tj hard to start

[captjanes]

i got a 2.5L 99 tj and i have to crank it and pump the gas for a very long time before it starts and when it starts it idles fine but when i hit the gas peddle she almost stalls out and she sputs then she will move ahead.. i thought it mite of been wet wires and distrubtor cap but it is all dry and in good shape. i has a little small exhaust leak in my donut gasket but i dont thik that would cause it.. would my upstream o2 sensor have ne thing to do with this? the engine light comes on about once every 2 days and it is p0135 i takes out the code with my obdii reader and she will run for a nother 2-3 days before i get it again.can any one help me thanks.

 

[SteelHeadz]

Check for proper fuel pressure and perform a leak down test. For the P0135, first check on the PDC under the hood and make sure the fuses are seated properly and clean from corrosion. If that checks out good, the O2 sensor is failing. (heated O2 sensor)

 

[captjanes]

how do i check for fuel pressure? and i checked the fuses and they all fine and i replaced the upstream o2 sensor and the jeep is still hard to start and when she do start she idles fine but when i press the gas she hesistates and sputs first then then takes off fine.

 

[xt master]

I agree with the fuel pressure.What I do is my Jeep sits for a few days is turn it to the on position wait for the fuel pump to turn off then turn off the ignition and repeat then I will start it with little problems.I know mine losses pressure when it sits just have not had time to figure what is causing the problem.

 

[SteelHeadz]

how do i check for fuel pressure? and i checked the fuses and they all fine and i replaced the upstream o2 sensor and the jeep is still hard to start and when she do start she idles fine but when i press the gas she hesistates and sputs first then then takes off fine.

You will either need to invest on a fuel pressure tester or take it to a knowlegable mechanic that can do it for you.

 

[SteelHeadz]

I agree with the fuel pressure.What I do is my Jeep sits for a few days is turn it to the on position wait for the fuel pump to turn off then turn off the ignition and repeat then I will start it with little problems.I know mine losses pressure when it sits just have not had time to figure what is causing the problem.

The most common reason why the fuel pressure bleeds down all the way is due to a faulty fuel pressure regulator. In some cases, the o-rings within the fuel pump also has been found to cause this concern, in which point, the fuel pump module will need to be replaced. In extended periods of the Jeep sitting, it is normal for the fuel lines to be completely bled down, however, there is a certain threshold that the lines are to be kept primed to a certain level and the bleed down test will ultimately determine if it's faulty or not.

 

[TJ_Jeep]

Just my $.02 but pumping the gas has no effect on a fuel injected motor, only on carburetor motors

 

[captjanes]

i changed the distrubtor cap and plug wires and i replaced the two o2 sensors and my jeep is still not running right.. i think she is getting worst but i dont think it is fuel pressure because she is fine sometimes and when a load comes on the engine she will sput and almost shut off and then it takes a while to start her.. and i turned the key ahead 4-5 times to build up fuel pressure but that dont work. and all my fuses and relays are fine.. i dunno what else to do.. i was thinking it mite be water in my gas

 

[xt master]

Could be a timing issue.

 

[captjanes]

i cant see it being the timing because on my obdii reader at idle she is steady at 920 rpm. if it was timing i would think that she would be hunting or raising and lowering in rpm. but she is fine at idle and she could drive fine but she only gets like it after a while

 

[xt master]

Im not sure but could it be a vacuum problem.

 

[abe]

i have a 97 tj and the same problem but not quite like what your talking about. my mechanic friend told me it was fuel pump or line problem i havent replaced the pump yet. because it starts fine when the weather is warm. and it only does it on first start up of the day.

 

[captjanes]

i am starting to think that it is fuel because she is getting worst. before she would only sput on start up and sometimes while driving but now she is like it almost all the time

 

[captjanes]

hey guys i finally got my jeep running i put new plug wires and plugs and distrubtor cap and checked timing and i made a fuel pressure tester and the fuel pressure and she was the same thing.. so i thought it had to be spark. i took off the ign. coil and it was rusted out and burnt out so i replaced that one and now she runs fine again .. thanks guys for your comments