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My bulletproof 1.7 sdi won't start....MOT due tomorrow!

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So in the tradition of a newbie, I'm here for help please! This is my 2nd Lupo SDi, the first had done over 250k so I know they should go on forever, which is making this problem even more frustrating! 

So 1.7 SDi went to start one morning a few weeks ago and it turned over but immediately cut out with a whiny/grindy noise. And has done the same thing every time I've tried to start it since. 

There is plenty of diesel in it so it isn't fuel starvation.

Battery is turning it over.

I'm all out of ideas, any suggestions? Could pop it in the garage as a last resort, but I wanted to pick your brains first...any ideas?

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basics.

is the timing belt intact?

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and we are sure it isn't battery?

tried bump starting it?

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You got anti freeze in it? Sudden cold snap and no anti freeze = stripped cambelt teeth on the frozen water pump.

I'd take the cambelt cover off and flick it over on the starter a bit at a time (or turn the engine on the crank pulley bolt) and check for missing teeth on the belt and make sure the timing all lines up.

if it is spinning over easy on the starter it has lost compression, so check timing.

 

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Starter motor engaging ok?

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3 hours ago, Rich said:

and we are sure it isn't battery?

tried bump starting it?

Yep, it did get to the battery at one point, but I've charged it and put it back on. No luck on the bump start.

2 hours ago, Sausage said:

You got anti freeze in it? Sudden cold snap and no anti freeze = stripped cambelt teeth on the frozen water pump.

I'd take the cambelt cover off and flick it over on the starter a bit at a time (or turn the engine on the crank pulley bolt) and check for missing teeth on the belt and make sure the timing all lines up.

if it is spinning over easy on the starter it has lost compression, so check timing.

 

Haven't tried this, makes a lot of sense, good call. Will check this tomorrow....Thank you!

 

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1 hour ago, mk2 said:

Starter motor engaging ok?

Think so...turns over fine and then makes a dodgy whiny noise and cuts out. So pretty sure its after the starter motor that the problem starts.

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easy start?

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So it turns over fine while cranking, cam belt is fine (there's an illustrated how-to cam belt check/change fyi). There's fuel. EGR doesn't make a huge difference while cranking or idling, but you could try disconnecting the vacuum pipe to the EGR system from the solenoid (block the pipe to the solenoid once disconnected). Its the whiny noise that has cought my curiosity.

I know that SDI starter motors make a whirring noise after you stop cranking when they get old, so it might be that what you are hearing, as it doesn't start. But why's it not firing up....? In diesels, assuming that mechanically all is fine, it can only be lack of fuel or the fuel system. Ah, just had a mad thought- i've once encountered a diesel engine that wouldn't start because- wait for it- there was water in the fuel and it was frozen solid,  blocking the pipe/filter...

just another thought- could be the fuel shut off solenoid valve, but unlikely.

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the fuelling issue is why i like the easy start diagnosis.

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1 minute ago, Rich said:

the fuelling issue is why i like the easy start diagnosis.

Yeah, good idea ? At least you can tell if it fires a few times, eliminating mechanical issues. I like methanol mixed with nitromethane... Mmmmm, power...

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3 hours ago, Rich said:

the fuelling issue is why i like the easy start diagnosis.

Easy start is fine for the occasional diagnostic, but it's just not particularly great for your engine. 

Still, in this situation I would endorse Rich's comment. You're in a pickle considering it's MOT day.

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So, had 

4 hours ago, mk2 said:

So it turns over fine while cranking, cam belt is fine (there's an illustrated how-to cam belt check/change fyi). There's fuel. EGR doesn't make a huge difference while cranking or idling, but you could try disconnecting the vacuum pipe to the EGR system from the solenoid (block the pipe to the solenoid once disconnected). Its the whiny noise that has cought my curiosity.

I know that SDI starter motors make a whirring noise after you stop cranking when they get old, so it might be that what you are hearing, as it doesn't start. But why's it not firing up....? In diesels, assuming that mechanically all is fine, it can only be lack of fuel or the fuel system. Ah, just had a mad thought- i've once encountered a diesel engine that wouldn't start because- wait for it- there was water in the fuel and it was frozen solid,  blocking the pipe/filter...

just another thought- could be the fuel shut off solenoid valve, but unlikely.

Cambelt definitely fine.

Can't find location of fuel shut off solenoid....

4 hours ago, Rich said:

the fuelling issue is why i like the easy start diagnosis.

Easy start, well with a helpful friend, we got it going on easy start as long as we sprayed it into the air intake it would start and run but as soon as we stopped spraying it died....so it does suggest fuel I guess. But I've never run it dry and it has over half a tank in right now!

Gonna have lunch and try again....

Edited by Vw-Joy

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Stop solenoid is on the top of the pump with a wire to it, it shuts off the fuel and stops your engine, or if it is faulty wont let it start. Test the wire for volts.

Running on easy start tells you you have compression, which is a good thing.

Edited by Sausage

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Ok, that means no mechanical fault. Good. So its down to no diesel being injected. Most common causes are blocked fuel filter, blocked tank strainer (unlikely), (frozen) water in fuel line, fuel shutoff solenoid (just above the 4 injector pipes on the pump- 8mm nut on wire terminal) or knackered injection pump (very unlikely). Removing the shutoff valve is a right pain as it's tricky to get to. You can just attach 12v to the terminal (with the wire disconnected) and listen for a click. If you hear it click, then chances are it's working ok. If that is fine, my bet it's something to do with fuel supply. If you remove any hose downstrem of the filter, bear in mind the injector holes are 0.170mm in diamter (hair width), so keep everything ridiculously clean. Then when the hose is off, supply clean fuel to the engine from a clean coke bottle. If it still doesn't start then it's something else....

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The tank strainers do get blocked to be fair. I found that with my SDI.

I would change the fuel filter first.  Check there is fuel in the lines as well. They're transparent so you can see.

Oh and try crank it after removing the cap on the bleed nipple.

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1. Try to put the transparent fuel hose (7 in diagram) in a tank with diesel fuel.

2. If it start replace the o-rings of control valve.

3. If it not start check the fuel shut off solenoid and timing.

 

fuel filter.JPG

n109.JPG

fuel shut off check.png

how to check the timing.jpg

Edited by lupo 1.7sdi
  • Like 1

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Those diagrams aren't the best in my opinion.

As a thought, by control valve you mean the thermostatic valve? Why would the O rings need replacing when they probably haven't been touched? Start with the basics, no point in over complicating the situation just yet.

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Well that diagram was useful to me... there's something I'd never realised- there's a diverter valve built into the filter assembly return that is temperature controlled. Ok, i get that the viscosity of diesel varies a bit with temperature, but the injection advance mechanism inside the pump uses the pressure differential between ambient and internal pressure to move the injection roller ring axially to affect the start of the injection time. So this means that the restrictor orifice on the exit of the pump isn't as significant at high temperatures. I guess it also means that the ECU must have an injection start time compensating map, dependent on temperature AND internal pump pressure. Well that explains why veggie oil is shite in a VE pump system- the viscosity is way off... interesting what you get from one diagram....!

Edited by mk2
Typo

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bring back the Bosch pump.

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3 hours ago, mk2 said:

Well that diagram was useful to me... there's something I'd never realised- there's a diverter valve built into the filter assembly return that is temperature controlled. Ok, i get that the viscosity of diesel varies a bit with temperature, but the injection advance mechanism inside the pump uses the pressure differential between ambient and internal pressure to move the injection roller ring axially to affect the start of the injection time. So this means that the restrictor orifice on the exit of the pump isn't as significant at high temperatures. I guess it also means that the ECU must have an injection start time compensating map, dependent on temperature AND internal pump pressure. Well that explains why veggie oil is shite in a VE pump system- the viscosity if way off... interesting what you get from one diagram....!

Could have told you that without those diagrams which for the OP i'm not convinced are that useful. Pretty sure I've done a few threads on the thermostatic valve and how it works and how it can be a nightmare but for veg oil running it's absolutely vital that the return line is there to warm the veg oil up a bit and that's from someone who ran on neat veggie in winter. The big issue with those thermostatic valves is they turn brittle over time and can crack. There are a multitude of things to diagnose but if we start with the basics then we can work our way through. I think the MOT situation is the bigger balls up here.

To the op, I would still try and start with the bleed nipple open. You might have air in your lines.

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On 27/02/2018 at 1:58 PM, mk2 said:

Ok, that means no mechanical fault. Good. So its down to no diesel being injected. Most common causes are blocked fuel filter, blocked tank strainer (unlikely), (frozen) water in fuel line, fuel shutoff solenoid (just above the 4 injector pipes on the pump- 8mm nut on wire terminal) or knackered injection pump (very unlikely). Removing the shutoff valve is a right pain as it's tricky to get to. You can just attach 12v to the terminal (with the wire disconnected) and listen for a click. If you hear it click, then chances are it's working ok. If that is fine, my bet it's something to do with fuel supply. If you remove any hose downstrem of the filter, bear in mind the injector holes are 0.170mm in diamter (hair width), so keep everything ridiculously clean. Then when the hose is off, supply clean fuel to the engine from a clean coke bottle. If it still doesn't start then it's something else....

Gonna try these suggestions as soon as possible, although I think the next few days will be full of snow activities!

On 27/02/2018 at 9:51 PM, lupo 1.7sdi said:

1. Try to put the transparent fuel hose (7 in diagram) in a tank with diesel fuel.

2. If it start replace the o-rings of control valve.

3. If it not start check the fuel shut off solenoid and timing.

 

fuel filter.JPG

n109.JPG

fuel shut off check.png

how to check the timing.jpg

Thanks for diagrams ??

Really appreciate all the suggestions so far.... Keeping me sane! Will let you know how it goes. 

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Yeah, that's what i'd do. Remember to keep everything really clean :)

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