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hesitation at partial throttle

noticed a lot of lean pop through the throttle body on my jeep yesterday as i said, so just now i put a fuel pressure guage on it and it only shows 20 psi of fuel pressure. when i first open the throttle it drops to almost 15psi and then goes back up to 20ish. im guessing i should change the pump and filter as a pair.
 
littlebill86 said:
noticed a lot of lean pop through the throttle body on my jeep yesterday as i said, so just now i put a fuel pressure guage on it and it only shows 20 psi of fuel pressure. when i first open the throttle it drops to almost 15psi and then goes back up to 20ish. im guessing i should change the pump and filter as a pair.
Click to expand...

Yup.
 
ok i looked and my cap and rotor are in need of replacement. i think at this point it is just good insurance. if my other car sells i think i ll get anew distributor and cap and rotor and plugs and wires. and double check the dist to be sure it is where it should be.
cruiser and mike i thank you for your help. i ll also look closer at my exhaust and see if any cracks.

scott
 
Gunter said:
ok i looked and my cap and rotor are in need of replacement. i think at this point it is just good insurance. if my other car sells i think i ll get anew distributor and cap and rotor and plugs and wires. and double check the dist to be sure it is where it should be.
cruiser and mike i thank you for your help. i ll also look closer at my exhaust and see if any cracks.

scott
Click to expand...

Cap and rotor with brass terminals. Good wires like Napa Belden, and NGK plugs.
 
X2 on the brass terminals, Cap and Rotor!
 
guys i know im full of questions im sorry. i have suspected my jeep of having a fuel pump/filter problem seeing as my fuel pressure only shows 20 psi. well tonight i was out playing with it and with a vacuum pump on the regulator i saw pressure as high as 30 psi. it ran great for a few moments and then went to crap again. how common is it for the regulators to go bad?
 
littlebill86 said:
guys i know im full of questions im sorry. i have suspected my jeep of having a fuel pump/filter problem seeing as my fuel pressure only shows 20 psi. well tonight i was out playing with it and with a vacuum pump on the regulator i saw pressure as high as 30 psi. it ran great for a few moments and then went to crap again. how common is it for the regulators to go bad?
Click to expand...

What year is yours? Have you checked the voltage at the fuel pump? Check the fuel pump ground quality? Should be less than one ohm back to the battery negative post.
 
ok men, i replaced my fuel pump and now it RUNS!!!!! thank you for all of your help. xj runs really good. taking it tomorrow to get it smogged so i can drive it all over the place. thank you all so much.
 
Before you replace the CAT run a bottle of cleaner through the intake manifold, I think Seafoam is popular one here. And run a bottle of quality brand of injector cleaner in the gas tank, and drive it some. Then change the CAT before the inspection. Carbon deposits in the combustion chamber cause high NOx emissions. So do partly clogged injectors, poor spray pattern. The cleaners will help clean the junk out, but it lands in the CAT next.
 
ok so here are my smog results, a couple of my jeep/slash auto buddies that i work with have been discussing this and want your opinons.

HC MAX-124, 104 Actual 201,209


CO MAX-.75,.95 Actual .87,.86


NO MAX-714,616 Actual 2029,2089


looking at the HC levels im running rich while looking at the NO levels im running really lean with hot combustion temps. let me know what you guys think. thanks
 
Last edited:
How many miles? Looks like your burning oil hc is unburn fuel also oil which probly took out the o2 sensor and cat also a dirty injector/injectors cause hesitation an lean/high NOx heck even a bad spark plug will do the same

FYI hc doesn't mean your running rich
 
Last edited:
sneakyjap96 said:
FYI hc doesn't mean your running rich
Click to expand...

While it can be running rich, it can be miss fires, poor combustion in one or more cylinders.

Needing a tune up, and a good cleaning with gumout (to remove carbon), and needing a new CAT can cause those numbers if the CAT is bad.
What year was this rig?
 
Re: Re: hesitation at partial throttle

Ecomike said:
While it can be running rich, it can be miss fires, poor combustion in one or more cylinders.

Needing a tune up, and a good cleaning with gumout (to remove carbon), and needing a new CAT can cause those numbers if the CAT is bad.
What year was this rig?
Click to expand...

Every thing I just said with out saying miss fire..

And a 88 look at the cat. Actually you can just unbolt the cat drop it Down an take a look at the honey comb see wat it looks like
 
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