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Run - No Run Mystery Solved; Runs great one time, another time it starts and dies.
Topic Started: Nov 24 2011, 08:47 PM (2,825 Views)
Neil
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John 20:31
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Geo Metro Run - No Run Mystery Solved
By Neil Waddell, Lake Mills, Wisconsin

Symptoms:
Runs great one time, another time it starts and dies. It seems to be worse when cold. When it dies it has spark & fuel and if you check compression it appears OK as well. But, when it cranks it sounds free, like there is no compression. Generally it starts but dies, right away or when the throttle is pushed or later. If you let it warm up without touching the throttle it generally will run fine.

Several local mechanics looked at the car and said “sensors”, “computer bad”, “try ground wire”. In guessing we changed a lot of components and nothing helped.

Solution:
Checked oil pressure and it would peg a 120psi gauge after about four revolutions. Dropped oil pan and removed retainer ring, retainer and spring on oil pressure relief valve. The plunger would not drop out and a magnet would not remove it. We removed the same assembly from another engine and the valve pulled out easily with a magnet. I turned a ½” steel rod to 0.482, an easy slip fit in the valve I had out. This diameter would not fit into the valve that was stuck. Therefore, I turned off ~0.010” and it slipped in. I dipped the rod in motor oil pushed it in as far as it would go and pulled down with a jerk. “Praise the Lord” the valve came out with the rod.
The problematic valve was about 0.001” larger in diameter and gauled. I polished the valve from the spare engine and used it in the reassembly. With everything back in place (including oil), it fired right up and runs very well.

Conclusion:
High Oil Pressure would over pump the HVL (hydraulic valve lash) adjuster and float the valves. The problem was worse when it was cold because the aluminum oil pump housing was smaller. If you let it idle and warm up the alum would expand freeing the valve. However, a slight increase in rpm too soon would increase pressure and over pump the HVL adjuster and float the valves. It all seems simple and obvious now.

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Edited by Neil, Nov 24 2011, 10:34 PM.
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Memphis metro


Question. What made you think to check oil pressure?

As for pictures, upload them here http://tinypic.com/ and copy the second line down afterwards and paste them in your thread.


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JellyBeanDriver


congrats!
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Neil
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John 20:31
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Thanks for the hint on adding photos.
What made me think to check oil pressure? An answer to prayer for wisdom. Thinking about it for weeks, checked it first with a cheap electronic gauge from Harbor Freight and did not believe the gauge, then found an old air pressure gauge and it pegged as well. Any abilities or good I do is only by the grace of God. (John 20:31 - Galatians 2:20)
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Memphis metro


hairydog39
Nov 24 2011, 10:45 PM
Thanks for the hint on adding photos.
What made me think to check oil pressure? An answer to prayer for wisdom. Thinking about it for weeks, checked it first with a cheap electronic gauge from Harbor Freight and did not believe the gauge, then found an old air pressure gauge and it pegged as well. Any abilities or good I do is only by the grace of God. (John 20:31 - Galatians 2:20)
Been there done that! How true that is! My problem is I am too hard headed and choose to struggle instead of asking. :thumb
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snowfish
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Basic GearHead

enginedoctorgeo
Nov 24 2011, 10:53 PM
hairydog39
Nov 24 2011, 10:45 PM
Thanks for the hint on adding photos.
What made me think to check oil pressure? An answer to prayer for wisdom. Thinking about it for weeks, checked it first with a cheap electronic gauge from Harbor Freight and did not believe the gauge, then found an old air pressure gauge and it pegged as well. Any abilities or good I do is only by the grace of God. (John 20:31 - Galatians 2:20)
Been there done that! How true that is! My problem is I am too hard headed and choose to struggle instead of asking. :thumb
Congrats! And boy can I relate with being hard headed! :banghead Still under development............... :news :gamerz :news :gamerz :banghead :news :wub: :thumb
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Old Man


Thanks for the "heads up"---I would have Never thought of that
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idmetro
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I am coming to understand that lifters in this engine are far more important than I had originally understood. Care and feeding of them seems to be key to engine longevity... Guess I am going to start buying better oil (MWebb would be proud).
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dayle1960
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Fastest Hampster EVER

Anybody have a picture of where this oil pressure relief valve is on a G10? mwebb seems to think this is the cause of burned valves, I just want to see/know where this item is located on the engine, so I can do further investigating.

Thanks.
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Memphis metro


dayle1960
Nov 26 2011, 07:40 PM
Anybody have a picture of where this oil pressure relief valve is on a G10? mwebb seems to think this is the cause of burned valves, I just want to see/know where this item is located on the engine, so I can do further investigating.

Thanks.
You joking or are you for real?

Its located in the oil pump housing and the oil pump housing is located behind your crank gear.

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dayle1960
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Fastest Hampster EVER

enginedoctorgeo
Nov 26 2011, 07:46 PM
dayle1960
Nov 26 2011, 07:40 PM
Anybody have a picture of where this oil pressure relief valve is on a G10? mwebb seems to think this is the cause of burned valves, I just want to see/know where this item is located on the engine, so I can do further investigating.

Thanks.
You joking or are you for real?

Its located in the oil pump housing and the oil pump housing is located behind your crank gear.

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No, I am not joking. I have never heard of the aforementioned item. I know that area of the oil pump, but never knew what was up in there and what it's for.

I guess mwebb believes that oily goo is suppose to make its way in there and screw up things. Hmmm, I wonder if it is symptomatic of non-ABC oil or maybe, just maybe the owner not changing oil frequently. Seems to me there should be some sort of product on the market that you could dump into your motor to clean out the gooey deposits hidden in areas like this.

Anybody care to expond on a internal engine cleaner?
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Old Man


dayle1960
Nov 27 2011, 01:13 PM

Anybody care to expond on a internal engine cleaner?
:hmm kerosene and a good stiff brush :D
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Bad Bent
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Facetious Educated Donkey

dayle1960
Nov 27 2011, 01:13 PM
I guess mwebb believes that oily goo is suppose to make its way in there and screw up things. Hmmm, I wonder if it is symptomatic of non-ABC oil or maybe, just maybe the owner not changing oil frequently. Seems to me there should be some sort of product on the market that you could dump into your motor to clean out the gooey deposits hidden in areas like this.

Anybody care to expond on a internal engine cleaner?
For the most part I use Marvel Mystery Oil (MMO) for some long term cleaning. Long term being add 1/2 quart when it is low and drive. Before an oil change I will ad 3-5 oz of Seafoam and drive it 200-300 miles then watch my oil color change to black. :D
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