2003 alh died while driving P0251

Car had been running flawlessly before this incident, picked it up 15k miles ago. 290k on the chassis, unknown lesser mileage engine. Replaced a few things in that time. (I'm guessing this is non essential information but i'll list it nonetheless). replaced fuel filter, coolant temp sensor, mass airflow, N75, last but not least turbocharger.
scenario:
Tank is full. I'm driving for aprox 10 minutes, everything is fine coolant had come up to temp properly. Suddenly it feels how a gasoline engine would feel running out of gas. This happened in a span of 5-7 seconds. Without lifting throttle cruising 40mph, loss of power - power comes back but not as before - engine dies. I'm on the side of the road trying to restart. Youtube link will be inserted of subsequent startup attempts. Erratically gets up to 1,200 rpm, dies, big plume of unburnt diesel. I've checked fuses, continuity on harness between the IP and ECM and found no issues. ASV and EGR check out fine. Really not looking forward to replacing an injection pump.

Check the ASV on the EGR assembly. That last code above indicates it might be flopping shut cutting off air to the engine... part of the big plume of smoke as there was no air to burn the fuel.

asv flap

Unfortunately no such luck. Disconnecting and plugging vacuum line at the asv + holding the flap open while having someone else turn it over yields the same result.

Check the integrity of the pump's electrical connector, but at this point it does seem like the QA inside the pump died or got stuck somehow.

Not related to the intake flap DTC though. That may be a chaffed wire harness where the two wires to that solenoid on the intake goes, near the firewall. Somewhat common.

Late timing will cause white Diesely smelling exhaust on a cold engine but runs ok when warm. Idunno about a hot engine.

But maybe your timing slipped?

I'd remove the top belt cover for a look and peace of mind.

Based on the Codes maybe a wire finally wore through or broke?

Maybe fuel starvation? Cracked hose somewhere?

I'm worried you're right about the QA, thinking about getting the cover off the top of the IP to see the sweep in the lever there. Looks like one of the four fasteners is a proprietary security nut. I have found those asv wires chaffed where you specified, will remedy that if I make it out of this debacle.

KLXD said:

Late timing will cause white Diesely smelling exhaust on a cold engine but runs ok when warm. Idunno about a hot engine.

But maybe your timing slipped?

I'd remove the top belt cover for a look and peace of mind.

Based on the Codes maybe a wire finally wore through or broke?

Maybe fuel starvation? Cracked hose somewhere?

Click to expand...

Yes I should have specified in the op timing was the first thing I suspected. After removing the cover, finding the belt still taught and looking good, and seeing that the three bolts holding the IP sprocket timing had not moved. The clear fuel supply line to the IP is full of fuel. Not saying it couldn't have jumped timing but I don't see it very likely.

Solved

Thanks guys for chiming in, replaced the IP with a used unit and is running properly again.

i can't avoid revive an old thread because an old thead should never die

have repaired mine once for the exact same issue somes somes years ago ,
car died on road never started back ,
passed over 3 month to find on internet and finally read on a forum the ''fuel pump cranology'' for the alh
it was an appreciable part of my life i would like to thanks the creator of this cranology again

my problem was the electromagnet actuator system inside the quantity adjuster

, removed the quantity adjuster from pump then putted back on my bench ,
started to disassemble it from top ,,
the tan plastic junction assembly needed to cut legs under the black rectangle cap to be removed ive unscrewed all unscrewable thing and finally the center actuator bolt , unsnapped the actuator by turning it at max and force to make it more than max ,
after this actuator assembly removed , found that the ferrite core under was hooking into the coil body , ive sanded the ferite core to have a nice gap , cleaned de QA , reassembled actuator assembly , and soldered back pins that ive cutted ,

it was a pain in the butt to readjust because car take his lower/upper limit reading at cycle on only one time so it needed a lot of on/off lot of lost seconds to resynk my 7$ vgagkkl cable each cycle . and set the lower/upper limits values in specs.. but it was a succes

it worked like over 40 000km , in fact this issue never come again

little funny story about this fuel pump , i was traveling alone quietly when i ear the turbo squish like a dump truck , and car died , smelled a diesel soot odor , looked in my mirror and see a fkin giant black smoke cloud ,

likre if car dumped 4000mg/stroke , , never be able to fix the issue live ( at this time i was thinking that my wiring for the evry was the culprit so i disconected everything from my ip harness with no luck )
then i started to desesperaly try non sens thing like plugging only one wire of the evry mod with the switch off , ,or only other wire with the switch on and by chance i managed to make it idle with only one of the 2 wire of my evry mod with the switch on !!( actually the most strange things ive never see with my tdi'S lol
look like if the 7 feet of switched wire acted like an antenna and changed the impedance of the grey wire enought to get the car idle ( dont remember if it was pin 2 or 3 )

( my profile picture comes from this storry )

as soon the car was started , it begin to smoke like my picture , as soon i toutched thethrottle , car reved like a dump truck then die lol

ive rolled back to house ( 23km) with this without toutching gas pedal lol ,as soon car was at 50kmh , it shuted off , speed droped to 20-30 then fuel kicked back to 50kmh

my 23km ride to comming back home drinked almost 3/4 of my fuel tank , , approx 2.4MPG ,

after investigation , one of my solder in the QA have broke off lol