1979 cj7 amc 304 engine power issue - JeepForum.com
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post #1 of 10 Old 05-23-2020, 10:01 AM Thread Starter
CJ7MAVERICK
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1979 cj7 amc 304 engine power issue

Hello I have a 1979 cj7 with amc 304 fully stock except the intake manifold and carb which are both edelbrock. So I was driving back home an decided to give her a little rip just before i got to the last road to my house. started from a dead stop going through all 3 gears an I noticed that just before I switch from 2nd to 3rd that it fell on its face at the top end of the 2nd gear didnt really think anything of it until I took it back out the next day an realized that it was down on power. Usually from 1st to going to 2nd I can spin the tires a good bit but when I tried to spin the tires it wouldnt even try if I tried to. It seems to be down on power overall through out the whole rpm range from what I am use to. Also the same day I noticed this issue that the motor had I slight knock but quickly went away after a few seconds an didnt do it again. I check the fluids everything look good. What could have cause the issue?

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post #2 of 10 Old 05-23-2020, 02:40 PM
SC401
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Might sound crazy but check to make sure the distributor isnt loose and rotating making the timing off.
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post #3 of 10 Old 05-23-2020, 08:42 PM
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Check fuel filter. Was Jeep low on fuel? Might have sucked up some garbage from tank.

Fuel Filter oriented properly - with return outlet to fuel tank on top?

Fuel Pump?

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post #4 of 10 Old 05-24-2020, 06:44 PM Thread Starter
CJ7MAVERICK
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Just got done checking fuel filters and fuel lines every looks good. I just replaced the fuel pump about 200 miles ago. Also checked timing while I was checking to see if the distributor came loose the distributor was tight still. I did notice that timing was jumping around a little bit about 3 to 5 degrees. I didnt notice this the last time I timed it about 5 months ago. Is that normal for these motors?
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post #5 of 10 Old 05-24-2020, 06:49 PM Thread Starter
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Also fuel wasn't low about 50% to 75% full of gas in the gas tank. I also replaced the gas tank 2 months ago so there shouldn't be much if any trash in the gas tank.
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post #6 of 10 Old 05-24-2020, 08:29 PM
pedal2themetai
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HI timing moving around at idle is a sign of a bad timing chain and or gears.
good luck
tim
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post #7 of 10 Old 05-24-2020, 11:06 PM
LJameson
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I may be jumping to the worst case scenario here, but to me it sounds like you spun a bearing. It might be worth pulling the oil pan and inspecting them.

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post #8 of 10 Old 05-25-2020, 08:19 AM
SC401
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3- 5 degrees is a good bit. But you need to make sure that it is actually moving that much. Sometimes the timing like can cause it to look like its jumping around when it really isnt. I would find another light and see if it does the same thing.
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post #9 of 10 Old 05-25-2020, 02:49 PM
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Quote:
Originally Posted by CJ7MAVERICK View Post
Usually from 1st to going to 2nd I can spin the tires a good bit but when I tried to spin the tires it wouldnt even try if I tried to. It seems to be down on power overall through out the whole rpm range from what I am use to.
Check to make sure you didn't spin a rear hub. It'll drive with a spun hub, but it will be gutless.

I would rather have a tool I don't need, than need a tool I don't have.
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post #10 of 10 Old 05-25-2020, 09:56 PM
oldschool74cj5
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hello

if your timing is jumping the first thing and easiest thing to check is the rotor inside the cap. when i bought my 7 with a 258 the timing was bouncing a couple of degrees. when i pulled the cap i found it was a cheap one and the rotor would rock some on the distributor shaft. when i changed it to the team rush with a quality brand cap and rotor my timing became rock solid. not saying you need to go to the team rush but saying that make sure that you have quality name brand parts other then omix or crown crap. i also never buy parts store brands either. there quality isnt that great eithor. unfor even napa parts have gone down in quality from years ago. then if want to see how much slop is in the chain you can have the cap off and move the crank clockwise to the zero timing mark by hand. then slowly move the crank counterclockwise while watching the ditrib rotor. stop once the rotor starts to move. you should not have more then a couple degrees. on the crank reading at the timing marks on the cover. the object here is not to move the camshaft at all just the crank by the harmonic bolt.

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