Calvinator

I was driving normally on the way home today and I noticed that my car sounded like a subaru. I assumed it was just a sparkplug wire that came out, but when I got home to check it out, My spark plug wires were all in tact. I figured it was cylinder #2 because when the engine is running, if I unplug cylinders 1,3,4, then it stumbles , but when I unplug sparkplug wire 2, nothing happens.

<U>Things that ive checked so far</U>
-im getting strong spark outta plugwire 2 and my sparkplug is working fine

- I swapped the fuel injector #2 with fuel injector #3 to see if it was that, but still no difference, so i Know its not the injector.

- Compression Test results outta cylinder 2 , 140psi

- Leakdown test Results 30% leakdown outta the piston rings because I can hear all of the air coming out of the oil cap.


My question is, even though the compression isnt so high and the leakdown is horrible, should that cause a cylinder to just stop firing? I would think that even though its bad, it would still fire up, because it complely stopped working.

My motor was never in the best condition. Its been boosted for 2-3 years on 2, on 3 different setups and has over 120k.

Thanks in advance. I'm thinking that its just my shortblock that I need to swap out, but i just want to find out if it could be anything else im overlooking.

HiProfile

Bad rings would allow the intake mixture & exhaust gasses to blow past into the crank case, as well as allow oil & previously vented exhaust gasses to be sucked into the cylinder when its on the intake stroke. The other possibility would be a cracked ringland. The last motor I tore down had #1 & #4 ringlands cracked really bad, and it barely ran while smoking like a fiend. Same thing, gasses blow past.

How bad is the plug? My guess is it would be very black and rendered useless. Even a new one wouldn't last very long under the conditions above.

Calvinator

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HiProfile &raquo;</TD></TR><TR><TD CLASS="quote">Bad rings would allow the intake mixture & exhaust gasses to blow past into the crank case, as well as allow oil & previously vented exhaust gasses to be sucked into the cylinder when its on the intake stroke. The other possibility would be a cracked ringland. The last motor I tore down had #1 & #4 ringlands cracked really bad, and it barely ran while smoking like a fiend. Same thing, gasses blow past.

How bad is the plug? My guess is it would be very black and rendered useless. Even a new one wouldn't last very long under the conditions above.</TD></TR></TABLE>

The plug was pretty much covered all black, but it still worked fine. The motor did smoke a lot under boost and high rpms. Would a cylinder with a cracked ringland stop firing? I would think that it would run weak or like ****, but cylinder 2 is just dead.

5thgenallmotor

cracked ringland for sure....

Calvinator

problem is fixed guys. I checked the voltage going to the injector clip on cylinder 2 and found that the ground was getting a weak signal. It ended up tracing to my resistor box, which was broken. Im just scared that I didnt lean out the cylinder to bad to cause further damage. .

komat

if it wasnt in wot while it happen. you be fine

Calvinator

I started up the car today, only problem was that all of the sparkplugs were fouled from the incident. It was bucking and idling really rough ,and under 4k, it was bucking and stumbling like crazy. At first i thoguht i fucked up my motor, but i changed out the plugs and its back to normal.

aalb1

Problem solved?!?!?!?

What about 140 PSI & 30% leakdown

Calvinator

well, the motor was already in bad condiiton from the start. Its just good to know that its running normally again. Its my daily driver so I just need to get around. Block is being swapped out in a week or so, so I can build this block on the side.