I have the new style 24# Accel injectors on my 350TPI. The cam I'm currently using is very mild (208/214 467/482), but the rest of the engine and TPI are ready for business! My problem is that the engine runs rich at WOT with Dynojet & Diacom A/F readings of between 10.8 and 12.2. WOT O2 readings are in the low-mid 900's at all rpms. My BLMs average 128, but haved spiked as high as 153 for an entire WOT 1/4 mile run while still reading rich by the O2. What's up with that?

My guess is that my 24#ers are too much for the small cam. What's the best way to adjust them "down" to a leaner level? My strange BLM readings do concern me, but I believe the O2 readings tell the real story. Would listing 22#s in the prom help or is there more to do?

 

Look for your injector constants in your tuning software...

running a 22# constant with a 24# inj will make it richer whereas changing it to the correct 24# constant will shorten the pulsewidth leaning it out as a whole(global change)

there was a decent discussion on inj constants here if u do a search im sure you'll find several

 

BLM"s at WOT are meaningless - the ECM is open loop at WOT. you can ignore them.

If your BLM's are good for most of your part throttole operating (say, 124-132 range) then you just need to lean out the WOT enrichment a bit. assuming you're running 730/SD/$8D, there is a table in there for WOT PE %, called P.E. %Change to Fuel/Air Ratio Vs. RPM, when you see it, it will make sense.

I'm assuming here that your VE tables have already been worked and are accurate? If not, you'll chase your tail.

BTW do not assign any meaning to your O2 reading at WOT - it's meaningless, as the NB O2 is just a switching device and is only good to tell you 'are you leaner or richer than 14.7:1'.

 

91L98Z28,

You are the MAN! Very good info. I'll be working on the prom and see what I come up with...Thanks again!

 

hang around DIY PROM awhile, there's a lot to be learned here! I didn't know squat about this stuff a few months ago, but learned a lot here. So i'm just passin' on the knowledge.

Check out traxions' intro articles, grumpy's postings, and others (sorry for anyone i didn't mention) as there is tons of good stuff in here.

 

I've already been researching. I just wanted info as to which direction to go with the current condiditon. Ed Wright is going to retune the chip for me once, but after that I'm on my own.

I can't wait to sit down and program my own chip! Buying the Diacom was my first step, so now I'm ready for the next! Thanks again for the advice...