# Help!! 97 Sentra won't start - need new engine??



## yitznmara (Nov 14, 2005)

Yesterday my wife moved my daughter's 1997 Nissan Sentra (about 80k) just so she can get her own car. By the afternoon when my daughter went to drive her car, it wouldn't start. It cranks and it's like the gas is not catching. Tried it without pressing the accelerator as well as with pressing the accelarator. 
Today I took it to my mechanic where he changed the spark plugs and still cannot get it to start. He did a compression test and found compression was at 75lbs. I don't know what all this means other than he says I need a new engine. A few questions:
+ What does the compression test check and why would the compression go low now, and what causes the low compression?
+ Are there any components going bad that could cause a low compression reading?
+ Should I get a second opinion? What would a second mechanic be looking for that this one may not have looked for?"


----------



## thestunts200sx (Jul 11, 2005)

I know nothing about compression....but you can check basically all the tune up things.

Plugs, wires, distributor cap & rotor, battery good ? , do you have a good connection on both battery terminals ?, how about the ground to the body/frame ? is that clean ??....starter ?, fuel filter ? , all the sensors/connections look in good standing and not loose ?.....is there gas in the car ? ....lol....sounds stupid, but you never do know....

is the car auto or stick ?? if its auto....is it in park and/or neutral....I know that sounds dumb as hell.....but a girl in my school parking lot couldnt crank over, had the hood up, with 3 other guys....looking it over checking everything....and i saw the shifter in drive...pushed it up, and cranked it over.....

Anywho, good luck....and let us know.


----------



## no1see2me (Oct 1, 2004)

yitznmara said:


> Yesterday my wife moved my daughter's 1997 Nissan Sentra (about 80k) just so she can get her own car. By the afternoon when my daughter went to drive her car, it wouldn't start. It cranks and it's like the gas is not catching. Tried it without pressing the accelerator as well as with pressing the accelarator.
> Today I took it to my mechanic where he changed the spark plugs and still cannot get it to start. He did a compression test and found compression was at 75lbs. I don't know what all this means other than he says I need a new engine. A few questions:
> + What does the compression test check and why would the compression go low now, and what causes the low compression?
> + Are there any components going bad that could cause a low compression reading?
> + Should I get a second opinion? What would a second mechanic be looking for that this one may not have looked for?"


 In your case there two major components that is making this car not run. Spark and Fuel. If it ran and was moved then all of the sudden it won't start, it is either not getting spark or fuel.


----------



## copperlite (Oct 12, 2004)

well...lets see here...

compression is at 75psi:
thats pretty low..especially at 80k so there's obviously something wrong internally. Regardless of that, your car should still run. no1see2me is right, you'll hear this a lot on here...

You need 3 basic things for your car to run:
Air
spark
& fuel

One thing i'd check before taking it to another mechanic is all the under-dash fuses. Then, I'd verify myself (or have a mechanic verify) that there is good spark and fuel pressure.



> + What does the compression test check and why would the compression go low now, and what causes the low compression?


When your engine sucks in air, it mixes in a specific ratio of fuel. Then this mixture is compressed in the cylinder and ignited. Low compression means less power as there is less air/fuel to be ignited. Low compression can be caused by a few different things...blown head gasket, bad piston rings, damaged valves are probably the main ones. A well maintained engine will keep good compression for way way over 80k. Maybe tell your mechanic to check the timing belt also.



Doing some simple detective work yourself i guarentee (sp) will save you big bucks!


----------



## bob89sentra (Sep 15, 2005)

If the battery was low from cranking it over for a long time, the compression numbers would be lower. I would not think you need a new engine yet, Especially since it ran, then just wouldn't start. Definitly check for spark and fuel delivery, as well as fuses.​


----------



## bigern45 (Oct 25, 2005)

75 psi of compression doesnt necessarily mean there is something mechanically wrong with your engine. you might not be getting spark, so the mixture is not being ignited, so all of the fuel may have washed down the cylinder walls, removing oil that is necessary for good compression. id make sure the mechanic checks those things before condeming the engine. and as someone else mentioned, it should still run with 75 psi, as long as you have good spark and fuel pressure. you could remove the dipstick and see if you smell gas in the oil. is the ignition coil an integral part of the distributor? ive seen many coils go bad, arc to the grounded distributor shaft, and then no start and much fuel in the engine oil and no compression due to oil washed out of the piston rings.


----------



## mikewiebe1987 (Nov 3, 2005)

sounds to me like you badly need a 2nd mechanicaly point of view, i suggest taking it to another shop, if he was committed enough for a compression test he should have told you more, maybe im missing somthing was it low on gas? i know i used to move mine every once in awhile and if it ran out of gas it would airlock and shit, what a bitch to prime , weak pump, but yeah second opinion man that mechanic sounds the shits


----------



## yitznmara (Nov 14, 2005)

*Thanks everyone for your help!!*

As it is I had it towed to a dealer. Their diagnosis was a flooded engine and injection cleaning.
Thanks to all of you for your help!!


----------

