chevota help (2 Viewers)

[franklin40]

i’ve got a rebuilt gen 1 chevy 350 with an edelbrock performer carb mechanical fuel pump. it’s been running great all winter but recently has had some fuel starvation symptoms. it’ll be running fine for 40-50km even at highway speeds and then out of no where it’ll start bucking and loose power. no backfiring or miss firing. just bucking and no power. i just changed the fuel filter fuel lines are all new (other than hard lines). can anyone give me advice at to where to look next? not exactly sure whatll cause this. carb was rebuilt before engine was installed last fall

 

[thatcabledude]

Vapor lock maybe?

 

[charliemeyer007]

Crack or pin hole in fuel pump diagram, new fuel pump. Water in the gas, add some gas dryer. Could be spark related too, something in the vacuum system.

 

[franklin40]

i’ve run a few tanks of fuel through it and some sea foam. doubt it’s water. i wonder about vapour lock. when it starts bucking i’ll pull over and let it idle. then it’ll go for a few more minutes just fine and then it’ll start bucking. maybe it’s cooling down just enough until i start driving again? how does one test for vapour lock and fix it? i suppose a new fuel pump wouldn’t hurt to try. i just don’t love throwing parts at something g with out knowing if its actually the problem

 

[charliemeyer007]

You could over wrap the fuel line to shield it from heat. You can scab in an electric fuel pump from ebay cheap >$20. Yes interment malfunctions can be hard to find and fix.

 

[charliemeyer007]

This is my electric fuel transfer system. Was about $50 to build. 5' draft 20' delivery hose, 10' power cord that can use cig lighter or connect to the battery. It has a filter, fuse and a water proof switch.

 

[White Stripe]

What kind of ignition stuff you got?

 

[pb4ugo]

Are you running a fuel return line? And what @White Stripe asked.

 

[B y r o n]

i’ve run a few tanks of fuel through it and some sea foam. doubt it’s water. i wonder about vapour lock. when it starts bucking i’ll pull over and let it idle. then it’ll go for a few more minutes just fine and then it’ll start bucking. maybe it’s cooling down just enough until i start driving again? how does one test for vapour lock and fix it? i suppose a new fuel pump wouldn’t hurt to try. i just don’t love throwing parts at something g with out knowing if its actually the problem

This sounds like there is a problem with the fuel pump. Pump working poorly but fills the carb fuel bowl. Drives fine until the bowl is emptied and it starts to buck. You pull over and while fuel use is low at idle the bowl fills again. You take off the the problem repeats.

Replacing the fuel pump should resolve this issue.

If you are leaning more toward vapor lock find some insulating cover you can put over the fuel line. This should cut down on heat getting to the hard/rubber fuel line and prevent vapor lock from happening.

 

[franklin40]

thanks guys. my fuel line isn’t that close to the exhaust except one area i can easily reroute it.
i guess i’ll pony up for a new fuel pump as that seems like the most logical place to go next.

 

[pbgbottle]

I had a bucking issue and it was the HEI cutting in and out check wires around alternator I had an MSD with bare wire shorting out and it killed the MSD 6aL. If it isn’t fuel maybe check some wiring

 

[FJ40RobQ]

I just had a similar issue with my Gen 1 SBC 350 and did all the fuel trouble shooting and replacing parts myself and still did not solve the problem. I ended up taking it to a mechanic that figured out that when my HEi distributor got hot it started to fail at the ignition coil which just caused my engine to die after 15 or 20 minutes, but would still start immediately after it died.

 

[pb4ugo]

Your issues could be fuel related or the ING. We ask if your running an HEI dist because folks have had similar symptoms like @FJ40RobQ describes. It's not uncommon. Sometimes when the pickup module gets hot it will start cutting out or totally fail. Once it cools down, it will sometimes operate as it should. It may also start cutting out at higher rpms. I also run a fuel pump with a return line to help cool the pump and to supply cooler fuel to the carb. I would also recommend running a hardline from the pump to the carb.
These may be your problem or not.

 

[franklin40]

i have a hei distributor. wouldn’t i have some misfiring or backfiring or running rough if it was ignition? i’m pretty new to HEI so i dont know a lot about symptoms related to them

 

[charliemeyer007]

I have used my fuel transfer system to eliminate all fuel delivery issues in sorting out issues like bad gas, intermittent blockage from crap in the tank or lines, weak fuel pump etc. If you temporarily hook in such a system and you still have problems, then its likely not fuel related.

I like old school stuff. Fuel injection is wonderful when it works, same for computer controlled spark, valves and all the rest of the modern gizmo stuff, however they can't shut down my unit remotely.

 

[pbgbottle]

What carb are you using.?
Maybe it doesn’t like all that fresh Saskatchewan air. Haha just teasing.

 

[EWheeler]

I just had a similar issue with my Gen 1 SBC 350 and did all the fuel trouble shooting and replacing parts myself and still did not solve the problem. I ended up taking it to a mechanic that figured out that when my HEi distributor got hot it started to fail at the ignition coil which just caused my engine to die after 15 or 20 minutes, but would still start immediately after it died.

My SBC swapped 40 with electronic fuel injection & ignition had the same issue as described above, except it wouldn't immediately re-start. It had to cool down for a whiel. Replaced the electronics in the HEI distributor and it works fine now. It would spit and sputter intermittently for a while and then just shut off . It would crank and crank and crank. Had fuel but no spark.

 

[peesalot]

Pick up a new ign module that goes inside the hei dist, they crapout. Symptoms act like my old sbc with carter 4bbl when I got river water/sand in rear tank and it got into carb, would start sometimes fine, sometimes barely, have a look at fuel filter & carb bowl, could be a sticky seat/needle.

 

[pb4ugo]

i have a hei distributor. wouldn’t i have some misfiring or backfiring or running rough if it was ignition? i’m pretty new to HEI so i dont know a lot about symptoms related to them

No, usually when the pickup module fails it's usually hot and there's sometimes a loss of power, maybe a sputter or it just quits. When it cools it'll most likely start. It might sputter or miss at higher at rpms too. For a vapor lock and old school/back woods fix used to be clip some wooden clothes pins on the metal line near the carb. They act as a heat sink.

 

[franklin40]

Pick up a new ign module that goes inside the hei dist, they crapout. Symptoms act like my old sbc with carter 4bbl when I got river water/sand in rear tank and it got into carb, would start sometimes fine, sometimes barely, have a look at fuel filter & carb bowl, could be a sticky seat/needle.

i’ve only run this engine for 4 months and the distributor was brand new. my fuel pump is much older though so i’d hazard a guess it’s my problem. i may be wrong. i have had brand new parts fail. all my driving has been during in canadian winter so i don’t think it’s likely a heat problem. i think it may be more like Byron said that my fuel bowl is not filling. it just feels
like starvation. so that’s where i’ll start searching.

it never sputters or stalls it starts without hesitation no matter the temp it just looses power and bucks and surges. it doesn’t miss or backfire and runs perfectly when not bucking