• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Built 400 Stalls and Dies after Seafoam

Change the power valves and check your vacuum to make sure it's the right one.
 
Change the power valves and check your vacuum to make sure it's the right one.
The 870 avenger I had was way off on the power valve and jetting, made a huge difference! I believe they come with a 4.5 and I ended up with a 6.5.
 
Is there a vacuum in the fuel tank?

Is the fuel tank vented, and is there flow through the vent lines in the trunk etc?

Is the fuel cap a vented or non-vented type?

Is there a return line to the tank?

There is a simple solution for this issue, but it will require a bit more diagnosis. Everyone is quick to blame a bad carb, but sometimes the answer is easier than that.

(No disrespect meant to any of the members who have suggested carb problems intended.) :thumbsup:
 
Interesting, maybe you were pig rich and now starving from junk being broke loose.

Since I don't know you, do you feel like you can tell the difference between an engine flooding out while driving vs starving? Flooding will bog and chug but usually take off hard if you floor it as demand is greater. Starving goes weak and won't recover.

It definitely goes week and won't recover. The 2nd time when it happened, I stepped on the accelerator and got no response from it, like it was already dead but not completely shut down. Curious though why it started after some time (30 minutes when i was stranded, then after i got it home, 24 hours before messing around again).
 
Is there a vacuum in the fuel tank?

Is the fuel tank vented, and is there flow through the vent lines in the trunk etc?

Is the fuel cap a vented or non-vented type?

Is there a return line to the tank?

There is a simple solution for this issue, but it will require a bit more diagnosis. Everyone is quick to blame a bad carb, but sometimes the answer is easier than that.

(No disrespect meant to any of the members who have suggested carb problems intended.) :thumbsup:

Not 100% if the tank is vented or has vacuum. Only a few years old, direct replacement from Vans Auto as well as a new neck and sending unit. I believe the cap is vented, that was a replacement from Rock Auto. For sure no return line to the tank. I know when it was replaced, he cut the 3 or 4 lines that were in the front of it and also removed the vapor canister in the engine bay and said it was no longer needed. Car ran without for the last 4 years and no issues, other than running rich and dieseling.
 
Check the power valve in the front metering block, maybe it ruptured. Something is making you pig rich.

Out of curiosity, on a scale of 1 - 50, how rich is pig rich??.....60+ or more??
If there were debris in the float's needle and seat, the OP, mentioned that the float bowls were ~ 1/2 to 3/4 full, this would not cause flooding.
As speculated, the primary power valve diaphragm MAY have ruptured, allowing manifold vacuum to pill fuel out of the bowl, causing an extremely rich mixture. BTW.....IMO, the Holley Street Avenger 770 is too large for your application. Why not use the Thermoquad for a 440 or a 650 CFM Holley. Personally, adding Seafoam will increase the possibility of detonation due to the lower flash point of the fuel mix. Just my opinion of course.
BOB RENTON
 
The pig rich comment was based off the pavement. Whatever he's got going now isn't as bad
 
Fuel tank is vented through the trunk, at least i think. Theres lines from the tank going to the trunk floor, which i thought were cut. Also attached pictures of the gas cap. And a picture of plug #2. All of the plugs looked about the same. Oil from the dipstick smelled a little bit like gas, and i think may be a little thin. Oil level was a little low, maybe half a quart.

tank vent lines.jpg gas cap 2.jpg gas pics.jpg oil.jpg plug.jpg
 
The pig rich comment was based off the pavement. Whatever he's got going now isn't as bad

Perhaps you should try and quantify your evaluation by percentages or some other methodology. Your term "Pig rich" is still undefined as well as "isn't as bad" (presumably now vs previous?).....its difficult to make a determination as to which way to proceed without a base point to start from.....just a thought....
BOB RENTON
 
Bob, I have no empirical data for what afr for what duration would cause what was pictured. Maybe you do?
 
Auto Transport Service
Back
Top