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Mark Sp 05-31-2000 04:05 AM

Well, I've got a freshly rebuilt 360 (same motor-taken out, completely rebuilt-reinstalled); rebuilt carb, new: radiator, battery, distributor, wires, plugs, alternator, starter, waterpump, hoses, belts... it's all new and the Wag' still runs like ****. It idle fine (RV cam). If I stomp it from a stop it bogs, hesitates then goes... slowly then pulls okay 'till the motor starts pinging. On the highway the motor stats pinging around 65 mph or if I acclerate from 60 or if I maintain 65 up a hill.

I am at a loss! The timing was set by several people - by the specs. I have spent several thousand dollars and the truck runs worse than before the rebuild.

Any ideas... any... thanks,

DLyons 05-31-2000 04:27 AM

If you get this "pinging" thing figured out, let me know. Mine has done that since I bought it. I've tried the timing,vac. advance, mechanical advance springs, and even a different distributer. I finally gave up for a while. It was giving me gray hair!!!

84 Grand Wagoneer
360 (401 someday)
Always Under Construction

Aaron 05-31-2000 05:05 AM

I would try EGR valve. That will make it fall flat from a start, and maybe make it ping?

Brown Bear 05-31-2000 06:03 AM

Check your timing, again, (I know, I know, I've been there, too). Then try your settings on your carb, I just rebuilt mine and it still doesn't run right for that reason. You can't always go with the settings on the factory stickers. Wear on the block and other things can cause you to have to adjust the timing to what may seem way out of whack. EGR vavle wouldn't be a bad idea, either along with other vacuum hoses.


1984 Grand Wagoneer
bone stock
P235/75 R15 Daytona Stag XT

Mark Sp 05-31-2000 06:53 AM

One more thing... I'm running 92/93 octane gas. And at $1.67/gal. I'd hoped for a cure... nope!

Should I retard the timing? I think that will help the pinging (detonating) but won't that make the acceleration even worse?

lrrh 05-31-2000 07:07 AM

I'd say check the timing. I think taking it back a little will remove the ping, but I don't know about the acceleration. Maybe try messing around with the mix screws. Hey, at least you don't have to pay $2.29 for the good gas.


trssho 05-31-2000 09:03 AM

I would recomend a few things. First I would start with the timing. Take you a wrench on a road test and keep backing off the timing till the ping goes away. now how does it drive? Drives ok? Then leave it. If not, I would run a 160 degree thermostat. That helped mine a lot. Another thing to look at which was previously mentioned is EGR. Chrysler has a tsb which does address this complaint and has a different EGR availabe.
The reason EGR helps with ping is that it cools the intake charge temp. So anything you can do to cool this charge the better. I actually don't run EGR on my Jeep, but it doesn't ping either.
One more thing that will help, is the fresh air intake snorkel. I tried running an open element and it made the pre detonation only worse. Remember, cooler is better.
Hope this information helps, and make sure that you reply back and let us all know.

1989 GW Tan w/106K miles
1989 GW Blk Cherry 69k miles

RUDY 05-31-2000 11:08 AM

i hope you get it fixed,and soon since my 88fsj goes into the machine shop in two weeks for a full rebuild...good luck!!!

Mark Sp 05-31-2000 10:21 PM

I'm going to try the timing. But first a (dumb?) question:
Should I turn the distributor clockwise or counter clockwise to eliminate the ping?

DLyons 06-01-2000 04:27 AM

Turn clockwise to retard the timing and counter clockwise to advance. I wish you luck! My 84 does the same. It has had the EGR and most vacuum hoses removed. I guess my first step should be returning this to original. Maybe then the pinging will stop.

84 Grand Wagoneer
360 (401 someday)
Always Under Construction

trssho 06-10-2000 03:44 PM

Don't keep us in suspence, did anything help fix your ping?

joe 06-11-2000 02:40 AM

Did you tune the rebuilt carb after you bolted it back on? Rebuilts need to be dialed in too. Sounds like you're running a bit lean. What color are the plugs? Should be a nice coffee w/cream color. Gray or white is too lean. Could also be a vacuum leak, bad EGR valve etc. If you removed all or part the smog/vac junk you may want to reinstall it. A plugged cat will also give you real low power but don't know if it'll cause pinging.

freddiep 06-11-2000 01:37 PM

With a little more info on your engine I might be able to help you. All the guys throwing timing at you are right on. But it is complicated to figure it out.
First tell me this, what is the compression ratio of your new engine? What is your cam specs? Did you degree the cam? What type of carb and manifold did you use? And what distributor do you have? Is it stock or modified? Do you know how many degrees total advance it is set for and how many degrees advance does the vacuum advance give you?
Stock settings won't work, that's for sure. You have to "find" your new engines timing.

Try this: Find TDC of #1 and make sure the "0" degrees mark is on the pointer. If it is, hook a vacuum gauge to the intake manifold. With the engine idling and the vacuum advance plugged, mark the gauge reading. Then slowly advance your timing until you find the max reading. Then slowly retard the timing until it decreases 1". Then advance again until it increases just slightly. This should be a good starting point.
Check with a timing light and see where it is. Then hook up the vacuum advance and see how many degrees extra it advances. It should be 12 to 16 more than initial. Then rev her up and record how many total degrees advance you have. Should be at least 38 total. Probably 42 is better with your engine.
Good luck. Both pre-ignition and hesitation are a result of improper timing. Carb setting won't help hesitation. When you hit the throttle, a carb uses an accelerator pump to squirt two big streams of gas directly into the throat. Provided the pump is working, the problem is timing.


Teach 06-12-2000 04:12 AM

You might try, I know this sounds elementry, a new dist. cap. The Beast ran ok, with some slight hesitations at acceleration after a rebuild, then ran(barely). Turns out the dist. cap went south and hadn't a crack visible in it.

'76 Wagoneer

Brazzy 06-26-2000 03:04 PM

There's is a tech article addressing the pinging problem, and the cure which I have used and attest to. I believe it is in the public chat or members chat/discussion, your problem sounds as though it is a multiple type of problem and after doing the " ping mod" you might check the dist. vacume advance for leaks.

Formerly abused 87 G.W. 162k stock

p.todd 07-04-2000 07:04 PM

Hey trssho,

I've been trying to solve my rough idling 360 (spark knock pre-ignition) for weeks. Even my mechanic couldn't help. Thank you soooooo much for mentioning the intake snorkle! What you wrote below makes total sense, but, I hadn't thought of it!

"The reason EGR helps with ping is that it cools the intake charge temp. So anything you can do to cool this charge the better. I actually don't run EGR on my Jeep, but it doesn't ping either.
One more thing that will help, is the fresh air intake snorkel. I tried running an open element and it made the pre detonation only worse. Remember, cooler is better.
Hope this information helps, and make sure that you reply back and let us all know."

I've had my GW for 14 weeks and been trying to solve the rough idle (only when engine is warm. It idled smooth when cold until it was fully warm). It is there in Park & Neutral and worse w/ the tranny in gear. The PO had a ripped up fresh air intake snorkle (ripped near the air cleaner) and I never thought......

My JEEP mechanic said "some of them just run rough". So I've been trouble shooting it on my own ever since. Timing adjusted, EGR-tested good, PVC valve replaced, PVC filter cleaned, spark plugs replaced, new cap and rotor, AMSOIL air filter, etc. The cap & rotor helped a little as did the less restricting AMSOIL air filter, but, 3 days ago I replaced the air intake snorkle (Mighty Flow #96077 2-5/16" X 3-11/16 RECT X28" LG W/90 degree twist. $10 @ PepBoys) and now it idles much, much better. I'd say I have 1/10th the pre-ignition I had -if not less.
Yes, cooler is better!


P. Todd
'91 GW 360/727/229/3.31s "The Swank Tank"

Mark Sp 07-04-2000 11:42 PM

No... no progress. Actually, it's running worse. Instead of trying the suggestions made here, I took the Jeep to a very reputable independent mechanic. I told him of the EGR, Vaccuum, ect... and other ideas mentioned here. The Jeep now stalls at lights and pings worse.

After four mechanics, I give up! I used to have an Acura with computer controlled varying valve timing that revved to 8000 rpm. I never had any problem having that tuned. Funny, a stock, new V8 with a 2 bbl would have seemed easy to make run well.
At the very least, I met four more nice people who are probably all very capable of changing oil, inspecting a car, replacing wiper blades or fixing a flat.
My next stop is NASA. These guys may have the advanced diagnostic computers to cure my terribly complicated engine problems... ooh wait, There's also those two scientists who just cracked the code of the 3.1 billion human genes! Those 2 guys just might be able to solve the pinging and stalling in my old Jeep!
Can ya' tell I'm a little disapointed the mechanical ability I've encountered in the last month?
I just dropped the Wagoneer at... (gulp)... the Jeep Dealership. I'll keep you posted... unless I have to sell my computer to pay the bill.

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