Hi everyone. New to the forum and wanted to say hi.
Let me get right into it....
I am having some issues with my YJ. Hoping someone can maybe come up with something I haven't tried yet.
93 YJ, 4.0 6cyl, 140K, automatic, motor was rebuilt by previous owner, so not a lot of info on that.
About a week ago, after a fill up I drove about a mile and she stalled. Wouldn't start. Cranked, but no run. Got it to a safe place and tried again in the morning. Didn't look like I was getting spark so I replaced coil. She started and was fine for 30 miles.
Next day, she was hard to start. Once running, it would randomly stall. Sometimes it will fire up right away, sometimes it will take some cranking. Sometimes it will stall while idling and sometimes while driving. Seemed to be no rhyme or reason as to when it would stall.
During the past several days, I have done the following:
new fuel filter
replaced throttle position sensor
drained fuel tank and checked pump. all good there.
new fuel pressure regulator
I was able to drive it without issue last night for about 6 miles only to have it stall right when I got to my driveway.
I am just at a loss as to what may be causing this. I hate to keep throwing parts at it.
Any input would be appreciated.
Does the engine have oil?
Is there water or anything not-oil mixed in, ir on the dipstick? (no need to drain)
Sounds like a fuel problem. I had gotten water in a tank of gas the first week I had my YJ and it was a pain to diagnose. I rebuilt the carb and discovered water in the fuel bowl...
Your fuel injected Jeep may have more than one inline filter. Usually one on the frame rail at the back of the Jeep, another in the middle or up under the hood before the fuel rail.
You say you drained the fuel tank, did any water come out? Did you add HEET, ISO-HEET or similar "dry-gas" product to evaporate moisture in the tank? I had to run Isoheet (red bottles @ walmart for cheap) every week for a couple months to be absolutely positive all water was dried out of the tank. Small price to pay, and good to run in the winter anyway.
Also try getting gas at a different station from now on or get the highest grade. Yes its more expensive BUT it contains more power content, the Jeep will run better, get better fuel economy and start easier in the cold. Mid grade 89 octane is 60/40 blend of regular and high test 91 mixed at the pump. Regular is straight 87, high test or super is straight 91/93. I run Sunoco 93 in everything, the few cents extra doesn't deter me from better fuel.
Another possibility is the maf or map sensor but I highly doubt it. From what you describe it sounds like either diesel fuel or water-containing gasoline was added. My money is on bad gas.
How does it stall? Slowly puffs out gently or abruptly stalls without warning or runs violently before shutting down? If its anything but peaceful then again my money is on bad gas.
One last thing could be O2 sensor going bad. Its rare that they die slow like this its usually one day it works the next it stops. Pull it out and clean it or possibly test and replace. Don't touch the bulb with fingers and if replacing use the same brand don't cheap out. For example if it came with Bosch use Bosch don't use a Denso. Same goes for spark plugs, Jeeps don't like the Jap plugs.
Let us know how you make out or PM me if you need clarification.
Welcome to the forum, plenty of people on here with lots of experience. There is a wealth of knowledge here and always take the time to listen to the poster. Que is a great example of the knowledge.
Check the crank position sensor. If the P.O. replaced it make sure it's the right one, there are two different sensors. One for auto trans and one for manual trans. I have seen where people have put the wrong one in and have issues like you are having.
X2 with xj. There are 3 common problems with a stall like you describe.
Tyne crank sensor and coil. You need to see if there is spark at the plugs when you can't restart it. The other is the fuel pump. Listen to see if the fuel pump is coming on and shutting off priming the fuel system when the key is turned on when you get the no start. Also on the fuel rail there is a valve. Push the valve and see if gas shoots out. Also check you codes. Follow these directions. http://www.jeepforum.com/forum/f12/h...codes-1257145/
There is a cam sensor. Its called a pickup sensor in the distributor. The fault codes are not always as precise as the OBD II because while they will tell you if a reading is out of range they do not look at rate change so if the sensor fails in range it will not throw a code. If you have a code then you need to deal with it...if you don't have a code it doesn't mean the sensor is good. Exhaust is definitely a possibility too.
Thanks to everyone for your input. I really appreciate it.
I did not realize that there could be another fuel filter near the motor. I will check further into that.
I have gone through the fuel system pretty thoroughly and am definitely getting fuel to the rail. I was starting to believe that something is prohibiting spark for some reason, and randomly. I did get her started again yesterday and while she was running, I began going through engine bay trying to find something loose (vac line, wiring, etc.) and see if I can make it stall. Well....when I got to the wires that lead into the coil, a slight push made the idle stumble. Another push, and she stumbled again. A harder push and she stalled. Could it be?? I am going to un-wrap them today and see if they are damaged. I think I might just be onto something.
Will update soon.
When mine had a similar issue I ended up running new wires... twisted a pair with an electric drill and ran new wires to the ignition module. Also the wires near the pickup in the distributor tend to get cooked I've noticed.
I don't suggest jumping right to adding wires, especially two of the same color like I did, I admittedly hacked it in but I needed the Jeep and didn't care what color wires made it drive again. YMMV.
Update on suspect wiring:
Unsheathed all nearby wiring.
Removed small black (relay??) box from back of alternator.
Found no obvious shorts or breaks.
Cleaned all terminals and re-installed black box.
Re-sheathed everything and taped up tight.
She fired up. A little rough, but kept smooth idle after a few seconds.
While idling, I again pushed on the three-way harness behind alternator (where all the wires split off), and each time I push down on this, I can get the motor to stumble...clears right up when I release it. If I keep pushing down, it will stall. I am now convinced there is a loose wire here and it seems to be one of the two wires (one is green and one is green/orange) leading from the harness down to this black module on the back of the alternator.
I am going to splice new lengths of wire in place and if it does not solve the issue, I will assume that they are loose/broken close to or within this black module.
What is this module? Would it be part of a new alternator, or a separate part I might replace.
I think I am close to success!!!
There is nothing special about it. It just located and stabilizes the wires.
Gotcha. It wasn't clear to me whether or not it had some function.
So, here's the latest.
I replaced the two wires that I suspected but it did not correct the problem. After another thorough session of pushing and pulling on wires in that area, I realized that something was losing contact in the input connector on the coil. When I pushed on the side of the connector, it would stall.....every time.
I took the connector off, removed the females from inside, pinched them a tiny bit (so they would squeeze the pins on the coil tighter), put the connector back together and plugged it in. She fired right up, runs great and pushing on the connector doesn't cause it to stall.
I think it's fixed. Sweet.
Thanks to everyone for their replies!!