Fouling Spark Plugs?

[forzaphil]

Hello All!

To refresh your memory, Valentina is a 1980 Spider 2000 FI. Navy blue with a nice tan top. I have been battling with her illness for some time now, and i'm sure it pains all of you as much as it does me to have her covered in a tarp. Over the past few months i have had the chance in between classes to troubleshoot her really rough idle (not driveable). I went through the Fi troubleshooting guide/ diagnostics manual and the good new is that all of the resistances for all the sensors seem to be within spec except for one of the AFM resistances (i can post which one tomorrow. it's 2 am and i don't feel like digging for my notes on the diagnostics). The fuel system also appears to all be in order; fuel pressure reads 35 psi at the rail, and bumps up a little while revving the engine then quickly levels back out at about 35 psi even with continued throttle (from my limited knowledge i think this means the fuel pressure regulator is working properly?) All injectors pulse and spray pretty much even amounts of fuel when engine cranks. The ignition system seems to be working properly (I replaced the white pickup wire that had melted against the manifold when all of my problems had started just to make sure my wire splice job wasn't the issue. Gapped the magnetic ignition pickup to spec and everything. Neat trick with the matchbook cover. I love this forum) All plug wires produce a mighty good spark when grounded to the body, So i assume everything up to the spark plug wires is okay. The tricky part I think is in the spark plugs. I tested all of the cylinders by killing them all one by one. Cylinders 1 and 4, when killed reduce the idle to almost nothing and the car almost dies. 2 and 3 however, when killed, no effect. That is obviously not good. I pulled the plugs and they are fouled with black sooty burnt on residue. I had replaced them several months ago, but they had fouled again over the course of my diagnostics. So something is continually fouling my plugs, and judging from the fact that after having cleaned them the best i could with some steel wool and returning them to the block, the car started and idled like a dream. Upon opening the throttle high to hear it purr, when it went back to idle it was nice and rough again. GRRRR. I had removed the air intake hose earlier to check for cracks and air leaks and found oil in the intake manifold and air hose. So my newbie guess is oil is fouling the plugs. AHAH! problem solved! wait not really.

So does anyone have any tips on what to do next, (oh and by the way, i had done a compression test and all read 150 psi pretty much straight across the board). Is it possible that after having sat for 6 months the cylinders are all full of oil and foul the plugs immediately? Can i run seafoam through it, or i also read in some random thread about hotter burning plugs? Is there a good combination of the two? I realize my futile stabbing into the dark is probably annoying, but i just miss my fiat so much. Any and all help is greatly appreciated. I know my knowledge of the car while growing is still small, so don't worry about hurting my feelings by pointing out that above assumptions are completely off base. I love how knowledgeable you all are and am grateful for your corrections. This forum is awesome. Thanks all in advance!

[puddin]

check out my post "now im nitpicking" i have excessive blow by that seemed to carbon up my plugs -- i removed the oil vapor tube and have clean plugs now but oil smell in the car....

[azruss]

worn valve guides and seals? do you get smoke out the back on decompression.

[mdrburchette]

Is the air cleaner clean? Might be causing a rich condition if it's not getting air.

[forzaphil]

Yes, It does puff some blue smoke out of the tailpipe as i am trying to troubleshoot, but i just figured that it had to do with the two cylinders that aren't really firing. As far as the air cleaner goes, it is very clean and seems to let air past just fine. I am pretty sure there is an oil leak, and my hope is that just after sitting for so long there is a lot of gunk in there that is fouling the plugs. Does anyone know about a hotter heat range of spark plugs?

[mdrburchette]

What plug are you running?

[forzaphil]

They are nothing special. Just inexpensive bosch ones I picked up from Napa. I can pick up nicer ones like the champions or ngks if you all suggest it, i have just been hesitant because of the fouling.

As far as the AFM resistance readings, in the diagnostics manual it says 'between terminals 6 and 8 resistance should be no more than 600 ohms.' - 366. Sounded Okay. 'between terminals 7 and 8 no more than 1200 ohms.' - 286. This one sounded relatively low to me. Between 8 and 9 no more than 350 ohms. Reading 202.

Am i recalling correctly that the resistance between 7 and 8 has to do with the sweeping arm in the AFM that is connected to the air flap? Would this low resistance mess with the air to fuel ratio perhaps? Thanks for everyone's help!

[forzaphil]

But Wouldn't worn valve guides or seals make compression uneven? I had solid 150 across all 4 cylinders.

And Puddin, the more i read other posts about it the more I think that blowby could be something that is fouling the plugs. I have tried to research the PCV system to understand it better. Is removing the cyclonic trap and the breather hose pretty easy or will i need to take the intake manifold off? Any suggestions greatly appreciated.

By the way, how does one figure out if the fuel is getting sprayed at the right time from the injectors? I know they are all spraying, but is it possible that somehow the ECU is sending the signal for them to open at the wrong time? just curious. Thanks all in advance.

[forzaphil]

Gah. Sorry. I kept digging and found a good post on the cyclonic trap. I also read TulsaSpiders thread about the supposed blown head gasket. It was like a mystery novel ; Great read. Does anyone recommend a good place for an Oil Vapor Separator Gasket?

[puddin]

removed and cleaned cyc trap -- waste ol time-- unless it's clogged it's just a circular path that oil vapor spins around and the oil liquid falls from gravity while the vapor excapes thru the hose. my hose wasn't clogged and hoses were good. ATT-- taking it off is easy but putting it on is difficult with intake manifold inplace.. the 13mm bolt is allowed to swivel around and trying to find the threaded hole is a PITA. -- i starting to believe that the oil smell i smells is the exh fumes entering the cabin. kinda like station wagon effect.. i give up -- just gonna enjoy the ride till it dies

[forzaphil]

Ha ha. Good Plan. Non saranno perfette mai, queste macchine. It is best to accept their faults and just enjoy the ride. They are too fun to not enjoy.

[forzaphil]

So, more information that hopefully one of you wise ones can say is the cause of all my problems? please please please. I opened the black cover on the AFM and saw that the sweeper arm inside had worn a track through the resistances. It was only reading like 300 ohms between 7 and 8, so i pushed it down more onto the track, but could not get the resistance to increase. Every post i read made it seem really easy... . I was able to scoot the PCB just a tad forward by unscrewing it a little and pulling it to a less worn part and retightening it, but in the end, it still read 360 ohms or so. Is this a problem? If so, anyway to fix it?

Oh and Mark, i figured out why the fuel pump runs no matter what, even with the right wire juicing it up. That kill switch inside the AFM that opens when the door closes completely isn't making any contact with the sweeper arm. I don't know if that matters somehow, but maybe.

Anyway, It's cylinders 2 and 3 that seem to be fouling plugs, but compression is 150 across the board. Any suggestions very very welcome. Thanks for taking the time to read these posts. sorry if it sounds desperate. I love my car and miss it dearly.