Turns over, seems like it’s misfiring, won’t start

Forty

Forty

TJ Enthusiast
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Hey all I’m at an impass. TJ ran great since motor rebuild, drove around one day, came home, went to leave several hours later and bam it won’t start, Sounds like it’s misfiring, but turns over just fine. I have searched a lot of threads here and cannot find what it might be.

Things I’ve done so far:
  • Checked intake tube for blockage
  • Checked throttle body for function
  • Checked fuel line and it’s flowing
  • Checked plugs- 3 were black, 3 were almost black
  • All electrical connections seem good
  • O2 sensors are new
  • Did seem to have a vacuum leak or TPS issue beforehand
Anyone run into this issue or have some good guidance?
 
Did you check the fuel pressure at the rail?

Did you check the coil packs to make sure you're getting spark?
 
I didn’t check the pressure at the rail
Chris said:
Did you check the fuel pressure at the rail?

Did you check the coil packs to make sure you're getting spark?
Click to expand...
but the supply going into the rail was very good. I’m not sure how to check the rail or spark for each plug individually.
 
Forty said:
I didn’t check the pressure at the rail

but the supply going into the rail was very good. I’m not sure how to check the rail or spark for each plug individually.
Click to expand...

I would check the fuel pressure at the rail and check the coil packs using this method:

 
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What do you mean you mean when you said you checked the fuel line and said "it's flowing". Did you check for proper (49 psi) fuel pressure with a fuel pressure gauge? Is the fuel pump turning on for 2 seconds then shutting off every time you turn the ignition switch on.

Try this procedure. exactly- cycle the ignition switch on-off-on 12 times without turning it to Start. Leave it in the On position for two seconds each of those dozen times. Make sure it's in the On position for 2 seconds each time. After you've done that then immediately try starting it and tell us what happens.
 
Jerry Bransford said:
What do you mean you mean when you said you checked the fuel line and said "it's flowing". Did you check for proper (49 psi) fuel pressure with a fuel pressure gauge? Is the fuel pump turning on for 2 seconds then shutting off every time you turn the ignition switch on.

Try this procedure. exactly- cycle the ignition switch on-off-on 12 times without turning it to Start. Leave it in the On position for two seconds each of those dozen times. Make sure it's in the On position for 2 seconds each time. After you've done that then immediately try starting it and tell us what happens.
Click to expand...
It acts like it wants to start as usual but doesn’t
 
Forty said:
Correction 113 and 522
Click to expand...

There was an OBD2 code list in the FAQ's but I can't seem to find it. Any way from Quadratec the codes are

The P0113 is - Intake Air Temp Sensor Voltage High: Intake air (charge) temperature sensor input above the maximum acceptable voltage.

The P0522 is - Oil Pressure Voltage Too Low: Oil pressure sending unit (sensor) voltage input below the minimum acceptable voltage.
 
05 Blue Unlimited said:
There was an OBD2 code list in the FAQ's but I can't seem to find it. Any way from Quadratec the codes are

The P0113 is - Intake Air Temp Sensor Voltage High: Intake air (charge) temperature sensor input above the maximum acceptable voltage.

The P0522 is - Oil Pressure Voltage Too Low: Oil pressure sending unit (sensor) voltage input below the minimum acceptable voltage.
Click to expand...
Does that mean just replace them or there is a short somewhere? I am not a good electronics guy other than the basics?
 
Forty said:
Does that mean just replace them or there is a short somewhere? I am not a good electronics guy other than the basics?
Click to expand...
I don't know enough to about the 522 code to know if continually cranking without it starting would produce the code or not, but for the 113 code check the actual reading - if it is good it should read the ambient air temp. Of course you will need a ODB scanner to see it.

And as Chris mentioned did you "check the coil packs to make sure you're getting spark?"
 
05 Blue Unlimited said:
I don't know enough to about the 522 code to know if continually cranking without it starting would produce the code or not, but for the 113 code check the actual reading - if it is good it should read the ambient air temp. Of course you will need a ODB scanner to see it.

And as Chris mentioned did you "check the coil packs to make sure you're getting spark?"
Click to expand...
I have not checked the coil packs yet but that is my next step
 
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