Beaver's Metro: is it running too rough?

[MetroMPG]

Apology guys: I went to move your posts here & deleted them. I've re-posted your text below...

Originally Posted by Beaver

BTW, I will be driving a 96 Metro 2dr HB base model. No options, 3cyl 5spd. It runs kind of rough; I don't know if that's typical for a 3cyl or what. (any ideas?)

Relative to what? . 1) Did you happen to do a compression check, and 2) is it idling low? Problems with either will wreak havoc on idle smoothness in these cars. They're known to have middle cylinder probs due to EGR blockages and an overheated exhaust valve, leading to lower compression there.

[MetroMPG]

Beaver replied...

Originally Posted by Beaver

Yes, I did a quick compression check, and the cylinders were low (@150), but about equal. The check was done on a stone cold engine however, so I'd expect low readings. It's a high mileage engine at 158,000 miles. I think it may be idling too low, as you mentioned, but isn't the idle speed set by the ECU? If not I could pick it up a couple of hundred rpm's and that would go a long way toward smoothing it out.

I haven't ever had a 3 cyl before, so I have nothing to compare it to except 4,6 & 8's.

I have to take it out for a short drive in a little while, and I'll ty to note whether or not it feels rough under acceleration or at speed. Thanks again, and I'll put some cars in the "garage."

[MetroMPG]

metroschultz jumped in...

Originally Posted by metroschultz

I am not sure if your car is actually rough running ,or you are not used to the three cylinder vibration. Feels 'somewhat' (not exactly, but not far off) like a Harley when at very low idle.


Sir, you will need to do some diagnosis before making decisions about the roughness of your car. as MetroMPG said first is a compression test and then I would go to a cylinder bleed test. These engines are a little sensitive in the valve area. Very easy to get one with a burned valve. My experience shows they generally burn # 3 exhaust. ( I've rebuilt 11 heads so far; #1 on 2 heads, #2 on 1 head ,#3 on 8 heads.) I keep valves in stock now just for the metro owners my old boss refers to me. He thinks I'm crazy too.

If these are good then you need to check you ignition system (you might do this first)it is easier and doesn't require replacement of the plugs. I just replace them any time I have to pull them, They're cheap and a good investment.

A good shop manual is your best tool, and a friend at the local repair shop won't hurt either.

I have "Mitchell On Demand 5.5" myself. Wouldn't trade it for the world. (not true, every man has a price, mine is just realllly high.)

[Beaver]

Thanks for starting the new thread on this... Yes, I checked the compression because I had read about the EGR / burned exhaust valve on middle cylinder problem. The compression pressures were a little low, but even across the cyls. Your mention of a too-low idle speed rang a bell, though. It does idle lower than I'd like. It even has a little rattly-squeak when the engine is warmed up and at its lowest idle. I haven't looked to see if there is a mechanical way to pick up the idle a little, but I'm sure that would help, at least at idle speed. I will take it for a drive shortly and let you know if it is rough at speed.
But fortunately I don't think I'll need a new head (not on the car, at least). I'll get back on the computer when I return from Blockbuster and fill you in on the power-on situation.
Beaver

[metroschultz]

That squeak/rattle may be important. pull your oil cap off when the engine is making that noise and see if you can tell is the noise INSIDE the valve cover. Very important. I have run into 2 Metro's that lost oil to the cam, they both had a squeaky noise inside the valve cover. One lost his cam, it broke right between #2 & #3 cam bearings. Please check soon and give me(really you) peace of mind. S.

[Coyote X]

do you know what the mileage is like on the car if it has been getting worse then it is probably burning a valve and it needs them replaced. If the mileage is not really changing it could just have the ignition timing set wrong.

Put a scratch mark on the distributor mount then loosen it and advance the timing a bit and see if it smooths out. If it doesn't then put it back to where it was. If the engine smooths out you should set the timing like it says under the hood to do it. I would probably advance it a degree or two past what it says though.

I would check to make sure the cam is getting oil first thing though.

[Beaver]

Hi Metroschultz.
The squeaky rattle seems to be coming from under the motor somewhere, but not from inside the valve cover. At first glance it appears that the oiling is okay under the valve cover; a cam lobe directly under the oil cap is flipping oil out the opening with the cap off. Of course that doesn't mean that the cam bearings are getting oil through the pressurized oiling system, but like I said, it doesn't seem like the squeak is coming from under the valve cover. Thanks for the heads-up, though, and I'll keep an ear out for that problem.
Beaver

[Beaver]

Just got back from Blockbuster, and it seems like the motor is smoother at speed although it is incredibly gutless... yes, I know, compared to what? Coyote X, I did check the ignition timing when I checked the compression. It was about where the hood sticker says it should be, but I'll try kicking it up a couple of degrees as you suggested, if it ever stops raining here. For my money it never hurts to kick in a few extra degrees advance as long as you don't get a ping.
I don't know about the fuel mileage yet; I haven't even put any gas in the car yet since it became mine. So you think that with 158000 on the engine it might be due for a valve job, or that it may be burning an exhaust valve? The compression test doesn't show it yet, and the exhaust pulse at the tailpipe feels smooth. But it sounds a little bit like other engines I've heard with a burnt exhaust valve, so I am inclined to think a valve job may be right around the corner. Based on what I've seen on eBay heads for this engine are pretty cheap.
So should I keep driving the thing, hoping it doesn't get worse? Will any other damage be done if it is burning a valve and I keep driving it until the symptoms are obvious?
What say y'all?
Beaver

[Coyote X]

I drove mine for months with a valve going bad. It won't hurt anything really other than your mileage and power. Normally the valve just burns and it doesn't hurt the seat or anything else on the head. So I would get on teamswift and get a set of stainless exhaust valves if you plan on keeping the car a long time when it goes bad. Just pull the head and seat the valve like any other valve and reinstall it.

Since it is gutless check the cam timing it might have jumped a notch. If the timing is set properly and the distributor isn't more or less centered in the adjustment holes it might be off a notch. The cam belts are cheap and pretty easy to change on these things. If you didn't jumper that one wire in the underhood diagnostic plug like it says on the sticker then you have the timing way off though

With that compression on a cold engine then there is really nothing wrong mechanically with the engine I say and it is probably just something out of adjustment or needing a good tune up. Off the top of my head here is the stuff I can think of to check

Distributor cap and rotor for corroded contacts
fuel filter
plugs and wires
ground strap
ignition timing
cam timing

I am sure I am missing stuff so hopefully someone will help fill in the list.

[Beaver]

I'll bet you're on to something on that jumper wire -- timing way off -- cam belt jumped a tooth thing. I asked the guy I bought if from if the timing belt had ever been changed, and he said he didn't know. I think that means "no." The car had been in his family since new, so he probably should have known if it had been changed. I plan to change it to be sure anyway, so I'll get right on that.

And no, I didn't jumper that diagnostic plug. I didn't know what plug it was referring to. Since, I have picked up a Haynes manual for it. New timing belt, first of next week!

Thanks again; you guys are great!

Beaver