I bought me a cj7 with an engine miss help!

[musclenut]

I bought a 1982 CJ7 AMC 258 i6 / 4.2l with 67000 original miles. It has a bad engine miss. The previous owner did a few things I'm not sure about. He put a poly tank on but had fuel problems afterward, he installed an inline fuel pump to fix this problem. It has a new weber carb. He adjusted the timing by ear???? I changed the plugs today. I think they were a little lean. Gold on one side white on the other. The closer to the firewall I went the golder the plugs got. Where should I start to track don't this miss? I also need a service manual. What is a good one? Thanks!

 

[motomom]

start simple check firing order and vacum leaks

 

[musclenut]

I forgot to mention he gave me a box of stuff he took off the motor. I think it's the emmsions junk. What is the hose about an inch that runs from the water pump to the intake manifold. It has a few pin holes in it?

 

[musclenut]

Something else I thought of yesterday after I shut it down it diesled/ detonated a few times after the key was off.

 

[musclenut]

The firing order is correct. The button is pointing to #1 cylinder. I need atiming light.

 

[musclenut]

I timed it to 8 degrees today the miss went away. But It backfires when I stomp it. What now?

 

[redmyk]

One thing I have done to remedy the low idle miss and added more power and fuel economy was the team rush big cap change.

 

[JR74CJ5]

I timed it to 8 degrees today the miss went away. But It backfires when I stomp it. What now?

It's a start

I would keep playing with the timing and carb adjustments until it runs right for you... Though running right and passing smog emissions are two separate goals in my experience... Not sure if you have a strict SMOG program (forgot to look at your location before replying ...)

Also, just some other out loud ideas:

Vac leak / vac advance issue?
Exhaust leak
Spark plug Gaps
Does the distributor have points on that year??? If so... Points

As far as a service manual, I dont know how good they came from the factory with your year, but in my experience with the 70's models, the Factory Serivice Manual beats the chilton / haynes / "parts-house" service books hands down...

I think Amazon, ebay, and another one I am having trouble remembering at this moment are good places to get original reprints etc...

I'll search in a min, see if I can't find you a link or two and post back...



~ JR

 

[JR74CJ5]

Not sure about this one... Robert Bently GJR2 - Jeep® CJ Rebuilder's Manual for 72-86 Jeep® CJ5, CJ6, CJ7 & CJ8 Scrambler - Quadratec

You can even get a further discounted price from them But I really like the books that are a little more narrowed down to my exact vehicle, instead of covering a spread of years / models...

Might try calling these guys... Jeep® Service Manuals - AUTO BOOKS

Jeep Owners Manual - 1982 CJ5 / CJ7 / CJ8 Scrambler | eBay

Rock Auto has a good one, but it's almost $80.00
Bishko If it was me... I would spring for this one if you plan on doing a lot of your own work on it...

You may have to go through their "online parts catalog"... You (if you've never been there) just click start (on web page) Jeep / Year (82) / CJ7 / Literature / and check out the results...

Here's the parts list. You can see the diff in cost is great, but I'm sure you'd be happier with the more expensive one

Hope I've helped you...



~ JR

 

[Jimbos76cj]

Have you replaced the cap rotor and wires? set the timing with the vaccuum advance line on or off? track down all your vacuum leaks? Im sure being from NJ you will have to get it inspected.. good luck with it.

 

[FL Jeep]

If you have a Webber carb you need a fuel pressure regulator. Webbers only need 3- 4 psi. If you have too much fuel pressure it will push through the jets and cause the problems you are having. Holley regulators work best.

 

[jdcaples]

I have a weber carb, and stock mechanical fuel pump. The previous owner did not have a pressure regulator. I bought one, but haven't made time to put it on.

I think I have all the vacuum leaks buttoned up.

I was able to choke the life out of the engine by stomping on it, usually with it spitting up or backfiring.

After a little liquid courage, I decided just experiment. Yes, I'm practically a red neck. "Hold my beer and watch this!"

I adjusted two screws on the weber carb; one on the passenger side, one on the driver side. They're the same size and at same elevation off the intake manifold.

The PO had them all the way in (they wouldn't turn to the right any further).

I backed each screw out 1/4 turn at a time and rev'd the engine on by actuating the linkage. Eventually, I got it to just rev and not hesitate, spit up.

I'll get around to the fuel pressure regulator after I work out the details of my fuel line re-route over the valve cover (or after I decide to just install an MC2100 with 1.8s and be done with it).

-Jon

 

[mtnwhlr]

I adjusted two screws on the weber carb; one on the passenger side, one on the driver side. They're the same size and at same elevation off the intake manifold.

The PO had them all the way in (they wouldn't turn to the right any further).

I backed each screw out 1/4 turn at a time and rev'd the engine on by actuating the linkage. Eventually, I got it to just rev and not hesitate, spit up.

-Jon

Those would be your idle mixture screws and they shoud be 1 1/4 to 1 1/2 turns out.

 

[jdcaples]

Those would be your idle mixture screws and they shoud be 1 1/4 to 1 1/2 turns out.

.. and 1.25 turns back out is where I landed.

Thank you, mtnwhlr!

-Jon

 

[FL Jeep]

Sounds like you figured it out. Liquid courage works every time.
FYI The stock fuel pump is somewhere between 6 and 7 psi. It will run smoother with the regulator. I just did mine because it ran rich and hade a bad mis.

 

[jdcaples]

Sounds like you figured it out. Liquid courage works every time.
FYI The stock fuel pump is somewhere between 6 and 7 psi. It will run smoother with the regulator. I just did mine because it ran rich and hade a bad mis.

Thanks.

My day job is in the way of re-routing my fuel lines and plumbing in a pressure regulator. I might start this coming weekend, but I might just fall over and sleep.

-Jon

 

[Goatboy4570]

with mine the miss would start at about 2200 rpm, it was drivable.... just.

i rebuilt the carb (2100) and replaced everything, did the big cap and e-coil too, still missed that left the duraspark ignition box, converted to GM HEI module on a old CPU heat sink and have run champ style ever since,
Went to crane MSD triggered by the hei for even more snort.

Look into a strait up msd box that uses your pickup coil and toss the duraspark,
bulletproof!

 

[Lumpy Grits]

IF the OP were to use the OEM type fuel filter and position the return port on the f'filter at 12 0'clock. You will have 3-4 psi at the carb.
LG

 

[Flex BT]

If it's running right, then great! But beware if he torqued down on those adjustment screws it can crush the holes the gas flows through, making them egg-shaped and can cause issues.