Edmunds Answers

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  • avatar zaken1 09/11/11 1:57 am PST

    I hear what you're saying. The problem is that Metros of this age are all very likely to have bad compression; and the XFI is even more likely than the standard model; because the XFI has only one compression ring on their pistons; while the standard Metros have two compression rings.

    By the way; the standard Metro, when it is has good compression, will get 47 miles per gallon in city driving, and 55 on the highway. XFIs in good condition will get as much as 64 mpg on the highway. Of course; the ethanol in today's fuel will drop those numbers about 10%.

    I bought my 1990 base model 5 speed Metro from the first owner in 1992, when the car had 58,000 original (mostly highway) miles on it. I insisted on checking the compression (which annoyed the seller) and found it was a perfect 195 psi all the way across. The owner had broken the car in on Castrol GTX 10W-30, and then changed to Castrol Syntec full synthetic 5W-50 when the car had about 5,000 miles on it. And he never used any other brand or type of oil except that. He also added an Amsoil bypass oil filter; which filters out particles down to about 1/10th the size of what a regular oil filter will catch. I have continued using only that oil, and also add a patented additive called Tufoil at every oil and (regular) oil filter change (which I do at 7,500 miles because the full synthetic oil can go longer than petroleum oil between changes). I change the $37 Amsoil filter cartridge at every 3rd oil change. My car now has about 300,000 miles on it; the engine is still in perfect condition, and has never been taken apart. It has more power now than it had when I bought it (because I have done some custom modification and fine tuning on it). I don't hesitate to rev it up every once in a while, but I keep it below 70 mph on the freeway. The only engine repairs were to replace the front crankshaft oil seal once, replace the distributor "O" ring once, replace the oxygen sensor once, and change the timing belt every 100,000 miles. I also replaced the alternator once, and the water pump once, and front brake pads twice. It still has the original clutch, starter, fuel pump, and rear brake shoes.

    The point I'm trying to make here is that this motor is more vulnerable to improper maintenance than probably any other car ever made; but it will also last far longer than other cars if given proper care and lubrication. So most Metro owners use whatever oil is on sale when it comes time to change the oil; and their engine loses compression at 100,000 to 150,000 miles. The Edmunds Metro forums are full of posts from people who bought a used Metro and did not check the compression; and then find it runs like crap and they can't tune it properly. This will probably go on for as long as there are Metros out there. There's a price to pay for all the power and economy from such a tiny motor; and the price is that it must be treated right. Practically nobody does that; and that's why Metros have gotten such a bad reputation for durability with many people.

    So that's what you are up against.

Answers

  • zaken1 09/09/11 12:09 am PST

    Without seeing it; I can't make sense of the line and hoses you saw. There are some vapor return lines which go from the fuel tank to the vapor storage cannister on the firewall; which someone might have disconnected. There are no lines which would go into the passenger compartment unless there was an air conditioning system on the car at some point.

    But I would recommend replacing the fuel filter and also replace the air filter (if light does not pass easily through the element) to deal with the power loss. If you're not mechanically experienced; I would recommend having a gas station or a shop change the fuel filter. It can be a messy, frustrating job. It also could be deadly to do if you are smoking. The fuel filter is underneath the car, on the fuel line which goes from the gas tank to the engine, on the driver's side just forward of the rear wheel. There is a metal cover plate, held on with 2 bolts; which is directly underneath the filter. I usually take the rear wheel off and support the car on a jack or jack stands; in order to reach the fuel filter. Once the cover plate is off; it should be easy to see the filter, and to reach the lines and clamps. Do not try to change the fuel filter when there is a lot of fuel in the tank; wait until there is less than 1/8 tank of fuel, and park the car heading uphill, if possible. This will make it less likely that fuel will pour out of the lines and run all over you when the filter is disconnected.

    Also check the resistance of the spark plug cables; they should have less than 1,000 ohms resistance for each inch of wire length, or just buy a new Bosch or BWD wire set.

    The distributor cap can also make the car run doggy; if it has carbon build up on the inside, or dirt on the outside. It should be cleaned thoroughly with a clean rag. If there are any signs of cracks on the inside; the cap should be replaced.

    If you installed NGK spark plugs; that is one reason why the performance dropped off. That brand just doesn't last in Metros. Autolite # 63 plugs run best in this motor. Gap should be set to .042"

  • zaken1 09/09/11 2:50 pm PST

    I forgot to mention (and it seems to always happen in posts where I don't mention this) that this site does not want people to open new questions in response to a question that haa already been posted. The proper way to post new information and feedback about an existing topic is to go to the original question, and click the "answer this question" button below the last response. Type your message in the box that appears; and click the "submit answer" button. This will automatically notify everyone who has responded to that post that a new message has been posted; and will keep the records straight and make it possible for others to be able to follow the progress of a topic.

    In response to the two new questions you have opened; 3 cylinder Metros are probably more sensitive to spark plug choices than any other vehicle on the planet. And the choice of plug that works best will change, in response to any other changes you make to the engine. I have owned a 3 cylinder Metro for the last 19 years; and have serviced and advised the owners of many others. This is a most amazing vehicle; but it is also extremely vulnerable; if abused or not maintained properly.

    The loss of mileage, the shaking at idle, and the exhaust smell are all signs that the motor is out of adjustment. But the adjustments which address these issues are so critical that I hesitate to recommend them to the average owner. An impatient, distrustful, or headstrong, or fearful owner will inevitably get into a huge mess if they go into this process. But if you are willing to follow instructions, and realize that the results will depend on how thoroughly and carefully you apply these recommendations; as well as on the mechanical condition of the vehicle; then you will be likely to end up pleased with the results.

    If you want to get into this (which, by the way, is my specialty) I will work with you; but it will require some tools which you'll probably have to buy, plus modest amounts of money spent on parts which may not end up being permanently used; along with doing some experimentation; which sometimes makes things temporarily worse, before they get better.

    A few notes on wires,rotor and cap: most replacement distributor caps for Metros are not adequate for service on this motor. The best cap to use is either a Beck Arnley # 1746959, or a Standard Motor Products # JH165T. Please do not use any other brands or part numbers. The JH165T must have the "T" suffix in the number. I am well aware that the Standard Motor Products "T" series is usually considered as a lower quality line; but this particular cap is made in Italy, and uses a brown color material that is a better electrical insulator than the higher priced caps. The Beck Arnley cap also uses a similar material. Also buy an Airtex # 4R1044A or a Wells # DR970G rotor. These parts may be available locally; and are also available from (www.rockauto.com)

    Please do not buy a wire set at this time. It will require some custom work, and there are other things which need to be done before that.

    I am concerned about the frequent use of fuel injector cleaner you have been adding. This type of product is basically a solvent; and its excessive use tends to dilute the motor oil which is in the upper cylinder area. This can damage piston rings and cylinder walls. So I would like to see the results of a compression test on this motor before we go further. Buy an accurate compression tester which screws in to the spark plug threads; not the type with a tapered rubber cone that presses in. NAPA parts stores would have such a tool.

    Before running a compression test; drive the car for at least 3 miles, and then let it cool off for 45 minutes. Disconnect the small diameter wires from the ignition coil before running the test, and tape the metal ends or secure them in a location where they cannot touch each other or touch any metal parts. Take off the cover of the fuse box that is just in front of the strut tower, next to the battery, on the driver's side of the engine compartment. Locate the fuel pump fuse in the diagram on top of the cover, and remove that fuse.

    Remove all the spark plugs, screw the compression gauge into one spark plug opening, and have someone in the car hold their foot about halfway down on the accelerator while turning the ignition key to the "start" position. Have them crank the starter until the cylinder has gone through four compression strokes (you'll see the gauge jump four times). Stop the cranking after the fourth compression stroke and read the gauge. Write down the pressure reading. release the pressure in the gauge, and move on to the next cylinder. Do this on all 3 cylinders. The cylinders are numbered 1-2-3 running from the fan belt end to the transmission end of the engine.

    The compression on a new motor is 195psi. The minimum allowable pressure is 165 psi. There also cannot be more than 15psi difference between any two cylinder pressures.

    Post the compression readings you get; and we'll go from there.

  • chac 09/09/11 6:55 pm PST

    Today i did compresion test, the 3 cylinders ranged from 139-147-143 in compresion. i also put in the autolight 63 plugs after setting matching gaps to spec, replaced new cap and rotor, as the old rotor looked in rough condition. So far I have not got back my lost horsepower, however it runs perfect besides the low idle of only 800 rpm that causes the engine to shake a little only when idling. If it was someone elces car I was test driving I would think the horsepower is normal for a 3 cylinder, but since I had it a while and seen the horsepower, and before I was getting 47 mpg and now 35 mpg, I know something isn't right. Do these cars have something like a mass air flow sensor. I do recall a time on a 2004 Impala 3.8 V6 after i orderd a generic mass air flow sensor on ebay, it caused the car to run low rpm and killed the gas millage similar to this. On the impala i bought the factory sensor and the car was fine again.I don't beleave it to be the fuel filter due to the loss of gas millage and low idle of 800 rpm, but I'm not sure.
    I just edited this to add that I did the compresion test today before i found your reply on doing it properly. After I posted this I seen your reply. While I was shopping today I bought all the parts and installed before seeing your reply, so i did the compresion test when engine hot. im way below the 190's I seen you posted. And had allready bought the plug wires before i read not to, but they were to short, so i did not install them.

  • chac 09/09/11 7:11 pm PST

    Hey great sight, I appolagise for posting responces in seperate titles. I meant to put all in same place. Thanks a million to Zaken for helping.

  • zaken1 09/09/11 10:40 pm PST

    Well; as you see, the compression is way out of specs. That is why your mileage has dropped off; and I believe it happened because all that fuel injector cleaner broke down the lubricating oil and destroyed the piston ring seal. There is no way this motor will run right or get good mileage with compression that low, period. Compression is basic to an engine's performance; and when it is low; NOTHING you do on the outside will change it. By the way; the Metro does not have a mass airflow sensor. It uses a different type of sensor, called a MAP (manifold absolute pressure) sensor to serve the same purpose. But MAP sensors do not go bad like MAF sensors do.

    The pressure numbers being so close together indicate that the valves are in good shape; and it is the pistons and rings which are not sealing properly. The standard way to fix this problem would be to overhaul the motor; reboring the cylinders and installing new pistons, rings, bearings etc. There is a top quality engine remanufacturer in Spokane, Washington called Hiperformer engines; which sells a freshly remanufactured motor for this car for about $1,700. It comes with a 7 year, 100,000 mile warranty. They ship these motors (at least the light Metro ones) by FedEx ground to your home. I don't know whether this would be affordable by you or not.

    Considering what probably caused this damage; at this point; there is
    some chance that it might be able to be improved by draining the motor oil, and using specific chemical products to restore the sealing properties of the pistons and rings. This is not a sure thing; but I have seen it work before. It may also work halfway; improving the compression but not bringing it all the way back up to new specs.

    If you want to do this; it will require ordering some products from suppliers in other states, waiting for them to arrive, and following specific directions about using them. The total cost of this process would be less than $100.

    If you decide to do this; I would recommend not driving the car much more until it is done. Right now; that motor is grinding itself down internally with every rotation of the crankshaft. And please don't change the oil now or do anything with the lubrication system; as it may just make it worse. I have a specific routine to deal with this; and it can be easily messed up by using other products or not following the proven method.

    If you can't afford to replace the motor; I would definitely recommend trying the chemical restoration rather than just letting it run until it dies.

    Let me know what you decide to do. If you go with the chemical route; please let me know what brand and weight of oil is now in the motor; how long it has been since the last oil change; and whether that grade of oil has been used in this car for a long time; or whether different brands and grades of oil have been used at different times or mixed together.

  • chac 09/10/11 6:16 pm PST

    It is do for an oil change. I have only put 3,200 miles on the car since I have owned it, and it had 800 miles on the last oil change when I bought it. I'm aware 4,000 miles is a lot between oil changes, but when i noticed the drop of horsepower i focused on that rather then changing the oil. The oil is still at the exact full line even with 4,000 miles on oil change. The other reason I did not change the oil yet, is I wanted to see if the car uses any oil. The engine hasn't used a drop of oil, and is still clean and clear. The engine sounds smooth and has no chatter or rattles of any kind at any rpm. Are you sure this 92 3 cylinder is suposed to be at 190 compresion, if so maby my compresion guage does not read correctly, its not a name brand or anything. I bought it last year to check compresion on a boat. This thing runs to quiet and uses no oil. I would think if rings and pistons are worn, it would smoke a little or use some oil after 4,000 hard miles. I dont baby it, i run it 75mph on the interstate and wind it up to 4,200 rpm between shifting, and 1rst gear up to 5,000 rpm before shifting to second when in a hurry. Is it just me, or do you think it would use some oil or smoke if it was in need of rebuild? Most I test drove when I was ready to buy 1 did not run near as quiet as this one. It's a one owner besides me. The lots of fuel injection cleaner was 1 can of seafoam cleaner in 1 tank of gas, and in second tank was the autozone fuel injector cleaner bottle, I didnt meen lots and lots, but enough to clean injectors if it was a minor blockage. Do you recomend adding heavier weight oil to it to see if it ads horsepower?

  • zaken1 09/10/11 8:43 pm PST

    I do NOT recommend going to heavier weight oil in this motor. You didn't say what brand and weight of oil is in it; or whether the previous owner always used one brand and weight of oil in this car. This is important to know; as changing from one brand of oil to another can ruin an engine; even though most people incorrectly believe that it can't make any difference. If you don't know what kind of oil the previous owner used in this car; please contact them and find out.

    I believe your compression gauge is right. When the compression drops in an engine; it loses power and fuel economy. The things you have noticed; the loss of power, loss of gas mileage, and exhaust smell all fit together perfectly with the compression gauge readings. And on this motor; there are only two other things that could make this all happen: One would be if you or someone reset the ignition timing, but did not disable the electronic advance circuit before doing so. Checking and setting the timing when the electronic advance has not been disabled will make the timing come out way too retarded. And that could cause your problem. If the car had a smog check; the inspector may have reset the timing. And all too many smog inspectors are ignorant about the need to disable the electronic advance. The other thing that could do it would be if the catalytic converter clogged up; or if the exhaust system developed a big leak. If it was not that; then the motor lost compression.

    Sometimes an engine can lose compression and not smoke or burn oil; other times it burns more oil, gets loose, and makes noise when the compression drops. It depends on which parts became worn and caused the compression loss. There are two kinds of piston rings in a motor. The top rings are called compression rings; and their job is to keep the cylinder pressure from leaking down past the piston. The bottom ring is called an oil ring. Its job is to keep the oil from going up into the combustion chamber and being burned.

    On some engines; the compression rings can get stuck in their grooves from carbon and start leaking compression, while the oil rings still work well. That will cause a loss of compression without any noise or oil burning. It sounds like this is what happened in this motor. I expect a bunch of carbon was loosened from the cylinder head by the Sea Foam, and got into the ring grooves. I have seen Sea Foam wipe out a set of spark plugs more than once from this kind of action.

    This problem is not going to go away by itself. Please find out what brand and weight of oil is now in this motor; and whether different brands or weights of oil have been used at different times. Also let me know about whether the ignition timing has been reset; or whether the exhaust system has any leaks in it. I'll show you an easy way to test the catalytic converter for clogging; if the other possibilities are not the problem. And the chemical restoration process I mentioned will often free up sticking piston rings. It can do this more easily than most other things; so there is hope; but it is important to not use the car more than absolutely necessary until this is done.

  • chac 09/10/11 10:48 pm PST

    ok, thanks again on getting back to me, timing hasn't been messed with or any smog tests performed. The sea foam wasn't added until after the problem was allready there, and it was added to try corecting the lost horsepower. It sounds like my best option is to cut my losses. The car was supose to have been mechanicaly sound with rust free body. I paid double what its vallue was with a bad top and tires, I have over 5,500 invested in it.
    Rather then invest in this engine, whats your thought on me doing this, supose i buy a 92-94 xfi with good running engine and trans, i wonder how much i could increase my fuel econamy using the xfi 3 cylinder and the xfi trans?

  • zaken1 09/11/11 1:57 am PST

    I hear what you're saying. The problem is that Metros of this age are all very likely to have bad compression; and the XFI is even more likely than the standard model; because the XFI has only one compression ring on their pistons; while the standard Metros have two compression rings.

    By the way; the standard Metro, when it is has good compression, will get 47 miles per gallon in city driving, and 55 on the highway. XFIs in good condition will get as much as 64 mpg on the highway. Of course; the ethanol in today's fuel will drop those numbers about 10%.

    I bought my 1990 base model 5 speed Metro from the first owner in 1992, when the car had 58,000 original (mostly highway) miles on it. I insisted on checking the compression (which annoyed the seller) and found it was a perfect 195 psi all the way across. The owner had broken the car in on Castrol GTX 10W-30, and then changed to Castrol Syntec full synthetic 5W-50 when the car had about 5,000 miles on it. And he never used any other brand or type of oil except that. He also added an Amsoil bypass oil filter; which filters out particles down to about 1/10th the size of what a regular oil filter will catch. I have continued using only that oil, and also add a patented additive called Tufoil at every oil and (regular) oil filter change (which I do at 7,500 miles because the full synthetic oil can go longer than petroleum oil between changes). I change the $37 Amsoil filter cartridge at every 3rd oil change. My car now has about 300,000 miles on it; the engine is still in perfect condition, and has never been taken apart. It has more power now than it had when I bought it (because I have done some custom modification and fine tuning on it). I don't hesitate to rev it up every once in a while, but I keep it below 70 mph on the freeway. The only engine repairs were to replace the front crankshaft oil seal once, replace the distributor "O" ring once, replace the oxygen sensor once, and change the timing belt every 100,000 miles. I also replaced the alternator once, and the water pump once, and front brake pads twice. It still has the original clutch, starter, fuel pump, and rear brake shoes.

    The point I'm trying to make here is that this motor is more vulnerable to improper maintenance than probably any other car ever made; but it will also last far longer than other cars if given proper care and lubrication. So most Metro owners use whatever oil is on sale when it comes time to change the oil; and their engine loses compression at 100,000 to 150,000 miles. The Edmunds Metro forums are full of posts from people who bought a used Metro and did not check the compression; and then find it runs like crap and they can't tune it properly. This will probably go on for as long as there are Metros out there. There's a price to pay for all the power and economy from such a tiny motor; and the price is that it must be treated right. Practically nobody does that; and that's why Metros have gotten such a bad reputation for durability with many people.

    So that's what you are up against.

  • chac 09/11/11 2:17 pm PST

    Well thank's so much for all your info and the time you spent with me on here. It has been greatly apprectated. I checked the compresion before seeing your reply that day with directions on checking it properly. So when I did check it, i never opend the throttle, all i did was cranked it over and checked it. I'm not sure how much difference that will make, but I will check it again just to see. Thank's again for your time and help. It's rare to find people helping each other these days with out a price tag on it. You are the best.

  • chac 09/11/11 6:49 pm PST

    In your responce saying (the compression rings can get stuck in their grooves from carbon and start leaking compression with out engine noise or oil burn).
    What is the product you recomend to free the compresion rings. Maby my hard driving caused this, as the original owner was old and never wound it up to clean the cobs out of it, he has every oil change logged in a book from the day this car was bought new, each change was done under 3,000 miles and i will need to check his log of brand of oil used. I never added the sea foam until after the problem arrose. So it definatley wasnt caused by that. Something elce I found in his log book, was he had this 5 spd trans rebuilt 3 times over the cars life leaving me to beleave he burnt out lots of clutches and the place he used just charged him for entire rebuild. So he prob never had the car over 2-3,000 rpm building up lots of carbon. Im wondering if I added a quart of tranny fluid to the engine oil, leave it sit and idle 20 minutes before changing oil, if that would free up everything. I have also heard of people adding diesel to the oil and running the car 20 minutes that way at idle right before an oil change. It realy does sound like the compression rings could be sticking like you had mentiond. Before scrapping this engine, I would be willing to see if adding something to oil before changing oil could be a quick easy fix.

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