ghetdjc320

I’d say the fuel gauge is secondary to gettin it running right. Let’s see what the fuel system needs first. Just my $.02

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).

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.

You just need the pump, not the whole sending unit. And the XJ sending units don’t fit MJ tanks.

There is also normally an emissions system diagram under the hood on a sticker

Here is a good fuel gauge adapter interface option: https://www.tanksinc.com/index.cfm/page/ptype=product/product_id=748/category_id=184/mode=prod/prd748.htm

The terminator has a built in map sensor (1 bar) and will need to be mounted in the cab somewhere since it’s not fully sealed. You will also need to make sure you have the exact numbers from your fuel injectors to enter the specs in the software. It is self tuning so it should run without further tuning but have Chris dial it in for you. Anything Holley efi I recommend efisystemspro.com They are super helpful and can get you what you need. You can upgrade to the Holley HP efi but will only gain full sequential injection (every so slightly more efficient at idle) and a fully potted ecu. It can run NTK oxygen sensors and has more capabilities for power adders like turbo and superchargers down the road though.

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.

I’ll post a more detailed reply later but the terminator x is a great way to go. And use the hyperspark distributor for the 258. That gives you full timing control and sequenced batch injection (1/5,3/4,2/6) The hyperspark has a built in crank sensor for timing. You’ll need the Holley CTS and IAT. Bosch 4.9 O2 comes with it. you can also run an obd1 sbec computer and have Chris @christuned socket and program it. He is the Russ Pottenger of ecu tuning for the 4.0

The tires the OP is putting on are the same diameter and a bit narrower. I think he’s just looking for pics of alloy 17’s with 35’s

Agreed. Pulley system is definitely 96+ also

Agreed. Only adjustment is that the CPS sensor connector changed throughout the HO years. 91-92 has a round plug. Others have a flat plug. I’m curious to see if there is an obd2 ecu in there or not though. Probably obd1/sbec but it may be an obd2 since that looks like a 96-98 engine

From the pics some things are clear and I could take an educated guess on others. You have an open loop cooling system which is a later design. Your throttle body looks like the standard HO throttle body and looks like between a 96-98 intake manifold. I’d guess the engine is probably a 96-98 given the barcode on the valve cover. Gauges look like your typical 91-95 HO set. Only question I still have is what ecu your running.

Need a pic of the drivers side inner fender well by the air cleaner too

The issue: in the mods and repairs section, we will have users who are in need of urgent help to repair their vehicle to get it back on the road but their threads sometimes get lost or have very late replies since no one really knows that help is needed. Those who are modifying typically don’t need immediate responses. If urgent assistance is needed, would it be helpful to just add “urgent” to the topic or would it make sense to perhaps have another section for those who are doing repairs and need help ASAP? Another option would be to separate “modifications” from “repairs”. Just some thoughts to kick around

Sounds good. This is all pretty straight forward stuff to take care of. Can you post pics of the gauge cluster in the dash. Also please post a pic of the drivers side inner fender in the engine bay. What I’m trying to determine is whether or not they swapped in the 94’ electronics as well along with the 4.0 swap. Once we narrow down the electronics that were swapped in its fairly straight forward to take care of these other issues.

You’ll save some weight on the tire too by having a larger rim. I run 33’s on 17” wheels. I know it’s not what your looking for but since no one else has chimed in here is a pic:

This thread is further proof of what @Pete M and others have said before: there is no such thing as a cheap v8 swap.

Yep that’s it. Is there a computer located on the front inner drivers side fender in the engine bay? If so, can you take a picture of it? The connection is not 91-92 and looks like possibly a later version to me but perhaps it is Renix. @Minuit or @cruiser54 May know what year connector that is. Out of curiosity, what makes you think your CPS needs to be replaced?

Look for the connector on this line:

can you snap a picture of the CPS connector? The question will be what electronics are in the truck now.

Lol, these topics are always a can of worms. So many opinions and different experiences. Many will say x oil gave them 100’s of thousands of trouble free miles while others will say that x oil destroyed their tranny & tcase etc. Many won’t trust even the manufacturers recommendations these days and occasionally that’s for a good reason. At the end of the day it will just be up to you because the suggestions will never end. I hate to say it but this is one of those topics that requires you do your own research instead of going strictly off of what your pears say. Otherwise this is about as subjective as health advice, in other words, everyone has an opinion and, of course, some great reason for believing their opinion.

Some new shoes

I’ve been using straight 30 weight motor oil in the tcase for a long time now. Excellent results. 10w-30 also works great in an ax15 and I believe a Mopar TSB even recommended it iirc.

97+ doors are also a nice swap with a larger door glass pane (that can also be swapped into the earlier doors). The striker and door seals are also a bit more modern design and quieter.