NEWS PARTS JEEP & 4x4 ATV & UTV

Rebuilt 258 not running right.

762 Views 14 Replies 2 Participants Last post by **DONOTDELETE**, Apr 3, 2000

G

Discussion Starter · Apr 1, 2000

I'm sorry to keep bothering everyone, but I just have so many damn problems. So, 1980 CJ7, New 258, Carter BBD without stepper (rebuilt also), "Team Rush" ignition. I went to break-in the motor this AM, but when I went to drive, As I give it more throttle it seems to bog down. Vaccum gauge shows 21 at no load idle, 16 stopped in drive. With light acceleration, seems to be OK, Vaccum at about 10-12, but when I push it a little harder, and by no means am I anywhere near full throttle, It seems to hesitate.

Since I got this thing in pieces and I dont have a good diagram, I dont have any of the emissions hooked up. only vaccum goes to PCV (Large port at pass side rear of carb) and Dist advance. I'm not exactly sure how this hooks up. But from the haynes and chilton, I have pass side middle of carb port to inside most (read closest to block) port of thermosensor at rear of block (Under manifolds). then middle port of thermosensor to dist. with delay in line. Finally, outermost port to manifold. Does this sound right??? It doesnt seem like there are any vaccum leaks at idle, and it idles smooth.

I also read the instructions with the vaccum tester that said that drops like this in vaccum could be caused by a exhaust restriction.

Any Ideas.
Bill

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LEVE

· #2 · Apr 1, 2000

1. Fill our your Profile, it helps...

2. Connect the gauge directly to the intake manifold vacuum. The engine must be at operating temperature. Start the engine, and run it at normal idle.
Normal Vacuum is 15-20 inches of mercury at idle. Cranking with the engine not starting reading should be about 1-4 in-Hg. A good engine should produce about 15-20 in-Hg at idle and about 19-21 in-Hg at 2500 rpm. Rev the engine up and down, note the gauge reading. During hard acceleration the vacuum shoud read about 0 in-Hg. During normal deceleration the reading should be around 21-27 in-Hg.

Good Jeepin'

Larry

G

Discussion Starter · #3 · Apr 1, 2000

You did replace your fuel filter, didn't you? Check your pressure, 4-6psi should be normal. Check your pump volume, 15 seconds of cranking should give you at least a cup of fuel into a soda bottle. Check your float level also. Bypass the timing vacuum controls, as a test, and connect the distributor up directly to the carb manifold vacuum port, the engine should speed up, (roughly 10 degrees more advance) to check the vacuum advance mechanism. Your initial timing should be around 9 before (for most years). Hope this helps, good luck!

G

Discussion Starter · #4 · Apr 1, 2000

OOOPPS. I signed up before I bought the jeep and forgot about the profile thing.

Larry, thanks for the info. I did that and all readings are what you said. I didnt realize that the the manifold vaccum would go to zero.

Well I ran it again and seems to just stumble right off idle to about 1200 RPM after that its OK. Any suggestions?

How about the dist. vaccum?? This time I just hooked it straight to the port off the pass side of the carb. Seems OK. Vac is around 4 at idle and jumps to 15-20 whith some throttle.

Yeah. replaced the fuel pump and filter. I haven't checked, but seems fine.
Bill

G

Discussion Starter · #5 · Apr 1, 2000

check the choke, it made be binding or need a slight adjustment...also, make sure your timing(distributor) is correct. i had the same problem recently..all it took was a slight choke-cover adjustment, and a slight counter-clockwise turn of the distributor...CHECK THESE!!

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G

Discussion Starter · #6 · Apr 1, 2000

Yeah, Choke is wide open. Dist set to 10 Degrees without vaccum, still not sure how to hook up the vaccum though.
Bill

G

Discussion Starter · #7 · Apr 1, 2000

vaccuum line goes from the distributer to a inlet/outlet/plug on the left hand side of the carb(looking into the engine bay)its right in the middle of the body

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G

Discussion Starter · #8 · Apr 2, 2000

Thanks, thats where I have it hooked right now. The manuals show something about a thermosensor and a direct manifold vaccuum connection, but they dont show my year. Ever heard of this.
Bill

G

Discussion Starter · #9 · Apr 2, 2000

bill
go to this site and is most valuable!
www.off-road.com/jeep/tech/258bbd/Major.htm

type in exactly and ye shall receive.
sorry i don't know how to attach files!
good luck
steve

G

Discussion Starter · #10 · Apr 2, 2000

It sounds like the distributer gear is off a tooth. Did you check the timing?

G

Discussion Starter · #11 · Apr 2, 2000

Ya know, I was thinking about that dist. off a tooth thing earlier, but the dist can rotate all over the place and timing is correct. Plus, it idles fine. I actually drove it again and seems better, maybe needed to be warmed up more or just worked in a little more, still does it, but not as bad.
So, if the timing is correct, can the dist. still be off????
Steve, thanks for that site. I thought i had been through most of the off-road. com stuff, but I had never seen that one. unfortunately (or fortunately) mine is an 80 and no computer and different vaccum components.
Bill

G

Discussion Starter · #12 · Apr 2, 2000

if you timing checks out with a timing light, and it still runs sluggish at acceleration...move the distributor by losening the bolt very slightly and turning the distributor by hand, either clockwise or counter clockwise until you actually hear the engine running better/revving faster. It made be a tooth off.

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G

Discussion Starter · #13 · Apr 2, 2000

Once I get this %$#@! tranny leak fixed, I will try that, though it still "feels" like a carb/fuel prob. Seems to accelerate ok once it gets to about 1400 RPM
Bill

171

· #14 · Apr 3, 2000

What you are talking about is a CTO =Coolent Temprature Overide and it switches the vacume sourcu from direct manifold vac. to ported vac. it is said to improve drivability during warm up and when sitting in traffic allowing the engine to speed up and cool better,regulated by coolent temperature.
the manifold source is at the back of the intake manifold it may have a plug in it if it was modified and it sounds as if it was stripped ....hope you don't have to pass emissions teste.
is your PCV valve hooked to your charcoal cannister if it has one ?
Ported vacume goes up as you accelerate manifold vacume goes down to an extent the only time you come close to " HG "is when you are really on it otherwise at any speed it will even off at about 10-15 HG=(inches of mercury)
I have a 1980 TSM here if I had a scanner I could hook you up with a diagram
check out your VIN number to see if it originally came with an automatic trans.

Learn to let go of what does not serve you ,but forces you to serve it

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G

Discussion Starter · #15 · Apr 3, 2000

Hey Unhuman, You think you could photocopy it and send it to me??? That would be a huge help. And yes I will have to pass smog when I move to Denver in about 3 weeks.
I didnt check the VIN, but it is a column shift with factory linkage and big brake pedal and I know the previous owner would not have gone to all that effort. Does it really matter though??
thanks
Bill

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