Hey hi to all and may i say im very happy to be part of your forum.

Is there anyone out there who can help me on this please?

I recently bought a clean 96 volvo 850 2.0, 5 cyclinder, and for some reason it keeps fowling up a spark plug now and again. when i change it she runs lovely but maybe next morning she fires up and while ticking over it starts missing on one cyclinder, ive had the compression checked and all is ok,and leads etc, A friend told me its something to do with the throttel body unit????? can any help before i have to take her in for a diagnostic test.

Jason

 

You might have a valve getting ready to burn up. Is it like a white chalky looking stuff on the plug?

Also I am going to move this post to the 850 section it will get more views there.
This section is for introduction only.

 

hi There

Thanks for moving trerad, The plug is and fairly black, but when replaced she goes great again for miles, then next day start up fine run fine for miles, but when left idling she starts missing?

 

Then maybe you have a bad injector and it is opening to much causing to much gas to go into the cylinder.

 

hi tech

Im gonna check the injectors this evening, its very possible! i hope so

 

Keep us updated.

 

Hi Tech

Does the auto choke mechanisim give trouble like stay on and cause them to run rich? At 2000 revs she's hunting/jumping the engine and giving out black smoke !!!!!!!!

Jason

 

Its just that all plugs are wet also

 

Can anyone else shed some light on my last two posts regarding auto choke?

 

The computer just ups the idle for like a minute and a half then it drops it back down.

Is there any codes?

Also check you fuel pressure regualtor.

 

i'll get my dad to check the codes, he is a machanic, but has'nt came across this problem with 850's before. the fuel regulator seems like a good bet, thanks tech for your help and time, i'll keep you posted

 

emmmm, how would you recommend going about checking the fuel pressure regulator tech, curious myself?

 

If you have the style that is controled by a vacuum line pull the vacuum hose of the regulator and see if there is gas in the vacuum hose. If there is it is bad.

 

would that be the style on a 1996 model? sorry for been sounding stupid here. but the car is at my dads garage 3 hrs away and im relaying info to him to check up on.

 

If depends there is 3 different fuel rail he would be able to tell pretty easy by looking at it.

 

Thanks alan. I'll have news tomorrow from dad, time to hit the bed, cheers

 

hi alan

My father came across a 850 in a breakers yard today, he got the airflow mass meter to try. As for the advice on the pressure regulater its fine. hopefully its the mass airflow meter. and if so then she will be coming home with me at weekend..

 

Hopefully that is it and all is fine from there.