The Shop > Project Cars
1986 AMC Eagle Wagon cheap rehab
zeebo76:
Hi, I tried to post just a little while ago and got an error, so I’m trying again.
I’ve got an ‘86 eagle that’s pinging/detonating on normal gas. Im running 89 octane at the moment and it works BETTER, but it’s still not gone. I think something’s wrong, but I’m stumped. When it starts to ping, it’s quiet at light throttle, loud at medium throttle, and goes away entirely at WOT.
Head is freshly machined (replaced head gasket a while back), I’ve tried richening fuel mix on the carb, retarding the timing, and it’s not running hot. What could be the issue?
EDIT: I realized that I should give more info. It’s the 258 I6, has a rebuilt Carter carb, vacuum wiring was totally screwed up when I got it from the PO and I think it’s mostly fixed now. I’ve replaced the ignition control module on the passenger side fender well. I don’t know when the timing belt/chain was last replaced.
Though the car doesn’t seem to run hot, it DOES change in temp very quickly depending on conditions. I can move from cool shade to warm sunlight and the temp will rise.
AMC of Houston:
First, I'd set the carb and timing per the AMC IS-12e service letter and see if that makes any difference. Next I'd be checking out the knock sensor system per the TSM (sensor, wiring, etc.).
Note my '85 with 200K miles sounds like its pinging, but its really the timing chain rattling on the timing cover! Its the original chain - I really need to replace it.......
zeebo76:
I THINK I happened upon the answer last night... Was doing a little forum searching and read that a machined head without a thicker head gasket to match will increase compression, and can therefore cause pinging on regular gas. Well... The PO drove this eagle on a bad head gasket and overheated it very badly, warping the head. The machine shop managed to machine it straight for me and it runs fine with exception of the pinging... Which is probably a result of them taking so much material off of the mating surface. Thoughts?
EDIT: Thanks for the input, Houston. This eagle only has 80k original miles, so I doubt it would be the timing chain by this age - but never say never, I suppose.
As for timing and carb, I’ll try to fiddle with those some. I should really buy a TSM...
zeebo76:
Just bought a vacuum gauge. Off the manifold I’m making 20 in. Hg at idle speed...
Mitch:
--- Quote from: AMC of Houston on September 05, 2019, 12:01:12 PM ---First, I'd set the carb and timing per the AMC IS-12e service letter and see if that makes any difference.
--- End quote ---
Here is IS-12E...
http://amceaglesden.com/guide/November_1987_-_IS_12E_-_Idle_Speed
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