WHATS WRONG WITH THIS THING!!!!!

[GUNNER44]

So I finally changed the fuel pump in my 89 YJ,thinking all my problems with the rig bucking real bad under accel would go away ha ha ha ha,if life was ever that easy.I didnt drive the truck for about three weeks until today took it around granby and simsbury,everything seemed perfect,until about 15 minutes into the run the bucking came back,almost worse than it was before I changed the pump,its getting to the point were I cant drive it.I dont get it checked my plugs their good,checked dist no moisture,I dont undestand,any advice would be excellent,thanks

 

[katrinka63]

Gee gunner I don't know squat about this kinda thing .......but I feel for ya  :biggrin:

 

[Warner Sister Dot]

Sounds like a vacuum leak to me but Im sure the guys who know a lot more about it will chime in soon. 


WOO HOO, this post made me a mall crawler !!!  bj:

 

[MasterDrazhar]

Where is the fuel filter on the YJ...  Almost sounds like a clogged filter...

They will clear themselves out while the jeep sits and fuel backflows, then clog up again while it's running.

I would find the fuel filter, get a new one, run it till it starts acting up, then quickly change the filter before the junk backwashes into the line or tank again.

.

 

[katrinka63]

Congrats Holly welcome to the mall !!!!!!!!!!

Sounds like a vacuum leak to me but Im sure the guys who know a lot more about it will chime in soon. 


WOO HOO, this post made me a mall crawler !!!  bj:

 

[GUNNER44]

Your right master but I changed the filter at the same time that I changed the pump.Still sitting here scrathing my head on this one.I was maybe thinking about dirty injectors or carb out of adjustment or timing could be off still not sure though?Any thoughts.

 

[MasterDrazhar]

Timing would be timing, should run shitty right from the start...

Same for dirty injector, should run shitty from the get go.

Maybe carb,  Does the YJ have the same type of throttle body that the TJ's have?  Perhaps it's bypass air controller needs to be cleaned.

 

[Pickle]

Since your yj has a renix TBI injection..you only have one injector.  You changed the fuel filter so rule that out.  You'll notice a plethora of connectors on the coil which is mounted on the firewall, check those.  A bad ground will cause many of sensor related issues.  It sounds like a lean misfire so disconnect the egr valve (which only opens after the engines warm), which is the first thing I would do.  If you take the vacuum line off the egr plug it up or it might cause a vacuum leak so it will stumble/stall at idle.     

 

[bugout]

sounds like a bad ground to me,check all even underneath where the gas tank is, the ground apper to look good untill you wiggle the ends and thats when they will brake off

 

[GUNNER44]

Bugout thats a good call,I noticed this morning when driving to work that when the rig is up to speed,it doesnt buck as much,its really under accel,but I noticed that when I hit a bump or manhole cover it would stutter just a little bit,then go back to normal.That leads me to belive theres a bad connection somewhere.Thinking about checking the connectors on the ecm first and then go from their?

 

[bugout]

I hope that helps