89maxaz

Well, I've had an erratic idle for several months. Dealer t-shot, said needs injectors and connectors on them. I replaced the injectors myself w/Bosch- had NO effect on the problem. I've had two other independents "diagnose" the prob. One didn't charge me anything because he had no idea. The other (last week), put it on a "Sun" scope, and said that the coil was oscillating, and that it could use plugs, wires, cap, rotor in addition to a new coil.

Well, now comes the problem.

I replaced everything he suggested, and started it up. Not only did the idle problem not improve, now that engine is making a LOUD metallic knocking sound. I put all the original parts back on (except the spark plugs), and it's still doing it. When I motor the starter with no plugs in it, it spins freely and makes no irregular noises. I checked the timing (noone has touched it) and it seems to be way out, but when adjusted, will still run. The Sun scope guy said something about suspecting the vacuum/mechanical/electronic advance, but he didn't think that was the idle problem. Well, now I think I've got an advance problem??? When idling a few times, it sits there knocking away, and then will slow down and shake a lot, then die. I'm thinking it's a coincidence as far as what I replaced having anything to do with it, but I can't figure out anything. I checked the computer codes, and it's all clear.

Any ideas anyone? It's an '89, with 87K on it, AT.

Thanks in advance for any help anyone may have.

nismo1989

check the timing with the plugs in. I think you have the plugs gapped wrong, but it's hard to tell without being there. Maybe that helps, maybe not. I would check the gap on the plugs...

89maxaz

I was told the gap should be .044, so that's what they're gapped to. Seemed kinda wide to me... Any idea what they should be???

Thanks.

nismo1989

I honestly don't remember, but I bet if you search the org archive you could find out. I do have it written down at home, but that won't do you any good until tomorrow. I'll check for you if you can't find it here, though...

try the SEARCH function first, though. I bet you'll find it there

mtcookson

iTrader: (2)

haynes says .044 inch is correct

89maxaz

Well, EVERYTHING is back on the car that was on it before the "tune-up"- plugs, wires, coil, cap/rotor, and still the hellacious knocking noise. I'm wondering now if the timing belt slipped a notch on one of the pulleys... I really think it's a misfiring noise, because the motor spins freely with no plugs in it- no strange noises at all.

Still perplexed/****ed...

mtcookson

iTrader: (2)

maybe try checking the compression

5spd92SE

Broken exhaust manifold stud syndrome?

nismo1989

That shouldn't sound like it's missing, though. I would also examine the plugs carefully. They are the tell-all when it comes to this stuff. Make sure above all that none of them are broken. Sometimes it's easy to overlook that...

RosenKen

Is there oil in it?

89maxaz

Yep. Has about 2K on the oil, and I already checked the level. The car's got 87K total on it, and has been in my family since '90. Never had a lick of engine trouble, and aside from little things like this idle problem, never any hint of major engine problems on the horizon. I think I'm going to have AAA come get it and take it back to the shop that looked at it last week. I'm done trying to troubleshoot it.

mtcookson

iTrader: (2)

the pcv can affect the idle, i'm not sure how bad but it can. it can also let oil into the intake if it's bad. you may check that. it's on the back of the manifold. there is a big black hose off of the top of ther rear valve cover that goes to a thing sticking out of the manifold, that is the pcv. they are really cheap.

89maxaz

Well, since it's got 87K on it, I decided to have the timing belt replaced, hoping that they'd find the old one had slipped, causing the knock. They're finished with the belt, and it's still knocking.

I wish I had a hand grenade handy...

89maxaz

Well, as I said before, when they got the timing cover off, they discovered the timing belt hadn't slipped. The knock was still there after they finished. Soooo, they poked around some more, and found a metal washer in one of the cylinders. Apparently I didn't see it down the plug holes, and when I pulled a plug it fell in. One of those tiny ones that apparently fell off of one of those vacuum hose clamps. I lucked out and they say it didn't do any damage aside from some dings in the top of the piston before it attached to the piston. Compression on that cylinder is still fine, and no oil smoke or anything is apparent. Those stinking recessed plug holes are a great idea, eh?

Well, guess I know now to examine down in there very carefully before changing the spark plugs! I posted my blunder here as a reminder to others... Maybe it'll save someone else from screwing the pooch like I did!

Thanks for the replies, guys.