When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go hereXJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
So my co worker bless his heart let me borrow a scanner of sorts to actually read some info on my jeep and looking at them, jeep goes into closed loop fairly fast which i guess is good and is 54 degrees out tonight when taking all this info the first 3 pics are at idle and the other 3 are at 2k rpms. i dont know exactly what im looking at in terms of these but i was hoping this will help me track down part of my fuel consumption issues. the o2 sensors are brand new and actually driving home my jeep felt fine none of the rev hang issues i been droning on about and gas gauge wasnt sinking like the other day but at the moment do anything in these pictures send a red flag? i wish i can get it on a bigger better scanner but this is all i have at the moment lol Idle Idle Idle
I should mention recently i do have a catalytic converter under efficiency code p0420 but in terms of the actual fuel consumption issue was WAY before this code even came up but im pretty sure it is a factor in this as well. 2k rpms 2k rpms 2k rpms
Im hoping some of these will atleast trigger a thing to replace cause i love driving my jeep but i cannot afford the gas issue cause the last calculated mpg i got was 6.3 out of a full tank of gas or atleast like 122 miles and 19 gallons filled back up (to the actual brim as before). My co worker also showed me something on all data that the iat, tps and coolant temp sensor all travel along the same wiring diagram route so any of those sensors could maybe throw off the mpg that badly and cause rev hanging issues? we also did a smoke test on the vacuum system and no smoke was seen or smelled. I just wish i can figure this gremlin out and maybe help others with the issue. I already have brand new ntk o2 sensors as well installed so i can rule those out for being faulty (maybe even why the cat code was triggered lol) the cat will be replaced as soon as i get some cash to spend on it.
Also the first time this issue ever happened was 2 years ago when leaving my sisters my jeep suddenly had that rev hang issue where i tap the gas pedal and the usual snappy throttle response turned into what felt like the gas pedal being held a little then released like its a sensor issue and on random days the jeep ran perfectly fine the whole day and then some days runs great for some time then i turn off and back on with those issues. it was just a random issue at the flip of a switch basically. i also did a tps test and the idle is what you see and the wot is at 75% which i looked up and says is quite normal.
From the pictures you attached, everything looks generally ok. Nothing is completely off. The fuel trims are the ones to watch (ST FTRM1 and LT FTRM1) short term and long term.
What concerns me is that when you switched to 2000 rpm, the short term fuel trim went negative by almost 5 percent (engine is running a little rich, so it is holding back fuel a little). However, the short term fuel trim bounces around quite a bit, so by itself, it is not alarming. What you should do is monitor those values, particularly the LT FRM1 and see if it gets more and more negative at 2000 rpm.
But again, from the pictures alone, everything looks within spec. And a short term fuel trim of -4.7 by itself is not cause for alarm (unless the numbers keep getting larger).
If the fuel trims stay normal like shown in the pictures, and you are still losing that much mileage, I would be concerned that you have an actual fuel leak somewhere.
i have looked! trust me i have checked every single frickin free solution and the fuel leaks i "did" have are now fixed. it was parked in a garage multiple times. no raw gas smell at all, nothing leaking even got my step mom to come out and take a gander around cause she is hyper sensitive to raw gas and she didnt smell a single drop even parked for a few days she hadnt complained once where as i had a small vent hose broken and she instantly picked it up lol. then again it COULD be leaking while driving but again im pretty sure at lights i would smell the gas and i smell nothing. I should mention the tip of my exhaust is extremely black compared to other jeeps and this last calculated trip was 2 months ago cause i been using my car alot and driving this one every so often so it isnt accurate but it is relevant cause i been calculating my range and 3-4 times it went this low with ac on up to atleast 150-170 miles a tank with ac on as an average. and without ac i can just *just* peg 190-200 range running it slightly under e on the gauge from full. none of this is really stop and go traffic nor idle time either i jump in my jeep let it warm up for bout 5 minutes then jump onto 19 and set the cruise for 60 mph and its a straight shot to work with no lights or stops. i should be getting atleast a better range imo. it seems whenever it acts up like that with the idle and rev hang issue it sucks down gas badly to where i do come up to a light and notice in about 5 miles the gauge went down a line. ill see if i can get this issue to trigger then post more pics.
I was also basing it off others mpg ratings as well and mine seems to be underwhelmingly low compared to other jeep cherokees. Also i should mention when it acts up the performance is very sluggish as well. anddddd sorry gotta bare with me cause i havent driven this in a good while and may be missing info as this was my only vehicle at the time and could get more accurate testing but the issue still persists. but since it is winter i am willing to drive it more cause the evaporator core decided to leak on me so i cannot test with ac at the moment but it does it without ac as well. just more common to happen with the ac on and especially on hot hot days.
Your intake air temps are crazy high. If they stay that way when driving, it's going to pull a bunch of timing out. No timing = no power and bad gas mileage.
sitting at half before driving 8 miles In driveway revved to 2k Pulling into driveway
sitting for 5 mins and revved at 2k idling for 5 minutes continued further downscreen idling for 5 minutes
so i just took it for a little 8 mile jaunt and watching the intake air temps while moving i was getting 60-85 degrees when moving at 55 mph but at a stop the temp was creeping up to 100 degrees after 30 seconds. the short term fuel trim while driving at 55 was bouncing around from 0, -2.2, -3.7 and usually blipping to -5.3 and when coming to a light sat at -7.0 for a bit then to -5.3 and then 0 and kept hovering around -2.2 at idle till i took off. long term while driving was also hovering around -2.2 as well but also seen multiple spikes of 3.7 positive but lemme go out to the driveway again and spin it around the block then hold it at 2k rpms for a bit and see what the long term does.
Those IAT readings are normal they’re always high when they’re mounted in the intake manifold . What concerns me is the TPS reading shows a 3% difference from idle to 2,000 rpms if I remember correctly it should be about 10 percent at idle not 16. I can’t see that your o2 is ranging in your snapshots so at idle is it ranging ?
I run a digital dash, and that IAT does not look crazy high to me. It should read about 30F higher than outside temperature when cruising (55-60mph). But when sitting it can easily go to 100-150F due to the warming of the engine compartment. I watch mine quite often, because it gives me an indication of outside temperature when I'm driving. Even if it was crazy high (which it is not) it would reflect in the fuel trim numbers (and would likely be lean...not rich).
When you first fill your tank, is the needle above the FULL mark? I'm wondering if perhaps your fuel assembly tank float arm is improperly adjusted, such that you actually have a lot more fuel left in the tank when you hit E on the gauge. Just to confirm, when you filled up from empty, you actually were able to put 19 gallons in at the pump (as recorded by the pump itself)?
yes 19 gallons to the brim (i know its a bad thing to do to fill it to the neck but i do for science lol) and that could be a possibility it is a new sending unit but everything seems to read like it should as before and by ranging you mean fluctuating back to 0%? then yes but during the drive about 90% of the time it was in the negative area.
Do these values look normal?
