common rail systems are seldom due to glo-plugs. They are almost unnecessary if the ambient is above 6 or 7 degrees. They do contribute to smoother running initially at higher temperatures but that's about it.
Slow cranking speed will do it. Generally down to a bad earth strap or a lazy starter motor. A jump to the block will eliminate the earth lead if the leads and contact are good. Alternatively you could with a meter look at the voltage between the block and the battery negative when cranking. If it's a few volts you have a problem in the earth strap.
Injector leak back will affect cold starts. If only one is bad the rail will not have sufficient pressure for starting. I don't know the JTD set up but a leak back test in principle is easy. Remove the return hoses and put four clear hoses into four drinks bottles. They all leak a bit. A bad one is easy to spot. Typically more than 40 cc a minute at idle is bad news.

 

[varesecrazy]

Most points covered already but anyway............
Diesel starting problems in modern common rail systems are seldom due to glo-plugs. They are almost unnecessary if the ambient is above 6 or 7 degrees. They do contribute to smoother running initially at higher temperatures but that's about it.
Slow cranking speed will do it. Generally down to a bad earth strap or a lazy starter motor. A jump to the block will eliminate the earth lead if the leads and contact are good. Alternatively you could with a meter look at the voltage between the block and the battery negative. If it's a few volts you have a problem in the earth strap.
Injector leak back will affect cold starts. If only one is bad the rail will not have sufficient pressure for starting. I don't know the JTD set up but a leak back test in principle is easy. Remove the return hoses and put four clear hoses into four drinks bottles. They all leak a bit. A bad one is easy to spot. Typically more than 40 cc a minute at idle is bad news.

Hi,

it's common rail - the world's 1st one..

and relies on cranking speed to get rail pressure,
so any issues with slow cranking can do it.. you can read rail pressures via plug-in OBD

I had a JTD estate that wouldn't clear the Immob. reliably,:bang:
are you 100% sure it's NOT the key..?? got a spare..?

Charlie - Oxford

 

[Pigpig]

Ok, thanks for all the replies! It's a nice day so I'll have a check on the car now. I have been meaning to do the leak back test as I read somewhere on either an Alfa forum or this one that one of the injectors was faulty? I'll have a go at doing a test and see if anything's obvious.
I'll see what I can do!
Unfortunately I don't have a spare key, that's what you get for buying at auction, still, can't complain for £100

 

[jazz452]

Not stopped raining here