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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Ok been chasing my tail on this one, I have a few ideas but want to run them past the collective wisdom here. L69 HO engine. Things seem to be in tune, plugs/rotor/wires/cap, dwell, timing, engine temp. Low speed driving, seems like I can do all day. When I am on a on ramp and trying to accel hard, I'll start to sputter and chug along. Sometimes I've cut out completely. Hard to restart once that occurs. No smoke out tail pipes while it starts to struggle. Let it set and can usually get it going once it cools/sits for a bit. Other times it'll wheeze along. Does not matter what gear, it just slows, almost like running out of gas. I was able to get a better test today as I did a few sprints around my neighborhood. Third lap I was opening it up and it struck again. I pushed it half a block, fired it up and drove home.
So I feel it's fuel related. I can run for an hour in the garage so I think I can rule out heat for the most part. The first filter was caked full of crap when I bought the car. Replaced it when I rebuilt the carb. Cleaned some things up recently and took another look at the filter. This time not caked in crap, but was full of rust. (~50-100 miles driven). New fuel pump too. I do NOT have the electric helper pump in the tank. Can vapor lock happen WHILE driving or just after a hot soak? I've got some AN fittings and hose on the way to remove that metal pipe that runs between fuel pump and carb and damn near lays on the front of the block, which can't be doing it any favors.
The next step for me to test I guess is to really gas it in the garage and see if I can get it to happen there, the pop the airhorn off and see if the bowl is empty/low, verify float setting. I was able to do my cam break in varying from 2-3k rpm in two 10 min intervals (had to address a cooling issue), without any problems. Does the engine pull more fuel under load? Like is 3k road rpm different than 3k garage rpm? (In terms of fuel consumption, etc). Given the rust I know I'll need to drop the tank at some point (and fix my non-working fuel gauge), but I'm trying to avoid that for as long as possible... I've done my clutch, and pretty much the entire top end of the engine (heads/cam/timing set/carb rebuild) so I think I'm mechanically capable of the fuel tank drop, I just hear it's not fun.. This problem existed before I did any of that work too so we can rule out the 'what did you change to break things' as well. And I'd rather not have to try and pull the airhorn on the side of the road just to verify if the carb is empty or not.
Start with a fuel filter. It's in the inlet nut where the fuel like hooks up.
Support the big nut (1" hex) with an open-end wrench, and remove the fuel line nut (5/8") with a tubing wrench. Then remove the big nut. The filter will probably come out with it.
In this photo, which the fuel line itself is obviously not stock although it bolts up the same, the fuel line nut is that blue one, and the filter is behind the big one that it screws into.
Filter was replaced before the cam break in, less than 10 miles/hour of run time ago. I did buy two so I'll check that out tomorrow and see if it junked up that fast again. Spring and check valve are good on it. If so then I know what I need to do the tank without any more doubt.
Condition of filter after maybe an hour or two total runtime. I don't think it's plugged enough to cause my issue (?), but that much crap that quick,
I think I do need to drop/clean/replace tank and make sure the lines/sock aren't all plugged up.
01-01-2019, 04:31 PM
