lostissues Posted May 29, 2009 Share Posted May 29, 2009 OK I'm hopefully going to acquire a 97 Cherokee that has been rolled, I'm looking to swap everything I can into my Comanche. the fenders and header panel should be pretty straight forward. I would like to swap the motor and drive train in and also the whole dash. what kind of problems will I run into? the motor and trans should be a pull everything put everything in new place correct? With the dash I have found 2 people that have done it so far, project 1999MJ and Project "Onyx" unfortunately 1999MJ looks like he did the swap before he joined the forum but does have a little info later in the project. Onyx did give me the information of needing to make the whole for the steering column larger, and also something about side A pillar brackets but I don't understand that. is there another place that I missed to gather some information? I will have to transfer all the computers and fuse boxes and everything from the Cherokee over to the MJ in order for the engine and everything to work. and I'm assuming that i will have to wire in everything from the seats back (lights, fuel pump, cargo light, and anything else back there.) any info you can point me to would be great. Thanks, Jonathan Link to comment Share on other sites More sharing options...
shelbyluvv Posted May 29, 2009 Share Posted May 29, 2009 It is not an easy swap by any means. You can't use your stock fuel pump with the swap. It will not provide the proper flow for the newer fuel rail. I am in the process of building my own tank and sender using TJ parts with a stock MJ tank. I got a fuel cell ring for Copperhead customs and it will require me to cut a 6" hole in the top of my tank. Another thing to note is the fuel gauge will not work right using MJ stuff. I am using a TJ cluster as well, because the pump/sender will be from a TJ and will run the engine and fuel gauge properly. The TJ cluster is a direct bolt in for the 97 XJ cluster. If you need some input on my truck please don't hesitate to ask me. I have been through it all at this point and look to have it running in a couple more months, FINALLY! Link to comment Share on other sites More sharing options...
Jeepman Posted May 29, 2009 Share Posted May 29, 2009 If You use a Stock 4.0L HO fuel rail with two Lines then the MJ Fuel pump will work fine as the Only thing different is the Fuel rail has NO Pressure regulator and that is becuase the newer system has the regulator on top of the sender instead of the Fuel rail... The newer system has slightly more Pressure then the older system but that will not stop it form working and the easier and the cheaper thing would be to add an adjustable fuel pressure regulator which can be bought from HESCO if not from other aftermarket suppliers and worse case add a larger volume Pump... Link to comment Share on other sites More sharing options...
shelbyluvv Posted May 29, 2009 Share Posted May 29, 2009 If You use a Stock 4.0L HO fuel rail with two Lines then the MJ Fuel pump will work fine as the Only thing different is the Fuel rail has NO Pressure regulator and that is becuase the newer system has the regulator on top of the sender instead of the Fuel rail... The newer system has slightly more Pressure then the older system but that will not stop it form working and the easier and the cheaper thing would be to add an adjustable fuel pressure regulator which can be bought from HESCO if not from other aftermarket suppliers and worse case add a larger volume Pump... REMEMBER, He is asking about a total 97+ swap. Not just the engine. There is a ton of things to take into consideration. With that said, The MJ fuel sender will not run the 97 fuel gauge. It will to a point, but it will be so far out of wack it would be pointless to even have a fuel gauge. I guess if you were to half _ _ _ the project you could go that way. I prefer to have all my gauges reading accurate. So far my only real sway from a stock Jeep part is going to be the modded fuel tank to house the TJ sender. He still has not even got into the taillight wiring which will require a few modifications to them. They need to have the plugs replaced with weather safe ones (they are inside on a XJ) and the wires need to be legthened about a foot. I Will not be using any of the old wiring from the 89. Once you get into the XJs harness you will see that each rear light has it's own bundle of wires going down each side of the Jeep. Where the MJ has just one bundle going down the drivers side that branches out to the passenger side. The XJs wiring is much more involved than the MJs. Link to comment Share on other sites More sharing options...
Jeepman Posted May 29, 2009 Share Posted May 29, 2009 Yup I forgot about the Sender which reqiure Reistance alterations which could be a real pain... I will be doing this same swap in the near future and I plan on using a 92 Dodge dakota Fuel tank as it is similar dimentions as the MJ tank but you can install the XJ Fuel sender/Pump into it... Link to comment Share on other sites More sharing options...
shelbyluvv Posted May 29, 2009 Share Posted May 29, 2009 Now that is some good info to have. I never thought about using a Dak tank in the MJ. A TJ tank will fit fairly easily too. Link to comment Share on other sites More sharing options...
Eagle Posted May 29, 2009 Share Posted May 29, 2009 Yup I forgot about the Sender which reqiure Reistance alterations which could be a real pain... Not just resistance -- that just makes the gauge slightly inaccurate, which they are anyway. The early ones go from zero to 88 ohms. The later ones have a range of 4 to 104 ohms (IIRC). Not so terrible. The real issue is that the polarity is reversed. What makes the early one read "Empty" makes the late model one read "Full." The only fix I can think of for that is to find the two wires on the gauge cluster connector that lead to the fuel gauge, and reverse them. But, since one terminal on the gauge is ground (or is it?), it is likely shared with other gauges and therefore can't be reversed. So the Plan B (which is, in reality, Plan A since I can't think of any alternatives) is to modify the cluster panel so the gauge mounts physically in the usual pace but is isolated from the printed circuit. Then hard wire the two terminals. Hornbrod -- possible? Link to comment Share on other sites More sharing options...
shelbyluvv Posted May 29, 2009 Share Posted May 29, 2009 The early ones go from zero to 88 ohms. The later ones have a range of 4 to 104 ohms (IIRC). IIRC, the 97 XJ values are 20 (full) and 170 (empty) there is a big swing between the newer XJs and the MJs. Link to comment Share on other sites More sharing options...
Eagle Posted May 30, 2009 Share Posted May 30, 2009 The early ones go from zero to 88 ohms. The later ones have a range of 4 to 104 ohms (IIRC). IIRC, the 97 XJ values are 20 (full) and 170 (empty) there is a big swing between the newer XJs and the MJs. [Mr. Spock]Fascinating, Jim.[/Mr. Spock] According to the 2000 XJ FSM, it's 20 ohms full, 270 ohms empty. So that means there are THREE permutations and combinations we have to be aware of. I hadn't gotten beyond the change on resistance and polarity between 1990 and 1991. Thanks (I think). Link to comment Share on other sites More sharing options...
shelbyluvv Posted May 30, 2009 Share Posted May 30, 2009 I knew it was 270 and have no idea why I put 170? :dunno: To add another slice to the pie, a TJ is sender is 20 (full) and 220 (empty). The nice thing is a early TJ cluster will bolt into a 97+ XJ dash with no mods required. This is the reason I am going with a TJ sender and cluster in my truck. I did a lot of reading of FSMs and on the web. I could not find any vehicle that ran the XJ values with a tank that would easily fit in the MJ location. I wish I would have known about the Dak tank with the XJ pump before I bought all the stuff to mod mine for a TJ sender. Hind sight is 20/20... :doh: Link to comment Share on other sites More sharing options...
Pete M Posted May 30, 2009 Share Posted May 30, 2009 What about keeping the older pump and using an matching fuel gauge in an A-pillar pod? Link to comment Share on other sites More sharing options...
Sir Sam Posted May 30, 2009 Share Posted May 30, 2009 Note of caution is that the TJ clusters switched to the PCI bus after 2001, so you need a 2000 down cluster to work with XJ wiring. Link to comment Share on other sites More sharing options...
Sir Sam Posted May 30, 2009 Share Posted May 30, 2009 Also, I don't know if anyone has considered this, but it would be fairly simple to build a converter pic with a 8 or 16 pin pic, and then have it open up a different circuit with the correct resistance. In this method you could specify which resistance on the sender means what level on the fuel guage, you could make your gauge completely linear, or make it more like the factory gauge. This is what I am planning on doing for my swap. Solves this whole problem entirely. Link to comment Share on other sites More sharing options...
lostissues Posted May 30, 2009 Author Share Posted May 30, 2009 Well unfortunately after some consideration I decided to pass on acquiring the 97 xj, I guess it would be way to ambitious of a project for me to undertake to swap everything in. it has taken me a VERY long time to get my truck to where it is now and that is that the truck is almost road worthy, just a couple more things and hopefully it will be on the road in less then a month. for the past few years I have taken my sweet time getting things done that most on here could have done in a fraction of the time. so a full swap would be way over my head and put my truck completion date way into the future. so the plan is to get the truck going, wheel it and then if something happens down the way work through a possible swap. But this thread has generated some great discussions and hopefully it could help someone looking into doing the swap somewhere down the road. If you would like to continue contributing to this post with everything you can thing of I'm sure it will help someone. Thanks for the input guys :wavey: Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 30, 2009 Share Posted May 30, 2009 OK I'm hopefully going to acquire a 97 Cherokee that has been rolled, I'm looking to swap everything I can into my Comanche. the fenders and header panel should be pretty straight forward. I would like to swap the motor and drive train in and also the whole dash. what kind of problems will I run into? the motor and trans should be a pull everything put everything in new place correct? With the dash I have found 2 people that have done it so far, project 1999MJ and Project "Onyx" unfortunately 1999MJ looks like he did the swap before he joined the forum but does have a little info later in the project. Onyx did give me the information of needing to make the whole for the steering column larger, and also something about side A pillar brackets but I don't understand that. is there another place that I missed to gather some information? I will have to transfer all the computers and fuse boxes and everything from the Cherokee over to the MJ in order for the engine and everything to work. and I'm assuming that i will have to wire in everything from the seats back (lights, fuel pump, cargo light, and anything else back there.) any info you can point me to would be great. Thanks, Jonathan Just noticed this post. I can prolly address possible solutions to the fuel gauge issue so that your planned 97 XJ cluster install into your 87 MJ will read accurately. Can you tell me what size fuel tank is presently on your 87? And is it a LWB or SWB? If this has already been stated previously I apologize. :cheers: EDIT: Since you are passing on the 97 - disregard. Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 30, 2009 Share Posted May 30, 2009 Also, I don't know if anyone has considered this, but it would be fairly simple to build a converter pic with a 8 or 16 pin pic, and then have it open up a different circuit with the correct resistance. In this method you could specify which resistance on the sender means what level on the fuel guage, you could make your gauge completely linear, or make it more like the factory gauge. This is what I am planning on doing for my swap. Solves this whole problem entirely. The fuel gauge is an analog input polarity sensitive gauge from a sliding pot, up to the input buss change. What you are proposing is a digital resistive stepping box, correct? Link to comment Share on other sites More sharing options...
Sir Sam Posted May 31, 2009 Share Posted May 31, 2009 Also, I don't know if anyone has considered this, but it would be fairly simple to build a converter pic with a 8 or 16 pin pic, and then have it open up a different circuit with the correct resistance. In this method you could specify which resistance on the sender means what level on the fuel guage, you could make your gauge completely linear, or make it more like the factory gauge. This is what I am planning on doing for my swap. Solves this whole problem entirely. The fuel gauge is an analog input polarity sensitive gauge from a sliding pot, up to the input buss change. What you are proposing is a digital resistive stepping box, correct? Basically yup. Just use the POT command in picbasic, and with about 10 more lines of code you have a converter. A 16f88 would be perfect(and I have some here) use two pins for the POT command, leaving the other 14 pins for the resistance steps for your particular gauge. Plus I am going to be using some PICS for some other functions as well, like generating the correct resistances for the cruise control and radio remote controls. Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 31, 2009 Share Posted May 31, 2009 Cool, understand. Would be wise I think though to do a bench test and see how the fuel float input slopping up and down affects the pic output to the gauge. But prolly the fuel gauge built-in damper in the meter movement would compensate. Link to comment Share on other sites More sharing options...
Sir Sam Posted May 31, 2009 Share Posted May 31, 2009 You could do it in software too. Have it read the value and average it over a period of a few seconds and then switch to that average output. If enough people have problems with these guage conversions I could make up a few sets at once for other people as well. I have some 40 pin pics here but those are kinda expensive and seem wasteful since we don't need that many. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now