Exhaust changes causes problems

[rogerzr1]

Originally Posted by Pete

Try this first,hold both heater up & down arrow buttons for 5 seconds you will see 00 let them go and just hit the up arrow till you see 16 now hit auto button that will be your engine temp in celcius let your car idle till it hits 75 celcius if it dies then the primary pump is gone.
We have 2 pumps both are on at cold start up @ 169 F secondary shuts off.


Pete

I did what you said Pete(pretty cool btw). The car didn't shut off at 75. I decided to take it for a drive with the power key off. It drove like sh**. When I applied the gas, the car shuttered and vibrated for a couple of seconds then smoothed out. My question is even though the car didn't shut off at 75, can the primary fuel pump still not be preforming correctly. Just wanted to see if this rang a bell with anyone. I plan on getting a guage tomorrow and trying what Jeff said to do.

BTW I appreciate everyone's help trying to educate my ignorant a**.

[XfireZ51]

Roger,

Have you checked injectors?

[rogerzr1]

Originally Posted by XfireZ51

Roger,

Have you checked injectors?

Injectors were all changed in August.

[Pete]

Originally Posted by rogerzr1

I did what you said Pete(pretty cool btw). The car didn't shut off at 75. I decided to take it for a drive with the power key off. It drove like sh**. When I applied the gas, the car shuttered and vibrated for a couple of seconds then smoothed out. My question is even though the car didn't shut off at 75, can the primary fuel pump still not be preforming correctly. Just wanted to see if this rang a bell with anyone. I plan on getting a guage tomorrow and trying what Jeff said to do.

BTW I appreciate everyone's help trying to educate my ignorant a**.

Yes,the primary could be performing poorly,you also have to remember the secondary Feul Pump will kick on at a certain throttle point.
I would then also try what Jeff said,take the secondary FP fuse out and try again,should have the stumble all the time if it's the primary.
If it turns out you do need FP just get one from a 1996 Chevy Truck 2500 the one with 454ci big block.
Pete

[XfireZ51]

Originally Posted by rogerzr1

I did what you said Pete(pretty cool btw). The car didn't shut off at 75. I decided to take it for a drive with the power key off. It drove like sh**. When I applied the gas, the car shuttered and vibrated for a couple of seconds then smoothed out. My question is even though the car didn't shut off at 75, can the primary fuel pump still not be preforming correctly. Just wanted to see if this rang a bell with anyone. I plan on getting a guage tomorrow and trying what Jeff said to do.

BTW I appreciate everyone's help trying to educate my ignorant a**.

Just re-reading these posts. Sounds like a fuel issue to me but its not the fuel pump or filter. He has backfiring on decel and stumble at tip-in which sounds like a lack of AE. I would suspect TPS or CTS. My $.02.

Originally Posted by rogerzr1

If it is a primary fuel pump, would I need to drive it to get the fuel presure or would it show the problem at idle. The reason I ask this is that I am having a hard time finding a fuel presure gauge that has a long enough hose to drive and check it.

Well, all you really need to do is pull the secondary fuel pump fuse and keep a gauge on the rail and key on. Pump should run for about 2-3 seconds and pressure should be between 48-5 psi and hold after the pump stops running.

If you can find just a gauge, and hydraulic hose shop can build you a custom length hose.

[Pete]

Originally Posted by Jeffvette

Well, all you really need to do is pull the secondary fuel pump fuse and keep a gauge on the rail and key on. Pump should run for about 2-3 seconds and pressure should be between 48-5 psi and hold after the pump stops running.

If you can find just a gauge, and hydraulic hose shop can build you a custom length hose.

My way is the lazy way just sit back listen to tunes and have a beer.

Pete

[XfireZ51]

Originally Posted by Pete

My way is the lazy way just sit back listen to tunes and have a beer.

Pete

[Pete]

Originally Posted by rogerzr1

I just replaced the stock exhaust with B&B and X pipe. The car seems to stumble in low rpm and hesitates a little during acceleration. The car acts like it wants to backfire, but doesn't. Any ideas?

Roger,have you done anything else to the car recently besides exhaust.

The symptoms you describe sound like bad spark plug wires,spark plugs or injectors.

You know what's funny is half the guys on here, had the car in front of them or took it for a test drive would figure it out in a second.

Pete

[rogerzr1]

Originally Posted by Pete

Roger,have you done anything else to the car recently besides exhaust.

The symptoms you describe sound like bad spark plug wires,spark plugs or injectors.

You know what's funny is half the guys on here, had the car in front of them or took it for a test drive would figure it out in a second.

Pete

I know, that's what is killing me. The injectors and spark plugs were changed in August. The spark plug wires were not changed.

The best I can describe it is:

As I step on the gas there is a little hesitation.
As the car speeds up it seems to catch back up and perform correctly until 3rd gear around 4500rpms it jerks (like there is no fuel) then continues to accelerate.

I don't know how better to describe it. When the power key is off, the car shakes and hesitates as I step on the gas. It seems like when the key is on, it makes the car drive better but it seems its just masking the real problem.

I don't know, now I am confusing myself.