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Daryl, Shop Owner, Certified Mechanic
Category: Car
Satisfied Customers: 12547
Experience:  28 years experience, Master Mechanic
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2002 Buick Century 3.1 V-6 automatic, no power, replace EGR ...

Customer Question

2002 Buick Century 3.1 V-6 automatic, no power, replace EGR Valve, Fuel Filter and Fuel Pump and still has no power. Any ideas
Submitted: 8 years ago.
Category: Car
Expert:  Daryl replied 8 years ago.
DOes it seem to be missing or is it just low on power? Is it low on power all the time?
Customer: replied 8 years ago.
No power on acceleration, but idles perfectly, it actually loses power on partial throttle, extremely hard to accelerate
Expert:  Daryl replied 8 years ago.
SInce you already replaced the TPS it sounds like your problem is the catalytic converter you might try to drop the exhaust off and see if it runs better, this is assuming you have the correct fuel pressure.
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Customer: replied 8 years ago.
I disconnected the exhaust at the manifold and got the same response
Expert:  Daryl replied 8 years ago.
Then you will need to verify that you have the right fuel pressure.
Customer: replied 8 years ago.
5o psi
Expert:  Daryl replied 8 years ago.

50 psi is not enough it needs 52 - 59 psi, you might have a bad fuel pressure regulator or not enough voltage at the fuel pump.

Customer: replied 8 years ago.
12 Volts at the fuel pump and I put a new one that came with a sending unit. It was a Delphi unit
Expert:  Daryl replied 8 years ago.
what came with the sending unit?
Customer: replied 8 years ago.
Fuel Pump and Sending Unit, Delphi Manufacture, which I believe is OEM, I did not replace the fuel pressure regulator, or the MAF unit
Expert:  Daryl replied 8 years ago.
Well then you will likely need to replace the regulator. Because you need 52 - 59 PSI for it to run right.
Customer: replied 8 years ago.
Not to be a Knucklehead but what if it's not the fuel pressure regulator.The pressore port for teting the fuel press. was between the fan belt and I was a little hesitent to in getting a reading
Expert:  Daryl replied 8 years ago.
You need to eliminate the obvious first and go from there.
Customer: replied 8 years ago.
I replaced the fuel pressure regulator and the engine still responds in the same manner.Poor throttle response, no power after partial throttle.
Expert:  Daryl replied 8 years ago.

If you believe the fuel pressure is now good another expert here suggested this to me

"If you have the ability to clear the codes, unplug the EGR valve and run the car with it disconnected. It's worth a shot. We have been finding some of these 3.1's with bad EGR wiring. The last 2 had a broken wire at the plug and caused this same problem. We thought it was the valve at first but turned out to be wiring."

Customer: replied 8 years ago.
Once again, the vehicle came in with a check eng lite and complaint of no power on aceleration at half throttle. I scanned the diagnostics and it had an EGR code. I replace the EGR valve NAPA brand.Cleared the codes,started the engine no check engine lite. I went to road test and the vehicle still had no power. Idisconnected the exhaust at the manifold and still had no power. I replaced the fuel fiter, the fuel pump, the TPS switch and the fuel pressure regulator that you thought might be the problem. I also checked the plugs, took a compression check 135 psi on a hot engine. I checked coil packs for spark at high rpms, replaced air filter and cleaned throttle body. Now, I disconnected the EGR connector it had a little and I stress little more power but not much more then avery little. It's a struggle after 20mph. Any other possiblities????
Customer: replied 8 years ago.
Hello, I've been waiting for a reply and in the mean time I have trouble shoot it and it is on the EGR wirng I have voltage going in but nothing coming out

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