Low Compression from Cylinder #2

robert0803 · **Low Compression from Cylinder #2**

Failed Emissions Test and had a code of "Cylinder 2 Misfire". I took the car to a shop for a full tune up and had my buddy there look at cylinder #2 and it was squeaky clean.
He told me there was no need for a tune up and that there was low compression. He recommended selling the car or replacing the engine.
I was blown away because I never saw the "Check Engine Light" come on. Turns oput the dealership that I bought the car from cut the wire to the light...bastards!!!

So I need an engine or would like to sell...

Anyone have any suggestions?? What would you do??

**Brent** · 03-24-2005, 04:27 PM

I bought a complete 3.8 engine (splitport) for 80 bucks... but I got a quote to have it dropped in and it was 1k dollars just to drop the engine in.... so I dunno man, I would probably try to sell it but be honest about whats wrong with it.... If you got someone that can put the engine in for cheap then go that route.

robert0803 · 03-24-2005, 04:29 PM

Shop quoted me $450.00 to put the engine in. I just have to buy the engine and drop at the shop.

**Brent** · 03-24-2005, 04:30 PM


Quote: Originally Posted by robert0803 Shop quoted me $450.00 to put the engine in. I just have to buy the engine and drop at the shop.

I would go that route then. Start shopping for a engine that you are 100% it is in good condition. What year is your car?

robert0803 · 03-24-2005, 04:33 PM

Its a 96 V6 Stang Automatic Trans!

Let me know if you know someone with an engine for sale.

**Brent** · 03-24-2005, 04:39 PM


Quote: Originally Posted by robert0803 Its a 96 V6 Stang Automatic Trans! Let me know if you know someone with an engine for sale.

That is exactly what I have and I was able to find a engine out of a 96 for 80 dollars. Just keep your eyes open for a good deal. Check all the major classified sites etc etc.

wiarumas · 03-24-2005, 04:49 PM

sell it on ebay.

**SpectorV** · 03-24-2005, 04:57 PM

I got random misfire CEL codes due to a loose Under drive pulley... DEFINATLY check this, if you have a misfire you WILL get a cel light, are you getting this?

Make sure to tq the crank pulley to 125ftlbs at least, its hard to do but can be done... see if this helps. The little gears on the back of the pulley, if even just a tiny bit out of alignment with the sensor, will throw a code so also inspect this. Did you have the cyilnder compression actually checked?

If all this fails you may just need new seals/head gasket aka time for heads/cam/intakes

Ponycarman · 03-24-2005, 07:41 PM

A loose pulley isn't gonna give you low compression though.

Steve

jedwards242000 · 04-08-2005, 10:14 AM

a low compression reading is due too either something wrong with the valves or the pistons or piston rings, you could have a valve thats bent or valve that is not seating properly. or you could have swallowed a piston ring, how was the car running when you took it in to see your friend and how low was the compression on that cylinder. basically low compression is due to the cylinder not being able to compress the air it took in on the compression stroke. so the air is leaking out somewhere. the only places it can go is out through the valves. or down through the pistons . hope this clears up what is going on with your car a little for you and helps you out if you know this already then disregard it just trying to be of some assistance

john

Danger Dude · 04-08-2005, 11:22 AM

Damn guys there is nothing to swapping a engine out especially if the are the same model. it can be done in haldf a day. disconnect wires, EGR tube fuel line, throttle cable from T/B remove electric fan and radiator and remove bell housing bolts rent a engine hoist and attach it to the motoe and lift out and reverse order going in. I know places that do this for $200 simple becuase it is not hard at all.

Ponycarman · 04-08-2005, 11:23 AM

Low compression could be a head gasket too.

Be nice to see the wet and dry compression numbers.

Low dry and low wet it's probably not rings.
Low dry comes up wet, it's probably rings.

Simply putting compressed air into the cyclinder via the spark plug hole and listening at the dipstick tube, the throttle body, header outlet and looking for bubbles in the coolant can help narrow down the possibilites.

Hear the air at the dipstick tube - rings
Hear it at the throttle body - intake valve
Hear it at the header - exhaust valve
Bubbles in the coolant - headgasket or cracked casting.

Steve

Danger Dude · 04-08-2005, 11:32 AM


Quote: Originally Posted by Ponycarman Low compression could be a head gasket too. Be nice to see the wet and dry compression numbers. Low dry and low wet it's probably not rings. Low dry comes up wet, it's probably rings. Simply putting compressed air into the cyclinder via the spark plug hole and listening at the dipstick tube, the throttle body, header outlet and looking for bubbles in the coolant can help narrow down the possibilites. Hear the air at the dipstick tube - rings Hear it at the throttle body - intake valve Hear it at the header - exhaust valve Bubbles in the coolant - headgasket or cracked casting. Steve

Good list Steve of how to determine if you have low compression. I will add the easiest way to listen for noise or the rush of air is to use a 1 ft to 2 ft rubber hole and stick one end close to your ear and the other close to the source where the sound might be coming from. This is also a good way to determine if you have a bad lifter or loose or bent pushrod when it the engine is ticking

Ponycarman · 04-08-2005, 12:19 PM


Quote: Originally Posted by Danger Dude Good list Steve of how to determine if you have low compression. I will add the easiest way to listen for noise or the rush of air is to use a 1 ft to 2 ft rubber hole and stick one end close to your ear and the other close to the source where the sound might be coming from. This is also a good way to determine if you have a bad lifter or loose or bent pushrod when it the engine is ticking

Yep the hose trick works great and you can even use it to figure out which lifter or rocker is ticking too. I have a mechanic's stethescope, but it hrt my ears to wear it for long, poor ergonomics. You can also use a long screwdriver as a stethescope, but be very careful using it around moving parts.

Steve

jedwards242000 · 04-08-2005, 09:44 PM

i did forget to mention the head gasket good thing there are a lot of helpful people to pick up when i forget thanks