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V8 swap issues.




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The list of possible things is long, and engine builds add to them. Mix in some used parts, etc, and it is tougher to diagnose. I'd aim at the injectors, given the investment so far, rebuilt units would be wise. But of course check through the easiest and obvious stuff first, wiring, timing etc.
 






I've seen guys put old injectors with 200,000 miles on their new crate motors and told me they rarely go bad besides he used injector cleaners often....:banghead:

MAM, O2's and injectors are everything when it comes to making a motor run perfect. I swapped my injectors out @ 80,000 miles with refurbished ones and the difference was immediately noticeable. Nice crisp off-idle response and less misses.

Around $100 for refurbished off ebay then sell your used ones for $40-50. It costs peanuts to replace something important.
 






Well, the camshaft isn't getting changed at all unless I do a head swap, and that's a few years off if it ever happens. I doubt it will.

Once this is all dialed in, it'll be a fun little truck.
 






FYI, finally got a fuel pressure tester. 64 psi when running, around 55 with engine off.
 






FYI, finally got a fuel pressure tester. 64 psi when running, around 55 with engine off.
That should do okay, I think about 60-62psi is a minimum level, before the PCM throws a lean code. The 55psi off is okay too, there are few vehicles that really don't leak down at all.
 






I think the "fuel injectors too big" is gonna end up being the cause of everything. I got to researching on some Mustang forums and found a great thread, let me see if I can find it, but basically talking about what a few of you said previously. Injectors pulses at X pressure vs Y pressure. Well, they may be 24# injectors at 39psi but at 63, they'll act like 30#s. 19# will act like 24#s. So goes right in line with the "too much fuel" that a few have been thinking.

Hopefully the tune can be rewritten to work around this. Just funky that it threw lean code, but I'm attributing that to the loose oxygen sensor and sucking air around it.

Will post back hopefully Monday/Tuesday when I have a new tune/video.

As always, the help is greatly appreciated.

(gotta get the damn axle now and some carbon fiber clutches for it!)
 






to be cautious, pull the oil dipstick and make sure it doesnt smell like gas. if it does, dont drive it, or start it. change the oil right away, and also have a look at the plugs. if they also look fouled, you might want to change them as well. hotroding is fun, but expensive.
 






I think you will like the "E" cam, I was thinking of the more radical in the alphabet series.....

The stock injector slopes/size in my tune are 22.871 Hi slope and 25.358 Low Slope. The computer fires the injectors with the Hi slope variable factored-in most of the time. When fired at idle they fire at Lo slope, 25.358 injectors in order to make-up for the fact that the injectors get fatter/richer at low pulse width. That has much to do with idle quality.

Why fire a 19lbs injector as if it's a 22.871???? Because of the higher fuel pressure. I guess Ford didn't want to rewrite the programming for the few and newer running higher fuel pressure? I need to get an idea for my tune, I will likely need a bit larger injector. A good starting point would be to increase slope sized by the same percentage Ford did for the stock injectors.

I will post the stock injector slope for an 01 4.0 SOHC also at 64lbs of fuel pressure.
 






As an aside the 4.0 SOHC the 19lb rated injectors slopes are increased too:
24.829 Hi Slope
26.544 Lo Slope

On the 5.0 I see the rated injector size increased by 20.37% (Hi slope above Idle) and the Lo slope (idle) is increased by 33.46%.

Follow the logic here? a 24lb injector could be input as a 28.80 (Hi slope) and 32.03 (Lo slope). I would start fatter/richer/lower and work toward those numbers checking O2's as you go.............
 






to be cautious, pull the oil dipstick and make sure it doesnt smell like gas. if it does, dont drive it, or start it. change the oil right away, and also have a look at the plugs. if they also look fouled, you might want to change them as well. hotroding is fun, but expensive.

Haven’t started it since i figured this out. Not trying to wash the rings out. I’m headed to the shop now with the programmer in hand. Gonna see if they can adjust the fueling and also their input on it.

Going for an axle tomorrow. I hope.
 












What's the good word Josh?

Went by Friday, tune wasn't ready. I dropped it off last Tuesday. apparently the guy who does the tuning and such has an infection in his leg and went home Tuesday morning? Never heard back on Wed or Thursday, stopped by Friday after work, still nada.

No call today either. Going up there tomorrow after work.

It sucks, but hey, if the guy isn't at work because of health issues, whatever. I haven't driven the truck in over a year, another week or two isn't gonna matter.
 






I just read this. you are seeing lean codes due to unburnt fuel in the exhaust. The earlier assessment that the tuner needs to scale the injector or 65 psi returnees fuel system is correct. When the tuner gets back, he could just work on the maf transfer function to fix this, but then there will still be other nagging tuning issues.

Make sure the guy tuning is reminded he is working with a 65psi fuel system, not 40.
 






All right so i went up there and talked to him and they looked at it. #3 injector is not firing. TO replace it I have to remove the intake which i didn’t want to do. Since i have to now, I’ll downsize to 17 or 19# if i can find a set for cheap.

Will update when i have something to report.
 






Do you think its the injector, or the connector?
Great to hear you found the issue.
 






When i pull the upper intake I’m going to disable the fuel pump relay, unplug the ignition coils, and turn it over with a noid light plugged in to see if it’s shooting the pulses.

At least it’s something to chase down.
 






No real updates. Been outta work for about a month and just started a new job. Replaced the "bad injector" with a reman unit and still acting as before. Tuner seems to hear my "the fuel pressure is higher and the tune needs to be adjusted for that" and it goes out the other ear. After a few weeks and paychecks I'm just going to purchase the SCT software myself and adjust what I know needs adjusting. At that point, I'll run it a few thousand miles and find a shop that can do the final tune. I'm done going in circles with a place that won't listen to what I need them to do. I'm paying, shouldn't be a problem right?
 






I'm done going in circles with a place that won't listen to what I need them to do. I'm paying, shouldn't be a problem right?

You are paying for time on the dyno.

Should be your call.
 



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You ever swap in 19lb injectors? Still have a miss? Try the factory tune? Mine runs ok on stock tune with my mods, the tuner just crisps things up.
 






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