Calgary Jeep Association
4x4 Related Groups => Tech Talk => Topic started by: blaker on March 17, 2006, 11:20:00 PM
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I've been having problems the past couple days, and I'm pretty sure it's with the fuel system. So to start, it's a 79 CJ7, 360 AMC, TH400 auto, 4 barrel edelbrock and intake. After driving a ways, the truck seems to sort of sputter. If I'm steady on the throttle, it cuts in and out, almost like I'm out of gas. It's not constant though, and sometimes it'll actually stall. It usually starts right up, but then again, a few times it won't start. It'll fire up, but won't actually run.
So I figured it was a clogged fuel filter, so I put on a new one, also sprayed some carb cleaner in the carb as well. It seemed to work alright, then starting cutting in and out again, and eventually stalled, and wouldn't start. If I let it sit for a while, it'll fire up again, but the same thing keeps happening. Any ideas what could be happening? Is it possible there's a bunch of crap in my gas tank? Seems unlikely I'd have another clogged fuel filter after only about 30kms...
I'd love to hear any feedback, also am looking for a good mechanic who's got experience with the older rigs.
Thanks!
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2 things spring to mind .. faulty fuel pump, or vacuum in the gas tank (lack of tank vent).
Are you getting fuel pressure to the carb ?
If you remove the gas cap does it hiss (suck not blow .. if it sucks you won't get a blast of fumes) ?
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Thanks! I don't think it's vacuum from the tank, I've tried popping the cap off, and everything seems to be normal there. I've got a truck I can swap parts off, I'm going to try swapping the fuel pump and we'll see what happens.
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So I ended up putting in a brand new fuel pump, and it was working really good, lots of fuel going to the carb. I haven't put too many miles on since, but last night, it started doing the same thing again. I know it's not a vaccum problem. When I had everything apart, I blew out the one line, also have a new filter on as well.
So after driving a ways, with my foot steady on the throttle, it hiccups and stalls out for a second. Sometimes it'll actually quit as well. I made it home last night and it quit right in front of my house. Any other suggestions?
Thanks!
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Why do you think its fuel? The reason I ask is I once had an older motorcycle that would die all the time... acted as if it was starved for fuel. I'd coast to the side of the road and a few mins later it would fire right up.... I was completely convinced it was starved for fuel. Then when I went to pull the carbs to rebuild them... I pulled the side cover to disconnect the batter before beginning work (safety first ;) ) and low and behold one of the battery cables was barely holding on. Tightened it up and never had another problem. While I'm sure this isn't your problem I just wouldn't want you to rule out some intermittent electrical problem.
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was it wet out? I used to have a dodge colt that would sputter and cough when it was wet out due to bad plugwires. Also have you thought about changing your distributor? I think one from an older ford f150 will slip right in? of course I could be wrong.
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was it wet out? I used to have a dodge colt that would sputter and cough when it was wet out due to bad plugwires. Also have you thought about changing your distributor? I think one from an older ford f150 will slip right in? of course I could be wrong.
Actually, it would do that just for being a dodge :wink:
They have been known to stall if you walk past them with an icecream cone. :D :D
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Thanks for the help! It very well could be electrical, I know the battery cables are alright because I disconnected and reconnected them all with the new fuel pump. I've had some wierd stuff happen, like my CD player completely died on me, and my horn no longer works, but I haven't had time to dive into the electrical yet.
This doesn't just happen when it's wet outside, just after I've been driving for a while. I put on a new cap and rotor last year (MSD), but I'll take a look and see how they look for general wear and tear tonight.
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have you actually thought of tuning the carb?? my randpa's got an edelbrock on his truck and sometimes the springs they use back the throttle and/or mixture screws out just enough to really lean or richen it out.... good luck, and you mind as well get a new harness now, or just a shop manual.
remember, hammers don't always fix things as much as we'd like them too.
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The carb was re-jetted last year, but could probably use a tune up. I think the problem was in my distributor, after checking out the cap, two of the spots were worn right in... After swapping distributors it seems to be working fine again, although it's in for some other general repairs. It's a motomaster distributor, but has an MSD Cap and Rotor fitted on, is it a fairly generic distributor? Any other trucks use the same one, so I can keep an eye out in the junkyards?
Thanks!