WTF??? Fuel pump/filter

WTF??? Fuel pump/filter

Jake

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Location
Nor Cal
Vehicle(s)
80 CJ-7 304 30/20 arb SOA 33's wrangler springs, np235, Dana 300, 4.56's , high steer, auto meter, family cage, working on fuel injection.....
Well, it was a perfect day to drive the jeep to work. It was about 90 here. I made it about 15 min and it started to bogg out. I pulled over, opened the hood and nothing..... I started it back up, ran fine for about two miles then started bogging out again. I got off the fwy and took the back roads. It didn't happen once all the way to work. When I got off work I tried the fwy, same thing. Had to get off. Once on the side roads, never had a problem. I was thinking fuel filter/pump but wouldn't I have the same problems even on a side road? It's still the same rpm?? I have 2 in line clear glass filters. One before the fuel pump and one before the carb. The one b4 the pump was gushing, the one before the carb wasn't? So makes me think pump. But once again, why wouldn't it happen on the side roads at the same rpm. Maybe the filter b4 the carb is getting too hot??

If you have any ideas or trouble shooting thoughts, please let me know. Also, I swapped diff covers last weekend..... Shouldn't mean a damn thing but you never know.

Thanks

Jake
 
:confused:

I would have thought the same as you about the filter, but not doing it while at same RPM on side roads is weird...

Is it just the same RPM or speed?

I had a problem on the freeway with bogging down out of no where after buying my jeep pulled over on the freeway for a sec, didn't even come to a complete stop, got speed back up and got to my exit...

Once home I checked my timing, and carb adjustments all over, checked the filter, and wiring all around, by the time I was done and went for a test drive it didn't do it again, so I have no idea what actually caused / fixed it, figured i might have something in my tank... but nothing was in the filter.

So... sorry I'm not more help man...

Hope you get it figured out... :cool:

:chug:
 
I would pull the spark plugs and put in new ones to start with. looking at the spark plugs can eliminate a good bit of issues. you can look on the internet and read about what problems are taking place by looking at the spark plugs.

the fact that one filter is gushing and the other isnt could be an indicator. somebody correct me if im wrong but there is a rubber membrane in the fuel pump that keeps the gas out of the oil. i wonder if the membrane has developed a leak and all the gas is going in the oil instead of into the carb because that would explain the engine starving and the weird stuff with the filters. if a bunch of gas goes in, an equal amount has to be coming out somewhere? you could change the oil and see if it has gas in it.
 
If you still have the mechanical pump they are ment to push fuel, not pull fuel. I would take off the filter before the pump and than see what kind of fuel pressure you have. The pump might be shot.
 
If you still have the mechanical pump they are ment to push fuel, not pull fuel. I would take off the filter before the pump and than see what kind of fuel pressure you have. The pump might be shot.
Agreed. Take the before the pump filter and replacce the after the pump filter with it. Problem sounds like a restricted filter. Check the pump while you are at it, or just replace it. There're pretty cheap.
 
Thanks everyone! Yeah, leaning to swapping out the pump no matter what. The question is, why would the pump fail on the fwy at 3200rmp but not a side street at same rpm? If I am going to swap pumps, should I look into an electronic fuel pump at this time? I have a strong feeling that the tank and lines are original so maybe a full overhaul is due. I have heard mixed reviews on the elec pump. What are your thoughts? I'm also thinking these glass clear filters are a waste of time? Maybe go back to a standard filter too. Don't ya just love jeeps!!

Thank you guys for the help, love this forum.

Jake
 
im replacing the pump in mine right now for the second time. the one i had went out then the new one i got i think was defected because it lasted about 2 months and then wouldn't produce any pressure. i got one with a good warranty this time. i too looked into electric pumps but i saw a bunch of mixed feelings about them so i think ill save that for another day. not to mention its easier to replace a $30 pump in 5 min and move on than it is installing and electric pump but if someone can explain a good reason to change to electric and can assure me its more reliable then ill do it tomorrow lol
 
Personally, I would go back to the original configuratiom on the fuel filter. They were designed that way for a reason. What ever that is. Also, a mechanical pump will deliver all the fuel you will need. If you want, you might install an electric pump for emergency use. But if you do, tie it into the ignition system so it shuts off with the key.
 
Thanks everyone! Yeah, leaning to swapping out the pump no matter what. The question is, why would the pump fail on the fwy at 3200rmp but not a side street at same rpm? If I am going to swap pumps, should I look into an electronic fuel pump at this time? I have a strong feeling that the tank and lines are original so maybe a full overhaul is due. I have heard mixed reviews on the elec pump. What are your thoughts? I'm also thinking these glass clear filters are a waste of time? Maybe go back to a standard filter too. Don't ya just love jeeps!!

Thank you guys for the help, love this forum.

Jake
even if the the motor is turning the same rpms, and you are using a diifferent gear at a different speed then the load on the engine is not the same. It will require more fuel at a higher speed in a higher gear turning the same rpm than a lower speed and lower gear.



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Thank you guys!! I will swap out the pump and put the original filter set up on. I am out of town on business but will let you guys know when I get back.

Thanks for all the help,

Jake
 
Thank you guys!! I will swap out the pump and put the original filter set up on. I am out of town on business but will let you guys know when I get back.

Thanks for all the help,

Jake

:popcorn:
 
Got the pump and filter swapped out. Runs great. The filter had been replaced about 6 months ago so fingers crossed it's not a tank issue. Thanks for all your help.

Till next time.......

Jake
 
Adding an electric pump is a good idea. I added one and it works great when the need be. Usually when starting the jeep after I haven't driven it
for a while. I haven't needed it when on the road but it's there if I need it.
 
Yea, my mech fuel pump went out on me, so i just decided to buy a blocking plate and put in an elec. fuel pump.. has run amazing ever since! i would suggest swapping it out for an electrical pump, and if you do... mount it right near the fuel tank.. works like a charm.. and use an air compressor to blow out the fuel lines before you hook it up.. mine were gunked up like crazy and it wasnt a pretty site.. but worth the extra $25-$30 bucks in the end to get the elec pump if ya ask me.
 

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