This 1991 XJ cuts out hard when accelerating. As you can see in the video, even the tach dips when it cuts out. You can accelerate smoothly with light throttle. these symptoms only occur in 1st and 2nd gear and appear to go away in 3rd and 4th gears. If you just keep your foot in it, it will eventually start to back fire thru the intake.

I appreciate your help!

 

Hey, how about you quit the grovelling?

"oh, please please please pleasey!"

What is with you kids these days? Haven't you got any self-respect?

The whole reason for this forum is to provide a place to get help fixing Jeeps, so how does it help anybody to put that in your thread title? What does it add to the discussion?

Try this instead: Instead of groveling, how about making the effort to create a thread title that intelligently describes your problem, so that people who are scanning the new threads know what it's about, so that those that have some information about YOUR problem can chime in?

"1991 XJ cuts out hard when accelerating" would have been an intelligent thread title.

"Please help me fix my Jeep!" is anything BUT.

 

Thanks for helping him out Mark! Anyways, it could be that the engine is having a long misfire. Try replacing your coil pack and se if that helps.

 

Some history of what has been done recently would be most helpful. Last time a complete tune up was done? Fuel filter change? Don't go throwing a coil pack at it (only has one coil) because someone says to. Do some diagnostic work first. Check the fuel pressure and put a vacuum gauge on it.

 

Thank you for your suggestions!
It appears to have had a recent tune up consisting of a new distributor cap, ignition rotor, spark plug wires ( 7mm and of questionable quality), and OEM Champion Spark Plugs. I havent noticed if there is a port on the fuel rail for a fuel pressure tester or not. I didn't look... I do have a vacuum gauge somewhere in the basement. Both of those things might point me in a direction. And if it comes to it, I found an ignition coil on Amazon for pretty cheap.

 

Sounds like a fuel related issue, which could be the MAP sensor, FPR, pump, or filter.
Start with the filter. Check the MAP vacuum line for cracks, test fuel pressure ... All the cheap stuff first.

 

91 XJ.......first. foremost..... turn key ON OFF three times fast.( ON/OFF, ON/OFF, ON/OFF, then ON)

wait..... CHECK ENGINE light flashes in a series of sequences.


you must have your handy-dandy shop manual or haynes manual available to tell you what the codes are...... if your MAP or any other sensor is freakin out, this little "test" will point you in a correct path to problem elimination.


Now, once you have read codes..... take batt cables off batt, (both POS and NEG)... hold them together for like 1 minute. (this will clear codes).


put cables back on.


run jeep again see if same symptoms occur. If so, once again energize the code sequence with the key. read codes again. if they are the same then you have a direction to solution. IF, and I say IF, you get NO codes at all, then you have more than likely a vacuum leak (intake manifold area somewheres. or fuel delivery issue)


best I can do for ya killer.....good luck!


cpnwrench


almost again seems like a fuel delivery problem.

 

Excellent advice right here^^.

And Mark said what I've been saying for years, but stated it better.

I'll skip over a HELP thread way faster than I will one that has a title that interests me.

 

When its not almost out of gas does it also do it ?

 

Shame Mark, shame. That is not helpfull and no skin off your butt on how HiC has begun the thread. CapnW has helped and nice call on the Freegdr.
Was the cutting out in evidence prior to the tune up ignition parts and why are the 7mm wires suspect?
Simple solutions 1st as the Wild Floridian suggests, add gas and report back.
Oh, also apparently never say please again.
(Your welcome!)

 

X2 on this. Put at least $10 of gas in it and see what happens. It sounds like it's running out of fuel pressure. You can borrow a fuel pressure gauge from an autoparts store and pick up a fuel filter while you're there. With the low fuel light on, your pump is sucking fuel off the bottom of the tank. If the tank is original to the 91, there will be water, grit etc that can block the screen on the pump or suck all that into the inline fuel filter plugging it good. It's pretty typical that the Jeep will run fine and even drive until you need to punch it and then the fuel pump can push enough fuel through that plugged filter or its' on it's last legs.

 

Rockfrog- Thank you for your ideas! I need to look and see if there is a threaded port on the fuel rail for a fuel pressure tester and then look up fuel pressure spec's.. I feel pretty good about the MAP vacuum lines, but thats just because i sprayed around with carb and choke cleaner looking for indications of a leak.

cpnwrench- Thanks for the idea about pulling the codes! I havent had any check engine lights so I wasnt sure if there were going to be any codes present. I'll recheck for vacuum leaks. Again, I sprayed a whole can of carb cleaner looking for vacuum leaks. I'm sure there is a better way.

cruiser54- I WAS trying to make a title that was interesting. Lesson learned.

freegdr- Yea, It pretty much does it all the time regardless of fuel level.

Peep- I'm not sure, it came into my hands running that way... I'm not sure about before the "tune up". The 7mm wires are suspect because I believe that 7mm wires are if lower performance and quality level than 8mm wires. For a long time there were two different quality and performance levels of spark plug wires. The cheap 7mm wires and the premium 8mm wires. Now, this is an old school and outdated thought process I have. I know that there are plenty of good 7mm wires out there, I just feel better with 8mm wires.

67 GMC- I think its a fuel problem too... I really need to check it out. Sucks having to do my repairs outside in the cold. No garage/apartment living... 23 degrees out there right now....

 

Hang in there and we'll help you along. 7mm new wires should be fine.
What plugs are in it? How do they look? Inside the cap?

Noggin pokin is needed as to those things.

 

A quick, easy test. Floorboard it at about 25 MPH. Does it quit it's "shenanigans", and go like a "perturbed" ape?

If so, I can't help, that one has me about stumped. Temp, or 02 sensor wire grounding, no idea.

If it does go, it's getting enough fuel and spark.

Idea here is...the 87-90 ignores a bunch of sensors and goes into "open loop", past around 80% throttle, and yours is likely similar. When my 90 (had one of those grounding), it blew the mouse nest in the air cleaner out the front grille, then I drove through the confetti. (No sign of the mouse.)

 

Here's a link with a list of the codes.
http://www.xjtalk.com/showthread.php?t=11574