Hello all, I just found those spark plugs on a 348 spider, just bought. My question is: It seems to me that they're not the right ones to use. I'll install, tomorrow new NGK DR8EIX. Any thoughts on these champion Spark plugs? The champions are "colder" that the right NGKs... I'm experiencing some rough handling with the drive. Tomorrow I will do a compression and leak tests. I've a steady idle, but I face some difficulties when starting hot. The hotter the engine the rougher it gets. On the other hand, I don't feel the 320 bhp... I don't smell petrol, I don't have any flashing lights inside, Slow down 1-4 or 5-8... What are the signs, besides the misfire of the engine, if one or more valves are burned/broken? Do I get higher temperature on water gauge? Should I hear some blows from the pipes? Any thoughts would be most welcome. Thanks, Mont P.S. What kind of damage should I get from colder spark plugs?
Check out my spark plug reading tutorial in the link in my tag line at the bottom of this thread. Hot start problems in 348's (which start fine when cold, anyway) are typically caused by one of two problems: 1. failing Fuel Pressure Regulator, or 2. a flywheel grease problem Check out the 348 Primer link below for details on both, but the easiest way to see a failing FPR is to pull off the little black vacuum hose that goes to each one. Fuel in that line indicates a failed FPR. As for cold spark plugs, they simply foul quicker. Spark plugs that are too hot are a different story. They can cause detonation.
No Doubt, Many thanks for the fast answer. I know that wonderful 348 primer pages, already. They are great help. My 348 just completed 50000 kms, I've noticed that the oxygen and thermic couples boxes are the black original ones, should I change both for the green epoxy? Just to be safe, I heard that they are upgraded. Also, regarding lack of compression what signs do I have? Thanks, Miguel
If your existing black exhaust ecus are currently working, then don't change them, just coat them entirely with silicon sealant right after a hot drive. They go bad due to moisture entering them. The hot drive will help evaporate any moisture that is already in them (as best as can be safely done), and the silicon sealant will then prevent them from degrading much more...so they will last some fair amount of time for your effort. This is cheap, easy, fast, and effective.
Unless you have an extreme loss of compression, you generally will only notice reduced engine performance. Before going to much trouble about such a thing, run a bottle of Techron fuel cleaner through half a tank of gas. When you refuel, add another Techron bottle to your gasoline. *And for every tank of gasoline from there on out, add 1/2 pint of Lucas upper cylinder lube to your gasoline. After that first tank and a half of gasoline has been driven (spiritedly!) out, you can then think to see if you have a real compression problem. Yes, you will also want to install new O2 sensors (they are cheap if you just buy the generic 4 wire O2's for 348's on eBay) and new spark plugs. ...but...before you remove your old spark plugs, go for a hard sprint up a long hill. Remove your old spark plugs when you reach the top of that hill, label them with their correct cylinder, photograph them, and post those photos here on Fchat. You can then reinstall the old ones or install your new ones right there on the spot. See my link below on reading spark plugs.
I'll do that. At first impression, looking to the spark plugs I can see that they all are same color brownish/grey, no oil or moisture, very nice according with your thoughts. Problems in the valves means a bad spark plug also, is that right? Thanks, again
