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I need help finding a cps sensor


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Pretty sure this is ecu    Having a hard time getting a pic of the other end of the cps   So the part I need is a 96 cps for an xj correct?  Also couple of terms I am unfamiliar with  HO? Renix? What are those in reference to   Thanks again

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The fuel pump is normally loud.  Renix Comanches have a ballast resistor in series with the fuel pump to make it quieter and I'm sure the previous owner threw it away when he made the swap.

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You have an obd2 system which is a return less fuel system (and we can say with some certainty that you have all 96 Cherokee parts swapped in). If you have the original fuel sender and pump from the 89 (which you obviously do since the gas gauges reads backwards) then you have no fuel pressure regulator at all in the system. You pump will be begging for mercy since the only pressure relief it has is the pressure relief valve in the pump itself. You need to add a fuel pressure regulator in the fuel circuit and set it to the correct obd2 psi (seems like high 50’s or low 60’s psi iirc). Then replace your actual fuel pump (just the pump) with a 4.0 XJ/MJ pump. The pumps always make some noise but it’s pretty minimal. There may be a resistor for the fuel pump right near your brake booster on the drivers side inner fender that was added to reduce the pump noise. It does help somewhat but also isn't necessary. Get a fuel pressure regulator and connect the return line to it so you can get the fuel system working the right way. This is something that always gets missed with these obd2 swaps. 
 

To get you speedo working, you will need to connect the vehicle speed sensor which is located in the transfer case output (see pic). The speed sensor signal should go to both the ecu and the speedometer. If your jeep dies sometimes when coasting or when you come to a stop it’s normally the speed sensor that is not connected to the ecu. 
 

fuel gauge: you newer gauge cluster is meant to read 0-80ohms resistance but your sender is like a 2**-30 ohms. Look for a signal converter from Dakota digital or you could swap out the sending unit to one from a 91-92 MJ but they are very hard to find and are only available used. Auto parts stores will say they are available new but they are for a Cherokee XJ and don’t fit. The signal converter is the easiest way to go here. 

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Man I can’t thank all of you enough for shedding light on my Jeep!!! I had one 22 years ago and drove it back from Alaska. I sold it and regretted it every day for the last 20 years   I finally got to a place were I could replace it   This Jeep is mostly the same    Shortbed , 4x4, 4.0     No stick but oh well    Other was a chief  this one a pioneer   Level of happiness restored   LOL Would you mind if I post pics of parts before I bought them to try and make sure I am getting the right thing   I’d like to get good at vehicle repair as I plan to drive this back to Alaska one day   Thanks again!

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No sending unit from an XJ will fit in your tank. This isn’t anything that quadratec will have. Here are some pump options: https://www.rockauto.com/en/catalog/jeep,1989,comanche,4.0l+242cid+l6,1181674,fuel+&+air,fuel+pump,6256

 

The newer XJ fuel system had a regulator that was in the fuel tank and only ran one fuel supply line to the engine at a preset psi. Your old MJ fuel system had a supply line and a return line going to the fuel rail. There was a pressure regulator on the fuel rail that set the pressure for the rail and allowed anything else to return to the tank. You are going to have to fab up something similar. You will need to find the correct fuel pressure for the obd2 system (96-01 XJ) and get an external adjustable fuel pressure regulator along with fittings and hoses. You need one with one inlet and two outlets. The inlet will be the feed from your pump. One outlet will be your fuel rail line that will need to have the pressure set (you’ll need a gauge for this). The other line will be a return line that will connect to your old return line (provided it’s still there and no plugged off somewhere). 
 

You may not need a new pump but running with no regulator will put undue strain on it. Let’s get a few more pics. Let’s see what your current sending unit looks like on the side of your fuel tank (just take a picture of it as is, no need to disassemble anything). Also, track the main fuel lie and the return fuel line and see what they did with the return line. My guess is that it has a cap on it somewhere but you’ll need to know for sure before you can order up any parts to modify things. 

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Looked up the fuel pressure spec for you and it should be around 50 psi at idle. That is a static fuel pressure and should not change on the obd2 systems. (On the 91-95 HO systems the fuel pressure regulator on the rail would change based on engine vacuum and the fue injection was programmed to run on this variable pressure. Not so on the obd2 engines. The ecu maps are based on a static pressure). 

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4 hours ago, Virden said:

I’ll take the pics tomorrow! Thanks  should I install this first? ? Haven’t order yet  just trying to figure out what I need    Much appreciated 

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I'm not sure that adapter does what you need. There isn't a huge difference in the ohm range from the old system to the new system. Going from memory, I believe the old system was 0 to 80 ohms and the new system was 103 to 5 ohms. Gas gauges are only approximate anyway, so that may not be a big deal. The bigger issue you have is the reversed polarity, and the description of that doohickie doesn't tell me that it can address that.

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14 hours ago, Eagle said:

The bigger issue you have is the reversed polarity, and the description of that doohickie doesn't tell me that it can address that.

 

I agree, I'm also not sure if that device can reverse the sender output.  Regardless, a circuit that would do exactly what you want is fairly trivial to make.

 

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Pretty sure I have everything I need to make this if you want me to ship you one.

 

 

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That metal line that is disconnected was your old fuel return line. There is no visible fuel pressure regulator here at all. I’d mount a regulator rather near the tank or in the engine bay and plumb the return line back in. Where does that rubber hose go off the tank sender that is pointing up in the pics? I imagine it’s plugged somewhere. 

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And just to clarify, that module from Tanks does what you need. It can reverse the resistance of any sender to fit pretty much any gauge. It can even do exponential signal sweeps. Pretty neat little device. 

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I’ll track down the rubber hose tomorrow   
what fuel regulater do I need? How hard to install?   This truck came with part receipts I’ll see if there is one for the fuel sender and  pump   Could probably try and pull the tank this weekend  how hard is that on a scale of one to ten?

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