Stroker novice, injection upgrade and map ??s

[Jeepin89701]

I have a 1993 ZJ, the motor blew so I bought a 4.6L golen stroker. I put denso (mustang)24lbshr injectors in it on a 2000 intake upgrade, as well as a hesco adjustable fuel regulator (left it set at 44psi per hesco),and I also installed a 62mm throttle body. Can the PCM handle this build with listed upgrades, Do I need a map adjuster? It runs but sounds lean and stalls when coming to stops sporadically(1 in 10) any advise would be helpful...

[Jeepin89701]

I have a 1993 ZJ, the motor blew so I bought a 4.6L golen stroker. I put denso (mustang)24lbshr injectors in it on a 2000 intake upgrade, as well as a hesco adjustable fuel regulator (left it set at 44psi per hesco),and I also installed a 62mm throttle body. Can the PCM handle this build with listed upgrades, Do I need a map adjuster? It runs but sounds lean and stalls when coming to stops sporadically(1 in 10) any advise would be helpful...

Forgot to put it out there it has 35 to 50 miles on it, have I just not put the mileage on it for the PCM to adjust??? I have a bee in my ear telling me this is my problem, I'm not sure????

[BADASYJ]

Your running an OBD1 system on that 93, I cannot see you running lean with 24# mustang injectors at 44psi. If anything id say your running rich, your fuel pressure should be around 30psi. That could be part of your stalling issue as the O2 sensor will read rich and the CPU will try to lean you out.
Also a faulty CPS will cause stalling issues and throw no codes. For some odd reason I've had CPS issues both times I pulled and replaced the block on my 91'. Stalling at stop lights or just cut out on ya while driving.

[Cheromaniac]

I have a 1993 ZJ, the motor blew so I bought a 4.6L golen stroker. I put denso (mustang)24lbshr injectors in it on a 2000 intake upgrade, as well as a hesco adjustable fuel regulator (left it set at 44psi per hesco),and I also installed a 62mm throttle body. Can the PCM handle this build with listed upgrades, Do I need a map adjuster? It runs but sounds lean and stalls when coming to stops sporadically(1 in 10) any advise would be helpful...

It shouldn't be running lean and you definitely don't need a MAP adjuster. I'm running the same injectors with stock FPR, stock ECU, and the AFR is right on stoich at idle/steady cruise.
Agree that your CPS could be at fault for the stalling but you might want to pull the idle air controller from the throttle body and give it a good cleaning. Also clean the inside of the TB and inside the barrel where the IAC resides.

[Jeepin89701]

SO go advise if at all dirty however the TPS, IAC, MAP and Throttle body all have about 35 miles on them from new. Possibly just needs more miles on pcm to adjust?? Maybe need to reset pcm and start adjustment period over. This jeep ran perfect with the 4.0L in it, I could be just overly worried due to not wanting to damage the engine investment. This is a learning experience for me all advise welcome, I still have the TPS,IAC and MAP that I replaced around(cleaned them up for back ups) will try swapping them back in to see if issues are still there. Thank you for your input it's good to know that someone with the same set up is up and running without issues.....

[Jeepin89701]

Your running an OBD1 system on that 93, I cannot see you running lean with 24# mustang injectors at 44psi. If anything id say your running rich, your fuel pressure should be around 30psi. That could be part of your stalling issue as the O2 sensor will read rich and the CPU will try to lean you out.
Also a faulty CPS will cause stalling issues and throw no codes. For some odd reason I've had CPS issues both times I pulled and replaced the block on my 91'. Stalling at stop lights or just cut out on ya while driving.

I'm running 44 psi per Golen(the engine builder)with the 24lbs injectors, my understanding is if I was running rich at the O2 sensor I would have a check engine code for sure. I have no codes none at all. As for a faulty cps it was running the 4.0L perfect 5 months ago when I started this swap, but I am very new to the whole stroker thing. So when you had stalling issues did swapping the cps fix it??? My FPR is adjustable down to 32psi and up to 48psi I believe. Also (and I could be wrong) but with the 2000 intake upgrade and the 4.6L stroker, what I'm being told by the engine builder is 30psi would not be enough. 24lbs injectors are tested to be 24 lbs at 43.5 psi. My understanding of injectors running at different PSI's is that the flow rate changes, for example 24.3lbs at 43.5 psi will run 25.7lbs at 48 PSI so they would run far lower than 24lbs at 30psi. I'm still trying to make sense of it, please educate me as I'm receiving conflicting info from multiple sources.

[Jeepin89701]

Have had 2 responses to my post, after reading back thru them in depth it sounds like I need to go back to a stock FPR 30psi for an OBD1. NOW I'm truly lost, this is different than I've been hearing for the last 5 months(44psi, taking a bit to wrap my head around) as I no longer have the stock FPR I will pick one up and try this as well to see if my issues are resolved. Any further input would greatly appreciated

[BADASYJ]

Forget what Golen or Hesco told you. Turn your regulator all the way down to stock pressure and see if that helps anything. I wouldn't worry about getting a stock unit, I doubt 1-2psi will make a noticeable difference There is no reason you need 44psi with 24# injectors though. I'm thinking 44psi would be for the stock 19# injectors from the 4.0.

[gradon]

You should have enough fuel with 24# injectors at 44psi. Try driving a little at 40psi and see if anything changes. Try 48psi--Im using 24#@43.5psi injectors on my 96's 49psi rail, so that'd be similar to your fpr at 48psi. Engines do take miles to break in as well as the pcm learning. With the 96+ obd2 pcms, we can easily look at fuel trims to see if the injectors are spraying too much or too little(but we don't have the return or fpr on the rail to adjust accordingly).

[BADASYJ]

Does it only shut down at a stop when you're off the throttle?
The TPS even though its new could be sticking, causing a slow open when throttle is at 0%, basically choking the engine of air. If the tps swap and lower fuel pressure don't help then my bet would be that its the CPS. Remember the cps will not throw a code when faulty.

[Jeepin89701]

Forget what Golen or Hesco told you. Turn your regulator all the way down to stock pressure and see if that helps anything. I wouldn't worry about getting a stock unit, I doubt 1-2psi will make a noticeable difference There is no reason you need 44psi with 24# injectors though. I'm thinking 44psi would be for the stock 19# injectors from the 4.0.

Thanks you for your help, I would not have ever looked at the FPR as an issue or thought to adjust it down. I'm not sure why I'm getting the upside down info from those guys as I've been very upfront as far as injectors I'm running and OBD1 ZJ. AS I have already bought the products that I was told I needed there is not a sells push going on, Strange. I will adjust the FPR all the way down and see what I've got at the rail for PSI, I agree that 1-2 psi won't change a whole lot. We will see if it actually adjusts down to 32psi (as I was told it does) Thanks again.

[Jeepin89701]

You should have enough fuel with 24# injectors at 44psi. Try driving a little at 40psi and see if anything changes. Try 48psi--Im using 24#@43.5psi injectors on my 96's 49psi rail, so that'd be similar to your fpr at 48psi. Engines do take miles to break in as well as the pcm learning. With the 96+ obd2 pcms, we can easily look at fuel trims to see if the injectors are spraying too much or too little(but we don't have the return or fpr on the rail to adjust accordingly).

I'm still learning here, but 40 to 49psi is on obd2 96+ for an obd1 95 and before I need 30 to 39psi. in general +/- 5psi will give little issue, my problem is +/- 10psi could and seems to be causing chaos. All info appreciated and considered....

[gradon]

'96-04 4.0ls have a 49psi all the time regulated at the pump returnless rail system.

[Jeepin89701]

That's good to know, my wife just bought a 2000 XJ 4.0L ( No cracked head ). So it's just the 80's/early 90's 4.0L's that have the 2 rail and regulator at the rail? ? 1996 to 2004 4.0L these have the in tank regulator as part of the pump @ constant 49 psi, got it...

[Cheromaniac]

SO go advise if at all dirty however the TPS, IAC, MAP and Throttle body all have about 35 miles on them from new. Possibly just needs more miles on pcm to adjust?? Maybe need to reset pcm and start adjustment period over.

Yeah, I think that may be all you'll need to do. I find it takes about 100 miles for the ECU to complete its adaptive learning.
FWIW i'm running Ford Racing 24lb injectors (rated at 39psi) with the stock 39psi regulator on the front of the injector rail.
Note that the injector flow rate is proportionate to the square root of the fuel pressure at the rail, so a 20% increase in fuel pressure will increase injector flow rate by 9.5%.