Can Seafoam Kill An Old 350?

Airspeed-Alive · January 25, 2009

Well, after Seafoaming my '86 Buick Regal, I had a bit left over and decided to pour half a can in the gas tank, 1/4 in the oil and the rest got sucked up from a vacuum line by the brake booster in our '88 Sierra.

We let it stall out once it sucked everything up. Started it up and ran it for a bit. Let the smoke finish. Then it sat for a few days (its a farm truck).

Ever since then, it seems to be a gut box. It'll start up and idle, but barely drives. As soon as you load the drivetrain, it wants to fall on its face.

This has happened about 3 months ago. We start it every so often and drive it around the land a bit. Nobody can figure out what's wrong with it. We replaced the wires, plugs, O2, fuel filter - all of which hasn't helped.

I had a scanner on it way back (late fall), and when I put it in 'bypass' mode (I think?) it was running fine. As soon as I took the scanner off, it went back to being a dog.

Any ideas? Could the Seafoam have loosened up too much crap that the engine can't get rid of (yes, I changed the oil after the recommended mileage was put on - and a lot of crap came out).

Not sure what to do with this... Maybe a swap is in order.

kuhl_530 · January 25, 2009

Sorry to say I've never heard of this kinda thing happening. I use sea foam all of the time in my 95 sierra and have never had a problem. Whatever it is, it sounds electronic, probably not mechanical.

Dash. · January 25, 2009

I'm Airspeed-alives' brother and theres one thing he missed, when you first start it she miss-fires a bit but when you put it in gear (if she doesn't stall) then the miss-fireing stops even if u put it back into P or N. Also we never reached the recommended mileage to change the oil after the seafoam, we changed it cuz she started puffing black and white smoke out of the exhaust. And we changed the O2 sensor and things started working better for approx 10-15 minutes but then she was back to being screwed up so i pulled the O2 sensor out and cleaned it with some gas and put it back in again it ran good but only for approx 5 minutes, so i disconected the O2 sensor and that didn't change anything either. Also we let her sit for around 2 months and i went out and started it and she was fine until being at operating temp for some time, but as I was driving it, she kept jumping in rpm (higher) and staying at that higher rpm until she would jump to a higher rpm again (she was screaming when i got back home). Then I started it the next day and i let her warm up to operating temp. put it in Reverse and she stalled and the battery died befor i could get her to start again.

pennzoil29 · January 25, 2009

Possibly a plugged cat.

98ChevyC1500 · January 25, 2009

Excuse me if i sound a bit ignorant here but...hum...What's seafoam?? Never heard of that before!!

txab · January 25, 2009

Excuse me if i sound a bit ignorant here but...hum...What's seafoam?? Never heard of that before!!

Seafoam

98ChevyC1500 · January 26, 2009

Excuse me if i sound a bit ignorant here but...hum...What's seafoam?? Never heard of that before!!

Seafoam

Aaaaaah! Now i see!!! Thanks!!

Heavy Cruiser · January 28, 2009

I would take and drain the tank as much as you can. There is a drain plug in the bottom, good luck will be needed.

You can remove the fuel pump relay and hot wire the socket to run the fuel pump continuously with a disconnected line from the TBI unit.

I would change the fuel filter, clean out the fuel passages of the TBI unit, and clean the fuel return line. Assemble all and add fresh fuel. Maybe clean or change the spark plugs.

Add a can of white gas to absorb moisture. And check the gasket between the TBI unit and adapter at the rear - could be gone big vacuum leak.

Bucknut · January 28, 2009

All good thoughts..One other thing, which has happened to me before...Using Seafoam is awesome, sometimes too awesome...

It may have cleaned a bunch of gunk up and lodged it downstream somewhere else as in maybe your TBI....

Just a thought...

norsemanberg · January 28, 2009

Possibly a plugged cat.

+1

98ChevyC1500 · January 31, 2009

Where can i find that stuff?? I think my Chevy would like that!! After 11 years, the engine must surely be a bit dirty inside..... Is it available in Canada?

Airspeed-Alive · February 7, 2009

Seafoam is available in Canada. I get it at the local NAPA / UAP / Ideal Supply. I think its around $10 a can.

I was just outside and started the truck up again. It wasn't stalling - but it is definitely running waaaaay too rich. I could smell the fuel. I put it in gear, and it plowed through a 3' snowbank like it was nothing. When the load came on, it did want to stall, and eventually did. There was black smoke coming out when I was ripping through the snowbank. Definitely a rich mixture. Hmm....

When spring comes (and warm temps), I'll try taking the catalytic converter out.

pennzoil29 · February 7, 2009

Seafoam is available in Canada. I get it at the local NAPA / UAP / Ideal Supply. I think its around $10 a can.

I was just outside and started the truck up again. It wasn't stalling - but it is definitely running waaaaay too rich. I could smell the fuel. I put it in gear, and it plowed through a 3' snowbank like it was nothing. When the load came on, it did want to stall, and eventually did. There was black smoke coming out when I was ripping through the snowbank. Definitely a rich mixture. Hmm....

When spring comes (and warm temps), I'll try taking the catalytic converter out.

Try drilling a hole in it. That might tell you. If it's not, you'll have to weld the hole.