Another ride home on a flatbed -- Problem found

[66gt350]

Twice in a week. Same problem. Got half way to work and the car went really, really lean and died. This time it did not restart in the garage. I checked my fuel filter to make sure that it wasn't clogged...everything looked fine. I had the wife start it while I looked at the fuel pressure gauge under the hood. It was fluctuating between 35-40 and then went to down to around 20 psig and started running like crap.

So, my problem has to be fuel related. I think that I've narrowed it down to either the fuel pump or the pressure regulator....maybe possibly the fuel rail.

Time to order some more parts.....

 

[Kooter]

Re: Another ride home on a flatbed

That sucks. I think that you are on the right track with it being fuel related. My armchair quarterback guess would bethe fuel pump. I hope that you get it figured out.

 

[Anonymous]

Re: Another ride home on a flatbed

Sounds like the fuel filter. Try to blow through it, there should be no resistance. You can't look at a fuel filter and tell it's bad. Course you might be able to tell after you replace it if the pressure stays stable and normal.

 

[MD69Boss]

Re: Another ride home on a flatbed

Sounds like the fuel filter. Try to blow through it, there should be no resistance. You can't look at a fuel filter and tell it's bad. Course you might be able to tell after you replace it if the pressure stays stable and normal.

Sounds like the pump, or a blockage 'tween the carb and the fuel tank/ cell...
Investigate before ordering parts would be my council...

 

[Fast68back]

Another ride home on a flatbed

Filter is the cheapest, I'd start there.

 

[Mach1Rider]

Re: Another ride home on a flatbed

Twice in a week. Same problem. Got half way to work and the car went really, really lean and died. This time it did not restart in the garage. I checked my fuel filter to make sure that it wasn't clogged...everything looked fine. I had the wife start it while I looked at the fuel pressure gauge under the hood. It was fluctuating between 35-40 and then went to down to around 20 psig and started running like crap.

So, my problem has to be fuel related. I think that I've narrowed it down to either the fuel pump or the pressure regulator....maybe possibly the fuel rail.

Time to order some more parts.....

Before you order parts... Test it.
Remove vac line from reg and watch pressure readings, it should run up but stay steady.
Test pumps bypass, turn key on and charge system. With key off watch pressure it should hold steady, if not the bypass valve is bad on pump.

 

[66gt350]

Re: Another ride home on a flatbed

Here's what I've found so far...The low pressure pump that leads to my accumulator tank is working good. The fuel filter is a Trick Flow unit that has a screen that can be removed and cleaned. The screen is clean and unobstructed. I've got a set of BBK fuel rails that I'm going to install and toss the stockers.

Tonight, I'm going to disassemble the high pressure fuel pump to see if it is gummed up or has any other issues.

I'm leaning towards the high pressure pump, since the pressure was fluctuating some before it dropped and died.

 

[Anonymous]

Re: Another ride home on a flatbed

What flatbed service do you use? I'd like to buy some stock :steer :roll

 

[stangg]

Re: Another ride home on a flatbed

I can't see how a fuel rail could cause a pressure drop unless there was a leak. Are you changing the regulator along with the fuel rail?

Also, check your wiring to the fuel pump and possibly the relay... maybe it's an intermitten electrical issue or loose ground.

 

[KBMWRS]

Re: Another ride home on a flatbed

What flatbed service do you use? I'd like to buy some stock :steer :roll

Hey that's not fair. I already paid for the truck! :bomb :roll

 

[66gt350]

Re: Another ride home on a flatbed

I can't see how a fuel rail could cause a pressure drop unless there was a leak. Are you changing the regulator along with the fuel rail?

Also, check your wiring to the fuel pump and possibly the relay... maybe it's an intermitten electrical issue or loose ground.

Agreed. the fuel rail is one of those, since I have it and while I'm at it, deals. I just had to have some "extra" holes from BBK's crossover tapped and plugged. I was contemplating replacing the regulator. The one that is on there has been there for awhile. It's an adjustable regulator from Steeda.

I've checked the wiring. With two fuel pumps back there, it's easy to hear when they're running!!

What flatbed service do you use? I'd like to buy some stock :steer :roll

With my luck...smart move.

 

[66gt350]

As soon as I got home, I started ripping and tearing apart the fuel system. I know that the low pressure pump is working, so I went to the high pressure side. It's a mallory high pressure pump, and luckily the instructions say that if the pump pressure lowers to take it apart and clean it. I took it apart, and everything looked good. When I reinstalled it, I decided to remove the fuel filter -- just to take it out of the equation. Got it all back in and just put power to the fuel pumps and nuttin'. The old stewart-warner low pressure pump is a loud SOB, so I unplugged it just to hear the Mallory.

Houston we found the problem. When the pump is operating, it's putting out somewhere around 40 psig. The gauge is fluctuating. Before with the BBK intake and fuel rails it was as solid as a rock at 39. That's one reason I putting the BBK rails back on. Then all of a sudden, the pump would sound weak and the pressure would drop to around 20. And sometimes it would even stop. I don't think that was due to the accumulation tank draining. The return line splits between the fuel tank and the accumulation tank. The motor has to be going.

I noticed that the fuel pump is only about 7" from the exhaust. I wonder if the heat killed it....

 

[manley]

Could debris around the pickup in the fuel tank accumulate as the car is running block it enough to cause problems? Not sure that idea fits, but something else to look at if all else fails, I guess.