: Hard starting - high fuel pressure?



oldmike
01-04-13, 12:21 PM
2005 STS V8 is experiencing intermittent hard starting. Meaning it turns over very well but does not crank until I get scared I am going to melt a battery cable or something. Then it will finally crank and run fine. I keep hearing about the fuel pressure regulator but I cannot find one on my Northstar engine. Where is it located? Would it be under the intake or behind the engine where it can't be seen? And the fuel pressure at idle is 69 psi with a gauge which checks out to be accurate. Isn't that extremely high? It drops to 60 psi when I turn the engine off. This vehicle has a constant P0171 trouble code and has been to the dealer 7 times, 5 times to one particular and once each to two other dealers. They can fix it from 5 miles to 500 but nothing permanent. I have given up on them. It also has a new air filter and a new fuel filter and a new battery. Any ideas about the cranking problem? And/or fuel pressure?

ddalder
01-04-13, 12:55 PM
What research have you done on that code? It relates to the PCM believing a lean condition exists. This can be caused by numerous problems that are more likely than a bad fuel pressure regulator. I'm not sure off hand what the normal fuel pressure should be for this engine, but that doesn't sound low so I'd be suspicious it's not the root cause of the problem. If you do some Google searches on that code, there are recommendations on several things you should check and rule out (vacuum leaks, exhaust leaks, dirty MAF, etc).

dkozloski
01-04-13, 01:53 PM
A really good start would be www.alldatadiy.com (http://www.alldatadiy.com) and a code reader that will read all codes including ABS, body etc.

oldmike
01-05-13, 07:56 AM
It is apparent that I did not make myself clear. The hard starting has been going on for 5 days now. The DTC P0171 has been displayed for 4 years. I do believe the 69 psi of fuel pressure is much too high but I don't know if this could be causing the hard starting. Also, I cannot find any fuel pressure regulator on this engine. Does it really have one? Nobody lists one for sale except Rockauto parts co. Thanks for the answers already given.

dkozloski
01-05-13, 09:43 AM
Subscribe to Alldata and get access to all the factory service data. If you don't want to do that you can purchase the Factory Service Manual from www.helminc.com (http://www.helminc.com) They have pictures, trouble shooting trees, and everything data wise you need. These are very technical and sophisticated cars that do not readily lend themselves to troublshooting by remote control.

ddalder
01-05-13, 11:08 AM
Subscribe to Alldata and get access to all the factory service data. If you don't want to do that you can purchase the Factory Service Manual from www.helminc.com (http://www.helminc.com) They have pictures, trouble shooting trees, and everything data wise you need. These are very technical and sophisticated cars that do not readily lend themselves to troublshooting by remote control.
Absolutely agree.


It is apparent that I did not make myself clear. The hard starting has been going on for 5 days now. The DTC P0171 has been displayed for 4 years.
No, that isn't what I got from the original post.

Unless the pressure is far too high and one or more injectors have been damaged letting too much fuel into the cylinder, I'm not sure that this will cause a hard start. If that was the case, you'd probably smell it in the exhaust.

You need to access the correct resources and approach this systematically.