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Compression on engin model 251417 -0137-01 - Cars & Trucks

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I put used engine in 08 chevy Equanox Junk yard gave me 05 it wont start help


Fuel, compression and spark.

Check the above. If you have adequate fuel pressure, reasonable compression and a good spark the engine should start. It may also be a good idea to check for compatibility with your engine control module between a 2008 model year and the 2005 model years.

Jul 23, 2017 | 2008 Chevrolet Equinox

1 Answer

What should the psi compression be thanks.


It can vary between make and model of car. However, a general rule of thumb is that 135+ average is okay. Less than 85psi is pointing at something seriously amiss in the engine.

It can vary - some cars may have 125psi as 'average' compression.

Don't expect each cylinder to give the same compression reading as there will be a fluctuation. Another general rule of thumb is that there shouldn't be more than 10% variation between the readings. That is, if cylinder No1 is 135 psi, cylinder No2 shouldn't be less than '125 ish'.

If you suspect you may have compression issues, it's quite easy to do a bit of fault finding. Warm the engine first so that the pistons are expanded in the cylinders. Then do a dry compression (normal) test.

Here's some examples of compression tests on a 4 cylinder engine:
130 127 129 127

All compression readings are within 10% of each other. Fine.

Example 2:
95 95 129 127
Here, a low compression reading on cylinder 1 and 2 suggests a problem. It may be due to a faulty head gasket/cylinder head allowing compressed gases to be transferred via the defective head gasket from one cylinder to another.

Example 3:
130 80 129 127
Cylinder No2 has a problem. It's compression is way down. The other three cylinders are fine. So .. what is the cause of the low compression on cylinder 2? It could be a broken ring/cracked piston or a burnt exhaust valve.

This is where you do a second compression test - called the 'wet' test.

Squirt some light engine oil into each cylinder. Aim for the cylinder walls so that the oil can find its way down the walls and around the piston rings. Place a rag over each spark plug hole and spin the engine to expel excess oil.

The oil that you have sprayed into each cylinder will form a 'seal' around the piston ring. Do another compression test and note down the readings. Here's example 3 again:
Example 3:
130 80 129 127
.. with the low compression on cylinder 2.

If after carrying out the 'wet' compression test you have a reading along the lines of
130 100 129 127
suggests that the bore/piston rings in cylinder 2 are at fault. The compression has increased on No2 cylinder because of the oil forming a seal around the rings.

If there is no increase in psi on the wet test i.e
130 80 129 127
This suggests a burnt exhaust valve.

May 17, 2016 | Cars & Trucks

1 Answer

Ford windstar over heated now wont start


What is model year?
Sometimes if overheated, it can cause internal engine damage. I'd check cylinder compression, first? If no or very poor compression, you engine is probably damaged. Will the starter motor crank it?

Jan 28, 2016 | Ford Cars & Trucks

1 Answer

No compression in engine


Not enough information to answer. Need manufacturer, year, model, engine size, 2WD/4WD/AWD, and Manual or Automatic transmission as applicable in order to answer the question.

Nov 22, 2015 | Cars & Trucks

1 Answer

My timing belt broke never made a sound I replaced it without a compression test. Nothing can you help


A lot of engines are no tolerance engines. Meaning when the belt breaks, the pistons will slap the valves. A compression test will find this. No compression. You'll be lucky if it only bent the valves. I have seen them break the valves off and punch holes it the tops of the pistons. Year make model and engine size would help.

Feb 13, 2015 | Cars & Trucks

1 Answer

Im looking for a spark plug wirng diagram for a 1966 corette 427


1966 - 1969 with 4 Barrel Carb (L36)
(Low Compression Model)
Max Brake Horsepower - 390 @ 5200 rpm
Max Torque - 470 @ 3600 rpm
Stroke - 3.76
Bore - 4.251
Compression - 10.25
Firing Order - 18436572

1966 with 4 Barrel Carb (L72)
(High Compression Model)
Max Brake Horsepower - 425 @ 5600 rpm
Max Torque - 460 @ 4000 rpm
Stroke - 3.76
Bore - 4.251
Compression - 11.0
Firing Order - 18436572


zjlimited_1418.jpg

283, 327, 396, 409 and 427 CID Engine 1965-1966
Firing Order 1-8-4-3-6-5-7-2


zjlimited_1417.jpg

350 CID Engine 1969-1974 Corvette, 427 CID Engine 1969 Corvette
Firing Order 1-8-4-3-6-5-7-2


Hope this helps (remember to rate this answer)

Jun 15, 2011 | Chevrolet Corvette Cars & Trucks

1 Answer

I don't have any engine compression. my toyota altis model 2006 3zz was overhauled but there was no compression when we assembled it back and tried to run the engine. was i wrong with the engine timing?


The engine timing being faulty would be a very likely reason especially if all the cylinders have no compression. Less likely reasons could be forgetting to install a cylinder head gasket, putting the wrong size valves in the cylinder head, installing new valves without lapping them into the valve seats, loose spark plugs, and piston ring gaps that are lined up instead of staggered.

Mar 05, 2011 | 2004 Toyota Corolla

1 Answer

97 model 626 will run fine then when warm will not start is getting feul and has good spark


Your problem is either lack of compression which is due to piston rings worn and having more than 4thou per inch per bore which when cold compression could be 100PSI but when the engine gets hot and expands and all metal parts do then compression could be down to 85 to 90 psi and you havent enough **** to **** in the fuel to burn and run, OR the engines is getting to hot . or the head gasket might be blowing slight compression into the cooling system which will cause the same.
Let me know more information about the problem Ron

Oct 20, 2009 | 1997 Mazda 626

2 Answers

Which Mazda diesel engine do I have? RF, RF-CX or RF-N


The engine is a RF- CX the CX denotes comprex pressure wave supercgarger

Jun 14, 2009 | 1988 Mazda 626 Turbo

2 Answers

Low compression in a 1999 sunfire. will not start, does fire


There can be several causes for low compression.
Chck the obvious first. the spark plugs must be checked that they are all in good condition. not burnt, the gap must be good( for your engine).Check the wires and coil so that good spark is obtained. Blue spark , not weak yellow spark. After everything is good. Check the cylinders to see if they have compression. To test the cylinders do the procedures shown below.

If the cylinder shows little leakdown or holds good compression when a little oil is squirted into the cylinder (wet compression test), it would tell you that the engine needs new valve guide seals and/or guide work. Most late model import engines have positive valve guide seals. Often, the guides are fine, but the seals are worn or cracked. The seals can be replaced on some engines without too much effort and without having to remove the head.

compression test will help you determine if the oil is getting past the valve guides or the rings. If the cylinder shows little leakdown or holds good compression when a little oil is squirted into the cylinder (wet compression test), it would tell you that the engine needs new valve guide seals and/or guide work. Most late model import engines have positive valve guide seals. Often, the guides are fine, but the seals are worn or cracked. The seals can be replaced on some engines without too much effort and without having to remove the head.

finally if the rings on one or more of the pistons can caus compression leak. It must be located and fixed.

Mar 03, 2009 | 1999 Pontiac Sunfire

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