[razzamorente]

Ok so I have been perusing the boards trying to find someone in a similar situation as I am in but to no avail.

My car keeps throwing a CEL and when i read it, its always p0301 (cylinder 1 misfire). this makes sense as my car has been running somewhat rougher than usual at idle. Also, I think I have been smelling some kind of gasoline smell at idle as well. The CEL appears when the car is hot as well as cold, and usually appears when the engine is not under a huge amound of load.

I thought it might be a bad plug so i took off the DI and swapped the cyl 2 plug with the cyl 1 plug... but it still threw a cyl 1 misfire later on so its not the plug... Also I noticed that there is some kind of rust colored gunk near the spark plug holes... Maybe this might have something to do with the misfire? Has anyone found a safe method of cleaning that out? I have also heard rumors of applying di-electric grease to the tips of the plugs... would that help my situation?

Or could this be a sign of the DI dying? I thought it would throw a p0300 (random cylinder misfire) if that was the case. I am in the process of finding a tester DI and hopefully my car doesnt break down in the process. I don't think it will as it runs fine except at idle where its just a little rough.

Thanks for your help.

 

[G96nt]

When my 9-3 Started chucking random CE lights for misfiring, it Was the early-signs of DIC-failure...

only thing I can think to suggest is putting some dielectric on the tips of the plugs(cold-side) and See if it helps..... otherwise, you may want to start looking For a new DIC


Ps... mine Always threw cyl 2.. not Random misfire

 

[bkrell]

G96NT's response is interesting because I've never heard of a dying DI throwing a specific cylinder misfire. They usually go random. Although, it is certanly possible since a specific coil going out should only affect that cylinder I suppose. I would start with the basics though.


First, get some new plugs. Remove the ones you have right now and toss them. This is not saying it's just plugs, it's just that swapping them around can really muddle things. I thought I had been careful when I was having the same problem and went thru all types of diagnostic procedures only to find that it was a cracked plug that I kept swapping into different cylinders.

The fact that you are smelling gasoline means that the plug is not firing correctly for whatever reason and gas is simply being sucked out the exhaust valve without being burned. This can be bad over time as it can ruin the catalytic converter.

As for cleaning, I would do the following:

1. Disconnect the DI.

2. Unscrew the black plug boot section (you don't have to remove the little screw around the wiring harness).

3. Reach into each plug boot from the inside of the piece and pull out gently on the springs. These are the connection between the DI's coils and the spark plug.

4. Gently remove any crud that may be on them.

5. Take some sort of rag or something and clean off the rubber tip of the plug boots if they are particularly cruddy. That rust colored stuff accumulates over time.

6. Apply a dallop of di-electric grease to the inside of the rubber section of the plug boot. Don't smear it, just let it sit there where the spring will be.

7. Apply another bit of di-electric to the exterior of the plug boot. This will help keep that crud from re-forming.

8. Reinsert the springs back into the DI plug boot section. Make sure enough spring is present at the plug end that it's even or just inside from the top of the plug boot. Don't worry too much about accuracy here as the springs should self adjust when fitted over the plugs. Now that you've cleaned everything off and greased it up, that's no big deal.

9. Reassemble the DI and try it out.

This may seem like a lot of trouble to go to but it will just take about 15 minuetes or so. The hardest part is just unscrewing all the screws on the DI! This will help you eliminate the plugs and their connection and move you on to bigger issues if the misfire continues.

From there, if the problem isn't fixed, I'd look at DI. There's always the possibility that it's the injector, though. But if you are smelling gas I'd bet not.

 

[razzamorente]

Thanks bkrell for the excellent directions.

Unfortunately after all that the car is now running a bit smoother but is still apparently missing as the CEL is aglow just as it was before.

So constant specific cylinder engine misfiring is definitely indicative of DI failure? Or could there be another culprit?

 

[bkrell]

No, that's not what I was trying to say. There are only so many things it can be though:
1. bad electrical contacts between plug and DI coil
2. bad plug
3. bad fuel injector
4. loss of compression
5. bad DI coil, requiring DI replacement
6. bad DI electrical harness (this is possible, and a tech would check for it, but I've never head of it being the culprit).

As for the check engine light, have you cleared it out? Typically a specific cylinder misfire will be very obvious. The car will have a bad stubling or hesitation to it. It can come and go depending on the culprit, underhood and ambient temps, but will come back unless properly fixed. Just disconnect the battery to clear out that light.

 

[earthworm]

Ok so I have been perusing the boards trying to find someone in a similar situation as I am in but to no avail.

My car keeps throwing a CEL and when i read it, its always p0301 (cylinder 1 misfire). this makes sense as my car has been running somewhat rougher than usual at idle. Also, I think I have been smelling some kind of gasoline smell at idle as well. The CEL appears when the car is hot as well as cold, and usually appears when the engine is not under a huge amount of load.

I thought it might be a bad plug so i took off the DI and swapped the cyl 2 plug with the cyl 1 plug... but it still threw a cyl 1 misfire later on so its not the plug... Also I noticed that there is some kind of rust colored gunk near the spark plug holes... Maybe this might have something to do with the misfire? Has anyone found a safe method of cleaning that out? I have also heard rumors of applying di-electric grease to the tips of the plugs... would that help my situation?

Or could this be a sign of the DI dying? I thought it would throw a p0300 (random cylinder misfire) if that was the case. I am in the process of finding a tester DI and hopefully my car doesn't break down in the process. I don't think it will as it runs fine except at idle where its just a little rough.

Thanks for your help.

Clean away the corrosion, use the di-electric(a must on all hi-tension electric connections), clean, re-gap the plugs(NGK BCPR 7ES, 1.0 mm gap) this for a '96, maybe some changes ???
The silicone di-electric grease assures a good corrosion free contact , use anti-seize on the threads...
Also check and record the compression while the plugs are out..(optional) and hope for the best..

 

[bkrell]

Hmm, I think that's about what I said! :roll: :cheesy: The plugs are the same on all 2.0 turbo 900 models. As both earthy and I mentioned, you can check compression if the plug aspect doesn't work and just before you break down for a new DI cassette. You can buy a compression tester from Autozone for about $30-40 at Autozone. It's a handy tool to have anyway.

Just remove fuse for the fuel pump, crank the car to the point it doesn't turn over, then disconnect the DI and pull the plugs.

Then screw the tester into the cylinder and crank for about 2-4 turns. The tester will record the max compression. Then reset and go to the next cylinder. I got I believe 180 or so when I tested mine. A problem will be manifested if one cylinder (I guess you're looking at #1) has more than a 15-20% variation (lower) than the others.

 

[razzamorente]

I have a obd-ii scanner and i have been clearing the codes right after i changed the plugs, cleaned the di, and coated both in dielectric grease and the same p0301 code keeps popping up.

If I test the compression and it is off, what can be done to fix that?

 

[bkrell]

Hmm, so you changed the plugs. Hmmm, as far as compression goes, I'd tend to think that'd be the LEAST likely problem, though I suppose it could be a stuck valve. A thorough test by a competent mechanic would be the BEST way to go in order to discern the true nature of the trouble if you do find low compression.

I would have to say the best option right now for you would be to find a spare DI laying around somewhere either from another saab owner or at a saab shop somewhere. If you seem to be getting the problem regularly, not under just certain circumstances, then that shouldn't be a hard task to figure out.

A new DI would be perhaps your best hope as far as the economics of you problem go, unless it turns out to be an injector related issue. If the DI checks out and a cursory pressure test seems to indicat no faults in that department, you may then turn to injectors. Your option for getting that taken care of is to go to a decent chain repair shop, which can clean your injectors. This can be done by either reverse cleaning them (done with them in the car still) or having them removed and flow tested and then if needed ultrasonically cleaned. This perhaps isn't a bad idea for ANY high mileage vehicle as injector spray patterns degrade over time due to bits of varnish and crud stopping up the mesh in them (sort of like the oil pickup).

It may even give a decent increase in fuel economy and power. Clogged injectors can not only suffer a degraded spray pattern, they can get stuck open and just dribble the fuel out instead of properly spraying the fuel for complete efficient combustion.

But first things first. Try to get the DI tested. Then investigate compression and injectors.