Seat Leon 2.0 PD Poor Start

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Seat Leon 2.0 PD Poor Start

Postby clark_rally » Tue Jan 13, 2015 9:22 pm

Evening folk, please be gentle as I really don't have much experience, but been looking at a Seat Leon that if left sitting for 10mins plus, has an extended crank to get the thing to start. If left overnight it takes a lot of winding over to get to fire. Engine code is BMN (2.0 PD TDi). 60,000 miles. 2007model. Its a new engine fitted due to a crack in block caused by a failed rocker on an inlet valve. Poor start was there before but mechanic assumed it was just due to the broken parts, however it is same with new (remanufactured) engine. All ancillaries were swapped over from old engine to new, it has non functioning swirl flaps (customer wouldnt fit a replacement). Injectors etc were all swapped over (new seals and adjusters fitted). Timing has been checked twice now with pins locking crank and cams. I have scoped the crank/cam but no idea if things line up like they should, cant find a good waveform to compare, but as pins are all good, am assuming it must be ok. I then thought I might aswell have a play with amp clamp and look at the injectors. Cyl 1-3 all produced an identical waveform, but number 4 is low on peak opening current and very low on closing current. There are millions of tiny air bubbles present in the fuel return line @ filter. Supply after filter is 100% air free and gd pressure. Dont have a suitable adaptor to check intermediate pump pressure tho. Once started car idles with a small lumpyness, but goes like a train out on the road. If anyone has any ideas it'd be much appreciated, but my thought are inj 4 needs looking at?

Many Thanks
Barry
Attachments
Inj-cyl4.psdata
Injector Cyl 4
(177.77 KiB) Downloaded 142 times
Inj-cyl1.psdata
Injector Cyl1
(1.71 MiB) Downloaded 113 times
Crank-cam.psdata
Crank/Cam Capture
(2.55 MiB) Downloaded 103 times
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Re: Seat Leon 2.0 PD Poor Start

Postby AuthorMike » Wed Jan 14, 2015 9:42 am

clark_rally wrote:Evening folk, please be gentle as I really don't have much experience, but been looking at a Seat Leon that if left sitting for 10mins plus, has an extended crank to get the thing to start. If left overnight it takes a lot of winding over to get to fire. Engine code is BMN (2.0 PD TDi). 60,000 miles. 2007model. Its a new engine fitted due to a crack in block caused by a failed rocker on an inlet valve. Poor start was there before but mechanic assumed it was just due to the broken parts, however it is same with new (remanufactured) engine. All ancillaries were swapped over from old engine to new, it has non functioning swirl flaps (customer wouldnt fit a replacement). Injectors etc were all swapped over (new seals and adjusters fitted). Timing has been checked twice now with pins locking crank and cams. I have scoped the crank/cam but no idea if things line up like they should, cant find a good waveform to compare, but as pins are all good, am assuming it must be ok. I then thought I might aswell have a play with amp clamp and look at the injectors. Cyl 1-3 all produced an identical waveform, but number 4 is low on peak opening current and very low on closing current. There are millions of tiny air bubbles present in the fuel return line @ filter. Supply after filter is 100% air free and gd pressure. Dont have a suitable adaptor to check intermediate pump pressure tho. Once started car idles with a small lumpyness, but goes like a train out on the road. If anyone has any ideas it'd be much appreciated, but my thought are inj 4 needs looking at?

Many Thanks
Barry


Hi Barry and thanks for the post.

Within our PicoScope automotive software we have a large selection of preset tests. Two of these relate to VAG PD engines. If you navigate to "Automotive>Actuators>Injector (Diesel)>VAG Piezo PD (current)" this test is the one you are after for comparison to

Regarding Crank/Cam, I've had a look and checked our Waveform library, and the nearest I could find was a VW 2007 2.0 PD camshaft/crankshaft signal. After using these as reference waveforms and comparing them to your traces, both seemed to be different to your waveform by around .5 ms but the engine code was different to that which you stated.

I am sure those who are more technical than I am will be along to shed some light and help. In the meantime let me know if you have any further information or findings...
Mike Valentine
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Re: Seat Leon 2.0 PD Poor Start

Postby clark_rally » Wed Jan 14, 2015 11:18 am

Mike,

Thanks for the reply, the PD injector preset was what I used to setup the scope and the waveform is identical to that I obtained for cyl 1-3 as far as I can tell. Just not really sure if the waveform for cyl 4 would be enough to cause the poor start or not.

I managed to get an adaptor this morning to test the pressure at the intermediate pump, and once running the pressure is good, and rises fast with revving the engine, but upon cranking it is very slow to rise, and only reaches 3 bar once engine has started. Question is, is the injector not closing right and therfore pump not fit to get the pressure up quick, or is the pump worn and lazy.

I know there are two different crank locking pins depending on the crank pulley, so different engine codes must have different setup. The waveform I did find was a 2007 VW Eos but it says the waveform is with the timing out, so not really useful to compare with
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Re: Seat Leon 2.0 PD Poor Start

Postby AuthorMike » Wed Jan 14, 2015 12:01 pm

clark_rally wrote:Mike,

Thanks for the reply, the PD injector preset was what I used to setup the scope and the waveform is identical to that I obtained for cyl 1-3 as far as I can tell. Just not really sure if the waveform for cyl 4 would be enough to cause the poor start or not.

I managed to get an adaptor this morning to test the pressure at the intermediate pump, and once running the pressure is good, and rises fast with revving the engine, but upon cranking it is very slow to rise, and only reaches 3 bar once engine has started. Question is, is the injector not closing right and therfore pump not fit to get the pressure up quick, or is the pump worn and lazy.

I know there are two different crank locking pins depending on the crank pulley, so different engine codes must have different setup. The waveform I did find was a 2007 VW Eos but it says the waveform is with the timing out, so not really useful to compare with


Barry,

I can't say I am too familiar with the 2005+ Leons, is it easy to change the injectors over? This way you could see if the suspicious injector trace travels with the swap over. At least this may highlight that particular injector operating differently to the rest.

I have been a SEAT fan for many years, and have been on their forums for years. A quick search has suggested a possible issue with Siemens injectors, which are only in the 170 version. Do you know if the Leon you have is the 170, or 140 version? You say it goes like a train, so I suggest it's the 170? It could be the 140 with an aftermarket remap, which is a popular upgrade in the VAG range of engines, especially the diesels (I have had these done myself on various SEATs I've owned).

Interestingly a post on the SEAT forum suggest wiring loom (which physically runs in the engine head) could be causing injectors to become faulty, all around this mileage too..

New injector, new wiring loom seems to be the fix...

This appears to be the old part numbers vs the new:

Injector
old Code 03G 1300 73 M
new Code 03G 1300 73 T

Wiring loom
old code 03G971033D
new code 03G971033L

I have no idea if this is actually what is wrong with your particular vehicle (so please do nothing based solely on my information), but it seems common for the mileage, age, and model.
Mike Valentine
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Re: Seat Leon 2.0 PD Poor Start

Postby clark_rally » Thu Jan 15, 2015 10:20 am

Mike,

The engine is the 170bhp version and we have already checked to see if there was an injector recall on it, which there isnt. Injector seals are also an issue on these, so we changed all them for new to eliminate that. Bolts are strech bolts, so little worried about reusing them too many times in swapping around injectors to test. Interestingly tho, the loom inside the head has been changed previously. Think the reason the car was traded in is becoming clear :lol: Anyway, we changed the intermediate pump yesterday and although things are slightly better there is still an issue there, so the boss has ordered an injector to fit and try. The new customer is kicking off wanting his (new to him) car back so they just want to try it and save having to deal him back out of the car.
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Re: Seat Leon 2.0 PD Poor Start

Postby AuthorMike » Fri Jan 16, 2015 9:25 am

Ahh keep me posted on the new injector, fingers crossed it works, expensive part (at least you won't need to replace the loom if that has already been done).
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Re: Seat Leon 2.0 PD Poor Start

Postby clark_rally » Mon Jan 19, 2015 11:33 am

Well the good news is that the injector fixed it, and I now have an example of a bad waveform :) Car starts on the button now. Left it over the wkend to check it again this morning and it was perfect. I can also stick two finger up to the warranty inspector as he said it def wouldn't be injector and had refused to cover it. :D
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Re: Seat Leon 2.0 PD Poor Start

Postby AuthorMike » Mon Jan 19, 2015 12:22 pm

Excellent news. If you are happy to do so a good and a bad waveform upload to the Waveform Library would be superb :)
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