VOLVO 850 TDI ???

HI EVERYONE!
FOR THE LAST THREE WEEKS I'VE BEEN HAVING NIGHTMARES WITH MY VOLVO 850 TDI - GLT, 1996. TO START WITH I COULDN'T START MY CAR SO RAC CAME OUT AND THEY COULDN'T DO MUCH ABOUT IT SO WE ENDED IN MY LOCAL INDEPENDANT VOLVO GARAGE. THEY FOUND WATER IN FUEL SYSTEM. DRAINED FUEL TANK AND CHANGED FUEL FILTER. CAR WAS RUNNING OK FOR 10 DAYS. AFTER THAT THE SAME STORY. THIS TIME I WENT TO SEE DIESEL SPECIALIST WHO HAS DONE SOME WORK ON MY CAR IN THE PAST. HE DID MANAGE TO START BUT AFTER 20 MINUTES CAR WAS DEAD. HE CHECKED PIPES FOR AIRLEAK, NOTHING. NO WATER, EITHER. HE SPENT TWO DAYS TRYING TO FIND OUT WHAT IS WRONG IN THE END HE POINTED INJECTION PUMP WAS WHAT I NEEDED. SO I BOUGHT ONE FROM VOLVO SCRAP YARD AND THAT ONE WAS FITTED NEXT DAY BUT WITHOUT LUCK COS' CAR WAS RUNNING QIUTE NICE FOR 30 MINUTES AFTER THAT REVS STARTED TO GO MENTAL FOR 10 SECONDS AND MY CAR WAS DEAD AGAIN. WE TRIED FEW MORE TIMES BUT IN THE END I LOST INTEREST AND MONEY. CAN ANYONE HELP?:(

[Andy Mcl]

Not sure but sounds like air in the system. Yhe same symptoms seem to happen when you change the fuel filter(you did change the fuel filter didn't you ??).
According to vadis as soon as you have changes the filter and got it running you must drive it - this purges the system of air - which causes poor starting.
As a thought have you checked all the connections that you have disturbed - air is a sod for getting in on diesels - it will pull air before it leaks diesel.

Other than that not sure.

Cheers

[warthog]

I'll concure with Andy. Most rotary diesel pumps will mismanage fuel delivery volumes if air is present in the fuel supply. Often with small quantities the car becomes undrivable due to an extremely sensitive and unstable throttle response.

On the 850 diesel there is only one fuel pump - in the injector pump itself, so the rest of the fuel system from tank to engine is under vacuum. On other diesels, I have found in the past that due to high underbonnet temps. the flexible fuel lines perish. This lets small amounts of air into the system. If it's possible on your setup, a way to check for air leakage is to substitute the last section of pipework into the injector pump with a section of clear fuel resistant tubing. Once purged of air, you shouldn't see any air bubbles travelling along this pipe at all. If you do then you've got an air leak - now the fun starts!

Another possiblity that I'm sure you or your dealer has looked at, but have you tried running the car with the fuel cap off? Could you be suffering from a combination of minor air leaks and a slightly blocked tank vent system?

Hope this gives you something to work with.

HI!
MY MECHANIC TRIED CLEAR FUEL RESISTANT TUBING WITH MY INJECTION PUMP, NO AIR BUBBLES! BUT WHAT'S NEW IS HE FOUND PROBLEM WITH ELECTRICS COS' HE MOVED BUNCH OF CABLES AT LEAST THERE ARE 45-50 WIRES GOING EVERYWHERE, FRONT LIGHTS, COOLING FAN... FROM SOMEWHERE IN THE MIDDLE, UNDER THE ENGINE AND CAR WAS DEAD. HOPEFULLY MOBILE ELECTRICAN WILL COME TOMORROW AND TRY TO FINISH THIS ENIGMA. THANKS FOR HELP.

[pollitt]

Hi Zack, a few thoughts....
1.The water ingress may be due to the filler cap seal not fitting correctly and the rubber cup that sits around the filler may have a blocked drain hole?? A small cable tie will safely clear it.
2. The fuel shot-off solenoid may be at fault (or the power supply to it). It sits in the pump at the front of the car, between the engine and the radiator, immediately feeding the injectors. The solenoid is on the left, try cleaning the connection. This is fed from a relay near the nearside suspension strut, also a possible problem.
The solenoid itself can be bought from any good bosch agent but sounds like you may have a spare one anyway now!

Good luck
Al