hard time starting when warm
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Joined: Nov 2008
Posts: 73
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Year: 1987
Model: Cherokee
Engine: 4.0
i have issues when the motor is warm starting. i8n the mornig it starts right up but after about 1/2 hour it will crank for 2 to 30 secs b4 starting. thouhgt it was a pluged fuel filter, it seemed to help but still does it every now and then. could it be an electric prob? i know my fuel pump is working good and i have the right amount of fuel psi along with a comlete tune up that was just done. any one have any ideas what it could be?

Renix Super Guru
Joined: Mar 2008
Posts: 24,653
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From: In yourz postez fissin jurr spelinzs
Year: 1990XJ/1989MJ
Model: Comanche
Engine: 4.0L Renix
The engine has to have a few things before the computer will allow it to start. The starter has to have spun the motor up to 300 RPM first. The CPS has to have sent 3 pulses to the computer so that the crank and the cam can be determined to be in the correct relationship and there needs to be adequate fuel pressure at the regulator.
Once all these criteria have been met the computer puts signal pulses to the injectors and turns on the coil to transmit spark to the plugs.
Knowing this about your Renix will allow you to check all the above things for proper signals and pulses. These all being met your Renix always has taken a few seconds to start, but that is the nature of the beast.
Once all these criteria have been met the computer puts signal pulses to the injectors and turns on the coil to transmit spark to the plugs.
Knowing this about your Renix will allow you to check all the above things for proper signals and pulses. These all being met your Renix always has taken a few seconds to start, but that is the nature of the beast.
Renix Super Guru
Joined: Mar 2008
Posts: 24,653
Likes: 19
From: In yourz postez fissin jurr spelinzs
Year: 1990XJ/1989MJ
Model: Comanche
Engine: 4.0L Renix
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