Hello, I have a 95 gsr. When i step on the gas the car will sputter slowely but anooyingly till it passes 2g rpm after that it clears away. I check and changed my spark plaugs and wires. Checked distributer and timing, checked injectors. Did a compression test and got back 240-240-240-90 psi. The cylinder closest to the distributer is the one that got 90 psi. And just a lil bit ago it started to back fire every now and then? Please if you have ne ideas or suggestions to what it may be I really would appreviate it. Thank you Very much

 

Try some Marvels mistery oil in your oil. That might bring up the compression, and I would suggest seafoaming that motor while your at it. The sputter could verywell be from the compression difference. Does it burn oil?

 

Its your timing

 

Timing wouldnt mess with compression tho would it?
I might be answering my own question but if timing is off, intake and exhaust valves could be open at the same time...?

 

its not really burning oil, and the timing wasnt really messed with. I mean i overrevved it a couple times (not an everyday thing though) it evern sputters on idle. Like is hesitates when i give it a little gas until about 2grand rpm then it clears. I really wish i knew what it was. It's kinda hard to tell. Maybe I'll just pull the head off.

 

Im not a man of wisdom when it comes to timing, but your belt could have stretched or skipped a tooth... I would get in there and check the hash marks...

 

if your experienced enough to pull the head, before you really get in deep, how about taking off the vavle covers to see if the valves need adjustement...

 

could be the O2 sensor, any codes?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by L.D.S. Construction &raquo;</TD></TR><TR><TD CLASS="quote">Its your timing</TD></TR></TABLE> Ignition "timinig"

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by WiLLMaTiX &raquo;</TD></TR><TR><TD CLASS="quote">Timing wouldnt mess with compression tho would it?
I might be answering my own question but if timing is off, intake and exhaust valves could be open at the same time...?</TD></TR></TABLE> I don't think it's a mechanical timing

 

timing will not make compression low in one cylinder. do the compression test again. take your readings. then take a little bit of oil an put in that cylinder. if the compression comes up you have either bad rings or scarred cylinder walls. something is no right to have just 90 psi in one cylinder. that is your sputtering problem. the reason it goes away is because at higher rpm you will not notice the cylinder that is not contributing. plus as oil builds up in the cylinder it helps with compression. but you do have aproblem far worse than timing.

 

ok so i end up pulling my head off today. Some people had said it could be a bent valve or it could be the lifters. once the head was off the car I poured lil portions of gas into the intake and exhaust side to see if it would leak through the valve on the bottom of the head. The machine shop told me to try this, they said it would determine weather or not the valve was sitting in it;s seat properly. So I tried it and no leaks from what i saw. i shook it around and check again, the gas just stayed inside the ports and did not leak through the valve. I have no idea what it could be. I was hoping it was the head. But i dunno. the car would backfire from time to time and it would pour white smoke from out the valve cover through where u pour oil in. Even on a cold start when the motor hasnt been started for almost a day it would sart up and as soon as i would open the cap on the valve cover white smoke would pour rite out. I'm pretty sure im loosing compression on my 1st cylinder cause the psi test came back once again 90-240-240-240., As what my mechanic told me. Does it look like its ne thing to do with my head? Or could it posibbly be my block? Oh ywa the cylinder with the weak compressions spark plug is way darker than other. Please ne suggestions or advise would help me greatly Thank you.

 

Could have been a bent valve but you checked for that. No way could it be the lifters. Just to double check. Take the head down and have them test it. If everything looks ok then you know its the block. Sounds like you lost a ring to me.

 

well it looks like #4 cylinder is gone. you're gonna need a rebuild soon. Have you checked your timing anyways just to be sure?

 

hey as a matter of fact, i turn the crank pulley so that the piston that was Top dead center was like in the middle, then i was able to see the cylinder wall of the piston that was losing compression. I noticed that the one that was losing compression had like a burnt stain on the wall but not really physically scratch when i felt it. The other 3 cylinder walls looked the same but the stained one. The stain look like it might of been the piston ring. So if my problem is in my block can I just buy a new piston and piston ring and replace it or is there ne thing else involved? Thank you