Is there an easy way to tell if I'm leaning out my engine on top end with the stock 19# injectors?
The engine is OBDII MAF with a few mods;
1)6.0 tune up
2)BBK 70 mm mustang throttle body (stock MAF)
3)PP typhoon intake
4)Comp 35-510-8 cam and valve springs (stock rockers)
5)Ford Racing shorty truck headers and F-250 down pipe (true dual all the way to the CAT) with an "All Flow" CAT (basically a 3" straight trough pipe with a fake CAT shell on it) and 3" to dual 2-1/2" Magnaflow muffler.

Should I just put 24#'s in it and call it a day?
I have too much invested to burn a piston in this thing. Plus it's my work truck.

 

You need a wideband O2 sensor.. or a tuner.

 

Ok. I have wideband in my Car but its hard wired. I guess I'll have to pull it out and make it mobile so I can swap it from vehicle to vehicle.
At some point I'd like to invest in a twEECer.
What's your thoughts on this tuner?

 

How about running it as hard as you can (highest rpm you will ever run, at WOT), then do a code reading to see if a lean run condition is indicated.

 

It usually takes something like 45 cycles before it will set a code on minor running issues such as a lean condition.

 

Also I forgot to mention that it has GT40 heads.

 

Do get the wideband on there.

I have one on my race car and it helps me keep track of the A/F while at full throttle.

I've read that Ford's 19lb injectors will pass enough fuel to make around 320-330 HP. Beyond that level the injectors are going to have to run at 100% duty cycle and the engine will then go lean. The question is how much power is your combo making and how often you take it to that point? If it makes over 300+ HP at say 5000 RPM and you visit that engine speed often (Rare for a daily driven truck IMO.) then you should get the 24lb injectors.

I had 24 lb on my '93 Cobra Mustang and it did make over 300+ HP and I did take it to 5800-6000 often while racing it.

 

I'm not sure what I'm putting down for power but I doubt its near or even at 300 HP.
Being a gear head, I even take my DD truck to 6000 RPM once in a while. It pulls hard from 3500 to 7000 so it's hard (mentally) to get myself to let off the throttle under hard acceleration.
I now have some 24's setting on my bench so I'm going to do a "before and after" AFR between the two size injectors.
I'm not sure if the OBDII will compensate for the bigger injectors or not but I will find out.

 

Unless you have done something to the EMC I don't see how you could hit 7000 rpm on a OBD II run engine. Ford usually sets a rpm limit of 6250. This applies to the 5.0L & 5.8L's. The newer 4.6L & 5.4L may have some other limit set for them.

My 2000 SVT Contours 2.5L DOHC V6 has a limit of 6750 even though it's still pulling hard at that RPM. It's mostly to protect the rotating parts and so that Ford can warrenty the engine.

 

Not without tuning.

 

7000 is a guesstimate because the factory tach stops at 6000 RPM but the needle goes past 6000 the same distance as there is between 5000 and 6000.
It's probably all in the calibration...and the fact that Ford never intended the needle to go that far. Lol


I removed the AIR pump, Cat converter, EGR and solenoid, the DPFE sensor, and its an Automatic trans PCM. It runs great in my book. I just don't want to burn a piston with a lean condition. Plus, (as I'm sure you know) while 14.7:1 may be the ideal AFR for power and fuel economy lower AFR is where the power is. I intend to get a tuner to turn the CEL off because of the 7 different Trans codes.

 

14.7:1 produces the most efficient combustion and lowest emissions, but best power is at 13:1 and highest economy at 15-16:1. These are the targets that the stock computer aims for, the older systems didn't have much(or any) programming for a lean burn mode which is used while steady cruising at light throttle, but all of them have load based fuel tables that fatten up the mixture when you're foot is in it. A handheld tuner would be the ticket, you won't have any problem dialing this motor in with that and a wideband O2 sensor.

 

What other tuners are available for the early OBDII trucks? All I have found is the TwEECer.
Which as you know isn't handheld.
What tuner are you speaking of?
Thanks guys, Steve