The saga continues - Sputtering, loss of power when accelerating

[Jmclendon]

So, I've finally had a chance to crawl underneath it (we've been moving..... No doubt it would've gone faster had the truck not been out of action) and there doesn't appear to be another inline filter anywhere between the tank and the one that's just before the carb.

There is an electric fuel pump. So, do we think there's any harm in disconnecting the battery and having a tinker to see if there's any scrud in the pump itself?

The only reason I ask is I've only ever done this kind of thing on a mechanical pump. Not sure if there's anything special I need to consider with an electric one (and the Google isn't helping much, because most of what I'm finding relates to fuel injectors etc....)

[TJ's GMC]

Disconnect the battery and jerk that ol pump out. Be sure to disconnect the line from the sending unit. Look into the ports and see if there is any crap. If there Isn't then check all the lines. Pull the sending unit out and check it, make sure there is a screen at the end. Also look into the tank while there. Then remove the line from the carb and pull the filter and blow compressed air through that line into a jug at the other end to see if any crap comes out. If so...there's your problem and check that filter as well. If there Isn't any crap in the line...replace the pump, filters, and all old rubber line. I'd do a double filter system with a filter behind and in front of the pump. Super cheap insurance and can save the pump. Saved mine, but I went with a new one anyway. Good pump if you end up needing one would be a Carter 50 GPH. Puts out around 4.5 to 8 PSI. USA made.

[Ed Snyder]

Originally Posted by Jmclendon

Driving along this morning and everything was fine. All of a sudden it starts sputtering when I accelerate and I'm not getting enough power.

I had the exact same symptoms one time. After a lot of checking things and head scratching, it turned out to be a glob of silicone sealant some previous owner had glommed onto the bottom of the pickup tube inside the gas tank. During normal driving it would run fine, but flooring the pedal sucked up enough gas that it would pull up the silicone glob (like a hinge) and block the tube.

[Jmclendon]

It's definitely looking like a sediment issue in the tank/lines. I took the fuel pump off (or, mostly off as I left it wired up) and blew some air through it (sadly, I don't have an air compressor, so when I say I "blew some air through it" I'm being quite literal) and what came out the other end was full of scrud.

After hooking it all back up, I was able to get a nice sounding rev out of the engine again. I've not taken it for a test drive yet, but I'm somewhat optimistic. I still don't think it's getting as much fuel as what it should, as the inline filter before the carb isn't as full as what I would like. But, at least it's a start.

Either way, I'm thinking it's going to need the thank cleaned (or replaced). I'm not keen on having this issue crop up every couple of months/weeks.

[TJ's GMC]

A full system flush at the very Least is in order. Pull the sending unit and look into the tank to see how bad it really is. If it's really bad Classic Parts can get a tank to you for a good cost. I'd also invest in a new sending unit, electric fuel pump, and two filters. One before and after the pump.

[Jmclendon]

Supposedly it's a "new" tank and a "new" fuel pump. The latter might be true, but I'm seriously doubting the former. Particularly if there's that much scrud going on?

The good news is I had already ordered (and have just received) a new sending unit, as the gauge hasn't worked from the start. All the wiring and whatnot checks out as far as that's concerned, so hopefully there's going to be a bit of killing 2 birds with 1 stone.

I don't plan on installing the sending unit though until the issue with the tank is sorted. Otherwise, knowing my luck I'll have to get yet another replacement far too soon.

[TJ's GMC]

Originally Posted by Jmclendon

Supposedly it's a "new" tank and a "new" fuel pump. The latter might be true, but I'm seriously doubting the former. Particularly if there's that much scrud going on?

The good news is I had already ordered (and have just received) a new sending unit, as the gauge hasn't worked from the start. All the wiring and whatnot checks out as far as that's concerned, so hopefully there's going to be a bit of killing 2 birds with 1 stone.

I don't plan on installing the sending unit though until the issue with the tank is sorted. Otherwise, knowing my luck I'll have to get yet another replacement far too soon.

If it isn't to bad you can always pull the tank and flush it. Then recheck. Main concern is loose rust from years water in the gas and condensation eating at the metal and gas itself. Had a tank that looked great, but after a hard flushing leaked like crazy. New tank was on the way and installed 6 days later. lol

[Jmclendon]

I'm a bit jealous as to how easy it is for folks in the States to get parts. It's a bit more of a time consuming/costly affair over here LOL

[TJ's GMC]

Originally Posted by Jmclendon

I'm a bit jealous as to how easy it is for folks in the States to get parts. It's a bit more of a time consuming/costly affair over here LOL

My bad, I thought you were in the states for some reason. haha

[Jmclendon]

It was a pretty safe assumption.... There aren't exactly a slew of GMC trucks down under.