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Discussion Starter #1
greetings to all. I have a 2001VWbeetle w/1.9tdi,w/A.T..We've had relatively few problems until 2 wks ago. My wife filled tank w/biodiesel, drove home(50mi.). This may be coincidental, but next day drove 1/2mi. and car died,and wouldn't restart. Pulled car back to house,hopefully not damaging anything.Pulled codes and got several .P1650(data bus powertrain missing signal from inst.panel)p1626(d.bus missing msg. from transm.contr.),P1780(torque retraction malf.) andp1850(data bus poertrain missing msg. fr. eng. control),various controls missing messages). P0118eng.coolant temp.circ.high.,andP0725eng.speed inp circ. malfunction. I could get no fuel flow. used vac. to pull fuel from tank and got decent flow of fuel,so not clogged lines or filter or leaks. Checked fuel shutoff valve(okay). Tried new diesel in jar, thru input hose to inj. pump, wouldn't pull fuel. Checked fuses and relays(okay), but found weak voltage on power legs of relay(12.5v. @fuse, 5v @relay).Battery may be getting weak seems to be losing voltage even when disconnected.checked grounds and for shorts,none. Found eng speed(rpm) sensor and it ohmed out oddly,but could this keep car from starting completely?found small leak at o-ring on ECT, but Eng. coolant temp. sw. seems to be ohming out fine.(checked @ room temp. then w/boiling water and resistances corresponded correctly). coolant level ok. My fear is that suddenly the engine control mod.(ecm) or injector pump died. Is there a definative test for these components. We can't really afford professional repa or towing to such. I guess I'm it! Please help...even if it's bad news, i at least know what's happening. Thanks so much
 

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Have you ever had bio before? Bio can cause fuel filter clogging (but you said this is not a problem) and can cause the fuel seals to swell (shouldn't cause any problems).

Double check and charge the battery, clear all codes, see what comes back. No definitive test for ECM other than swap it and see. These are pretty reliable unless you toss them into a swimming pool or unless the area under the windshield turns into one because of leaves forming a dam. In very rare cases, coolant migration causes random failures but you would have noticed coolant inside the plugs (see the faq for more on coolant migration). If the fuel shutoff solenoid isn't getting power, it won't let fuel pass. Even if the engine speed sensor was bad the fuel pump would still pull fuel since this is a mechanical thing.
 

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Discussion Starter #3
thanks ccbb

hi, well ,i'm finding,battery may be dying.once i get some $$$ ,i'll start there.With jump, I can get eng. to turn over,seemingly strong enough,but i could be wrong. I have to say, nothing makes me feel as helpless(and stupid) as German engineering. One question, what are common ways these pumps mess up.if fuel was interrupted, I imagine they could burn up mechanically. Is there any electrical control of pump, besides fuel shutoff valve? I guess I'm just hoping against hope that it's not the Inj. pump,repair of which is very expensive and complicated. Any other ideas would be greatly appreciated. Thanks again
 

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The only fuel pump on your car is the injection fuel pump. Even if you run out of diesel it's still about 1/3 full. It won't be damaged from running out since it's not dry. It's lubed by fuel.

The pump is controlled by the ecu. The fuel shutoff just blocks flow when you turn the key off.
 

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Discussion Starter #5
dear mr chi.Thanks for suggestions,I'll have time(and sub100deg.temp)tonight to try them. This is a rather frustrating mystery, for which my natural(though somewhat inept) mechanical side demands satisfaction.I don't relish replacing inj.pump, but, if necessary, feel safer attempting thanks to your FAQ's section. It's also great to hear other's similar queries,and realize i'm not alone.
 
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