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Fuel system differences in '97+ XJ's?

steady 49psi no vacuum port/input/decrease in fuel pressure, returnless fuel system, fuel pump and regulator are in the tank.

Why do you ask?
 
I've read recently that E-15 has been approved by the EPA and was wondering if the standard fuel systems would put up with and adjust themselves accordingly for the extra 5% Ethanol in the blend. Mileage won"t be a problem since the truck is no longer my DD.
 
I too heard that E15 has been approved for sale. 01 and newer vehicles.

But it's not going to (yet anyways) be REQUIRED to be used in 01 and up vehicles. It simply "allows" it.

If they are going to let the marketplace decide on this one, I think it's going to be tough sledding for E15. It could be a very long time before you even start seeing the pumps.

They're claiming that it has gone through rigorous testing and is safe for 01 and newer vehicles. But not so fast. The American Fuel and Petrochemical Manufacturers and the American Petroleum Institute, along with several motor vehicle and other engine manufacturers, have said that more comprehensive tests revealed potential damage from using E15.
 
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I know of that "test", but considering who all is involved in that study and their financial stake in Ethanol failing, I'll take it with a bag of salt untill I get a chance to read it. I have heard that most ofthe "failures" were engines that still ran, but not to their full capability and I thought one gave up prior to seeing any Ethanol in testing.
 
Here's the general run down
-96 First year, the ecu has no security or check-sum routines and very few people can flash these, uses the onboard tach driver for the cluster.
-97 First year for the checksum and security routines, also the first year for a CCD driven gauge cluster
-98 Minor mapping differences between the 97 ecu.
-99 First year for jtec+, switched from a resistive oil pressure sensor to a 0-5v oil pressure sender, the code is completely different from the earlier jtecs.
-00 They added 2 more ignition drivers to run the ignition cassette and made a few minor mapping changes.
-01 Other then a few minor mapping changes it's pretty much the same as an 00 cali emissions ecu.

Feel free to correct me or add to anything here.

I also have a feeling that if you run E15 in a jeep it will push the fuel trims further into the + range and might even throw a lean mixture code. Right now on E10 I'm at +6% on my long term fuel trims.
 
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So 703 injectors would work well with E15.
 
We have E15ish here and have had for a very long time. It actually varies between 10% and 15% depending on it being Winter or not. It is an "Oxygenated" fuel. HIgher concentration during the Winter.

My Heep runs just fine as does everything else up here...

The pump says "Contains at least 10% Ethanol".
 
In keeping with the theme of what are the differences b/w '96 and '01'

Correct me if I am wrong-

-99 distributorless, coil on plug ignition, New 'curvy' intake manifold
-00 dual headers with dual downpipe cats (?only calif cars), 4 02 sensors
 
Here's the general run down
-96 First year, the ecu has no security or check-sum routines and very few people can flash these, uses the onboard tach driver for the cluster.
-97 First year for the checksum and security routines, also the first year for a CCD driven gauge cluster
-98 Minor mapping differences between the 97 ecu.
-99 First year for jtec+, switched from a resistive oil pressure sensor to a 0-5v oil pressure sender, the code is completely different from the earlier jtecs.
-00 They added 2 more ignition drivers to run the ignition cassette and made a few minor mapping changes.
-01 Other then a few minor mapping changes it's pretty much the same as an 00 cali emissions ecu.

Feel free to correct me or add to anything here.

I also have a feeling that if you run E15 in a jeep it will push the fuel trims further into the + range and might even throw a lean mixture code. Right now on E10 I'm at +6% on my long term fuel trims.

One thing this post got me curious about the above post, if 15% becomes available here and I do start to use it in my XJ, how would things work if the to fight a possible lean condition if I unhooked the battery for 30 seconds to let it reset and relearn settings?
 
It will start to relearn the fuel trims as soon as it the O2 sensors come on line, with in a minute or so. Really, I don't know why anyone would want to run E anything other than for boost or a high compression engine (think real high compression)
 
I've been running 85% in my 200 since the saturday before Memorial Day and found it to be much more driveable in hot weather and that it ran cooler as well. The Pentastar motor in that runs about one point higher on the compression than our 4.0l motors and is a VVT motor, which should work better as a full flex fuel engine than a standard, non flex fuel engine like the 4.0l is. If I was building a fresh engine for the truck, I'd consider building it to run on at least 91 octane gas and set it up to run E-85 as well. Only real problems I've run into with E-85 on the 200 is that the mileage is between what it and my XJ would normally get on 87 octane and it's a slight PITA to get around here.
 
In keeping with the theme of what are the differences b/w '96 and '01'

Correct me if I am wrong-

-99 distributorless, coil on plug ignition, New 'curvy' intake manifold
-00 dual headers with dual downpipe cats (?only calif cars), 4 02 sensors

99 still had the cap and rotor.. it got the fancy intake upgrade that's all.
 
I went ahead and decided to splash blend my XJ this morning since it was nearly empty and winter is coming (I last filled it right after Easter!), 3 gallons of E-85 and 14.706 gallons of what should be Chicago Winter Blend gas (still probably 10%) which combined should have been equivalent to E-23 and an octane rating of around 89.6 according to a calculator I found. I then reset the OHC and put about 31 miles on it between the time I left the station and arrived at home. The engine temps stayed consistant, maybe more so than normal considering the radiator is currently a bit iffy. Idle was a bit rough at first but smoothed out nicely and by the time I got home the tone was cleaner and crisper than before and the throttle response was a bit better as well. Gas mileage according to the OHC was a 15.5mpg even though I made sure to get on it hard several times while watching for a check engine light that never came on....in fact, I'm kinda thinking O2 sensor #1 might have seen better days though. Since winter is coming up, I figure I might was well give it a try as it's not going to be sitting as long between uses, especially if we have a fairly normal winter.
 
Well guys, time for a little update!

First off, It was starting to develop hard starting issues that Dad figured was the check valve had been gummed open like his two Renix trucks had suffered from as they got older. He and I had both taken to cranking it over a couple times, backing off the key while pumping fuel into the lines and starting it like normal. Dad went to move it last Wednesday and proceeded try and crank it, let it sit, and crank again, only to have it fire almost instantly......literally within a couple cranks! I've been driving the Jeep for the last several days for work and found a few interesting things.

#1. Gas mileage seems to be about the same on E-21 as it has been on E-10, won't know for sure until I top it off again and I will be trying to maintain a 20%-25% blend for now!

#2. The truck has continued to start almost immediately, even on the cooler mornings like we've been having of late and hasn't been overly "cranky" like it can be when it's cold out, this winter will tell me more on this as it gets colder around here, but I'll be seeing that on the 200 too.

#3. The truck is running better, throttle response has improved, the way it sounds has changed as it now sounds more aggressive and "cleaner" or "crisper". I can't say if it's quicker as between the dieing power steering pump dragging the engine down some and having spent the better part of the last 6 months driving a fwd sedan with 280+hp and a 6 speed auto that has a granny low first gear, my ability to perceive such things is royally screwed up as of right now :laugh:

#4. I've had no new leaks, funny smells that shouldn't be, or check engine lights appear....even if I'm hammering on it!

#5. Engine temps, besides the P/S pump dieing, the all brass 3 row Dad and I put in the truck some years back is going away too. That 3 row had allowed the engine to run much cooler, especially during the winter. As that radiator has started to go away over the last couple years, engine temps have returned to running stock temps in cooler weather and getting a little warmer than I like during hot weather. So far, once the T-Stat opens up, the truck will pretty much stay at a much cooler temperature that was similar to how it ran when the 3 row was in good working condition for these weather conditions.......and again, it don't seem to matter how hard I beat on it either. I even talked to a friend with a later production 4.0l ZJ (around the same age and miles as my XJ) that has experimented with his own home brew in it's tank and has seen the same cooler running temps....literally to the point that prior to talking to each other, we independently thought there might be sensor or dash problems with our Jeeps.
 
Not to hijack this thread but quick question. In my 96 xj 4.0 ax15 i've replaced my steel tank bc it was rotted but now i'm on sending unit/pump assembly number 3. They keep rotting out as well. Going to switch to a 1997 plastic tank and sender/pump. I know it will plug in fine/strap in just the same and pump fuel as long as i modify fuel feed and vapor lines. As i understand it i can make the sender read fuel at half the actual level which works good enough for me. I searched around a bit for diagrams but i'm not seeing anything. Does anyone know which wires i have to splice? If not a fsm should be able to help me here for factory diagrams?
 
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