Gojira94

A bit of exhaust is siphoned into the intake manifold upstream of the injectors. There tends to be a gummy/ sooty buildup of stuff that would normally be going out the tailpipe in the EGR valve and in the intake where it's attached. We normally would picture nothing but clean filtered air and fuel going in the intake... Reduction of combustion temps via EGR matters the most for newer generation engines with relatively high compression that depend on EGR for: using all the timing it's calibrated for to produce/ maintain rated power/ torque levels (reduced temps/knock retard) to minimize NOx to meet emissions standards For an old engine design essentially from the end of the 50s, with 8.8:1 static compression, that runs on low octane fuels, EGR isn't doing a lot for it.

Totally agree with getting rid of the EGR if your state won't ding you for it. Surprisingly, the siphoned exhaust gasses help reduce combustion temps. Two benefits - reduce chances of pre-ignition/ detonation from elevated combustion temps and reduce oxides of Nitrogen (NOx). High NOx is what fails emissions when EGR is deleted or not working properly. Most people don't like the idea of the buildup of combustion by-product in parts of the 'clean' intake side of the engine.

I would never suggest arbitrarily spending $260+ just to have a REM II, though it can give a lot of insight as to what's going on. Depending on where you are, there might be a member who has one, not too far from you, who could stop by and get some data that might help spot some useful clues?

I was just changing out the transfer case front output yoke seal (thought I'd done it but nope) and noticed something just peeking out at the trans inspection cover/ spacer. If you know what this is, you know how I'm feeling right now. I've had it with internal slave. Advance Adapters conversion kit ordered today. After swapping the clutch master with a LuK LM206 shifting into 1st and reverse when warm was a lot better, briefly. Slightly cockeyed slave engagement took that away. At least I know what happened... The level of frustration with not being able to just get out and drive is getting to me. Spent a decent chunk of yesterday doing a blower motor in a Volvo XC70 (ask me how much fun that is). Today was my day to replace the transfer case seal and take it out for some more miles in nice weather.

Just a thought, what you asked your MJ to do is probably well outside of how you normally would drive it. WOT would ask a lot of steps of the IACV, and immediately followed by a lot of steps the other way on hard decel. If you've had any carbon buildup in its normal range of operation (fairly narrow), it may have stuck itself close to closed off on hard accel. That smoke could have been from some of the buildup breaking away and being ingested/ burned.

You can have this 2WD cover plate for the console if you want it. Not in the greatest shape, it looks like something rubber reacted with the plastic a long time ago. But the tabs are all good/ unbroken. You and I are local-ish to each other, let me know.

@schardein makes and sells them. Highest quality materials and craftsmanship:

Maybe not controversial, maybe it is... Ultimate engine swap of the future will be a hydrogen cell conversion for any GM Gen 5, Mopar or Ford small block. GM Gen 5 already has direct injection provisions needed to do the swap. All the power and beautiful noise with near absolute zero emissions. And no BS electric crap and all its impacts on mining Lithium, rare earths, geopolitics around those materials, etc. And I'd go nuts if someone started making DI retrofit heads for SBC Gen 1 & 2 as well, since I've already got 2 of those.

Looking at your pics - it appears you've got most of what you need there. That looks like the Renix fuel rail and throttle body, both just kind of sitting there. Eagle_SX4 is spot on, you'll need to adapt the Renix TB and linkages to the HO intake and make a way to secure the fuel rail. The Renix fuel pressure regulator will have you at the right pressure. Those injectors look like 33007127, from a 91-93 HO, not the 53030778 grey tops that would have come on a 96 engine. Also looks like you already have a temp sender or fan switch in the thermostat housing, which is it? EDIT - forgot to mention that you'll need a Renix distributor, the HO one won't work due to the CPS to sync sensor signal incompatibility. That begs the question of what transmission is behind this engine you've swapped as well. An AX15 will need a Renix flywheel, AW4 will need a Renix flexplate.

I bought the regular price one from the same seller about a year ago. I messaged them asking for confirmation that all the pieces needed to swap the shorter turbine pump were present. They responded quickly and sent me pics of everything, which I was impressed with. What came was a NOS genuine Bosch pump in a Carquest box. I think they (and some others) jumped on the big sell-off from Advance/Carquest cutting back operations in 2024-2025. https://www.ebay.com/itm/176281211480

The arm pockets do squeeze in a hair when the bolts are torqued during (the last) installation. You can use a prybar and a scrap of lumber to open them a little and then install the arms. Get the bolts just snug and put her back on her feet before torquing to spec.

Minor update - I swapped injectors today to some Bosch EV6 I haven't seen anyone try yet. These are spec'd as: 0280155702 | EV6 | Long | Jetronic |4-hole | 200cc/min | 16 Ohm (very dark grey) I checked the resistance and found them all to be 16.8 - 17.2 Ohms. Not a bad thing necessarily, was shooting for 16 - 16.3. I ran them at 31psi confirmed fuel pressure. The STFTs at idle show just a touch fat at 110-114. I'll need to drive it a while to let the LTFTs set themselves but it looks like a solid winner for my particular rig. It's like a tiny bit smaller version of the 746. I'd like to see real world Ohms resistance on a set of 0280155700. If they're 'real-world' above 15.2 Ohm, I'd pronounce the 'Volvo 700' the most ideal injector possible, bar none. I say this because my motor is HO, 7120 head, bored TB, 2.5" exhaust and it still doesn't seem to really want more fuel than a stock Renix, except possibly above 3500RPM, where the better head flow makes a bigger difference. Renix and 91-95 HO cams are identical. What I took out were the ones that were in the motor from the 93 YJ, old Bosch-for-Ford 20#: 0280150943 | EV1 | Long | 4-hole | Jetronic | 210cc/min | 14.3 Ohm I had to turn those down to 24psi fuel pressure and it still smelled rich, and the oil was getting fuel-contaminated.

I'm not trying to be an a$$/ 'that kid' but some clarification is in order... In a nutshell, all we're trying to do is replace an old injector with a new one that acts electrically like the old one, very close to the effective flow rate of the old one and can be had reasonably easily. Better atomization from an updated spray pattern is just a post EFI stone age bonus. We're not looking for more power, that won't happen without more displacement, head airflow or both. Or altering the Renix calibration, which we can't do at this time. To start, if the latency/ Ohms resistance of a chosen injector is too low, the injector flows fuel before the intake valve is open enough to ingest the fuel, and as much as 33% of the fuel puddles on the back of the intake valve. In response, the long term fuel trim goes up, asking for more fuel via a longer injector pulsewidth, wasting more fuel than it would with a vacuum leak, smelling rich and running erratically. Engineers who write the calibrations, including the Renault/ Bendix engineers, know exactly how the injector behaves and literally build the 'tune' around that. These days, we alter more modern cars' calibrations with characteristics of the chosen injector with things like HP Tuners, TunerPro RT, QuarterHorse, standalone systems, etc. Ohms resistance determines how long it takes the injector to start to open and get fully open. The original Renix injector has a resistance of 16 Ohms +/- 5%. A 12 Ohm injector will start to open and get fully open in only 75% of the time it takes a 16 Ohm to do the same at a given voltage, delivering fuel too early in the 'suck' phase of the cycle for a Renix calibration. That's why, even before looking at the flow characteristics, we need to consider Ohms resistance. I did a huge amount of work some years ago with getting "Bosch for Ford" data from multiple injectors into GM calibrations so modified LT1 F, Y, B and D body cars could run better injectors (that have substantially more resistance/ latency) in place of the 12 Ohm Rochesters. For those cars I could easily modify the calibration ("tune") to change everything related to injector characterization. Since we can't modify the calibration for Renix computers, we have to use an injector that behaves electrically like the original and flows an appropriate amount of fuel, that the Renix computer can set a usable long term fuel trim for. The original Renix single hole injector 53003956 has bench flowed as much as 240cc/min in the real world. But as it's used by the Renix computer, its pulsewidth/ on time (duty cycle) isn't very long except in power enrichment. So most of the time it acts like a much smaller injector (19lb/hr or so) and atomizes decently well for what it is, at lower pulsewidths. And it met the emissions standards of its day, when gas was about $1.30/gal, and wasting some portion of the fuel with first generation injector design wasn't a big deal. Any injector swap that initially makes the engine happy or seem to pick up some power is because it's running rich, in the 12.5:1 - 13.4:1 AFR range where more power (and higher emissions) is expected. The computer sees that at the O2 sensor and tries to adjust the long term fuel trim to where short term fuel trim can yield 14.6-14.7:1 and it runs like it did before the swap (if the injector isn't too big to begin with). So shorter pulsewidths are the computer's solution to an injector that's too big, but just small enough to manage. Long term fuel trim will be below 128, maybe well below for an injector that's too big. And injector duty cycle will be very, very low. If it's too big to manage, the computer likely won't stay in closed loop. It smells rich, and fuel economy suffers accordingly (Neon injector 0280155703). Now, to flow rate, number of holes and connector - we already have widely reported great results with the "Bosch for Ford" injector 0280155700 (14.2 Ohm - 191cc-192cc/min.) and "Bosch for Volvo" 0280155746 (15.9 Ohm - 208cc-209cc/min.). Both are 4 hole injectors with a plug and play Jetronic connector we already have in our Jeeps. Both of these injectors are manageable by the Renix and 91-95 Chrysler SBEC computers. They're more efficient at atomizing fuel, so more of each pulse is mixed and burned, and the computer gets to its target AFR with just a smidge less fuel than with the Renix 53003956 or 91-93 HO 33007127. The 0280155700's slightly shorter latency does mean that some fuel (12-13%) is delivered early, but the 'early' fuel is atomized/ suspended well enough to be almost entirely ingested as the intake valve gets above .100" lift. 12 hole injectors are almost 100% exclusively going to be equipped with USCAR connectors, which means an adapter is needed (though fairly cheap). But I don't see any substantial benefit with a 12 hole (yet) until everything good with 4 holes/ Jetronic connector becomes scarce. 12 hole does fully atomize the fuel a little closer to the injector nozzle than the 4 hole does, suitable for cars with the intake valve extremely close to the injector boss. I suppose the 4.0 does seem to fit that category... Disclaimer: A fair amount of the fine detail data for Bosch injectors isn't available outside what Ford does for their performance injectors made by Bosch. Things like High Slope, Low Slope, Breakpoint, Minimum Pulsewidth, Battery voltage offset compensation, etc., the last 3 being the most important for idle stability/ idle AFR. Other car makers have this data and usually don't publish it, but they most certainly do use it to write their calibrations. Even the Renix calibrations are going to have a couple of offset and battery voltage compensation tables to handle adding some pulsewidth time at/ near idle based on the original Renault/Bendix characterization data for the 53003956. But that's a whole 'nother discussion. IF you have an adjustable fuel pressure regulator, you can turn a smaller injector up a bit or turn a larger one down. IF you have a REM II, you can tweak pressure until your long term fuel trims are within a couple points of the median value of 128. Warning - too large an injector at lower pressure may lose its good atomization characteristics. Better to turn up a smaller one, but there is a point of diminishing returns there as well. If you don't have an adjustable FPR (most of us) you need to find out where fuel pressure is with a gauge as a starting point. Injector work needs to follow established healthy fuel delivery at expected (or manageable) pressures. P.S. - Stay away from anything Bosch with a V-spray pattern. They're for 2 intake valve applications.

First, welcome to the forum! Second, update your signature with year, engine, trans and trim level when you get a chance. Third, add your VIN to the registry - https://comancheclub.com/forum/28-comanche-registry-vin-decoding/ And to your question- I've done an enormous amount of research on this subject for the 87-90 and 91-up 4.0. Much of it applies to the 2.5, though slightly smaller due to its shorter stroke/ smaller displacement per cylinder. For an 87-90 ("Renix") era 4.0 I recommend an injector that has 4 characteristics: 190-196cc/min flow rate as measured at 3 bar/ 43.5psi (approximately 18lbs./hr.) Is a Bosch "long" style EV6 injector with a Jetronic injector harness connector, for a direct swap on length and connection to the wiring harness 4-hole nozzle- sometimes description will include the term "conical spray" pattern, which is fine Impedance/ resistance of 14.5-16 Ohms For a 91-92 Comanche or 91-96 Cherokee 4.0, recommendation is as follows: 196-208cc/min flow rate as measured at 3 bar/ 43.5psi (approximately 19lbs./hr.) Again, is a Bosch "long" style EV6 injector with a Jetronic injector harness connector, for a direct swap on length and connection to the wiring harness Again, a 4-hole nozzle- sometimes description will include the term "conical spray" pattern, which is fine Impedance/ resistance of 14.5-16 Ohms I use a number of sources for reference but the deepest library I've seen is at https://www.injectorplanet.com/. You can search part number and get specs for a specific injector. I like to sort by flow rate and see everything they've cataloged that matches the characteristics above. I've never bought from them but they have an Ebay store with 99.7% positive feedback. I've encountered about 2 dozen great candidates, more if you include standard length, which you can use with an adapter. Also a good number that have the USCAR harness connector, with a Jetronic to USCAR adapter. I've done business with Injector Rehab, they're fine. Avoid anything that's been "rebuilt, with improved flow." Cleaned and rebuilt and flow-matched is what you want. Bosch 0280155700 is an excellent injector for 87-90. Bosch 0280155746 is an excellent injector for 91-96. It's the most talked about "Volvo" injector but its popularity has made it somewhat scarce. Give us some specs on your MJ and we can make some recommendations of what/ where to get it without dealing with knock-offs.

Thanks for the confirmation. I found one locally for only $10 more than the cheapest price I saw on Amazon. It only has about .4-.5mm slack at the rod. I said screw messing with the parts house master, I'm returning it for a little more than I paid for the LuK master.

Limited through programing, not a mechanical governor. So they really screwed the pooch with a horrible tune method. Someone worked really hard on that and only succeeded in endangering lives. SMH…

Mechanical governors that limit throttle travel are incredibly stupid for exactly the reasons you stated. However, maximum speed settings in a PCM/ECM/ECU work VERY well. No effect on acceleration capabilities, just a fuel cut when a speed value in hexadecimal is reached. One example - GM speed limited their 93-02 F-Body cars to 117MPH with zero negative effects unless you wanted to go past that 117MPH barrier. They used 2 values for fuel cut and fuel resume. All the ones I've tuned I set the value to 255, the hex & binary max values, so no limit. But it could easily be set to 130, 90, 85, whatever. Still holds true for almost any EFI car/ truck sold today.

For a quick fix, try plumber's tape on the screws to give them a touch of extra bite in the worn out holes. To fix it for good, you can fill (JB Weld epoxy) and re-drill the mounting holes in the header panel behind the bezels. I had to do a number of screw holes for my lower dash panel screws this way.

It may not have one, not all were equipped with it. We have lots of documentation on 87-90 stuff, not as much on 91-92. Some stuff is the same but some is different. This pic is from an old copy of Mitchell and it does show that the connector is next to the wiper switch connector like it is on 87-90. Also shows the 3 relay sockets including the horn relay. I can post up some wiring diagrams if you want. Someone might have a FSM for 92...

I think I read carefully enough not to miss any mention of the heater core. I know relatively little about the 258 setup in an Eagle, but does it have a heater control valve? And if not, it could be restricted enough to cause issues. If you bypassed it and it ran noticeably cooler, that might be telling. And I agree that the old rad may be a restriction as well.

Here's a good writeup and explanation on where it is and how it works:

Part # 53000510, Radiator Brace for 2.5L. Has a slight twist, should straighten out easily Transmission harness for either 89 4.0 with BA10-5 behind it or 87 2.5 with AX-4/AX-5. Never was sure. Extra connector if you want it, not part of the actual harness. 2 brake light switches, one with 2 sets of pins, one with 1

Forgot to mention, @eaglescout526 hooked me up with replacement gauges for temp and oil pressure. Thanks again!

It's been a while, 2 jobs and life stuff taking most of my time. A couple weeks ago, I tackled the pulsing lights at idle issue with the Durango alternator/ external regulator issue. Wrote that up on the DIY section. This past weekend, I got the fire extinguisher mounted under the passenger seat, using existing holes in the front bracket. I'm satisfied with it, easy to remove for vacuuming and reminds you to check the date when you do... Made by Shield, right here in Kings Mountain, NC. The bed hasn't been empty since I started pulling it apart back in April of 2022. Feels good. There are 3 small dents in the rear wheelhousings I'm going to work out soon. I have a ton of odds and ends for sale locally on CL. I have a tiny handful of Renix-specific stuff I'll post in our classifieds. It now has a temporary tag and is legal to operate on NC roads. I want to iron out the clutch master to 100% confidence vs warm restarts/ difficulty getting into 1st and reverse, and I need to tweak the toe adjustment. I found my custom fasteners for the passenger fender liner right after I ordered more. It hasn't been over 40MPH yet and lots of stuff needs to be tested/ verified at higher speeds: - Cruise control testing/ adjustment - Death wobble testing - Road feel with fairly little caster/ higher rear end than I like - headlight & fog light aiming/ adjustment - Overall engine performance/ driveability under differing loads & conditions Oh, and my personalized plate will read: 87-99 MJ

The Ford Modular V8 (4.6L) is Bosch 0280155700. It's 192cc/min. I want to say a couple guys on here have gotten those from Trevor as well and had great results. Those should be easy to find in the US boneyards. Mustangs, Crown Vics, some Explorers, Expedition, F-150, E-series vans, to name a few. They're a yellow EV6 long size body with Jetronic connector. Around 14.5 Ohms, good choice.