Carb question - fuel pump runs all the time, jeep runs rich (355 chevy), ideas on leaning it out?

[2002wranglerX]

Hey guys,

Ok, so my YJ has a 355. it has heads, cam, intake, etc.

It runs REALLY rich. like, you get out of it and you smell like fuel. The fuel pump runs all the time. no shut off. so if you turn the key on it just runs, no prime and stop like normal fuel injection.

can that cause overfueling? or do i just have to much carb?

[jackb1]

no prime and stop like normal fuel injection.

or do i just have to much carb?


Do you have injection or carb?

[jackb1]

Injection, maybe? I can rationalize how it would but I don't know this.

Carb, no, it shouldn't. The float should be shutting out flow into your bowl. If anything was getting by, I would be surprised, and expect a very rough idle since fuel would be overfilling the bowl and dripping into the intake. You may just be jetted to rich.

PS. You know you're driving an old jeep right? I run a closed loop injection system and I still wear exhaust cologne for a while after I get out of it. I think its part of the allure of old jeep ownership.

[2002wranglerX]

Injection, maybe? I can rationalize how it would but I don't know this.

Carb, no, it shouldn't. The float should be shutting out flow into your bowl. If anything was getting by, I would be surprised, and expect a very rough idle since fuel would be overfilling the bowl and dripping into the intake. You may just be jetted to rich.

PS. You know you're driving an old jeep right? I run a closed loop injection system and I still wear exhaust cologne for a while after I get out of it. I think its part of the allure of old jeep ownership.

lol, it's a Carb.

i know. it doesn't bother me, but i'm not super wild about the 3 year old having to breath it in.

[2002wranglerX]

is it possible that the 4 barrel is opening too early?

[jackb1]

I don't think the secondary is adjustable on most carbs without modification of the linkage. Any clue what model carb/cfm you have? People always over-carb. I did.

I hear you about your reasoning and of anybody, you've had enough old jeeps to know. Just joking.

[2002wranglerX]

LOL, it's a holy avenger offroad carb

https://www.holley.com/products/fuel_systems/carburetors/avenger/off-road_truck_avenger/parts/0-90670

670 CFM with vacume secondaries...

Robert (the guy i got the jeep from) mentioned i could possibly do a spacer since you're supposed to add a bigger jet to do it. that it might lean it out...

[2002wranglerX]

http://www.amazon.com/Pressure-Regulator-Universal-Adjustable-140psi/dp/B00K1T982G/ref=sr_1_1?ie=UTF8&qid=1426522474&sr=8-1&keywords=universal+fuel+pressure+regulator+with+ga uge

thought maybe i'd put that on it just to see where i'm at.

[jackb1]

You're probably a little bigger than you need but it isn't like you have an 850 on there. You probably just need to tune it.

It's a shame nobody actually knows carbs any more. Finding a place to correctly tune it is probably all you need but good luck with that.

[2002wranglerX]

You're probably a little bigger than you need but it isn't like you have an 850 on there. You probably just need to tune it.

It's a shame nobody actually knows carbs any more. Finding a place to correctly tune it is probably all you need but good luck with that.

i hear ya. I'm going to have jason at jtech look at it. I'm going to troubleshoot a little too. check to make sure the pump isn't pushing fuel past the float.

that carb needs 5-7 psi. so nothing crazy. i'll probably toss that FPR on there and make sure it's good fuel pressure wise.

[5 SPD XJs]

So you have an electric fuel pump with a carb? any return to tank line? Ryan I have a Holley carb and manifold manual and trick kit instructions. Did you already set the levels of floats so they don't overflow the bowls? the bowls themselves come off to change the jets. especially the primary's. Jets are numbered so lower number the lower the fuel orifices. You'll need bowl gaskets at the least. They always tear coming apart. They really aren't that tough with the manual's guidance

[2002wranglerX]

So you have an electric fuel pump with a carb? any return to tank line? Ryan I have a Holley carb and manifold manual and trick kit instructions. Did you already set the levels of floats so they don't overflow the bowls? the bowls themselves come off to change the jets. especially the primary's. Jets are numbered so lower number the lower the fuel orifices. You'll need bowl gaskets at the least. They always tear coming apart. They really aren't that tough with the manual's guidance

Electric fuel pump.

It actually does have an fpr. Way on the back of the motor mounted low on the firewall. And it has a return on the fpr.

I've never messed with the levels or anything.

[Christopher]

Does it idle rough?
Holley has a power valve. It was known to blow out if it has ever backfired through the carb. It is a diaphragm that basically dumps fuel when you floor it, so if it leaks it will cause an over rich condition. It also may have never had mixtures set correctly.