I have a 1992 Cherokee Laredo. It has this little spit and spuder issue where when it starts it takes about 20-30 sec to start. When its running sometimes it sounds like only a few cylinders are firing. I have replaced the plugs, cap button, wires are good ( i believe no archs). What is the issue. Also i put stp fuel system cleaner in it and it made it worse. I have replaced the fuel filter also. HELP!
thanks in advance!

 

Check for proper duel pressure, check and clean all engine grounds, check for GOOD spark, and then go from there.

 

I do not have access to a fuel pressure gage. but ill check the rest ty

 

Auto parts stores usually have a FP gauge for loan or rent. It's worth it. Sounds like a fuel issue, and without knowing what's going on you'll end up playing the guess-and-spend game.

 

I HATE that game lol but i ran codes and code 52 popped up...... running too rich.......... HOW do i fix????

 

Too rich is often an o2 sensor issue. My TJ had similar problems and finally I unplugged the o2 sensor to see if that would isolate it. It did, no more sputter and I eventually just replaced the sensor. Try unplugging it. If you have a bad sensor, it will clear the problem up, but your gas mileage will drop.

 

What did the plugs look like when you replaced them? One or more show signs of running too rich? Black- sooty, etc..

Before you get too far, go through Gee Oh Dee's post, esp. ground points and presence of good, consistent spark. "rich" and misfiring might be a fuel problem, or a spark problem, gotta find which it is and spark is easiest to check first.

 

I unplugged the O2 sensor and it ran WORSE! UGH!

Plugs were Red/orange with like a white ish look to them. No black, no oil, and dry.
Plug wires are new. Cap and button are new. Fuel Filter is new......

So the question is.... Fuel injectors, partially clogged line, Fuel pressure regulator, IDK

Also today i noticed there is a rubber hose leading from front axel up to the fire wall that is zip tied to the fire wall with a white plug to it..... Thats not factory! lmao im guessing its a vac for the 4x4.

Also if i take the vac line off that goes to the manifold closest vac to the front, the truck idles higher.

I also forgot to mention that Oil pressure gauge is out of wack (i believe) cause it will turn to where the pin is (max oil pressure) it has done this for a while so im guessing its not really that pressure cause it would have blown up or blown headgasket seal.
Most of the time it works fine. (normal pressure readings)

About a month ago i put STP fuel system cleaner in the tank and it got worse. I keep thinking its the injectors but i really dont wanna spend the $250 and find out it was a simple thing. Please help!!!!!!!

Thanks again !!!!!!!!!!!!!!!!!!!!!!

Mike

 

ok guys the hand of logic just hit me in the head....... When i put the fuel system cleaner in the tank with a full tank of gas and it ran worse. Wouldnt that mean its pushing all that build up and **** out? Wouldnt that mean my injectors are dirty and need cleaned? I was in the middle of taking one of the wiring harnesses off of the fuel injector doing the whole muilti meter checking to see if it had 3-6 ohms of resistance (meaning they were bad) both that i tested were at 15 ohms.

Does any one know how to clean injectors at home with out equipment?? If i clean the injectors and its still doing it. I think my next step would be fuel lines. As i said before fuel filter is not even 2 months old. Fuel pump sounds to be working fine. Im going to call when the store opens to see if i can get a fuel pressure gauge to see if thats the issue meaning pump going bad, fuel lines clogged, MPI is clogged.

 

cant help with the rest but the rubber hose with the white plug IS factory, its the vent for the front diff

did u clean all the grounds as suggested and check spark, read post #6 on this link



https://www.cherokeeforum.com/f2/bad...kee-xj-114007/

 

thanks! didnt think it would be but hey you never know !

 

You really need to check fuel pressure, if its fine at idle I would tape gauge to windshield and drive it around at higher rpms, like hold it in second. If fuel pressure drops then that means u have a volume problem, which would still be the pump.

We cleaned injectors by pulling them out, putting a piece of hose over the end (the part that sprays) Opening the injector up with a 9v battery and spraying cleaner through the injector

 

fuel pressure gauge is 150 + tax for loan ...... im workin on that part today if i can

 

OH and stupid me ..... What should the pressure be?

 

For a 1992, I believe it is 30psi. For later models it is 49 psi.