VW van intermittent fault

[Olderisbetter]

The LT35 ANJ 2.5 tdi threw a wobble a few nights ago as i was driving, it suddenly sounded like the engine was not timed properly and lost power, after plugging it in we got a P1248 code and cleared it but the issue is still there and the code returned, The physical timing looks fine as in no jumped belts so a quick google seems to point to "Start of Injection Timing Regulation not OK" which in my head means the pump timing or some king of electrical timing being the issue, is there any common fault or issue that this could be, the vehicle is a well maintained 150,000 2004 plate but i did drive over a rubble road 2 days before this happened that shook the daylights out of it, the LT was scanned again and the same code is back P1248, both the N108 AND G80 are within specs, i have now got a new N108 on the pump but as i drive it seems to have no power then suddenly burst into life and pulls like a train again, but that issue is not always there but has only started since it threw a wobble while driving, It starts fine hot or cold and does not smoke, i have wiggles everything i can get at so not i am stuck, anyone ever has an issue like this?

 

[msmbus2000]

pin the engine to confirm timing diffo ok sounds like it's out a tooth

 

[msmbus2000]

have the top 3 13mm bolts on the camshaft came loose?

 

[Melvyn Best]

Not an engine I’m familiar with unless it is the 5 cylinder with the rotary pump driven off the rear of the cam as used in some Volvo cars. Think you have to remove the pump pulley from the cam to check /set the cam timing then use a DTI to set the pump lift at TDC? I have seen the pump timing fine tuned on a Volvo using diagnostic equipment with the engine running by altering the 2 belt tensioners
I had an intermittent problem on a petrol LT years ago, kept losing power and when checked the ignition timing was retarded every time . The 2nd time it happened I marked the position of the distributor to the head , the 3rd time the breakdown company altered the position of the HT leads to get it going so I checked the cam timing which was correct then found the distributor drive gear on the rear of the cam wasn’t keyed , as a temporary measure I spot welded the gear to the cam , never had a problem after

 

[carbon]

unless it is the 5 cylinder with the rotary pump driven off the rear of the cam

A quick google search shows it to be 5 cylinder. So if it’s like the older acv then it has no keyed pulley except at the crankshaft. Yes you have to remove the pump drive pulley to check the cam timing Mass airflow sensor may be damaged?

 

[Olderisbetter]

Yes it is the t cylinder engine and i will check the timing next as its a.logical thought thanks, we swapped the 2 MAF type things for the ones from my T4 and the same fault was still there,iwill keep looking.

 

[T5 TDI]

I had a T4 with an ACV engine. If your engine is like that then pay special attention to the crank marks. On mine, what looked to me to be marked O/T (on time you might think) on the flywheel isn't actually TDC. The correct mark is nearby and just a simple single cut across the flywheel that lines up with the pointer.

 

[Olderisbetter]

Update.. not cured it yet but now starting yo wonder if the tensioner on the diesel pump timing belt has gone duff which means the pump timing might be out, ordered a static timing kit today with a dti gauge and a usb yo odb lead to run vcds to dynamically time it, at least it rules something else out.

 

[T5 TDI]

You might not be able to use the timing checker plug-in feature in VCDS unless you have a registered version. But setting it manually should put it pretty close. I checked mine after fitting the two new belts with VCDS before the plug-in was available by plotting the start of injection and the fuel temperature on the graph that was available on the VCDS site.

The cam needs confirming with a setting bar across the end and the (correct!) crank timing mark needs to be lined up the bell housing window. If I remember correctly on mine you needed a mirror to see the pointer on the pump.

It seems odd that the fault can cure itself at any point once the pump belt has jumped a tooth but it's still worth eliminating. If you haven't already seen this thread on the T4 forum it worth a look.

 

[Newlands]

My T4 five cylinder had a weird problem that turned out to be the crank pulley - apparently they are more than just a pulley as they affect the timing somehow (maybe someone can explain it better than me!!). Anyway, a replacement transformed it from totally gutless to normal.

 

[carbon]

The crank pulley is also a damper, if it fails it can make running a bit rough. If left without repair it can snap the crankshaft at the front of the engine

 

[Olderisbetter]

Thanks all, i will take it all on board and just keep looking till i cure it or till the men in white coats take me away

 

[Olderisbetter]

You might not be able to use the timing checker plug-in feature in VCDS unless you have a registered version. But setting it manually should put it pretty close. I checked mine after fitting the two new belts with VCDS before the plug-in was available by plotting the start of injection and the fuel temperature on the graph that was available on the VCDS site.

View attachment 340422

The cam needs confirming with a setting bar across the end and the (correct!) crank timing mark needs to be lined up the bell housing window. If I remember correctly on mine you needed a mirror to see the pointer on the pump.

It seems odd that the fault can cure itself at any point once the pump belt has jumped a tooth but it's still worth eliminating. If you haven't already seen this thread on the T4 forum it worth a look.

yes i found you need a mirror so i must be looking at the right bit lol and that is a very detailed link thanks

 

[carbon]

I’m not sure on this engine but some had a plastic covered cam belt tensioner. They can crack and the plastic break off. The tensioner then takes up the slack and the engine still runs but the timing moves enough to make it run but not were it should be, the ecu will then compensate for the shift in injection timing.

 

[T5 TDI]

For your problem, the physical things being lined up should be good enough to eliminate any possibility of pump belt jump as long as you make sure everything is bang on.

If you are going on to check it dynamically using the VCDS plug-in or the graph method then first make sure the (G62) coolant sensor and the fuel temp sensor are showing sensible figures live from cold (matching ambient) and then record (log) them as the engine warms up on the road. You can do all this by clicking the log button while using 'Measuring Blocks' (live data) in VCDS with these two temperatures on the screen. Good luck!

 

[finyuk2005]

does it sound very harsh and tractory by any chance? if so it could be the timing solenoid, its on the bottom of the pump, and can be changed if you can get a hold of one

 

[Olderisbetter]

does it sound very harsh and tractory by any chance? if so it could be the timing solenoid, its on the bottom of the pump, and can be changed if you can get a hold of one

It does but if it is the N108 solenoid on the pump we changed it for a working one a few days after the issue started

 

[finyuk2005]

It does but if it is the N108 solenoid on the pump we changed it for a working one a few days after the issue started

not sure what its number would be, but this is what i was talking about, i might have the pump on your van wrong though!

Pardon our interruption...

 

[Olderisbetter]

not sure what its number would be, but this is what i was talking about, i might have the pump on your van wrong though!

Pardon our interruption...

That is the part that is referred to as the N108 on VW engines with a bosch VE pump, it has been changed and ruled out but thanks for pointing it out.

 

[Olderisbetter]

After running a full copy of vcds lite i got way more info that the expansive garage machine we first tried, tomorrow we are doing a full swaps of all the belts and pulleys inc water pump with a gates kit as i am now convinced the timing has slipped, lets see if that cures it

5 Faults Found:
17656 - Start of Injection Timing Regulation: Control Deviation
P1248 - 35-10 - - - Intermittent
17552 - Mass Air Flow Sensor (G70): Open or Short to Ground
P1144 - 35-00 - -
17957 - Boost Pressure Regulation Valve (N75): Open or Short to Ground
P1549 - 35-10 - - - Intermittent
17849 - EGR Valve (N18): Open Circuit or Short to Ground
P1441 - 35-10 - - - Intermittent
17946 - Fuel Shutoff Solenoid (N109): Open or Short to Ground
P1538 - 35-10 - - - Intermittent
Readiness: N/A

"after clearing it still shows"
VCDS-Lite Version: Release 1.2
Friday, 08 April 2022, 14:13:56:0

1 Fault Found:
17656 - Start of Injection Timing Regulation: Control Deviation
P1248 - 35-10 - - - Intermittent