Jeepjeff859 Posted November 25, 2015 Share Posted November 25, 2015 I just did a 4.0 swap and when ever I get to higher RPMs the engine starts to stubble like it's not getting enough fuel or it's getting to much. Any ideas? I'm running the ES2000 pump like most recommend with a fuel cell in the back along with -10 fuel line up to the pump Link to comment Share on other sites More sharing options...
HOrnbrod Posted November 25, 2015 Share Posted November 25, 2015 You'll need an adjustable fuel pressure regulator and a set of gauges to adjust the pressure up or down until you get it right. Pull your plug(s) and look at the color - it will give you a hint of which way to go. You do mean the engine stumbles, right? Stubble is what you have on your face if you forget to shave. :yes: Link to comment Share on other sites More sharing options...
Megadan Posted November 25, 2015 Share Posted November 25, 2015 You do mean the engine stumbles, right? Stubble is what you have on your face if you forget to shave. :yes: Unless you let it stubble too long, and then your vehicle will beard. Does it stumble no matter what the throttle position is? When my TPS was out of adjustment I would get a stumble at a very specific throttle position in a very specific RPM range. Otherwise, I agree with everything Hornbrod said/suggested Link to comment Share on other sites More sharing options...
HOrnbrod Posted November 25, 2015 Share Posted November 25, 2015 Unless you let it stubble too long, and then your vehicle will beard. True. Especially if you live in the rust belt. Link to comment Share on other sites More sharing options...
Jeepjeff859 Posted November 26, 2015 Author Share Posted November 26, 2015 The local jeep nut where I live was telling me the reason it's doing it is the way the factory system was designed, he said the factory tank, pump, and fuel regulator were designed to work together. But when you change the pump and tank the factory regulator wasn't designed to work with that pump and tank so I need to find a way to put the factory pump in my fuel cell or I need to buy a aftermarket regulator Link to comment Share on other sites More sharing options...
HOrnbrod Posted November 26, 2015 Share Posted November 26, 2015 The factory regulator and injectors will work with any fuel pump as long as it is capable of putting out enough pressure and flow rate for the injectors. In your case if you are running a 94 ZJ engine the pumps needs to be capable of at least 39psi out and a sustained flow rate of 21.0lb/hr or more. The regulator's job is to keep fuel pressure and flow consistent with the ECU's fuel demands no matter what pump is installed. So what are the specs of the ES2000 pump you installed? Or did you mean an E2000? Why don't you throw a set of gauges on the fuel rail test port and see what you have now? Link to comment Share on other sites More sharing options...
Jeepjeff859 Posted November 26, 2015 Author Share Posted November 26, 2015 E2000 Link to comment Share on other sites More sharing options...
HOrnbrod Posted November 26, 2015 Share Posted November 26, 2015 E2000 Okay, then what are the specs of the E2000 pump? Link to comment Share on other sites More sharing options...
Jeepjeff859 Posted November 26, 2015 Author Share Posted November 26, 2015 Maximum Free Flow Rate (gph): 40 Maximum Pressure Range (psi): 95 Minimum Free Flow Rate (gph): 30 Minimum Pressure Range (psi): 70 Link to comment Share on other sites More sharing options...
Jeepjeff859 Posted November 26, 2015 Author Share Posted November 26, 2015 i replaced the spark plugs as well to see if it helped any.... it didnt Link to comment Share on other sites More sharing options...
Area51Werks Posted November 27, 2015 Share Posted November 27, 2015 Those are not the plugs you just installed. If those are the plugs you installed new then read them. If not put a couple miles on the truck with the new plugs and pull them and examine them. Google plug results and check the condition of your plugs against photos. https://www.google.com/search?q=spark+plug+diagnosis+pictures&safe=off&biw=1188&bih=535&tbm=isch&tbo=u&source=univ&sa=X&sqi=2&ved=0ahUKEwiI_pvCw6_JAhVKVT4KHWxxDhkQsAQIHA Did you test the cap, rotor and leads? If there not new they could have failed due to age. May have worked fine when you left them be on the old engine but pulling a crispy lead and installing it on a new plug can be more then it's life can handle. BTW: 90% of fuel related problems are electrical. Link to comment Share on other sites More sharing options...
HOrnbrod Posted November 27, 2015 Share Posted November 27, 2015 Maximum Free Flow Rate (gph): 40 Maximum Pressure Range (psi): 95 Minimum Free Flow Rate (gph): 30 Minimum Pressure Range (psi): 70 Should be fine, but "throw a set of pressure gauges on the fuel rail test port and see what you have." You can rent them from AutoZone or similar. Oh - and you did run the vent line to the new tank, right? Link to comment Share on other sites More sharing options...
Jeepjeff859 Posted November 27, 2015 Author Share Posted November 27, 2015 Oh crap I just relized when you said that that I left the caps on the new fuel cell, I'll try taking one of them off and see if it fixes it Link to comment Share on other sites More sharing options...
Jeepjeff859 Posted November 27, 2015 Author Share Posted November 27, 2015 To recap I have a pump that can handle the 4.0 needs, I have fresh gas, now I have brand new spark plugs, made sure the tank has a good vent, but it is still doing it so my next step is the after market regulator Link to comment Share on other sites More sharing options...
Jeepjeff859 Posted November 27, 2015 Author Share Posted November 27, 2015 Just ran out and got a fuel pressure tester and not driving the fuel pressure stays around 30 while reving it Link to comment Share on other sites More sharing options...
HOrnbrod Posted November 27, 2015 Share Posted November 27, 2015 What does it read at idle when you pull the vacuum hose off the regulator? Pressure should read ~30 psi w. vacuum, ~39 psi w/o vacuum. Link to comment Share on other sites More sharing options...
Jeepjeff859 Posted November 27, 2015 Author Share Posted November 27, 2015 Ill try to explain this best I can At idle it stays at 30-40 psi When driving it stays at 30-40 psi When ever I give it a little to much throttle while driving it falls on its face. If I baby it it won't do it until it gets to higher rpms, if I press the clutch in when it does it. It will stop. When its not moving it can rev all day Only thing I can think of if its not fuel or ignition would be the clutch not holding but I would think that would be at almost any rpm rang If this new regulator doesn't fix it then my next thought would be ignition coil and distributor Link to comment Share on other sites More sharing options...
HOrnbrod Posted November 27, 2015 Share Posted November 27, 2015 Pull the vacuum hose off the regulator and see if the pressure jumps up to 39-40 psi. That will tell you if the regulator diaphragm is intact and it's regulating. Do you have a vacuum hose that doesn't leak hooked up to the regulator? Pressure should read ~30 psi w. vacuum, ~39 psi w/o vacuum. Link to comment Share on other sites More sharing options...
Jeepjeff859 Posted November 27, 2015 Author Share Posted November 27, 2015 Ill will try it tomorrow its time to go to work now Link to comment Share on other sites More sharing options...
Jeepjeff859 Posted November 28, 2015 Author Share Posted November 28, 2015 I tried that and it does jump to 40. My fuel system isn't the problem Link to comment Share on other sites More sharing options...
Doc. Posted November 29, 2015 Share Posted November 29, 2015 This sounds kind of similar to my issue. Talking to a mechanic buddy of mine we are speculating coil issue. If it warms up outside, and I remember, I figured I'd go swap one and see if there is any change. With my issue the warmer the truck got the worse the issue got to the point it would not restart. The next day it started and ran great until it got good and warmed up, then began to stumble so I just parked it. Link to comment Share on other sites More sharing options...
Jeepjeff859 Posted December 1, 2015 Author Share Posted December 1, 2015 I replaced the TPS but now the engine won't start it just dies out Link to comment Share on other sites More sharing options...
big66440 Posted December 1, 2015 Share Posted December 1, 2015 Did you adjust it? Assuming you have a Renix here you go http://www.naxja.org/forum/showthread.php?t=1072534 Link to comment Share on other sites More sharing options...
Jeepjeff859 Posted December 1, 2015 Author Share Posted December 1, 2015 i don't have a renix, I'm going to start i new thread to recap on all of this Link to comment Share on other sites More sharing options...
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