1993 Jeep Cherokee fuel

Tiny
MICHAELREVERT
  • MEMBER
  • 1993 JEEP CHEROKEE
Engine Performance problem
1993 Jeep Cherokee 6 cyl Four Wheel Drive Automatic

jeep wont run replaced fuel pump, has fire, seems to want to run, beleive its afuel problem notsure
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Monday, January 19th, 2009 AT 10:09 PM

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Tiny
BLUELIGHTNIN6
  • EXPERT
Need to test fuel pressure at rail with gauge. If proper pressure exists, check for pulse at the injectors.

Post results and I will follow up.

Thanks for using 2CarPros. Com!
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Monday, January 19th, 2009 AT 10:32 PM
Tiny
MICHAELREVERT
  • MEMBER
How do I "test" the pulse at fuel injector? Does it require special equipment?
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Tuesday, January 20th, 2009 AT 5:00 PM
Tiny
MICHAELREVERT
  • MEMBER
Additional note:

40 psi fuel pressure at rail.

Michael
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Tuesday, January 20th, 2009 AT 5:02 PM
Tiny
MICHAELREVERT
  • MEMBER
Continued Additional Information:

As of 5:15 CST - Jeep started for 10 seconds and died. Seemed to run well?

Michael
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Tuesday, January 20th, 2009 AT 5:17 PM
Tiny
BLUELIGHTNIN6
  • EXPERT
Yes, it requires an "injector pulser" tool to energize the injectors. To perform this test, turn the key on or energize the fuel pump for a few seconds to build up static pressure in the fuel system. Then turn the key off, pulse one injector for the specified time and note the pressure drop for that injector. Turn the key back on to rebuild static pressure and repeat the test for each of the remaining injectors. An injector that is pulsed 100 times for five milliseconds should produce a minimum pressure drop of about 1 to 3 psi, and no more than 5 to 7 psi, depending on the application. The difference in pressure drop between all the injectors should be 2 psi or less. If you see more than 3 psi difference between the highest and lowest readings, the injectors are dirty and need to be cleaned or replaced. If you see no pressure drop when an injector is energized, the injector is clogged or defective and needs to be replaced. If the pressure gauge needle bounces, the injector is sticking. After cleaning, repeat the test to see if cleaning did the trick. All injectors should show about the same amount of pressure drop (less than 2 psi difference) and no more than 7 psi drop at 100 pulses for 5 milliseconds. If there is no change in the readings or the drop exceeds these limits, the injector(s) need to be replaced.
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Wednesday, January 21st, 2009 AT 12:08 AM

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