How hard to remove upper intake on 2001 4.3L V-6?

The Chev Dealer tells me I probably have a bad fuel pressure regulator, and most ridiculously Chev put the blasted thing inside the intake manifold on the 2001 4.3 V-6 with SCFI system. The book says you have to remove the upper intake and plennum to get to the regulator, anyone know how difficult this is, and is this a reasonably mild task that one could do at home, versus $6-800 in the shop? As usual, it takes $600 of labor to get to and replace a $50 part. Thanks.

45 minutes to pull off tops. Its all nuts, bolts, connectors, and vacuum lines. No special tools (you might need a torx bit for the regulator. The gaskets are readily available. For the average tinkerer this would be no problem.

Thanks Airjer, what about the A/C compressor and any of the lines for that? The Haynes repair manual said you might have to remove some of that stuff. Also do I need to worry any about the plastic injector lines and or bending cracking them when pulling off the plenum?

Thanks

You would have to remove the compressore if you where to do the lower intake. It can be unbolted and swung to the drivers side without removing any lines.

The Poppets (plastic lines) are fixed into the lower intake. The plenum is nothing more than a cover. Nothing is attatched to it on the inside. Basically all you have to do is remove the air snorkel, Throttle linkage and brackets, Coil brackets, PCV tube, Breather tube, Misc. vacuum lines, Misc. EVAP lines, Misc. connectors, and the bolts/nuts that hold it onto the lower intake.

I've done enough of them that it takes me about 10 - 15 minutes to pull them off.

Once you get it off you'll think to yourself, that was it!

Good luck, let us know how it went!!

Very good, sounds not too bad, I'm sure I can handle it then. I just hope that solves the problem, mine is not starting well when warm, it starts fine when cold. One guy said to check the IAT and ECT sensors, I don't have a scanner to check them, there is no check engine light on, I'm thinking it's the fuel press regulator, the vehicle has 100k miles and it resembles the same problem I had on other GM cars. With the exception that the others started hard whether hot or cold, this one is only hard starting when warm, it fires right up when cold. So perhaps I should have it checked by a certified mechanic before I tear into it. That would really be a flamer if it was the O2 sensor on the intake tube being the problem and not the FP regulator.

That would really be a flamer if it was the O2 sensor on the intake tube being the problem and not the FP regulator.
The what? I think you are describing the IAT (intake air temp) sensor. All it does is measure the temp of the air. Or the MAF (mass air flow) sensor which measure the volume of air going into the engine. Proper terminology is absolutely critical with making sure you get the right parts and the right advice!!

If there is any doubt about fuel pressure it is pretty easy to hook up a fuel gauge and see if it holds pressure. If the pressure regulator is leaking the gauge will drop and you will be able to confirm by placing an inspection mirror into the throttle body and looking towards the back of the plenum. You will see it dripping onto the lower intake. The fuel pump can also let the fuel pressure drop so that is not out of the question as well!!

Yeah, that's correct, another guy suggested getting a scanner to get readouts of sensors that could be causing the problem, he specfically mentioned the IAT, Intake Air Temp sensor and ECT, Engine Coolant Temp Sensor and that they should be reading within 10 degrees of each other. You need a scanner that enables the sensors to be read while the engine is running, I got one from Autozone but it did not allow readings, only codes for engine lites. Anyway, his point was that it may not be a fuel issue.

I have a fuel pressure gage, I will have to recheck but if I recall correctly, I had about 60 psi when ignition was switched on and it dropped to about 55 psi and held pressure there. I will have to check for drop off.

As I say, it may be worth taking to a mechanic just to see their opinion and if they conclude it's a FP regulator, I can take it from there.

Got any other suggestions for trouble shooting?

It should hold that pressure for hours. If it drops significantly within an hour than there is an issue.

Very good, thanks again. One final question, do you think if the regulator were bad, the engine should be hard to start whether hot or cold? Something sounds suspicious of a regulator being the problem that it starts cold but not as well hot, like if the regulator was bad it would be hard to start at all times. Your thoughts?

It's extremely rare for the fuel pressure regulator to fail on this system. Key on, engine off, pump running, pressure must be 60 to 66psi. If the pressure is within that range, and the leakdown rate is not excessive, the regulator is good.

Thanks Old Master, I'll put the pressure gauge on one more time and look closely this time. If FP regulator failures are rare on this model, got any other ideas as to the cause?

Check for excessive leakdown: When checking fuel pressure, after the pump shuts off, fuel pressure must remain above 55psi for 3 to 5 minutes. Always check fuel pressure and leakdown when the engine is COLD to avoid any erroneous readings. If the engine is warm, heat from the engine will increase the pressure of the fuel in the fuel lines. Post your results.

When the engine is hot and fuel pressure bleeds down the fuel in the fuel lines boils. More pressure = higher boiling point, low pressure = low boiling point. Essentially you get vapor lock. The pump then has to pump liquid fuel back into the lines and push out the vapor before the vehicle can start. If the regulator is leaking now you have added a lot of uneeded fuel into the intake, essential a very rich condition and possibling causing a flooded condition. All of this equals an extended crank after a hot soak.

When the engine finally cools down the fuel lines cool down and if the pressure regulator was leaking the excessive fuel has evaporated. The pump takes a lot less time to repressurise the system since it doesn't have to push out the fuel vapor. cold start in the morning and it fires right up.

Thanks again Old Master and Airjer, I'll do one more thorough pressure check, when engine is cold and see the results and go from there. Your explanation on hard start when the engine is warm makes sense Airjer, it likely is the FP regulator but now I've got enough info to see for sure, that was my original diagnosis since I've seen the same problem on a 2000 Silverado and 98 Caddy Deville, only those were real easy fixes, since the regulators on those are on the fuel rail outside the intake manifold.

Thanks guys for all the good advice, I got her done, I pulled the plenum cover yesterday and you guys were right, it wasn't that bad, I didn't take it all the way off, just unbolted and lifted the rear up enough to access the FP regulator and changed it out. I cheated a bit, didn't replace the gaskets they looked okay and let her go from there. So far so good, it's starting fine and holding pressure at about 40 psi aftter shut off, which isn't as much as you guys were saying, so I don't know if I have a further problem or not. But it's running and starting okay when hot, so I think I'm good to go. I really don't care for that type of injector system on this vehicle, and I've had it 8 years so it's time to peddle it and upgrade before something else goes. Thanks again to all who provided advice!