Hard start when sitting over night
09-10-2015, 07:42 PM
#1
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Model: Cherokee
Hard start when sitting over night
I just bought a 99 jeep grand Cherokee about 3 weeks ago and this problem just started happening yesterday every thing has been working perfectly untill now after sitting over night I go to start it it turns over but takes about 5 seconds to start and backfires after that it fires right up no smoke and no issues starting after the first start it starts first hit of the key after that so idk what the issue is but its got me I'm new to jeeps its a straight 6 4.0 any ideas will help allot
09-10-2015, 09:57 PM
#2
Old fart with a wrench
Welcome to CF!
Get, rent, borrow a fuel pressure gauge an screw it into the fuel rail, park it for the night, and in the morning, see what kind of pressure you've got when you turn on the key. Don't crank it yet. The fuel pump only runs for a second or two to bring up pressure before starting. If the check valve in the pump is leaking, the fuel will drain back to the tank overnight and it will take some time to fill the rail in the morning, causing you extended cranking time. You should have about 30 lbs. before you start cranking.
If that's the case, just cycle the key several times before trying to start it. The only other thing it could be is a leaking fuel injector loosing pressure in the rail, but that usually doesn't cause it to not start.
Get, rent, borrow a fuel pressure gauge an screw it into the fuel rail, park it for the night, and in the morning, see what kind of pressure you've got when you turn on the key. Don't crank it yet. The fuel pump only runs for a second or two to bring up pressure before starting. If the check valve in the pump is leaking, the fuel will drain back to the tank overnight and it will take some time to fill the rail in the morning, causing you extended cranking time. You should have about 30 lbs. before you start cranking.
If that's the case, just cycle the key several times before trying to start it. The only other thing it could be is a leaking fuel injector loosing pressure in the rail, but that usually doesn't cause it to not start.
09-10-2015, 10:09 PM
#3
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It starts but extended start time like you said but what would cause the back fire cause I'm not misfiring once its running and it doesn't have this problem if I start it every couple of hours
Welcome to CF!
Get, rent, borrow a fuel pressure gauge an screw it into the fuel rail, park it for the night, and in the morning, see what kind of pressure you've got when you turn on the key. Don't crank it yet. The fuel pump only runs for a second or two to bring up pressure before starting. If the check valve in the pump is leaking, the fuel will drain back to the tank overnight and it will take some time to fill the rail in the morning, causing you extended cranking time. You should have about 30 lbs. before you start cranking.
If that's the case, just cycle the key several times before trying to start it. The only other thing it could be is a leaking fuel injector loosing pressure in the rail, but that usually doesn't cause it to not start.
Get, rent, borrow a fuel pressure gauge an screw it into the fuel rail, park it for the night, and in the morning, see what kind of pressure you've got when you turn on the key. Don't crank it yet. The fuel pump only runs for a second or two to bring up pressure before starting. If the check valve in the pump is leaking, the fuel will drain back to the tank overnight and it will take some time to fill the rail in the morning, causing you extended cranking time. You should have about 30 lbs. before you start cranking.
If that's the case, just cycle the key several times before trying to start it. The only other thing it could be is a leaking fuel injector loosing pressure in the rail, but that usually doesn't cause it to not start.
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