I have a 90 jeep cherokee with 170,000 miles on it, fuel pump and filter replaced maybe 6 months ago. The jeep is used very little and probably not even 100 miles have been put on it in that time. It died on the road and will not start. I can hear the fuel pump run and pressure up and i get fuel at the rail but what pressure should it be not running. Maybe its something else but it acts like fuel it will chucle and shake a little bit when you try to start it. Any help would be greatly appreciated.
CF Veteran
possible cps went bad ,check the wires going to it for broken and bare spot touching metal its located back of valve cover next to firewall driver side
tjwalker
CF Veteran
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- Join DateNov 2010
- LocationIn the middle of Minnesota!
- Posts:5,840
- Year1999
- ModelCherokee
- Engine4.0
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Likes:156
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Liked:117 Times in 104 Posts
1. Check for spark and spark QUALITY. You must have a strong, blue, snapping spark. Yellow/orange/white indicates a weak spark, which may not be strong enough to start the engine.
2. Spark GOOD? Try a small splash of gas into the intake. If the engine starts well and runs momentarily, you have verified a fuel delivery problem.
For testing fuel delivery, you'll need a gauge (call around, some parts stores rent them)
For 87-90, you should have 31 psi at idle. Then disconnect the vacuum line leading to the fuel pressure regulator and the pressure should jump to 39 psi. Be sure the vacuum line is pulling GOOD vacuum and if that line is wet with gas, your regulator is shot.
2. Spark GOOD? Try a small splash of gas into the intake. If the engine starts well and runs momentarily, you have verified a fuel delivery problem.
For testing fuel delivery, you'll need a gauge (call around, some parts stores rent them)
For 87-90, you should have 31 psi at idle. Then disconnect the vacuum line leading to the fuel pressure regulator and the pressure should jump to 39 psi. Be sure the vacuum line is pulling GOOD vacuum and if that line is wet with gas, your regulator is shot.




