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Running Rich - Read Spark Plug Photo

2K views 36 replies 10 participants last post by  daytonmvp23 
#1 ·
JZW Stage 4 - 2000 9-3 SE Vert Automatic

Mileage is down. Plugs are 7es gapped to .036

I drive mostly stop and go (mostly stop) in city...Some "very spirited" driving.

Just pulled the plugs yesterday...They are all uniform as the photo..

Should I go back to 6es plugs (maybe it's not burning enough on stop and go)



 
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#7 ·
I've checked and double checked all vac lines...most are silicon..BPC hoses are new...could the forge BPV cause a lower vac reading or the BPC...both are new...the only old part left is the Purge Valve...every other sensor has been replaced as well.
 
#10 ·
He said he's using NGK's.

It could be the BPC. I purchased a used one (which I later found didn't work properly) and it definitely screwed with my idle and vacuum a bit, although not continuously. Swapped out with a different used BPC, and we're good now!

If you're sure the BPC is fine, and you've checked ALL of those vacuum hoses, I'm not really sure... My plugs look similar to your's, I don't really think that's the problem. I could be wrong though!
 
#11 ·
I'm curious: Does your exhaust tip turn black at the lower rim?

My car gets 21mpg, has some cold running issue, and if I clean the exhaust tip, it turns black again at the lower rim within about 30-40 miles.

This is not my car, but the exhaust tip looks the same:
 
#13 ·
Better rich then lean when you have a tune and those plugs look fine, but maybe a tad old, drop gap to .34 and do not change heat. Plugs are not going to increase mileage unless they are shot. Maybe it's the change of fuel (winter to summer gas) and the fact that there is no snow and were all flogging it now that the roads are somewhat dry. Winter I get better mileage as I'm putting around more.
 
#14 ·
plugs

Ok so the plugs look like the standard copper ngk as they have bigger nubs compared to plats and iridiums. The only thing noticable is the white ash deposit which would suggest too much fuel additives. so if you are using SHELL ultra and then putting in some other additive like say octane boost or fuel cleaner constantly that is why your plugs look that way. Plus if I remember correctly Trionic can read octane ratings and if you go low octane it goes into (as I call it ) granny mode. less performance and better fuel economy where as high octane nets better performance and less fuel economy especially if you flog it! I noticed the drop in MPG as well when I put 95 octane in even when keeping driving conditions similiar. This more noticable on my trionic 7 Saab 9-5 then my trionic 5 9-3. But you could always get a vacuum tester and do a vacuum test of the system first. Or get a leak down or compression tester and make sure everything is good in that regards. If you have the cash leak down and vacuum are the 2 best ones to get to check the health of your engine.
 
#18 ·
Good advice...I do have a mityvac...and I do use Shell ultra but I don't use any additional additive. I'll run through the vac lines again and I think I have another BPC to try out.

Ok so the plugs look like the standard copper ngk as they have bigger nubs compared to plats and iridiums. The only thing noticable is the white ash deposit which would suggest too much fuel additives. so if you are using SHELL ultra and then putting in some other additive like say octane boost or fuel cleaner constantly that is why your plugs look that way. Plus if I remember correctly Trionic can read octane ratings and if you go low octane it goes into (as I call it ) granny mode. less performance and better fuel economy where as high octane nets better performance and less fuel economy especially if you flog it! I noticed the drop in MPG as well when I put 95 octane in even when keeping driving conditions similiar. This more noticable on my trionic 7 Saab 9-5 then my trionic 5 9-3. But you could always get a vacuum tester and do a vacuum test of the system first. Or get a leak down or compression tester and make sure everything is good in that regards. If you have the cash leak down and vacuum are the 2 best ones to get to check the health of your engine.
 
#19 ·
Stage 4 JZW upgrade do you have the bigger fuel pump, injectors, and an adjustable fuel pressure regulator(FPR)(with gauge)? If not this is where I would start looking. Also does it still shift like it should or at least like it had before the problem start occuring?
If you have not done the upgrades to the fuel system specifically the FPR and injectors I would suspect these 2 maybe the culprit as the FPR diaphram maybe overloaded and the injectors running over their normal duty cycles. Plus since it is a 2000 it has a knock sensor right? So it could be giving false signals (but would normally throw an engine code) making the system run rich by retarding the timing too much.
 
#21 ·
I have stock fuel pump and stock injectors (as per JZW). Stage 5 is injectors/turbo 18t. I do have a 3.5fpr. It's an automatic so shifting is fine. I upgraded the fpr when I upgraded the tune. Not sure about the knock sensor. no codes at all
 
#24 ·
fpr

Does the fpr have the pressure dial on it? Just trying to save a step. Reason I asked about shifting is because if it is acting funny sometimes automatic tend to bind themselves up the more power you throw at them causing drastic changes in engine loading. But if this was the case you would notice higher rpms before the trans shifted.
And while not required the extra hp from the upgrade is pushing the limits of the stock components. Did you make sure your dump valve (BOV) is working at the proper pressures and that the wastegate is actuating properly? Should of asked if you used a different filling station then normal? Especially if you run high test as you could of been sucking up more water then gas depending on how long it was sitting in the tank. Happened to my 9-5 over winter as I was at a quarter tank and in the part of town you don't want to run out of gas at so filled up at a shady station and the water in the high test made the car run horrible the next day and froze my fuel lines the day after that when it hit below 0 for a couple of nights. Had to put the heater in the garage to thaw it out.
 
#25 ·
Great question...I Did have the transmission rev higher before it changed gears. I thought it was older trans fluid so I did a couple of fulid changes and it's been fine ever since...What would be another cause for the binding transmission besides fluid? I have a forge bpv and friday afternoon I took it out, cleaned and lubed with mobil synthetic grease...The car definitely feels like it's holding boost better but the mpg is still off...I'll check tomorrow but I thought the vacuum was a little better too. Not sure how a sticking BPV would cause vac problem though. The wastegate is a forge unit...with yellow 9psi spring...works perfectly. I usually fill at same sunoco station...I'll run a botle of techron through on next fill up. FPR is from GS...3.5 not a dial type.

Does the fpr have the pressure dial on it? Just trying to save a step. Reason I asked about shifting is because if it is acting funny sometimes automatic tend to bind themselves up the more power you throw at them causing drastic changes in engine loading. But if this was the case you would notice higher rpms before the trans shifted.
And while not required the extra hp from the upgrade is pushing the limits of the stock components. Did you make sure your dump valve (BOV) is working at the proper pressures and that the wastegate is actuating properly? Should of asked if you used a different filling station then normal? Especially if you run high test as you could of been sucking up more water then gas depending on how long it was sitting in the tank. Happened to my 9-5 over winter as I was at a quarter tank and in the part of town you don't want to run out of gas at so filled up at a shady station and the water in the high test made the car run horrible the next day and froze my fuel lines the day after that when it hit below 0 for a couple of nights. Had to put the heater in the garage to thaw it out.
 
#28 ·
oh boy here we go

The fuel additive battle begins... I prefer seafoam or lucas but I am not going to say that any are better then the others just that I have seen seafoam and what it does for various engines like rotaries and piston alike. and I am sure with a fd3s rx7 you should know how well it works right?
Unfortunately there is no solid answer here since there are a lot of expensive could be that don't fix it. I would get it hooked up to an actual diagnostic program or at least looking at the parameters of how the systems of the car are operating. I don't know if the JZW tune brings up the diagnostic info on screen or not but if so I would check it out or have it checked out by a good saab tuner who understands the JZW tune.
 
#31 ·
Ummm, they really aren't that expensive... :roll:

I got my set of G-power Platinums for $2.50 a plug ($10 and change for a set). The ones that are like 9 bucks each are the Iridium ones, those are expensive...

Spark Plug - G Power Platinum
Product Line: NGK
Compare: NGK 7088
Price: 2.49
Unit: Each
 
#37 ·
weird science.....ah hahaha

It is elementary my dear Watson... sorry little science humor.
Copper vs platinum vs iridium
Copper periodic number 29
Platinum periodic number 78
Iridium periodic # 77
Copper very conductive especially at the range coil packs like to put out. However also very soft in terms of the metals.
Platinum and Iridium not so conductive but still operate very well at the coil pack output levels however also very hard metals compared to copper.
Copper is generally less likely to have problems because it is more like to conduct and release the charge (very minute difference for most applications but when you are dealing with getting the most power out of a tune it is a big help having all the little advantages in your favor)
In essence the reason why platinums and iridiums have such a small tip. #1 they are expensive metals so the tips are usually the only part that is actually platinum or iridium and #2 by making the tip small you have a greater potential energy in a given space...taking all the charge at a needle head compared to a blunt copper head is better at focusing the energy to a given point. Also Copper would work better in this setup as well but being a softer metal the benefits would be only usable for say a couple pulls of a drag car and meaningless almost detremental to a street car.
My uncle worked for the champion R&D team back in the 70's we still have some gold snowmobile plugs that he worked on and was given to test in the real world. In short awesome plug our snowmobile pulled better and got better gas mileage then anyone else running equal equipment minus plugs but they only lasted half a season compared to the coppers which last a whole season. Now we just take em to a jewelry store and the guy builds the electrodes back up for us. Well until gold went way up haven't used them for a couple years since they are so expensive but brilliant working plug.
 
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