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Howard Jones · 04-15-04, 02:06 PM

Adam may be on to something with his milling question. I had a big ford,460, once that had a warped intake manifold. This resulted in two cylinders , the last two side by side on one head, fowling plugs. I replaced the intake gasket and right away the problem came back. In the end taking everything apart to crack check the head, intake , resulted in finding the warped intake. I believe it was cast bad from the begining. The engine ran okish and I wouldn't have found this problem if I wasn't doing a tune up and noticed the two different plugs readings.

You might want to really have a look at the intake to head surface for flatness. If a given cylinder goes super lean, 40-50 to 1 or more because of a leak then the fuel charge might not even burn resulting in a fowled plug. This might also be the cause of your low speed ruffness. Low engine speed\ high vacume would be the worst case for this if this is it. At a higher engine speed low vacume condition the entake charge might just fatten up enough to fire. Here's your higher rev power coming on.

That is all I can think of, except if you are going to tune the FI again check EACH cylinder fuel\air ratio. This is going to be hard with your exaust system. You might want to fit up some cheepo exaust manifolds with sensor bungs in each exaust port just for the setup of your FI system.

I hope this helps.

04-15-04, 02:06 PM	#14 (permalink)
Howard Jones 10 tenths Join Date: Jun 2002 GT40: San Francisco Bay Area California USA Posts: 1,921 Rep Power: 26	Re: wierd plug fouling condition Adam may be on to something with his milling question. I had a big ford,460, once that had a warped intake manifold. This resulted in two cylinders , the last two side by side on one head, fowling plugs. I replaced the intake gasket and right away the problem came back. In the end taking everything apart to crack check the head, intake , resulted in finding the warped intake. I believe it was cast bad from the begining. The engine ran okish and I wouldn't have found this problem if I wasn't doing a tune up and noticed the two different plugs readings. You might want to really have a look at the intake to head surface for flatness. If a given cylinder goes super lean, 40-50 to 1 or more because of a leak then the fuel charge might not even burn resulting in a fowled plug. This might also be the cause of your low speed ruffness. Low engine speed\ high vacume would be the worst case for this if this is it. At a higher engine speed low vacume condition the entake charge might just fatten up enough to fire. Here's your higher rev power coming on. That is all I can think of, except if you are going to tune the FI again check EACH cylinder fuel\air ratio. This is going to be hard with your exaust system. You might want to fit up some cheepo exaust manifolds with sensor bungs in each exaust port just for the setup of your FI system. I hope this helps.