07 Rendezvous Crank no start

[TimeTravel]

I have a 2007 Buick rendezvous.
It cranks but doesn't start.
Usually happens when it's been sitting for 12 hours or so like before and after work.
A mechanic replaced the fuel pump.
A mechanic also replaced the theft deterrent control unit and programmed it.
It will try to start when I add starting fluid but doesn't stay running.
I've tried starting it in neutral.
I tried removing the vent solenoid fuse.
This is an intermittent problem. Sometimes it will start up after 30 minutes or so and sometimes it won't.
I also have a cheap code reader and no code showed up. Although I did get the expected code after pulling the vent solenoid fuse of po449.

Any help would be greatly appreciated.

 

[MelsRegal]

Did anybody do a fuel pressure test to see if you have leaky injectors that flood the engine after you turn it off?

 

[TimeTravel]

I don't think they have. I bought this. I just have to figure out how to use it 😂.

Did anybody do a fuel pressure test to see if you have leaky injectors that flood the engine after you turn it off?

Thanks for the suggestion.

 

[TimeTravel]

I have zero fuel pressure. So I guess I have no power to the fuel pump. Any suggestions on where to check for power? When should the pump have power? Continuously when the key is in the on position? Or only for a few seconds? I can't say I've ever noticed the pump making noise so I'm not sure I could hear it if it was on.

 

[MelsRegal]

Is the engine running?

 

[TimeTravel]

It took me 30 minutes or so to find my voltmeter. I tried to start it and it's running fine again. Fuel pressure is at 60 PSI while running. I know it wasn't working from about 7:30am this morning when I attempted to leave until about just after 10:00am.

Is there anything that I can check now that it's working or anything you'll think I should check when it breaks again?

 

[TollKeeper]

Under the car, almost directly under the drivers seat, is the C-305 connector. It is extremely prone to corrosion.

Also, under your hood on the left side is your fuse/relay panel.

You didnt indicate which engine you have, so..

Fuse Box Diagram Buick Rendezvous (2002-2007)

Fuse box diagram (location and assignment of electrical fuses and relays) for Buick Rendezvous (2002, 2003, 2004, 2005, 2006, 2007).

fuse-box.info

Fuse 1 is for fuel pump
Relay 51 is for fuel pump
Check the power on Fuse 1
Jump the relay on 51 for the fuel pump

See if you get fuel pressure.

 

[TimeTravel]

Is the engine running?

I just had the key in the on position. It wouldn't start at the time ( about an hour ago)

 

[TimeTravel]

Under the car, almost directly under the drivers seat, is the C-305 connector. It is extremely prone to corrosion. There should be 3 plugs. The larger one is for the fuel tank/pump/emissions, the others are for rear ABS and rear AWD (If equipped).

Also, under your hood on the left side is your fuse/relay panel.

You didnt indicate which engine you have, so..

Fuse Box Diagram Buick Rendezvous (2002-2007)

Fuse box diagram (location and assignment of electrical fuses and relays) for Buick Rendezvous (2002, 2003, 2004, 2005, 2006, 2007).

fuse-box.info

Fuse 1 is for fuel pump
Relay 51 is for fuel pump
Check the power on Fuse 1
Jump the relay on 51 for the fuel pump

See if you get fuel pressure.

It says 3500 V6 on the engine cover. It has abs and its 2wd

 

[MelsRegal]

It took me 30 minutes or so to find my voltmeter. I tried to start it and it's running fine again. Fuel pressure is at 60 PSI while running. I know it wasn't working from about 7:30am this morning when I attempted to leave until about just after 10:00am.

Is there anything that I can check now that it's working or anything you'll think I should check when it breaks again?

You are supposed to see how long pressure holds after turning off the engine to check for leaky injectors.

 

[TimeTravel]

I just turned the car off and fuel pressure is at about 58 psi.

 

[TollKeeper]

It says 3500 V6 on the engine cover. It has abs and its 2wd

At least you have the better engine.. Just need to check for power at the relay/fuse, and to see if power is getting thru to the C305 connector next time you get into a no start condition.

My Aztek had this same problem years ago. I bypassed the C305 connector by hard wiring everything, and it solved my problem. Not saying you should do this. The Aztek and Rendezvous are the same truck, just letting you know where I got my experience from. Even my current daily driver, a Saturn Relay is the same truck as the Rendezvous..

 

[TollKeeper]

More info about the C305 connector..

Fuel C305 wires, please help

so im an idiot. and a new to the whole car fixing stuff, so i bought used buick rendu with bad c305 connector, i wanted to cut the wires and connect them directly , i toke a few pictures before cutting the wires, but my phone deleted the pic's, and now i have no idea how to connect the wires...

buickforums.com

 

[TollKeeper]

Typed version of the TSB..

Multiple codes HERE IS OUR SOLUTION!!! - Car Forums and Automotive Chat

Multiple codes HERE IS OUR SOLUTION!!! Montana/Montana SV6 Car Forums

www.automotiveforums.com

 

[TimeTravel]

You are supposed to see how long pressure holds after turning off the engine to check for leaky injectors.

I understand. I just had to get somewhere this morning but I'm back home. Before I left the pressure had dropped from 58psi to 38psi in about an hour. I will test and record for a longer time now that I'm free.

 

[TimeTravel]

At least you have the better engine.. Just need to check for power at the relay/fuse, and to see if power is getting thru to the C305 connector next time you get into a no start condition.

My Aztek had this same problem years ago. I bypassed the C305 connector by hard wiring everything, and it solved my problem. Not saying you should do this. The Aztek and Rendezvous are the same truck, just letting you know where I got my experience from. Even my current daily driver, a Saturn Relay is the same truck as the Rendezvous..

I will do that. My c305 looks like it's in good shape.

 

[TimeTravel]

The plugs also look shiny.

 

[TimeTravel]

Although I have not drilled the rivets out the top side shows no sign of corrosion either. Maybe there is a broken wire somewhere.

 

[TimeTravel]

I would also like to point out that my fuel gauge has been slowly fluctuating up and down an 1/8 of a tank or so.

 

[TollKeeper]

Your C305 looks good, dont mess with it any further other than to check for voltage at your next no start/no pressure condition.

Next step is to check for voltage at the fuse, relay, and the power lead wire on the C305 for the fuel pump with the relay jumped.

If you have voltage, and still no fuel pressure, take your fist, or a dead blow hammer, and pound on the bottom of the tank, and you may hear the fuel pump engage. Which means the windings on the fuel pump are getting weak, and the pump needs to be replaced. Had this exact problem last week on my neighbors K1500 Silverado.