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4.0 L Wizards, HELP! Left turn hesitation

JarheadJon

NAXJA Forum User
97 Jeep Cherokee
4.0 4wd 125K miles
AW4

My Jeep started hesitating when gassed hard from a dead stop making a left turn. It would start off the line hard then the tach would drop along with the engine noise coming to a stop. Immediately letting off the gas then reappling would return the vehicle to normal operation. If I continued to stay on the gas she would buck. I had the fuel module ($401 MOPAr PART) put in at the dealership afterI was eventually stranded. After the replacement she acted flawlesslyuntil today. Its back but worse. Now I get the same knock/hestation even on low rpm starts (still above 2000 rpm) and on a on ramp (left turn) on to the freeway. Any Ideas? Is it an ignition issue? Fuel starvation issue? Imclueless and need help. Thanks

Jon
 
Definitely a fuel starvation issue. When you take a left turn, the fuel moves to the right in the tank and away from the pump. If the tank is low on fuel, the pump can run completely dry.
 
I'm going to have to agree with the good Dr. on this one.

I would suggest doing the same thing u've done that makes it hesitate, but turn right instead.

If it hesitates when you go to the right then u might have something mechanically wrong and not just a fuel starvation issue.
 
The ugly part that I failed to mention is this happened with a bonafied true half tank. I coud see if it were a 11/4 or lower but I did have half a tank because I filled the tank up tonight to ensure.
 
That may be a sign that the fuel pump is slowly on its way out. Unfortunately it's an intermittent problem which makes it harder to diagnose by a mechanic, and he'd probably check it and find nothing wrong unless the pump acts up at the right time.
 
There's a neoprene hose that connects the fuel pump to the housing outlet, that may be loose or cracked. It is located above the fuel pump, therefore at about the 1/2 tank level.

Does it do it with a completely full tank?
 
I have the same problem with my 99 at 110K, at half a tank it starts stalling out when turning left hard. I pulled the tank yesterday and noticed that not only does the sensor on the float look trashed likley giving a false reading but the filter screen looks like an old rusty, crudy brilo pad. Im going to replace the pump but at $380 dealership price their has to be a better solution I have seen some aftermarket pumps by Carter & Walbro for less Walbro even has a proformance upgrade of 225lph both for way less.
Has anyone herd of or tried these pumps? I wonder is it just the pump or is it the whole asembly screen,filter, float ect.. just like the stock pump. I would love to hear from someone who has experiance with this.
 
I finally changed the fuel pump and assembly this weekend every thing seams to be running fine I’m let you know if it happens again but I think it solved the problem.
 
I should of posted this 30,000 mile ago. I will now just incase someone does the search and I can help.

It was a result of me running premium. After replacing the fuel pump (the whole gas tank assy) and 640 stealership $$$ later, The case improved for about a month or so. The dealership was stymied, and after a few days called me up and said they knew what it was... Simple and free fix via an official ChryCo letter about 97 XJ 4.0's Why just XJ's I dont know, but that was the word. I hope this helps my fellow XJ'rs

Jon
 
Social Waste said:
I finally changed the fuel pump and assembly this weekend every thing seams to be running fine I’m let you know if it happens again but I think it solved the problem.
how bad was changing the fuel pump and assembly?
does the tank have to come out?

also - do you have to release the fuel system pressure? what do you do with excess fuel in hoses etc....?

and BTW - i've always noticed my 96 runs better on cheap gas than premium...no idea.
 
Last edited:
The dealership did the replacement. But I do remember that dropping the tank was required.
 
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