One cylinder not working.

[Off Road SHO]

AZ SHO OFF's 95 MTX is not firing on cylinder 4. It's got good compression, a good spark, new fuel injectors, verified the correct ohms on the wire (even changed the wire out), new spark plugs. I can't think of anything else that it could be.

If it was a coil pack problem, I'd have problems on two cylinders, right?

Any ideas?

Thanks

Tom

 

[AutoSHO]

Tom, you might check out the #3 cylinder that #4 shares on the coil pack. If its grounding it could be causing #4 to never see any fire.

If it has and fuel it ought to be kickin' unless it has a burned valve, but then it wouldn't have good compression.

You might try swapping the coil pack for good measure. Perhaps one of the towers is cracked or not making a good enough connection.

 

[Off Road SHO]

Chris,

Dusty can attest to there being enough spark. The compression is at 160 psi which is about 20 lower than adjacent cylinder, but it should still fire the charge.

While we did not measure it, there is fuel pressure in the rail. We will put in a new fuel filter and measure the pressure tonight.

I will also ground out #4 fuel injector to get it to squirt full time and see if that helps.

Thanks

 

[AutoSHO]

Do you have a stethescope you can put on the injector to make sure its clicking away like it should be?

I'm surprised it only has 160 psi compression, thats pretty low for a SHO motor. Did you have the throttle wide open when you did the test?

 

[Off Road SHO]

Chris,

We didn't do a full test, just a quickie one, on two cylinders. And we used a cheapie tester that is so old it's made of wood. wink

We'll try with the stethescope and see if the injector is firing. Tried to make a wink light out of a test light with an incadescent bulb, but the rise time is too slow for our pulses.

Tom

 

[Off Road SHO]

HA! Chris, you were right again. We changed out the plug wire to #3 and now #4 works! It's running on all 6 again with lots of power.

Chris, you da Man! beer

Tom