Interesting Segment on Car Talk Today
 

Indirectly this is MB diesel related....Woman has an 84 Volvo diesel wagon. Mechanic rebuilds injection pump. Now car dies at EXACTLY 4500 ft. elevation. Roll the car back down the road a few hundred ft. (i.e. road length, not elevation) and car starts fine. Click and Clack thought fuel leak or some problem with rebuild....but had no idea what the problem might be.

Any thoughts?

Something to do with a vacuum shutoff maybe? Do the Volvo diesels have those?

I heard that segment today and was intrigued. They are no longer producing new shows and I believe this was a rerun. The caller after that lost his cell phone in the duct work under the passenger seat of his BMW and I know I have heard that caller and situation before. I am going to miss those guys on Saturday morning. I expect that the reruns will lose their appeal quickly.

Richard

I thought it wasn't till September that they'll stop producing new shows....but I guess today still could have been a rerun.

'Car Talk' hosts retiring from hit show - CNN.com

I just did a search and found that they are stating October of 2012 as their retirement date. I suspect that they mixed in some old material today. I did wonder why I remembered the cell phone problem but not the Volvo diesel problem. I would have remembered a diesel problem.

Good guess. Could be a fuel tank vent mechanism, misadjusted A[L]DA, faulty MAP sensor if equipped...

Sixto
87 300D^2

It was a recycled puzzler on a new show I think. I heard the bmw guy.

I believe that more that a few people from this forum could produce a good "Diesel Talk" show for NPR.

If the vacuum shutoff is sensitive and is not vented when the vehicle is in the "run" position then theoretically travelling to very high elevations could cause a slight vacuum in the shutoff line/unit and shut the car down. Could be related to the altitude compensation not working properly also and starving the engine for fuel. Vacuum in the fuel tank is also a possibility, but an easy way to disprove that one would be to make the trip with a full tank.

yeah i was thinking the aneroid compensator in the ALDA, but i don't know what kinda setup is in that volvo

Electrical shutoff
 

I read that the 80s Volvo diesels contained VW engines. According to wikipedia, the VW diesels had electrical shutoff mechanisms.

Volvo 200 Series - Wikipedia, the free encyclopedia

I heard that CarTalk as well and remembered the BMW phone thing but not the Volvo diesel story. Click and Clack should check out the internet. Search "Volvo Diesel Altitude" and you quickly see that there is an "altitude compensation solenoid" on the injector pump: "when de-energized, it reduces the injected fuel volume and advances the fuel injection timing ( this is to compensate for the thinner air at higher altitude)."

My guess is that Helmut the IP rebuilder messed this up on rebuild. A quick fix of wiring that thing to be powered when the key is on disables the solenoid at the cost of more unburned fuel at elevation. Or maybe he cross-wired the altitude compensation and fuel shut-off solenoids and then misadjusted to compensate.

The funniest (saddest) part was that she took her car in for a stuck glove compartment door and the mechanic found a fuel leak and ended up rebuilding the IP for $3000.

I remember one call about a year ago where someone called in with a problem they were having with Mercedes diesel. I believe it was an early 80s 300D. Click and Clack seem to be pretty weak on the subject of diesels and especially that era of Mercedes diesels. I have a lot of respect for them, their breadth of knowledge and their diagnostic skills, but it is much stronger with gassers than diesels.

Thought it was hilarious. Took it in for glove box repair, and then "AAAAAH it is leaking diesel. DIESEL! You must call Helmut!" Altitude compensation gone wrong was also my thought.

NPR should do a diesel call-in show, and call it clack and clack.