#1 wont fire.
 

Hi there,

I have a M1 with a 93 1.6 greddy turbo, intercooled and msd timing boost. I am having a problem with #1 cylinder,it will not fire. I have replaced the plugs,injector,checked spark(it's good),no codes are being thrown. Checked timing it is fine. What could possibly be the problem. The boost guage is bouncing everywhere in vaccum. I am also now blowning smoke on throttle.

what happened before #1 wouldn't fire

traveling at @ 100 mph and suddenly there was a loss of power and temperature guage flew in the H zone , had to let off throttle and temp came back to norm and has stayed there since but #1 won't fire.

seized?

not seized. car runs just #1 not firing.

you're either not getting spark, not getting fuel, or have no compression.

Check your compression. Could have a stuck/burned valve or blown head gasket. Leakdown test preferably.

may have melted a ring land...

if you have spark in #1 then you dont have enough air or fuel...

I'd go with a leakdown test and see where your compression is going.

My money is on bad compression. Sucks but everything else is there. Is the smoke white, blue, gree, purple? Elaborate please.

If you end up wanting to buy the tool, harbor freight sells a leakdown tester for $39.99 and it goes on sale for $19.99 sometimes.

smoke is white.

three guesses.

#1 melted piston
#2 blown headgasket
#3 combination of #1 & #2

I'm leaning towards fragged piston... just because there have been a dozen in the last few months on this forum.

no compression for #1 cylinder.

Well there ya go. When's the teardown taking place?

already started. Just have the head to remove, everything else is off.

Bent intake valve(s) if your gauge is bouncing at idle. My guess. 'corse the lack of vacuum from a toasted piston could make it bounce as well.

broken exhaust valve on cylinder #1. Thank god it was nothing more serious. Time to replace and put back together.