95 Bronco MAF big block swap issues
 

Hi everyone I have just completed a 460 maf swap in my 95 Bronco. I reused all the factory wiring and adapted it to the big block using a way1 computer. My question is, is I've tuned in the engines fuel pressure and timing with the mass airflow sensor plugged in the truck almost acts like its starving for fuel but once it's on plugged it runs great can anyone tell me anywhere to look I pulled codes in the only code that appeared was an air charge temperature sensor which I replaced and cleared the code and still have the issue

That PCM was built for a truck with 19lb injectors but your 460 has 24lb injectors on it so you need a tuner.

I ordered a 80mm Mass Air housing calibrated for 24 pound injectors to compensate for that. Brian at 5 ology racing says that there should be no reason that the 302 computer should not run the 460 on a base tune in that having it tuned is only to pull every ounce of power out of it

These MAF "calibration" tricks really only work as expected at WOT and when the engine under control matches the programmed displacement. A big block has very different fueling requirements than a 5.0 all across the board so simply scaling the 5.0 fuel map up won't cut it and you will notice this most at the small end of the scale. The fact that your motor runs better with the MAF unplugged.. which makes the computer revert to open loop maps confirm that the data it is getting from the MAF is no good.

Yeah I was testing the mass airflow sensor earlier and everything tested out fine so we're thinking there's an issue with my PCM. If what you're saying is that I can't use it to the effect that I'm trying to how exactly are people using way one computers to swap in Big Blocks and what mass air meter housing and mass air flow sensor would I use with a WAY1 comp

With a tuner. That gives the computer accurate numbers to work with, it will know what size engine it is feeding, the injector size and the MAF flow data so the calculations made will be accurate. And you can use any MAF meter you want you just need the flow data for it.

so how is brian at fiveology building the kits with the way1 ecu and selling them and peipke arnt having to tune them?? everyine has a different opinio. it seems.. personally ive seen my BB run great at cam break in but for some reason there an issue now.. i think its going to be a sensor or the ecu. but i guess ill find out one way or another

It depends what they are putting the kit on and what they are doing with the vehicle. On a 5.0 with some upgrades it'll work fine but the further you get away from that the worse the results... unless all you're interested in is 1/4 mile times.

no its in a DD/Off-roaded bronco. the kits he sells are to convert BB F-series to MAF, and its a layover harness with a selected MAF housing size calibrated to your choice of injectors and uses a WAY1 ecu to run it all along with repinning 4 injector wires to match the 460s firing order and he told me hes never had a customer have to tune it to run right and that tuning qill just net every horse available. when i broke my cam in the motor ran smooth as a babies bottom

No tuning is about dialing in all the subtle behavours.. idle quality and throttle response. It doesn't take any accuracy to build max horsepower.. you can do that with a carb.

So it's a flat tappet, is it a stock replacement or something else? Have you done a compression and leak down test? Maybe a cam lobe has been wiped.

https://cimg4.ibsrv.net/gimg/www.for...151fcd0957.jpg

yes its a flat tappet. its not much more then the factory cam. we've also verified the cam isnt flat.

so what did Brian say about the problem.

he had me run a test procedure on the maf and it tested good.. so hes leaning toward a bad computer. so i popped the cover off and found that moisture had been in it at one point but found no burnt capacitors
https://cimg2.ibsrv.net/gimg/www.for...883c985688.jpg

just to ask a stupid question are you getting a CEL or are there any codes. you using a ACT sensor. did you put in a new ECT sensor.

Yes all sensors are new other than the idle air control valve the mass airflow sensor and the canister purge valve. Also the computer was about 5 years old