Ok the blm are at 160 at idle you can smell that it is rich the plugs are black my ? is how can the blm be at 160 and still be rich this is on a 86 maf car with a 406 gutted maf 190afr heads 296/288advertize comp cam mini ram 58mm tbody car runs strong. Thanks for any and replys.

 

Well, let's start with the basic stuff:
1. O2 sensor not working
2. One or more injectors not working
3. One or more plugs not firing

Try looking at those first.

 

I you told me your blms were higher than 128 and that you smelled fuel at idle I would suspect a lean idle miss. Is it possible that the plugs are colored black from WOT driving?

John

 

Have change the 02 senor and injectors have 30#in now did same thing with 26# and have new plugs no vaccum or exhaust leaks car runs strong blm 160 at idle in closed loop so why is it showing lean when it indicates that it is rich.

 

This sounds a lot like my problem, which Ive been chasing for a few months now. I actually gave up for awhile and just rode my motorcycle for the summer. Now is a good time to get to the track and pack up the bike, so Im tuning again. Im running SVO 30#s, and have a new heated o2 as well. I may agree with the lean miss theory, so you might want to lower your inj size in prom to 30 or so. I put 33 lbs in my prom and it ran horribly (really rish smell and very bad gas mileage) then I went a little lower to 30, and it got a little better. I now have it at 28lbs and it runs great and I get some great gas mileage. I still have a fuel smell at idle, but not when driving(at least I cant smell, and no complaints from friends driving behind me) I still have a lot to play with, but these are just a few things that Ive encountered in the past few weeks. My plugs were too fouling out after the new engine, too bad it turned out that all of my valve springs took a dump and completely distroyed all 16 valve seals. That wasnt a pretty site!
So far my plugs look great after all the work, and the prom is actually getting me better gas mileage. I was getting 13 or so mpg with 33lbs inj chip, but with it at 28, im getting closer to 16. And I havent even played with highway mode yet!
Good luck, and please get back to me if you find your prob. Im going to try a new o2 and ECM to see if anything else changes. After this, im getting rid of the MAF crap, and going SD.
Joe

 

I had the same problem, and it turned out to be an air intake leak after the MAF sensor.

 

Same with me....it was a blown intake manifold gasket on the drivers side, where the o2 is.

 

I had this problem on and off for a while. First time it turned out the underside of two of the primaries on the headers were leaking, so i got some better gaskets. That solved it for a while, but now i have the same problem again, so im suspecting another exhaust leak on the o2 side.

 

Hey plant protection how did you determine that the intake was leaking.THANKS FOR ALL REPLYS AND ANY FUTURE RESPONSE

 

Carb cleaner around the gasket didn't work because the gasket blew out on the lifter valley side, which explained the oil on my plugs also. I had just changed all my runner gaskets and still had a vacuum leak so I figured it was the manifold gaskets. Best performance mod I've done, my g-tech times went from 19.06 to 14.7, hehe.