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33 mpg 1.0L? Rebuild needed?
Topic Started: May 14 2012, 04:29 PM (2,059 Views)
Michael_B
New Member
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'95 Geo Metro hatchback 1.0L 5-speed

I have done a tune up, (plugs, wires, fuel & air filter, pcv valve) replaced cat (from 25mpg to 33mpg). Compression test is at around 140 on all 3 dry and around 145 wet. I used about a 1/2 teaspoon or more engine oil. Maybe not enough? Engine warm and WOT. Engine is not burning any oil that I can see. Once warm nothing visable out of the tailpipe. The only thing I can figure on poor fuel ecnomy is need an engine rebuild. When I bought it the guy said he was told the head had been done not to long ago but could not verify for sure. In the last 3 weeks the car has developed a metalic rattle at low rpm and under load. It is coming from the top of the engine so I'm thinking a lifter. I have heard a bad rod bearing before. I know it's not that. The noise goes away when I rap on the throttle a little and when I increase the rpm a little.
I have noticed that when I pull the spark plugs it's wet at the seat and that's after I cleaned in a few weeks before (mostly #2 cylinder). Doesn't seem like coolant, maybe gas not sure on that.
I haven't rebuilt an engine since school ('96) so any help would be great. Thanks
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Deleted User
Deleted User

The first thing you really want to do is make sure your PCV valve is not plugged and the passages and hose are clear. A plugged PCV valve will pressurize the crankcase, blow out a seal, your engine oil will depart the property, shortly after which one of the connecting rods will exit through the side of the crankcase.

8 ounces of Marvel Mystery oil in the engine oil may help with the compression.

However, Marvel Mystery oil will not fix broken metal parts.

Are you able to post a video so we can listen to the sound?

:popcorn
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95-3banger
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If they are all reading the same I would say you are at least evenly worn out. How many miles on yours?? My 95 had 165k on it and also had the ticking lifter, and a pretty bad oil leak on the front crank seal (oil pump). I pulled it out and all it really needed was the front seal and the lifters cleaned out and I'm sure it would've gone another 50-75k without a hickup. Even the clutch was in pretty good shape. I ended up replacing everything and got it back together and it gets a consistant 28 mpg so I think you're doing ok. :D I have actually come to the conclusion that my computer is bad making the car ignore the O2 sensor at cruise rpm. I have another one on order and I'll let you know what happens.
Edited by 95-3banger, May 14 2012, 09:22 PM.
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Nappers
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Wet plugs? not firing or too small spark....Check your gap? Check spark? Wires okay? I had a wire grounding against block on a car (97 Kia, deep plugs in valve cover) which ate up mpg's. a wire was cracked. I took it to a mechanic that charged me and I found the problem after hearing it arcing on the valve cover. Didn't even get a discount! :banghead
Edited by Nappers, May 15 2012, 04:13 AM.
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Michael_B
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I did repace the PCV valve. There was actually no valve in it at all and it was causing a surging idle. I do have 1.5 oz of sea foam per quart in the oil. Thought it may help clean something out and make tick/rattle go away, but no such luck. I will get some audio posted.

I have over 215000 miles. Alot I know.

As far as spark plugs I put in new plugs and gapped them per spec. They are just wet at the seat under seating ring(where they contact head) so maybe it's coming from outside and getting down in the sparkplug well but it's dry all around except under spark plug seat. I'll keep an eye on that.

I have considered a weak spark and will be checking that soon. It was my plan just replace the ignition coil anyway seeing how it probably was never done. I was just putting it off because I've spent alot in the past few months. I know a strong spark can make a difference.

Note: As far as oxygen sensors go all they do is monitor exhaust to keep fuel/air mixture as close to 14.7 to 1 as possible. All about emissions not fuel economy. I would bet that computer will not fix your problem. I hope you did not spend to much. My brother had a bad oxygen sensor on his 2001 Dodge Ram 1500 V8 and ran with the oxygen sensor unplugged for several weeks before getting a new one and his gas milage was unchanged. He did say it had a bit more power.
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idmetro
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Michael_B
May 14 2012, 04:29 PM
'95 Geo Metro hatchback 1.0L 5-speed

Compression test is at around 140 on all 3 dry and around 145 wet.
Factory minimum is 156psi although many members are running less than that, the most critical part is that the cylinders are even. That said as the cylinder pressure declines so will the performance and mileage...

Did you do the compression test as outlined here: http://geometroforum.com/topic/2574993/1/ ?

If so then a rebuild is in your future
Edited by idmetro, May 15 2012, 02:32 PM.
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Michael_B
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Yes I did compression test correctly. I was thinking engine rebuild too, just wanted to exhaust cheaper options first.
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Michael_B
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I guess this will work. Video of rattle in engine.

http://youtu.be/s0Yb3JdFOdE
Edited by Michael_B, May 15 2012, 03:34 PM.
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Bad Bent
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Facetious Educated Donkey

I would suggest a mechanic's stethoscope to pin point the noise. I was about to open up my wife's '96 Geo and then I traced the noise to the EGR. I took it apart and found that the gasket had blown and basically I was listening to a vacuum leak.
On my '91 I traced it to the vacuum advance and insufficient vacuum to advance the mechanism which rattled like a lifter. :lol

Posted Image

On the compression I use Marvel Mystery Oil long before an oil change, like 2,000 miles if something sounds like it's sticking. Then 300-500 miles before the change I add 5-6oz of Seafoam to the oil. It will turn dirty oil pitch black with carbon that it cleans out. Seafoam Maintenance.
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Deleted User
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That sounds like a broken piston skirt. I could tell you in a second if I were there. I can hear a broken piston skirt from 50 feet. Over the internet, it's hard to tell.

The symptoms match my experience. Rattles at idle, goes away when RPM's increase and when driving.

If you want to check. It's not too hard. Drain the engine oil and remove the oil pan. You will see chunks of what used to be your piston skirt laying on the baffle in the oil pan.

Or, if you don't want to check, that engine will run as is for a while. I drove one in that condition from Charlotte to Philadelphia to Kansas City before making the repair.

Oh yeah. Bad Bent's stethoscope. Good for diagnosis. I'm not sure where to get one of those.
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MikkiD
Fresh Fish
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I had a rattling similar to that only not as bad. I went to auto zone and they recommended CDL a chemical used to clean the litters of the grime from the oil. I added the whole bottle like directed. And am supposed to give it a week to see if the ticking goes away. I also had my timing checked and it was off a little bit. I don't know if you have checked your alignment on your distributor cap to help minimize the shacking of the engine while idling. I am still needing it adjusted but I am going to also be getting my CV joints and axles checked. I already think tthat the steering boots on my steering column need replaced as the drivers side one is closer together than the one on the passenger side. Also. If you are going to rebuild your engine I found a rebuild kit with all u need on line for $218 and the gasket replacement kit is $45 when you factor in labor you are looking at a little over $500 to rebuild your engine which considering the cost for other cars tthat is a good deal. Let me know what u do so I can possibly check it out too.
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Bad Bent
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Geo Glenn
May 15 2012, 05:24 PM
Oh yeah. Bad Bent's stethoscope. Good for diagnosis. I'm not sure where to get one of those.
Forgot to mention the cheap method is to use a long screwdriver where you hold the handle end to your ear and touch the metal pointy end to the engine parts. :-/ Someone mentioned using a 2-3' long 3/8-1/2" I.D. (?) hose held to your ear and use the other end to detect sounds.

Harbor Freight has the stethoscope on sale for $3.99 (regular price $4.99) http://www.harborfreight.com/catalogsearch/result?q=stethoscope

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Michael_B
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A mechanic's stethoscope is a good idea. I'll try that.

Broken piston skirt. And I just did the oil pan gasket too! lol (just before rattle started) Oh well I will check anyway. Thanks for the tip. As I have listened to this rattle for awhile now it sounds less and less like a lifter. It has a sharper sound as well as sounding like a bigger object hitting something. I guess I'll have to take the car out of use and use my much nicer F150 at 12-13mpg. (Lots of short trips) I've been really enjoying that cheap transportation! Tin can on wheels though! lol

I will double check timing just to make sure but the shaking/rougher idle started with the noise. I have found those cheaper rebuild sets but am hesitant to get it. I'm partial to Fel-Pro myself but I'm trying not to put to much more money in this thing. As far as labor I'll be doing most of it, if not all of it myself. I did want to see how much to get a head rebuilt though.

CV axles. If your boots are bad just get a reman axle. Much cheaper. You can get remans for about $50/exchange but watch out for resurfacing on the axle shaft mating surface. I had to get a brand new one for the passenger side because the remans were ground so much it caused a major tranny leak. Use calipers to measure old axle and measure "new" one at the store. Even at .003" under I still had a pretty good leak. Went through 2 remans. I have had those axles out so many times that I can get one side in and out and the shop cleaned up in an hour.

Hey how do I get the blue box around a quote? Can't seem to figure it out. Thanks.
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Michael_B
May 16 2012, 05:17 AM
Hey how do I get the blue box around a quote? Can't seem to figure it out. Thanks.

If you were Coche Blanco, I would have most possibly edited in something that Coche was thinking, but did not say, or something to that effect . . . :D

Click on "Quote" on the Post that you want to quote. Edit out the quoted content, or add your own humorous words of wisdom in the lower text box. Then type what you want in the upper box.
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bogs
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Duct tape heals all wounds

Geo Glenn
May 16 2012, 11:14 AM
Michael_B
May 16 2012, 05:17 AM
Hey how do I get the blue box around a quote? Can't seem to figure it out. Thanks.
- If you were Coche Blanco, I would have most possibly edited in something that Coche was thinking, but did not say, or something to that effect . . . :D
Click on "Quote" on the Post that you want to quote. Edit out the quoted content, or add your own humorous words of wisdom in the lower text box. Then type what you want in the upper box.
Or you could do it the easy way, and check that little box next to quote before clicking on the quote box ;)
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In fact, you could check that box on multiple posts and click on quote on the last one, and voila, lots of blue outlines would appear !

This time saving tip brought to you by Moderators-R-Us :type
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