Bucking, chugging, poor idle...solved.

[agfours]

The other day, I took ‘Dark Helmut’ for a spin and the car started to miss, then turned to a chug, bucking, and barely got her home…very poor idle and wouldn’t drive above 2000 RPM.

Checked fuel pump…ok. Replaced CHT sensor…ok. I have a Solid state DME, but swapped with a known good one…ok.

Hmmm…fuel filter? This is what poured out of the filter…[see below]

Recently refueled, but drove 50 or 75 miles before the issue started with vengeance. Wonder if this was lingering and finally got bad enough or if this was a bad tank of gas…leaning toward the latter. Thoughts?

Replaced the filter and it ran better than ever, with much better throttle response and smooth idle.

I am thinking I will just drive it and see if the clog comes back, and if so then drain the tank and replace the filter again (to see if this was built up over time, or if because of a recent fill up). Any advice in addition, or to the contrary?

[Alan L]

I would be draining the tank, and more. That stuff came from somewhere and the tank is a good start place. The new filter will only cope with so much before repeat scenario.
Been thru similar recently with both my cars - replacing pumps, filters. Cleaning tank as best I can - back flushing fuel via return hose at tank, trying to clean swirl pot. When you have the drain bung off, feel inside - gritty??
Hint - easy way to empty tank first is siphon thru the fuel sender hole.
Alan

[proporsche]

there is a date on you fuel filter...how old is yours?

Ivan

[911obgyn]

Take the sender off and look in the tank.
Dont drop your flashlight in like i did!

[proporsche]

if your fuel filter is over 2 years --quite normal deposit, if u are changing different gas stations

Ivan

[agfours]

Yes, I have had the car 2yrs, and the filter was at least one year older than that. It just seemed like a lot of sediment, and rusty in color.

I need to burn down the tank a bit as it is full, but I will pull the sending unit for a gander when I get to E….

[kach22i]

Originally Posted by proporsche

if your fuel filter is over 2 years --quite normal deposit, if are changing different gas stations

Ivan

Really?

I'm overdue for a fuel filter change then.

Another thing on my list.

[proporsche]

I used to change the fuel filter on clients car every year.
Back in LA i did some testing.I went for 1/2 year to several different gas stations and it was almost like the above pic.But mind you in LA you drive a lot usually 20k a years no problem
After i did another 1/2 year just one station and it was clean as a whistle..
Ivan

[1979-930]

Older cars the fuel filter was a 15k maintenance item. Once a year.
I find it interesting that you can’t change the fuel filter on most new vehicles


Sent from my iPhone using Tapatalk

[Snitzler]

Originally Posted by 911obgyn

Take the sender off and look in the tank.
Dont drop your flashlight in like i did!

Use your cellphone camera. Too big to fall in the hole, has a built in flashlight and you have a record. Looks cool as well.

[Quicksilver]

Looks like you got a load of gas with a huge bunch of sediment in it. Were you in the area where they ran out of gas in the stations? When the storage tank is drained and they refill it, it can stir up all the sediment in the tank. If you show up soon after the tank is filled all that stirred up sediment can still be in suspension.

I would look at cleaning out the tank and "while you are there" replace all the rubber lines from the tank to the pump and from the pump to the fuel line in the body. Most cars have the original rubber and it is a ticking time bomb.

And in general I make a point of not filling my cars from a station where they are filling the tanks and I only fill with Chevron (Techron really is that good of an injector cleaner) or Shell ("Nitrogen enriched" additive is good too) as a backup.
I also try to use a gas station with a pretty high volume of business. At a really slow station the gas can sit there until the ethanol starts to settle out and they can get all sorts of problems with their tanks, lines and pumps.
If you have a station that sells "pure gas" (no ethanol, not "oxygenated") that is good to stop corrosion in the car's fuel system and you can just add some Techron from time to time.

[agfours]

Originally Posted by Quicksilver

Looks like you got a load of gas with a huge bunch of sediment in it. Were you in the area where they ran out of gas in the stations? When the storage tank is drained and they refill it, it can stir up all the sediment in the tank. If you show up soon after the tank is filled all that stirred up sediment can still be in suspension.

I would look at cleaning out the tank and "while you are there" replace all the rubber lines from the tank to the pump and from the pump to the fuel line in the body. Most cars have the original rubber and it is a ticking time bomb.

And in general I make a point of not filling my cars from a station where they are filling the tanks and I only fill with Chevron (Techron really is that good of an injector cleaner) or Shell ("Nitrogen enriched" additive is good too) as a backup.
I also try to use a gas station with a pretty high volume of business. At a really slow station the gas can sit there until the ethanol starts to settle out and they can get all sorts of problems with their tanks, lines and pumps.
If you have a station that sells "pure gas" (no ethanol, not "oxygenated") that is good to stop corrosion in the car's fuel system and you can just add some Techron from time to time.

Yeah, I have been having some cut out at high RPM over the last few months, which I tried to troubleshoot via replacement of DME (with solid state), new Coil. But this came on quite suddenly over a single drive, where it went from intermittent at high RPM to 'wouldn't run over 2k RPM' which left me thinking it was a bad batch of gas. However, could certainly be that this last tank or the timing was just the straw that broke the camel's back. I see this happen with my pool filter pressures...it's fine until it hits critical threshold, then it goes from good flow to clogged in a day or two.

This was an older, but heavily trafficked Texaco, and I'm not in the gas shortage area here in Austin. I use a bottle of Techron additive every few tanks as well.