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Alright so update is that is was mainly the timing... i say mainly because after adjusting it some i took it out for a test and it did so much better but as it heats up and i keep driving it even jus a few miles it acts up again and bogs out and sputters like its not getting enough fuel, im out of ideas
How many miles on the engine? I had a similar problem on a 78 F350 with 150k + on it. Turned out the distributor was worn out, causing what you described.
This is starting to sound like vapor lock. Make sure your fuel line isn't too close to your exhaust manifold. Also note where it runs from the pump to the carb. You could be heating up your fuel enough to cause this problem.
I do think the gas line is too close to the exhaust actually... i will try to post a picture or two tomorrow... if thats the case what could be done? and i think its stock, im not sure but wouldnt that have always been a problem?
I do think the gas line is too close to the exhaust actually... i will try to post a picture or two tomorrow... if thats the case what could be done? and i think its stock, im not sure but wouldnt that have always been a problem?
1979 Jeep CJ5 with 304 V8, T18 Transmission, Dana 20 Transfer case with TeraLow 3:1 gears, 4.88 axle gears, Detroit Locker up front and Ox Locker in back with 1 piece axle shafts, 36" SuperSwamper SX Tires, Shackle reversal, MileMarker Hydraulic winch, MSD 6A ignition.
This is starting to sound like vapour lock. Make sure your fuel line isn't too close to your exhaust manifold. Also note where it runs from the pump to the carb. You could be heating up your fuel enough to cause this problem.
I have had vapor lock on my '79 CJ5 . I tried every trick in the book. I replaced the fuel pump. I wrapped heat insulation around the exhaust and around the fuel line. I vented the hood. A mechanic told me there is no cure for vapor lock except for installing fuel injection. He said that's because the biggest source of heat is the fact that the carb is mounted on top of the intake manifold and engine. I didn't buy it.
I finally got rid of vapor lock by mounting an electric fuel pump next to the gas tank. That fixed it for good. When my engine gets warm and I pull into the gas station. I open the hood and I see vapor bubbling into my clear fuel filter. That tells me I still have vapor but it never causes my engine to stall out. That's because, with the fuel pump back by the tank it keeps pushing the fuel to the engine. It may turn to vapor but the pump just pushes the fuel and vapor to the carb.
Back when I had vapor with my engine mounted pump it stopped pumping because it couldn't suck the vapor and gas from the tank.
The reason for vapor lock can drive you crazy. Here is two I have had in my years. I had a '68 Charger with a big block that I fought this problem with for many years it ended up being the rod that pushes the fuel pump off the cam had wore down so the fuel pump wasn't pumping as it should. Next I had a Buick Riv that would vapor lock every time it got hot out and replacing the fuel pump fixed it. And the vent tube for the gas tank not working like it should can cause it. So it's not always about your fuel line getting hot. I hope this helps in some way good luck.
1979 Jeep CJ5 with 304 V8, T18 Transmission, Dana 20 Transfer case with TeraLow 3:1 gears, 4.88 axle gears, Detroit Locker up front and Ox Locker in back with 1 piece axle shafts, 36" SuperSwamper SX Tires, Shackle reversal, MileMarker Hydraulic winch, MSD 6A ignition.
mtnwhlr has a good point. You could try replacing the fuel pump. I'm sure the jeep ran great when it was new.
When I had vapor lock I tried to replace the pump but that didn't help.
Actually I was very reluctant to install an electrical fuel pump. Mechanical pumps are so much simpler. If you install an electrical fuel pump and you have fuel problems there are so many factors that could cause problems: bad pump, bad wire, bad ground, bad fuse. Anyone that has a CJ or any other older vehicle knows electrical problems are common.
On the other hand don't be surprised if a new mechanical pump doesn't fix it.
I do think the gas line is too close to the exhaust actually... i will try to post a picture or two tomorrow... if thats the case what could be done? and i think its stock, im not sure but wouldnt that have always been a problem?
Age and heat can weaken hoses and cause them to collapse. You'll see that with a fuel pressure and volume test. What you want to do is run this test while you are driving so you can see the pressure while the problem occurs.
The reason I dont believe it's the pump is a mechanical fuel pump is not susceptible to heat. They either work all the time or they dont...but a weak pump will affect power as extra gas is needed for the carb...at least that's been my experience. But this problem seems to only appear after the jeep is warmed up.
A collapsed line is unlikely as it is a hardline all the way up to the engine bay and almost to the pump. And generally it is a hardline from the pump to the filter which should be just before the carb.
Im not trying to be a know-it-all.....just trying to throw my thoughts into it as well to try and eliminate one thing at a time.
Along with a fuel delivery problem....Im not so sure we still dont have a problem with the carb. carbs are finicky to heat if something is wrong with it or misadjusted.
Alright so i took the jeep over to a mechanic who specializes in carbs and his diagnosis was the heads... he said a valve could be broken oh and also the carb lol... still not completely sure till i take it apart and assess the damage... thank you all for your time and suggestions... i will keep everyone posted
Alright so i took the jeep over to a mechanic who specializes in carbs and his diagnosis was the heads... he said a valve could be broken oh and also the carb lol... still not completely sure till i take it apart and assess the damage... thank you all for your time and suggestions... i will keep everyone posted
I'm a little skeptical of that...
Cracked head, would make more sense, but I doubt even that. If a valve is "broken" its BROKEN.... You can bend a valve and it wont seat right. Burn a valve and it wont seal. Broken valve and it would probably have dropped into the cylinder and you would have KNOWN IT WHEN IT HAPPENED.
Its hard for anyone to diagnose this via the internet, but it sounds fishy to me.
Recently someone posted a problem with a broken harmonic balancer. The mechanic told him the engine needed to be rebuilt!!!
I'm a little skeptical of that...
Cracked head, would make more sense, but I doubt even that. If a valve is "broken" its BROKEN.... You can bend a valve and it wont seat right. Burn a valve and it wont seal. Broken valve and it would probably have dropped into the cylinder and you would have KNOWN IT WHEN IT HAPPENED.
Its hard for anyone to diagnose this via the internet, but it sounds fishy to me.
Recently someone posted a problem with a broken harmonic balancer. The mechanic told him the engine needed to be rebuilt!!!
All good points. I broke a valve face on the original 4cyl and it sounded like the world was coming to an end. And it sounded this way all the time, whether cold or warmed up.
I know it might sound like a bit of a headache....
But...... IF you've ruled out timing.....pop the valve covers off..
watch it idle...
watch for all of the rocker arms to be moving the same amount as each other..
I dont want to be mr doom and gloom.... but as I wrote before it is possible that your cam is just worn out...
I'm writing this again, because it is important to rule this out. Especially if you cant seem to find another reason for the power issue. Sorry for the already-dead horse I'm beating again!
My 360 ran fine in december of 2010.... tranny went out... I ran the heck out of it that night...It took me a year to get off my butt and put some time into my Jeep... When I restarted it in december 2011, there was a ticking and total loss of power when I started to put my foot in it. I put a new ignition system in it because i thought it was a timing problem. I was considering putting a new carb on it as well because I thought it might be a carb issue.
When i finally decided to pop the valve covers, I noticed there were 3 rockers that were noticeably moving far less than the other 13. After determining that it wasnt a bent pushrod, or collapsed lifter, I pulled out the camshaft, finding 5 cam lobes that were nearly completely round.
Just prior to discovering this, I had bought another 360 from a guy who had already disassembled it. My first thought was I could potentially use the camshaft from that engine to swap temporarily into mine until I could rebuild the newish 360. When I dug it out of the pile of parts on the shelf, guess what??? It had 4 lobes nearly worn out as well.
Since the government (its ok, we're here to help) took additives out of motor oil, worn out camshafts with flat tappet lifters are becoming more and more common. Luckily I had a AMC 304 sitting on a stand with about 30K on its cam... I took it out and swapped it into my 360 and its all good now...
But for some reason your mechanic said it could be a broken valve... I wonder if he felt it wasnt hitting on all cylinders and drew that quick conclusion.
Since you have basically ruled out timing, take the time to pop the covers off and watch the rockers move... the only thing you will have wasted is a set of valve cover gaskets...
As I wrote before, this may NOT be what is going on, but it is becoming more and more common to see this type of problem...
good luck....keep posting what you find.
BTW: anyone reading this should begin using additives in their oil to prevent this type of issue.
Just had a very similar problem on an 86 CJ7 with the AMC 258 i6 / 4.2l . Ended up being gelled fuel in the carb even though I had rebuilt it just a few weeks earlier.
Couple of things I did that might help you out - all recommendations from the forum:
1. Run a separate fuel line from a gas can with fresh gas to the input of the fuel pump. Run a tube from the port above the accelerator pump to the canister to vent the carb. This will eliminate most fuel system issues except for the carb.
2. Check the pressure with a pressure gauge on the line going into the carb. Do this with the original fuel line connected to the pump and with the gas can setup. Pressure should be 5 - 7 PSI. Mine was 6 1/2 - 7, consistently with either setup.
3. Check vacuum at the distributor (provided you're using vacuum advance). If you have the motor craft dizzy vacuum should start near zero and then climb to 15 - 20 inches as the motor increases rpm. Advance should be connected to the port underneath the choke.
4. Check fuel mixture on the carb. Set screws fully in and back off 3 full turns to start. Set idle at 680. Connect vacuum gauge to PCV port with a "T". Turn mixture screws in 1/4 at a time and watch gauge. Wait a few minutes between turns. Once you notice the vacuum drop, screw back out 1/8 to 1/4 to get highest setting.
And a question. Once you stop driving, does it continue to stumble/miss or does it go away once you let off the gas?
Even after I did all of this it still ended up being gelled gas in the carb bowl. But hopefully some to these will help isolate the problem more.
