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  #1  
Old 02-07-2003, 01:25 AM
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Bigerik Bigerik is offline
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Default Weird, weird problem (long)

Hi
Have a weird problem with my 85 Fifth Ave. It has been almost completely rebuilt. Engine (Jasper 318), Edelbrock intake, rebuilt Q-Jet (which was a HUGE improvement over the Edelbrock 1406 I had), K&N filter, MSD 6A, Blaster coil, mopar perf distributor, new Accel wires, and recent Champion plugs, rebuilt 904 with no lockup, etc. Problem is, I can't seem to get it to run quite right. For instance, recently we were playing with the timing. At 11 degrees, throttle response and cold starts are good, but once you get over about 45 mph, she seems a little strained. If you push harder, she will cruise smoothly enough at 65 or 70, but never feels quite like a decent small block V8 should. Experimenting, we turned the timing down to 6 degrees. Although cold starting sucked, and gas mileage dropped, the engine felt much smoother and punchier. Kinda like the "pulled along on the end of a rubber band" feel you expect of a luxury car. Not quite how it should be, but much closer. We put the timing back up again, and she didn't run as well anymore. Fuel economy came back up again (got about 18 mpg on a highway trip at 65-70 mph, with 4 studded snows).
I just can't figure this out. I thought the rule of thumb, from mechanics 101 was that a car ran better with more advance, up to the point of detonation, and worse with less. Mine seems to be the opposite. What I am wondering about now is the exhaust side. All 3 cats are still in place. I am especially wondering about the pre-cats. This thing had lots of blow-by apparently before the engine was changed (about 25, 000 miles ago) and when I got it, it was runnning so rich that you wouldn't want to be within 10 feet of it with the engine running. Could a partially plugged cat cause odd behaviour like this?
Anyone have any thoughts?
Erik
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  #2  
Old 02-07-2003, 02:14 AM
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JVMopar JVMopar is offline
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Yes plugged cats will cause weird problems. But it usually causes a complete loss of power and possibly won't run at all. I wouldn't doubt that they are plugged.

I'd get rid of those champion plugs. They are junk. Lots of bad luck with them. I had one set that didn't have the resistors in them, completely missing. The car started ok but step on the gas and it'd die. I like the autolites. And if I have to say so (they work ok) AC Delco. eewwww
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  #3  
Old 02-07-2003, 03:01 AM
George G. Leverette George G. Leverette is offline
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Having the same type of problems getting a 360 to run right, kept trying to dial in a lot of advance, finally went to factory spec of 2 1\2 degrees before, still runs rough at idle but above 1500 RPM it runs great. Edelbrock intake HHMMMMM
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  #4  
Old 02-07-2003, 08:01 AM
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dkn1997 dkn1997 is offline
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I would go for the basics first. put a decent exhaust on it and some quality plugs. You might want to check your timing sprocket alignment. I had a truck once where I was one or two teeth off, ran smooth, but no power, had to advance the crap out of the timing to get to run decent. I corrected it and it was like a different truck.

also, dont' rule out parts mismatch. which edelbrock intake do you have? that reman engine may have a cam profile that is not compatable with your intake/carb/comp ratio. just things to look at if the simple stuff does not pan out. also, tell us the comp ratio, rear gear, cam specs. would help the truly knowledgable (not like me) guys on the board to help you out.
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Old 02-07-2003, 08:05 AM
mtrv8n mtrv8n is offline
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The problem is that you have a performance motor setup with smog motor attachments.

Your cats will clog quickly if they haven't already from running this motor. The cats were designed to run in a very lean exhaust, as well as a very hot one.

Since your motor doesn't meet emissions specs even with the cats, take em off.

Then, you have to check timing at total at 2500rpm, vacuum disconnected(or pinched). that should be at 35-36degrees for a small block.

Cold running will always be a problem with an aluminum intake, as it condenses fuel badly until warm.

check your fuel filter and fuel pump, float settings, make sure its getting there...and yes,
change those plugs.. I run Bosch +4 platinums

they will NOT foul, and cannot be gappped wrong.
Also, check the plug wires, make sure they're on tight..one loosy and the cylinder will fire erratically, but with a V-8 you may not really notice it except for lack of power.
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  #6  
Old 02-07-2003, 10:50 AM
littlecampbell littlecampbell is offline
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Whats the deal with different brands of plugs? I remember 25 years ago we all got our plugs from a place called Canadian Tire. (Champion)...They were cheaper by close to half than that of a dealership. Then I found out the reason they were cheaper...a very inferior grade of copper was used and who knows what else. Even today plugs are half the price at CT than at the dealership. I will never buy anything except maybe a 24 pack of shit tickets(sorry bout the language) from them. So if you come across plugs that are alot cheaper than elsewere, beware!
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  #7  
Old 02-07-2003, 10:56 PM
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Bigerik Bigerik is offline
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Default More details....

Hi again
More details, huh? Well, from what I understand, the engine is a stock Jasper rebuild of an 85 Chrysler 5th Ave 318, meaning the new for 85 heads, 9.0 to 1 compression, etc. Now, I do know that there is a little bit of play in the timing chain (so much for high quality parts that Jasper is supposed to use), and at some point, probably when the manifold was done (it is a new Edelbrock 318/360 Performer purchased from Summit), the distributor gear was installed incorrectly. It was off one spot on the cap, so we re-wired the ignition accordingly. It still has the stock TALL 2.27, 7 1/4 inch rear. The 904 was rebuilt, but without the lockup on the torque converter. I always figured it wouldn't breathe right, since all the mods had been done on the induction side and not on the exhaust side. When I asked the previous owner why he had not done anything, he said that he was told that you could not run a freer flowing exhaust with a 318?!?!?!?!?!?!?!?!?
What I want this car to be is a swift, smooth highway cruiser, with decent fuel economy and clean emissions.
Now everyone says use decent plugs. What do you consider to be decent?
Erik
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  #8  
Old 02-08-2003, 12:57 AM
Doug Wilson Doug Wilson is offline
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lc..... what the hell is a shit ticket? Somthinn only available in Cananadia?

About the problem - you are getting good advice. I'd first get rid of the cats, and at the same time, put a new timing chain and gears on it - expect to pay about $100USD for a premium double roller. That's aboot $10,000 Cananadian, eh?
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  #9  
Old 02-08-2003, 02:40 AM
littlecampbell littlecampbell is offline
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Nah...I think you must have them at your place too, Doug. When you have a seat in that room with all the plumbing there should be a roll hanging off the wall right next to you I missed ya
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