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4.6L stroker in the works

That is some sexy shit man. The piston slap you have is normal of a lower silicon piston, as long as it goes away once warmed up.

However, I doubt the injectors are the cause of your 3k lean spike. Normally an overworked low imp. peak/hold injector will go full open and it will peg rich before slowly leaning out as the RPMs increase... However, I'm not exactly an expert on chysler ECUs. Also a 23lb injector does sound VERY small for that motor. Are you consistently getting that spike?
 
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Talyn-
I would recommend finding injectors from an 03 Mustang Cobra or Mercury Marauder. They are 25 lb injectors and have the correct electrical connector for your 2000. They are NOT ford motorsports injectors though. I've had them in my stroker for almost 30k miles and not a single fuel related problem.
 
I know the pistons slap is normal for the KB944 pistons.. just some people say that they have slap and some not.

Well, someone pointed out that 42psi is too low for the fuel pressure.. I knew the rail should be 49, but I thought 42psi was with in spec. I went back and took a look at the FSM and the minimum is 44psi. So, do I get just the pump and screen or do I get the whole assembly with the pressure regulator?

I had the Cobra injectors in the short rod stroker I had before and it ran way rich with them. They are rated at 24 lbs, but that is on a 39psi rail. On the 49 psi rail they would flow 27 lbs.

Jeepinwi, do you know what your LTFT is with those injectors? As is now, with the 23.8 injectors and my crappy fuel pressure it is at +35%
 
Bryson said:
However, I doubt the injectors are the cause of your 3k lean spike. Normally an overworked low imp. peak/hold injector will go full open and it will peg rich before slowly leaning out as the RPMs increase... However, I'm not exactly an expert on chysler ECUs. Also a 23lb injector does sound VERY small for that motor. Are you consistently getting that spike?
Click to expand...

From the limited time the scantool works it looks like it is open loop when it does that, so I was able to get most of the problem gone with the apexi, but it still isn't normal for it to happen so low in the RPM range and not even under WOT. The injectors aren't over working, the PCM is just telling them to reduce flow.
 
jeepinwi said:
Talyn-
I would recommend finding injectors from an 03 Mustang Cobra or Mercury Marauder. They are 25 lb injectors and have the correct electrical connector for your 2000. They are NOT ford motorsports injectors though. I've had them in my stroker for almost 30k miles and not a single fuel related problem.
Click to expand...

Do you have a wide band on yours?
 
Bryson-
I do not have a wideband or any air/fuel controller. I am running the original 99 Jeep PCM.

Talyn-
I have no idea what my fuel trim looks like. I believe I am running slightly rich as my fuel mileage is 19-20 mpg on the highway. I think I could be doing better since I have a basic 2 door XJ SE, 5 speed, and 225/70/15 tires. My 4.0L got me 22-23 mpg.

Could you explain to me what the fuel trim actually means? When yours is +35%, what is that in relation to? Also, if you're replacing the fuel pump, it makes sense to replace the pressure regulator as long as everything is apart. I had to do the pump and regulator on my wife's 00 XJ. I think it's actually more common for the regulator to fail.
 
gradon said:
It means his pcm maxed out trying to add fuel, so he definitely needs 27# injectors.
Click to expand...

Is 35% considered maxed out? I thought it was more like 45%
 
I can't speak for your 2K, but 33-35% was about where my 96 maxed out. When you tune the Apexi, you'll try to zero the FTs in closed loop(you'll have to reset the pcm a couple times to reset the LTFTs to verify that the Apexi is set correctly). For those that don't know the overall trim is LT+ST. The smaller the swing, the better the response, and the less thinking that the pcm has to do(imagine it pulling 10% out one sec and the next it's adding 20%).
 
IH8EPA said:
Still have your titan around?
Click to expand...
Yeah, its in a pile of parts at the machine shop.

tonofclay2 said:
I guess thats why im in health care and can pay for freakin quality like this...damn
Click to expand...

Even if I could afford to pay someone to install it I wouldn't. Gotten ripped off and/or crappy work way too many times.
 
Swapped out the fuel pump today. What a freaking pain. I think I rather change a head gasket. That thing is just a magnet for mud too. You would think that lock ring that secures the pump would be easy to put back on... nope. It was a pain in the ass starting it. Haven't rechecked the pressure yet, but that issue is still there.. I think.. didn't drive it enough to really notice it. Only thing is when I removed the pump the gauge read under 1/8 of a tank.. when I left it read around 1/4 of a tank. I just hope that is some sort of erroneous first time reading and it isn't a faulty sender.
 
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Ahh, you too have had to fight with that lock ring. When I did it, I think my 4 letter words persuaded it to finally go on. Did you replace the pressure regulator or just the pump? You'll have to get a guage on the fuel rail and find out if the new pump helped. My wife's 00 XJ put out 50 psi with a new pump.
 
I just did a stock replacement module. Regulator, pump and strainer. I didn't feel like doing an upgrade right now and I wanted to replace the strainer and regulator anyhow. Besides I don't think I need more than 49 psi. I just hope that the level sender isn't faulty.
 
jeepinwi said:
Ahh, you too have had to fight with that lock ring. When I did it, I think my 4 letter words persuaded it to finally go on. Did you replace the pressure regulator or just the pump? You'll have to get a guage on the fuel rail and find out if the new pump helped. My wife's 00 XJ put out 50 psi with a new pump.
Click to expand...

I wanted to take an axe to that damn thing.. one side would start then the other side would go off. And while you are trying to get the ring started you have to hold the pump down too.. lots of fun. I replaced the whole thing. The regulator was like $110 by itself.

I'm going to check the pressure after work tomorrow most likely... but if it didn't help the pressure I don't know what then. The pump is getting the correct voltage, and I replaced the whole module.
 
Some older posts about the head that is on this block:
http://www.naxja.org/forum/showthread.php?t=953786

http://www.jeepforum.com/forum/showthread.php?t=535604

It appears to be running better. I haven't noticed the lean condition as much, so maybe the fuel pump fixed it. I still have yet to test the fuel pressure after the pump, but will swing by the machine shop and borrow their gauge soon. No weird sounds to speak of. Its running well, but still has under 200 miles on it.

I got a set of used injectors off ebay to give a try as well.
 
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