Cant figure it out!

Cant figure it out!

KSaleh

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Hi

I am new to the forum but i have a problem i just cant solve... I have a 1980 CJ5 pretty much all stock... it is a v8 4spd. my problem with it right now is when putting it in gear and trying to drive it goes but it starves for gas and doesnt rev up... Ive cleaned up the carb and put in a new fuel filter...when it idles it sounds great and revs up fine but when in gear it sounds like its misfiring and doesnt speed up when i accelerate... Any ideas or suggestions would greatly be appreciated...

Thank You
 
Maybe fuel pump.
To verify remove the fuel line at the carb. Hold the fuel line where it wont spill where you don't want it. Maybe over a can. Crank the engine and make sure fuel comes smoothly out the fuel line.
 
Catalytic converter
 
x2 on the cat. if starts fine and revs ok then taking the fuel line off and cranking is not going to show you anything. You need to start it and let it warm up some and check the temp of the pipe on both sides of the cat. if it's real hot before and not very after then your cat is plugged.
 
Did it do this when you bought it?

All of the above are possibilities but let’s talk about the fuel filter; it should have one line in and two out. The top one goes back to the tank through the return line, the other to the carb. Without the return line you will have problems. Also it could be a vacuum leak. Check the hoses and the base of the carb. Could also be a timing issue. If it does it only on initial startup or after sitting for a few hours then the choke comes to mind.
 
Fuel supply line from tank may have a rust/pin hole and you could be sucking air.
 
Alright so i checked it out and i dont have a cat on it, i had already a new fuel pump... installed it today same thing.... my fuel filter is only 1 in and 1 out so i will definately get that replaced... so one line goes in and 2 out? where does the second return line go one the carb?
 
Not all filters are dual exit...I ran a single exit for many years on a few different motors. The carb will have an overflow line that goes back to the tank. Many times these are capped in the event of a dual exit filter being used. Webers and Edelbrocks are good examples of this
 
Two other things to look at:

Damaged or misadjusted float.
And the other thing is bad power valve. The seals tear very easily on these.
 
Alright so i checked it out and i dont have a cat on it, i had already a new fuel pump... installed it today same thing.... my fuel filter is only 1 in and 1 out so i will definately get that replaced... so one line goes in and 2 out? where does the second return line go one the carb?

Most likely the cats fell off years ago (he he). The return fuel line does just that, returns extra fuel to the tank that the carburetor is unable to accept. Regardless if you have a stock or replacement carburetor on your 304 the fuel return line needs to be functional so you may as well get that work done now as it will cause problems. The return line may be capped off and still be in the engine bay; you’ll need to look around. If not there follow the main line back to the tank.
 
X2 power valve need that extra shot of fuel.
 
Since im running one in and one out fuel filter. If i replace the filter with one in two out where does the second out line go? Would not having the right filter cause it to run like this?

Also on the top of the float area is a line where does that go? Heres a pic next to the ID tag.

Also adjusted the float dry to 1/2".
 
Since im running one in and one out fuel filter. If i replace the filter with one in two out where does the second out line go? Would not having the right filter cause it to run like this?

Also on the top of the float area is a line where does that go? Heres a pic next to the ID tag.

Also adjusted the float dry to 1/2".

The second line is fuel return to the tank. The nipple on top or the carb is the bowl vent. It should go to the charcoal canister.
 
Did it do this when you bought it?

All of the above are possibilities but let’s talk about the fuel filter; it should have one line in and two out. The top one goes back to the tank through the return line, the other to the carb. Without the return line you will have problems. Also it could be a vacuum leak. Check the hoses and the base of the carb. Could also be a timing issue. If it does it only on initial startup or after sitting for a few hours then the choke comes to mind.


I agree with this.... sounds like a timing issue... Putting it in gear puts a load on the engine, and really shows a mistimed engine...

I would have said fuel pump, or possibly the sock in the tank IF it stumbled while NOT in gear with the rpms up....
 
just re-read your post...
I'd bet the farm on timing... (but I dont actually own a farm, so I guess I'm just strongly suggesting that)
 
We've got guesses all over the place. In your original post you implied you thought it was a fuel delivery problem. Some thought it was a clogged exhaust. Jeepboy thinks it might be an ignition problem. He may be right but we really need to narrow this down with some troubleshooting.
Let's make sure you are getting fuel. Disconnect the fuel line at the carb. Do you get a steady stream of fuel when the engine cranks over?
To check the spark use a spark tester.
ignition_spark_tester.jpg
 
Alright well thank you all for you help and suggestions... so today i replaced the power valve with a new one...again same thing... I checked the fuel line going to the carburetor and its pumping fine... i have already messed with the timing quite a bit... but tomorrow i will focus my attention on it... i jus don't know what else it could be... maybe replacing with a brand new carb?
 
Id start by checking your fuel pressure and volume. You can get a cheap gauge at vatozone and search online for the correct volume. PSI should be around 5.5-6.5. You'll need to get x amount of fuel in a given time.

Most low pressure fuel systems (carburetors) dont require a return line.

The spark tester that Busa showed is a decent way to check the amount of power your coil is putting out. We know you have spark but its possible that its weak.
 
Hi

I am new to the forum but i have a problem i just cant solve... I have a 1980 CJ5 pretty much all stock... it is a v8 4spd. my problem with it right now is when putting it in gear and trying to drive it goes but it starves for gas and doesnt rev up... Ive cleaned up the carb and put in a new fuel filter...when it idles it sounds great and revs up fine but when in gear it sounds like its misfiring and doesnt speed up when i accelerate... Any ideas or suggestions would greatly be appreciated...

Thank You

I initially thought "timing" as I said above...

This might be a longshot, but I'll throw it out there anyway...


I have to ask this: Does it seem to knock loudly, or backfire through the carb?

I have an AMC 360. Last month I thought i had a timing issue, and to my amazement, I had 5 cam lobes nearly worn completely to a round surface. As a result the lifters on 5 cylinders werent moving and I had no power as well. I didnt discover this until I popped off a valve cover and watched the rockers NOT moving like they should.

It idled perfectly, but as soon as I put it in gear, and gave it about 30% throttle, it began to act up and had no power. Then at about 60% throttle, it began backfiring. (sounded like a rod was about to shoot through the oil pan!!)... Obviously this is a worst case scenario... Its just a thought.

I hope its just a timing issue, or carb related.

good luck and let us know what it ended up being...
brian
 

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