Engine/Transmission (1998.5 - 2002) Fuel Filter

[Don Bellamy]

I changed my fuel filter today, now I start the truck it idles at 450-500 rpm, has no throttle response and idles rough as a cobb, any thoughts?

Don

 

[RolandJ]

im assuming you have stock filter or is it after market.

 

[Grizzly]

Wow! I hope you didn't get dirt into the canister. Sounds like something clogging the injectors.

 

[Wyomingcowboy]

any chance you spilled fuel on an electrical connection or maybe bumped one loose?

 

[SHuber]

Did you have good pressure from the lift pump to prime it back up? That's how I discovered once that my lift pump went bad (before gauges)

 

[Don Bellamy]

Yes I have the stock filter with the pump mounted to the rear with the Vulcan kit, the fuel canister and lid were clean, I drained the fuel prior to removing the lid then removed the filter without any spillage. Don't know what electrical connectors would have been disconnected around the canister but I will look. Lift pump pressure was 14psi when primimg. I did notice when the engine did start it was when I let off the key not while I was holding the key in the start position and then I watched the fuel pressure drop down to 2-4 psi while idling, sound and felt like a monster cam in the thing?

Don

 

[PC12Driver]

Sounds like air in the system to me. And not much, since it is actually idling. To get dirt downstream into the pump it would have to enter into the top of the center pedistal in the filter housing. Not impossible, but pretty unlikely.



I'd look at the plastic filter cap. It doesn't require much torque (25 ft/lbs), and can easily crack if you get carried away. Earlier versions also had what looked to be a recepticle for a 1/2" drive ratchet (not the intent though), and using that method for installation/removal would eventually crack the cap (the square slot was turned into a circle in later caps to prevent the temptation to use the ratchet directly on the cap). Or maybe it's something simple like the o-ring getting rolled out of place or torn.

 

[blacksheepdiesel]

Yep, air entering somewhere. Most likely place is the o-ring on the filter cap.

Godspeed,
Trent

 

[Don Bellamy]

If the Cap is cracked or the o ring is out of shape this would allow the system to suck air but not leak fuel? Thank you all for your input, hope to get it figured out.



Don

 

[SHuber]

I agree with air in the system, but it seems like if something in the housing went awry then you should also have fuel leaking from the housing? The 2-4 psi at idle indicates either a draw problem, or lift pump failure, if your gettting air in the system it's because the pump is (pulling) it in, so the problem should be somewhere between the lift pump and the supply (fuel), could even be a line leaking somewhere between the pump and the tank, just remember the possibility does exist that it may be just bad timing that this started after you changed the filter, might not have anything to do with the filter at all? good luck.

 

[HBarlow]

I didn't think the cannister operated in a vacuum. In other words, I thought as long as there is fuel in the cannister the transfer pump will push it through to the injection pump. I didn't think the injection pump was sucking it from the cannister. I never tried starting one with the screw on cap loose or off but I would think a missing or bad gasket would only leak fuel. Am I wrong?

 

[SHuber]

I agree with you on that HB, I do believe the VP will pull enough fuel under certain circumstances to make the engine run, I don't know how but when I had a lift pump fail once (before gauges) The only way I knew I had a problem was when I was towing a 16,000 lb. backhoe and I had my comp set up on the highest setting, the truck would start to shutter when I would pull a hill under full power, other than that it ran perfect, so the next day I put a new fuel filter in it thinking it was the culprit and when I tried to prime it up via the lift pump was when I discovered the lift would run it's normal cycle but not a single drop of fuel was being pumped, I even pulled the line directly off the lift pump and still nothing. That's when I put a gauge in (and a new lift pump). The VP never did fail and I guess I probably put 150 miles on it after it started acting up. That was a close one.