01 Dakota hard start

I have a 01 Dakota 4.7L auto trans. Hard as ever to start cold. sometimes hard to start even warm. I have to crank it 3 or 4 times as a norm, unless I
shut it off and start it within a couple minutes. There are no codes showing. I have already changed the Idle Air Control Solenoid Valve (dealer shop recommended) and completely cleaned the intake area, including the throttle position sensor. Resistance readings on the TPS show nothing wrong. Once it starts it runs fine. There is a hissing (like a vacuum leak) behind the intake throat, I can't track down, and the dealer svc center says is normal. Has anyone else here experienced this? What was the fix?........any suggestions from the rest? Thanks in advance, Joe
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Original battery?
FMB (North Mexico)
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I would have the fuel pressure checked to make sure you have the proper fuel pressure at start up.
Mike

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Hmm,. I'm not sure if it's the original battery, but it cranks very quickly, so I didn't consider that as a problem. I also thought about fuel pressure, but I can floor it from a slow rolling start (about 20 mph) up to 90+ mph and it doesn't bog down, so I counted that out. Joe

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Gunner wrote:

Finding the problem is the fix. :-)
I would have the truck sit and cool down over night. The next morning I would remove the air intake ducting and spray a little ether or pour a little gas down the throat then crank it and see if it starts normal. If it starts normal, then you have a air/fuel mixture problem at start-up, which means you are either getting too much air or not enough fuel. I am not familiar with the 4.7 but if it starts after my suggestion, I would check the choke or MAF (Mass Air Flow) sensor if it has one.
Good luck and keep us posted.
Hank
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Also, if you have a vacuum leak, that is letting in more air than needed at startup. You might want to get that "hissing" sound fixed.
Hank
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CHECK YOUR FUEL RETURN LINE CHECK VALVE OPERATION IN YOUR FUEL TANK AND CHECK FOR YOUR GAZ PUMP CHECK VALVE,IF ONE OFF THIS STAY OPEN GAZ RETURN IN TANK AND YOU HAVE AIR IN GAZ SYSTEM AND ENGINE WILL BE TAKE MORE TIME TO START ..

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Thanks folks. I'll try your suggestions this weekend. Gunner

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These trucks have a returnless fuel system. They also have no in-line fuel filter to change. I haven't checked the fuel pressure yet, but I'll bet it's probably ok. What that leaves, so far, is the fuel pressure regulator/filter assembly. This is mounted on top of the tank and the truck has a full tank of fuel for now. The wife just went shopping though >:(.

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That's correct. Fuel Filter is integrated with the fuel pump in the tank. I had a 2000 4.7 with a similar problem. I recommend taking it to a Jeep dealer (not Dodge) and have them put a pressure guage on the fuel rail. Dodge dealer will tell you that since engine is not throwing codes, there is no fuel pressure problem. That is not the case.
The fuel pump could not be pressurizing the fuel rail enough, and you wouldn't really notice even flooring the gas pedal from 20 to 90 mph. The fuel pump assemblies were quite problematic, and DC kept that info "secret squirrel." In 2003 DC redesigned the Fuel Pump and have been reinstalling the new part to replace the old pump design.
This happened to me twice with my 2000. The only times I ever noticed a problem were upon starting the vehicle, and on long trips (1500mi+ continous driving time). After a while the RPM of the engine would studder and spit when it down-shifted to go up hills or into passing gear and would slowly decrease over time. Eventually, I would have to stop when the studdering would start at 1500 rpm. I would leave the truck sit for a few hours, then it would operate normally for a few hours before studdering again. It took Dodge 6 months of troubleshooting and they could figure out nothing. After suggesting the fuel rail pressure they just blew me off. Jeep check it as their first indication and proved that was the problem. I strongly recommend having the rail checked, or you will be buying a ton of parts you don't need trying to troubleshoot.
I also had a TPS problem in connection to this one. (they just happened to run concurrently, they were not related.) First sign of a TPS problem on the 4.7 is to look for hunting in the speedomoter when driving a highway on cruise control. If the engine is warm, you will see the RPM needle hunting. In both hunting cases, it will sit steady at a predetermined RPM and every few seconds it will pulse.
wrote:

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Thanks Twix, That sounds interesting. How much does the Tach hunt when hot? Joe

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