Last post on Nov 27, 2013 at 12:52 PM
You are in the Chevrolet Metro/Geo Metro
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Geo Metro, Chevrolet Metro, Hatchback
#1413 of 1867 First Chevy Metro
Oct 10, 2008 (11:07 am)
God Bless you guys,
Hi, I am now in the family of Metro owners. But not yet happy as I am believing I will be. Bought 1998 Chevy Metro 3 cyl 5 sp w/ 83K miles. Zippy little thing and in nice shape by not happy with gas mileage. Only getting 32 mpg city. Shouldn't I be looking more toward 50 mpg in town or is that all hype? What is best way to improve mileage?
What about adding computer chip to increase HP and gas mileage good or bad idea?
Oct 10, 2008 (11:28 am)
Change for new:
Oil, brake fluids, distributor cap, plugs and wires.
Check: EGR valve, air filter,fuel filter, tire pressure and wheel bearings.Don't drive with your foot slightly on the brake pedal, check to see that the brakes are clear also. Every little bit helps.
It is NOT a sport car, don't drive it as if it was one. Usually the driver behind the steering wheel needs some adjustment.
keep it clean, keep only the essentials in the trunk. If you are a travelling salesman with brick samples...I suggest that you change jobs.
Have fun with your metropolitan car.
#1415 of 1867 Re: First Chevy Metro [ayejay]
Oct 10, 2008 (4:22 pm)
50 mpg in town is hype, that is best case on the highway. the best I have managed to get out of my 98 is 41 on the freeway, and I have completely rebuilt the motor and drive train.new clutch drive axels everything. the best thing for you to do is check your compression it should be over 180lbs per cylinder. check your vacuum it should be a steady 20-21 lbs. check your egr valve, when these valves malfunction it burns exhaust valves which causes poor fuel economy. low compression or low or fluctuating vacuum could mean you need new rings or you have a burnt valve. if you havent changed your oil yet change it and make sure you use 5w-30 only, use about 2.5 to 2.75 quarts of oil and fill the rest to the fill line with slick 50 it can help boost compression.if milage improves put new rings in it
#1416 of 1867 Re: First Chevy Metro [ayejay]
Oct 10, 2008 (4:23 pm)
Welcome to the club!!!
Gas mileage will vary greatly, depending on the ambient air temperature, the length of your trips, the mechanical condition and state of tune of the engine, and the restraint with which you drive. That said; my experience has been that 32 mpg city is at the very low end of the expected range. But I would not expect your car to get 50 mpg in city driving under any condition; particularly when using today's fuel blends. My 1990 5 speed got 48 mpg in city when tuned perfectly, and got 55 mpg highway. The newer Metros will not do quite that well. If your city driving consists of trips that are mostly shorter than 5 miles; you will be lucky to ever get over 40 mpg. And in the winter, it will probably be even worse.
I will give you one piece of advice; which is distilled from 16 years of professional experience with these cars. ANY modifications which increase HP will REDUCE your gas mileage. You can have mileage or power; but not both at the same time.
The so called "computer chips" being sold for Metros are not really computer chips. They do not go into the computer, like a real chip does. These items are only connected to the inlet air temperature sensor. All they can do is to fool the computer into thinking that the incoming air is colder than it really is; so the computer will then richen up the mixture. But the last thing that a Metro needs is a richer fuel mixture. They are already set too rich, in order to make them less sensitive to poor fuel or going out of tune. And that is very likely why your car only gets 32 mpg in the city. If you want to spend $400-600 on dyno tuning; a qualified shop might be able to tweak the computer to optimize your air/fuel mixture; but that is by no means a certainty. Metros are the most sensitive engine I have EVER seen; and they are designed so that many engine controls have overlapping effects. Because of this design; just about any modification that is made to improve these engines under a certain condition will make it run worse in some other area. So my advice is to NOT MODIFY IT AT ALL!!!
What you can do to improve the mileage is to first make sure the car is absolutely stock, and then tune it properly. The most critical area is the exhaust system. The catalytic converter and all the stock mufflers must be present, and must all be of the original design, and there can be no leaks anywhere in the system. Any muffler which has been changed, removed, or is at all different than the stock part can be expected to ruin the mileage. This goes for both aftermarket performance parts and stock type parts made by a manufacturer other than Chevy. The pipe diameter must also not be altered. I cannot stress this strongly enough!!!
Once you are sure the exhaust system is in perfect, stock condition; check to see that the original design air cleaner housing and all the rubber connecting ducts are still there. Remove and inspect the air filter element. You should be able to see enough sunlight pass through the element, so that the shadow of your hand should be easily visible when you place it over the filter. If you can't see that shadow, then replace the air filter element.
At the mileage now on the car, I would also replace the timing belt.
In my experience, NGK spark plugs have never worked well in that engine. Because of their popularity, that is very likely the brand that is now in the car. I would only use either Autolite #AP63, or Bosch Fusion #4506. If you want to go custom, you can use an Autolite #AP5503 or Champion truck plug #4430. Both of these plugs are improved designs; which are still similar in heat range to the AP63, but these plugs take a 5/8" socket, while the stock plug takes a 13/16" socket. Be sure to set the plug gap to.044" (but do not try to gap the Bosch Fusion plug) and apply a light coating of anti seize thread lubricant to the plug threads before installation.
Check the ignition timing with a timing light; following the procedure printed on the emission label that is on the underside of the hood.
If you do all that, come back and post how you now feel about the car. I'll give you information about correcting the fuel mixture at that time.
IMHO, I would not use Slick 50 in an engine that is in good mechanical condition. There is a different additive called Tufoil which does not contain a carrier oil; and thus is not likely to create problems due to chemical incompatibility with your existing oil. I've used it in my Metro for over 200,000 miles; and the engine still shows no loss of compression or power.
#1417 of 1867 Re: First Chevy Metro [ayejay]
Oct 11, 2008 (7:35 pm)
Welcome. You and I have the same car with about the same mileage (I have 80K)!
#1418 of 1867 Re: First Chevy Metro [c29160]
Oct 11, 2008 (7:44 pm)
I own a '98 1.0 with a 5-speed and I achieve 44 city and 52 highway (at 55mph). Seriously.
#1419 of 1867 EGR preventive maintenance?
Oct 11, 2008 (7:54 pm)
So, I've heard two sides to the EGR on these models (and I know Joel is reading this).
Some have told me to take it off and clean it as preventive maintenance. Not sure if that's worthwhile of not.
I did try to take the vacuum hoses off the EGR modulator and from the vacuum hose that connects to the bell-shaped housing of the EGR. No luck. They are stuck on. Some have told me I need to cut them off and buy new ones if I intend to clean the EGR valve.
That's about the extent I've done just out of curiousity.
What do you think? Yes? No? I hear so many people tell me the EGR valves on these cars are a "contributor" to the problem of burnt exhaust valves. And, I do know you told me the EGR's on these cars are pretty sturdy.
#1420 of 1867 Re: EGR preventive maintenance? [brokestudent2]
Oct 11, 2008 (11:56 pm)
Well, Joel was reading this; but he hasn't read any posts for the last month or so, because the system had stopped sending him prompts. That is now fixed.
I've never personally experienced a Metro with burned valves, so I can't say either way; whether a clogged EGR valve has any causal relationship. But I would guess it is more an issue of which came first. My sense is that when valves burn, the fuel mixture then goes rich; which causes the EGR valve to plug up.
The fuel mixture on my car has always been kept right; and my EGR valve has never needed cleaning. Is this only a coincidence? I doubt it.
But I will say one useful thing about buying vacuum hoses for Metros; the metric diameter hoses used on Metros are smaller than the vacuum hoses used on American vehicles. As a result; I usually find that the vacuum hose sizes carried in most auto parts stores are too big to seal on the Metro spigots. But windshield washer hose works just fine.
#1421 of 1867 Re: EGR preventive maintenance? [zaken1]
Oct 12, 2008 (5:21 pm)
I thought I'd just look at it for the heck of it next month. I immediately was hesitant to cut off the old vacuum hoses.
As far as the fuel mixture, I assume the fuel mixture on my Metro has always been kept right. I just keep hearing over and over again that Metros are notorious for EGR valve problems.
Nonetheless, I need to get my exhaust fixed next month. There are some small holes betweent the manifold and the converter, as well as immediately afterward. There is no muffler on the car. I've heard this will cause burnt exhaust valves. True?
Speaking of that, I'm sure the exhaust job is going to cost quite a bit.
#1422 of 1867 Re: EGR preventive maintenance? [brokestudent2]
Oct 12, 2008 (7:57 pm)
The exhaust issue would cause burned valves, if you drove it at high speed or heavy throttle; because those are the conditions under which the mixture goes too lean with an open exhaust. However, the mixture at moderate throttle and moderate speeds will probably not be off that much, and I doubt it would burn valves if it were only driven conservatively.
Although getting all new exhaust parts will indeed cost quite a lot; you might well be able to get a complete stock used exhaust system from a wrecking yard, in good condition. And that would cost a lot less. A good wrecking yard will have a parts interchange book; which lists the range of years and models with exhaust systems that are interchangeable with yours. Since this exhaust system is made of stainless steel, it is more durable than most. So there is a good chance of finding one in serviceable condition. Many wrecking yards also have a nationwide hotline; which they can use to put out a call for a specific part from all wreckers who subscribe to that service. If any one of them has the part, it can then be shipped to the yard that you had phoned. The best places to look are in states which do not have much population near the ocean; and which do not get much snow, or put salt on their roads in winter. Northern California, Nevada, Utah, Texas, New Mexico & Arizona would be the best. But it would be difficult to specify states on a hotline request. However, you could specify that the exhaust be in very sound condition.