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1996 Jeep Cherokee will not start...

ericfx1984

NAXJA Forum User
Location
Kansas City Area
1996 Jeep Cherokee will not start...

every once in a while I noticed that the Jeep would hesitate, normally right after being started...

right now it just cranks and crank, but does not start

it has a 4.0HO
 
Getting power to the coil doesn't mean much except the ASD relay is likely working, are you getting spark? The coil triggers at the ground side, so getting power to the coil isn't the same as getting spark.

It will prime for a second or two if you turn the key to run. The fuel pump relay won't close *again* and run constantly unless the PCM gets a CPS pulse (during start or when the motor is running).

Two most common reasons for a no start are the IAC is stuck closed. You can usually get a start by giving a little pedal (it needs air to start). Sometimes it floods and may be hard to start even with some pedal. The other reason is a faulty CPS, it can fault in two ways.

A bad CPS will usually set a CEL code, but not always. It will almost always mess with spark.

Fuel pumps are expensive and can be a pain to change. I'd do a fuel pressure test and jump the fuel pump relay or run a hot wire directly to the pump for the test.

A lot of 95's and a few 96's are showing up with rotted rubber fuel hoses in the tank. Empty out the filter and see if rubber pieces come out.
 
The initial prime when the key is turned to run on the way to start doesn't build much pressure, the pressure doesn't start until the PCM detects a pulse (during cranking or engine running) from the CPS and closes the fuel pump relay.
Do you have spark?
 
I would definitely look for spark too man. I had the same problem with my 96 HO. i was driving to college and it just cut out. right in the middle of driving 35 mph. Double check your fuses under the hood. Thats all mine was, look for a little wire that may be close to the exhaust manifold, thats what cause my short.
 
The initial prime when the key is turned to run on the way to start doesn't build much pressure, the pressure doesn't start until the PCM detects a pulse (during cranking or engine running) from the CPS and closes the fuel pump relay.
Do you have spark?

this was tested hooked directly to a battery...

yes, I have spark... soon as I installed to new pump it fired right up...

it feels much stronger at full throttle now... MUCH stronger
 
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