1999 S80 T-6 P0303 Error even after changing parts

diamond963 · Post by **diamond963** » 08 Jul 2012, 22:01

OK, basic info 1999 S80 T-6 with ~205,000 miles. I have owned it 5 years and do almost all repairs myself that I can(financial reasons)

I have replaced in the past 2 of the ignition coils and have had the spark plugs changed 3 times as well.

Last week I had the same symptom again. rough idol, engine Shakes like crazy at stoplight(top engine mount is broke also.. lol) so really shakes.

Having had this symptom before I bought a new coil and replaced the number three coil(3rd one from the left). I have an OBDII scanner so I reset the codes and after driving a while no change as same error code came back. So today I replaced the Spark Plug just for Cylinder 3. Made sure everything was connected properly.

I am still getting the rough idle. I did just read on another post that sometimes the wiring can short with the engine block, so i will inspect that, but the connector and everything else looks real good. Everything is seated properly and I even moved the new coil to another Cylinder just to see if anything diferent. No, I still get P0303 on the scanner.

Any ideas. because this one stumps me...

Thanks in advance for your help.

oh, one thing to add in case it makes a difference. Engine is hard to start when warm.. most of the time takes 2 tries of cranking 3-5 seconds.. when cold from overnight or extended sitting, always starts the first time.

Thomas

Post by **boosted5cyl** » 09 Jul 2012, 16:21

Could be an injector fault as well. Or, dare I say it, low compression in that particular cylinder. Swap the injector with #1 and see if the misfire moves with it. Or, throw some B12 fuel system cleaner in there...

diamond963 · Post by **diamond963** » 10 Jul 2012, 20:28

OK, I purchased a compression checker and it rates a big fat ZERO in the third cylinder.. I am not liking the sound of that... I did check cylinder #2 at it came in at ~110.... I was hoping my new tester was broke.. LOL

Post by **boosted5cyl** » 11 Jul 2012, 09:02

Oh crap.... Few things to bear in mind...

Target PSI is 160ish, if you wanted to be OCD you could try and compensate for air density, but without knowing if the psi is meant to be at 100% RAD it could be a wild goose chase).
Test Must be done on full throttle, or throttle body/inlet manifold maniold removed.
If the ignition is left on for more than 2mins without the motor starting/firing, it ECU wil close the throttle. So, turn ignition on and off after each cylinder compression check.

Next step would be to either to a wet test on #3, or a leakdown. I think I'd just do right to a leakdown or even just add 30psi of air in there and listen. Thats quite a drop in pressure you have there.

diamond963 · Post by **diamond963** » 11 Jul 2012, 23:54

Thanks for the feedback. I am going to do the leakdown test as soon as I look it up and see what that means. LOL Though I have done alot of work on my volvo I have never touched an engine so this is my first foray.. we did turn off the ignition after each test and removed the key. and the 3rd cylinder showed Zero both times. I didn't bother doing the others yet.

How do you ADD 30psi..

ok I am clueless about engines.. I fix computers for a living and can do anything with instructions but a little lost here.

I do have a specific question. I am planning to get a newer car within a year.. what if I was to drive it like this. whats the worst case other than car totally losing it.. am I causing a major issue. it never dies just idles really rough especially when AC is on and I have tried not to use it when sitting at a light.. My finances are limited until December then a $700.00 monthly payment comes off the books and I can get a newer car..

What would you guys do.. if it is the valves just replace the 1 or 2 to get by.. just curious

to set the record straight I have no issues doing the actual work if I can afford the parts.. I probably can spend $500-750 total..

Thanks for anyones feedback..

diamond963 · Post by **diamond963** » 12 Jul 2012, 03:48

I do want to ad I watched a video and got all the info about a leakdown test.. I will try that this weekend... and post results.

Post by **boosted5cyl** » 12 Jul 2012, 11:33

Yeah Im a computery person too...

By add 30 psi I mean literally put compressed air into cylinder #3 via the plughole and listen for where it comes out. Basically a leakdown test without the gauge part. Since you have no compression. Hopefully its just a burnt valve or better still a broken valve spring. There's hope that you will be able to get this running right in your budget, or half, but you will need to remove the head if it is indeed a valve. Even a piston with no rings in it will give you a little compression.

Without knowing exactly why the compression is zero on the cyl its hard to say what the longer term ramnifications and risks are..

diamond963 · Post by **diamond963** » 12 Jul 2012, 19:34

Boosted I want to thank you for your help.. its been invaluable.. but today something worse happened.. I did not think that was possible. I went to start the car and it started to turn over and then nothing.. like the starter broke.. I have lights everywhere and all the auto locks work.. and lights on the dash.. but when I go to crank the engince I get a really funny noise.. to be honest and this is just my opinion. it almost sounds like the whirling of a blade not touching anything. almost if the starter was like two inches away form the motor.. it sounds likes it works but There is no engine turnover what so ever.. there was the first .5 second when I tried this morning.. now just a pinch of high end clicking whirling noise... any ideas

I am just ready to shoot this thing.. LOL

Thomas

Post by **boosted5cyl** » 12 Jul 2012, 20:14

Oh I know your frustration only too well. Sounds like it might be a simple starter issue. Is your battery strong? How about the cables going to the starter? Good, clean ground?

diamond963 · Post by **diamond963** » 13 Jul 2012, 01:17

yes, good clean ground. Starter is fairly new but it may not have been high quality. and I have put extra stress on it the last few weeks with all the lengthy starts with the 3rd cylinder.. I realized I have let the starter stay on way too long sometimes.. so I am hoping this is it.. I should be able to pull it either tomorrow ight or saturday morning.. is there a quick test I can do to verify thats it... Thanks again