my 454 swap

[black dawg]

Well, I got the 454 prom to work for me. It seems my balancer has slipped, so timing was way to advanced. I also lowered my fuel psi from 15 to 12 and this leaned it out to where it works. I think these injectors are to sloppy, because I have never seen that little of pressure change affect the o2 as much as this did. The injectors do look drippy at cold start.

what would you expect to see for warmed up open loop idle o2 readings at 3500ft? I am .89ish
what would you expect for WOT? I get from .96-1.0

[gregs78cam]

Well in a TBI dropping from 15 to 12 psi is about a 10% difference in flow. I would think an OL idle should be close to .50 maybe .60, ideally .45, but that will depend on your VE table. 0.89V at idle sounds really rich. .96 - 1.0 at WOT sounds only slightly rich, but a NBO2 is not even close to being useful for WOT tuning IMHO.

[EagleMark]

Well, I got the 454 prom to work for me. It seems my balancer has slipped, so timing was way to advanced. I also lowered my fuel psi from 15 to 12 and this leaned it out to where it works. I think these injectors are to sloppy, because I have never seen that little of pressure change affect the o2 as much as this did. The injectors do look drippy at cold start.

what would you expect to see for warmed up open loop idle o2 readings at 3500ft? I am .89ish
what would you expect for WOT? I get from .96-1.0

3 psi is not a lot on MPFI when base pressure is 43.5 but 3 psi is a lot on a TBI system based on 13 psi.

The O2 readings your showing are rich, but at 3500 feet I would expect that.

Narrow Band O2 sensor is only measuring 1 volt and designed to be about .45 for 14.7 to 1 AFR so higher is richer and lower is leaner. But it is only accurate around .45 and ECM keeps it swinging back and forth there.

Wide Band O2 sensor uses 0 to 5 volts so it is 5 times more accurate and designed to measure AFR, not just keep it at 14.7 to 1.

Having these old injectors serviced is great money spent. If you don't have someone local look for Mr Injector. I've seen between 5 and 13% difference in injector flow rates from service.

With the cam change your only option for great running engine is a chip tune. If you don't have equiptment needed, then you've really done all you can. You need to get these mechanical issues in order before tuning anyway. If you want to get into tuning then buy equiptment and spend some time. If you don't want to spend time and money then buy a cable to record data and you can buy a tuned chip. Either option is about $150. to do it right.

[black dawg]

Thanks for the replies and info guys. What do they do to service an injector?

I will most likely get into tuning myself, just have to save up a little. I spent way to much on this project already.

[EagleMark]

They test the electrical side first, then run cleaning fluid through them at high pressure with ultrasonic vibration. I've watched the service and can see the difference in spray pattern. Pretty cool!

[black dawg]

Well now I am really confused. I decided to try my motorvac injector cleaner on this thing, and it did make the injectors much cleaner. What I did learn though is that I had 30psi fuel pressure. When I checked the other day, I checked at the filter and with a different adapter to my gauge, and it showed me 15psi. So now checking fuel psi at the throttle body (verified with 2 different gauges) I have 30 psi. I have been having problems with it being rich, so I lowered it way down to 19psi, And it will hardly idle it is so lean. Is lean accross the board at 19psi. I played with the pressure some more, and it takes 22-23psi to make it run right. I checked the injectors numbers and they are the early 454 injectors.

I put in a better pump before I did the swap, so that I would have some room to pressure tune if I needed to.

Am I overlooking something really stupid, or have these injectors been screwed with?

[black dawg]

I should add that I got this throttle body from my brother in laws truck, And it never ran right. Had some lean issues and eventually burnt valves. It was a 92

will the pre-94 regulator make over 20psi? I basically cut the spring in half to get the pressure under 20psi.

[EagleMark]

Something is wrong? Fuel pressure gauges are notoriously inaccurate! Your pressure should be almost identical after filter and at TBI unit.

What injectors do you have?
http://www.gearhead-efi.com/Fuel-Inj...d-part-numbers

If you had to cut a spring in half I'd say you just cut a good high pressure spring in half that came on later BB TBI units that run about 30 PSI... if numbers you are at now are accurate you have enough pressure for early BB injectors for about 500HP and should be pig rich at idle with stock chip.

Or you have a restriction in return line? Return line should be 0 PSI anything above that raises feed side by same amount.