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Can anyone tell me why my 3.1 diesel starts revs then cuts out. It will only run if I hold throttle at about 1500 revs for several minutes. Once it reaches a certain temperature it runs fine .
A diesil motor dose not have spark plugs it works by compressing the fuel air mixture until it explodes which it dose when the pressure is great enough. Of course it works best when warm in fact if it is to cold it won’t start at all. To get around this problem diesil motors have a warming plug, since I have never been in a jeep grand Cherokee I can’t tell you if the plug has a separate switch or it is imbeded in the ignition key. You should either hold the switch down for 30 sec before starting or turn the key the the warming position before ignition. If you have done this and it is still problematic check the fuse for your warming plug or the plug itself might have burnt out. I hope this helps
