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i have a '94 turbo wagon that keeps setting 4-3-3 (and sometimes 1-4-3) for the knock sensors. Should I start with a tune up or go directly to the knock sensors? Is that code supposed to detect an error with the sensors themselves or an ignition/firing problem? I have read the archives and am confused about the right approach - some say it is the ECU, some say sensors, others tune up. Hasn't seen new plugs for 50k so I thought I would start there.
Matt
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http://volvospeed.com/Repair/knock_sensor.pdf
good luck!
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-woodsytf '95 850 wagon 160k
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Try the easy things first. Mine was trigering the knock sensor error code all the time (within one day of clearing it) until I replaced the fuel filter. It hasn't showed up ever since(several months ago).
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finished tune up - not the answer, but worth doing anyway. now it is on to the main course, knock sensors. I'll use the instructions from volvospeed and matthewsvolvosite, both are detailed write ups with many pictures. I'll post back when it is done, not sure if I can tackle it in one night.
~matt
'94 855 turbo w/150k
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anyone have a clue? just had an indy mechanic do the knock sensors and oil trap and right away codes came back. then i swapped in another ECU (mechanic has a stash of them). this momentarily cleared codes but in 5 mins they came back. i am at a loss. i have done the high grade gas, fuel filter, complete tune up, oil trap and now the KS. the indy shop says they can get to it but it may be many hours of testing for continuity at each pin or running through the volvo diagnostics with various computers/tool. is there another strategy or approach, any other connections to check? it looks like a straight shot from the KS harness to the engine harness to the ECU, not much to go wrong. should I take this to the dealer (last resort)???
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Just one idea left. Have your mechanic let the intake manifold suck in a can of SeaFoam cleaner. If done correctly, it will remove any carbon deposits in the combustion chamber. Lots of smoke initially, but if you have hot spots from deposits, they will cause premature ignition when the engine gets hot.
Be careful if doing this yourself. The vacuum will empty the can in a few seconds if not done properly and you could bend a connecting rod or 2 (new engine). The can must be sipped by the engine vacuum over a 2 or 3 minute period, then shut off for 30 minutes, and at restart it should blow out the carbon. It will also help clean the valve seats, etc.
Klaus
PS On vac for a week.
--
I still miss my 164
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just spent the weekend getting at the sensors. took about 9 hours total - major pain to remove egr bolts, fuel lines/rail, etc. found that the shop had not installed them correctly - one was not tightened at all, just loose hanging, the other was installed at the wrong angle (close but not right).
now all is good (I think, time will tell).
thanks for the help,
matt
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good for you. glad you found it. there is a fella in the V70 group who just had an issue with knock sensors that were not torqued properly also...
i wonder if us volvo owners are replacing loosened knock sensors sometimes... hmm...
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-woodsytf '95 850 wagon 160k
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It took me 9 hours to do my oil separator, 4 hours of which were just wasted time because I didn't know what I was looking at or why I was looking at it :)
Nice catch! One always assumes the "professional" mechanics are better than the typical shade tree type. We know better, because when we DIY, we make sure things are done carefully and cleanly. No rush to the coffee wagon or to punch the clock.
I like the write up over on Volvospeed re: knock sensor. It has allowed me to work on other things with more confidence.
Klaus
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I still miss my 164 and my 854T. Just driving a V70R :)
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Car does seem to accelerate much better, more turbo pressure I think. I wonder if 1-4-3 DTC was holding it back? Anyone know?
Matt
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It certainly will slow thing down. If engine management cannot get a signal from the knock sensor, it will treat the engine as if there is a knock.
Have fun spinning the turbo :)
Klaus
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I still miss my 164 and my 854T. Just driving a V70R :)
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this did not help (fuel filter), but looked to be original so I was glad to replace it. I'm planning on finishing the tune up tonight (plugs/cap/rotor/wires) then see what that does to codes. I'll probably not remove the injectors/rail from the IM - the directions on matthewsvolvosite for PCV system are good - maybe better since it is an 850 not V70. I think they changed a few things besides the name in 98, like turbo hoses. Haynes is not helpful on cap and rotor, BTW. Turbo makes a big difference. ALso, I only plan on replacing the oil trap, not all hoses. I will clean them, w/brake cleaner, but unless I see damage, don't want to shell out another $200 to replace good tubing.
thanks to all who have helped thus far. total materials (from eEuroparts) is running $270, including knock sensors, IM gasket, oil trap and tune up.
matt
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Time to replace the knock sensors. A tune up will reduce the amount of engine knock, but the sensors are no longer working properly. If you do this yourself, the intake manifold needs to come off, Volvospeed has a pictorial write up I can send you. It is also a perfect time to replace your oil separator and vacuum lines, two birds with one stone!
Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)
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How do I find the engine number? I see different oil separators based on engine number - is it the stamped number in the lower right (looking at engine with plastic plate off)? Mine is 1001621 P01 - does that look right?
matt
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That is the number for the valve cover. The engine number is on the block facing the firewall.
This is the part you want: http://www.fcpgroton.com/product-exec/product_id/14143/nm/1994_Volvo_850_Turbo_Oil_Trap/category_id/65
I suggest you go for the "kit" for a turbo. It is also listed on the left side of the screen above.
--
The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)
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any more ideas klaus? i think i've ruled out ks, fuel filter, tune up, gas octane. seems like it could be electrical....
matt
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i've read this is a nasty job - true? how involved are the vacuum lines and oil separator parts of the job?? the car has 150k. i've never removed the IM, but I did the plugs/cap/rotor at 90k. turbo intercooler pipes seem to be in the way...thanks for any details or links you can send my way!
matt
nashville, tn
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posted by
someone claiming to be fixit2003
on
Fri May 9 03:03 CST 2008 [ RELATED]
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You probably definitly could use some new plugs after 50K miles but maybe different or higher octane gas would also help. Check the distributor cap also.
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