bad day compression numbers mean??

[dcmarf]

Well my car sat for 3 years due to me being broke and now I had the money to get a new 4g63t and I bought it on ebay about 3 weeks ago. It took me this long to get it installed and I have fire and spark but it still wont start just turns over?So I just did a compression test and got 185-105-185-145 ?????Does anybody know what I should do now? I couldnt run it with the engine warm obviously since it wont start but does that really matter since I got 185 on 2 of the cylinders? Is this engine junk?

 

[my dreamt dsm]

Not really a motor head here but do you have fuel going in. When we did my buddies swap it took a while for fuel to get it going. Numbers do look junk though. Do a boost leak test... nah... just kidding! I wanna see what's wrong though... I'll stay posted to this thread.

 

[dcmarf]

Yea new fuel pump, gas tank , and fuel filter. Also put in a evo pump so its getting plenty fuel

 

[gvr4550]

you should do a leak down test to see where your losing your compression in #2 and #4 cylinders

 

[Aproductions]

if you have fuel spark and compression, it would start right?

 

[dcmarf]

Yea why no start definately need a leak down test but maybe timming is off so it wont start??

would bad timming cause these low numbers

 

[VETTE_50_TH]

Yea new fuel pump, gas tank , and fuel filter. Also put in a evo pump so its getting plenty fuel

Evo 8 or 9 pump. You know the evo8 pumps are junk right?

 

[dcmarf]

not sure bought it from a guy on here who said it was good forgot if it was a 8 or 9?he said it was as good as a walbro 190

 

[Aproductions]

i usedan evo 8 fro awhile, when rewired they are like a 190lph correct?

 

[dcmarf]

but definitely getting fuel took rail off and its there -maybe the injectors are bad?

 

[Blitz_86]

the injectors being clogged was an issue on my friends vr4 when it sat 4ever.

 

[dcmarf]

yea Im gonna test em tomorrow they sat on a bad engine for 3 years but I havent checked the timming either although it ran in the car it came out of so I didnt think I had to

Still wondering why my compression numbers are low

any wisemen out there

will bad timming cause low compression in one cylinder and not in another?

 

[VETTE_50_TH]

The 9 is the better one. The flow falls off hard on the evo8 pump after 20psi.

 

[dcmarf]

I asked and he said it was the evo 9 but thanks tho.

 

[VETTE_50_TH]

If your timing is off, you wont have good compression the 3 and not in one. It could be a few things. Bad piston rings, valve isnt closing all way. Or your piston or cylinder bowl has a crack in it. But I highly doubt its a crack. More than likely bad rings. Either way, youll have to pull it and rebuild.

 

[dcmarf]

cylinder 3 was 100 dry and 180 wet???whats that mean

 

[VETTE_50_TH]

You should only do a compression test when the motor is warm. More than likely though, your rings are bad.

 

[dcmarf]

yea but it wont start due to bad injectors I quess so I cant??

 

[VETTE_50_TH]

The rings are worn. The motor needs a rebuild. When you pour oil down into the cylinder and test it, and it goes up, the rings are done.

 

[dcmarf]

So should I send it back for a refund or are rings not a big deal?
I could still get my money back

or do I need to do more tests and open it up before I make my decision?

 

[VETTE_50_TH]

No its a big deal. SEnd it back.

 

[dcmarf]

thanks brother I saved up a long time to buy this baby and I dont wanna be ripped off. Im just confused bc I tested the injectors and there working?? Still it has yet to start just turns over. So I was thinking it was the timming and if it is will that cause my low compression numbers?

 

[VETTE_50_TH]

You didnt have the injectors dumping fuel did you? You pulled the fuse right?

 

[dcmarf]

Ya I pulled the fuse and tested them with the ohm meter they all read fine btw 3 to 4 ohms

 

[VETTE_50_TH]

Oh ok. Yea. Send it back.

Please report my posts as helpful if you felt they were. Thanks