Slight misfire and back fire and now loud tapping

[ghostrider]

Alrighty then. This stinks. I was really enjoying the niceness of my new ride, the 92 in my sig. Yesterday I went outside to start my car and warm it up a bit before I left work. It was bitterly cold out. zero degrees, -20 with the windchill. Anyways, I start up my car, and I notice its running a bit rougher then normal. I head back inside and let it sit there. 15 minutes later, I go back out and its still running rough. I get it up to full operating temp, and its still misses a bit, and back fires if I'm at 1500 RPM in third. Now, there was a full 60K done maybe 10,000 miles ago. I checked the plug wire connections on the front bank along with the coil pack. All were good. I haven't been able to check the firewall side of the motor yet. It's wicked cold outside, and I have no garage to pull into. All my fluids are good. And the CE light hasn't come on. I haven't pulled any codes, but will try to tonight. Anyone have any ideas as to what is causing this? Any and all help is greatly appreciated.

<small>[ January 31, 2004, 05:59 PM: Message edited by: ghostrider ]</small>

 

[sdpatt]

if ( sparkMisfire && no_CE_Light )
then
plugs
else
plugWires
endif

Man, I've been working too much.

 

[Bizzy]

Here's a good topic for you to read.

And another

<small>[ January 30, 2004, 09:57 PM: Message edited by: Bizzy ]</small>

 

[ghostrider]

Well this evening, I was able to pull me car into a garage and took a semi closer look at whats causing this. All wires are in the correct spot. They look good, as do the spark plugs. Someting new has risen up in the symptom list though. A fairly loud ticking/tapping sounds coming from the #4 or 5 cylinder head. Definitely coming from the upper end of the motor. The ticking increases with RPM's. The car is parked right now, to try and lessen any more damage from happening. Hopefully nothing has thrashed the inside of the valve cover. As of right now, I do believe I need some assorted shims to do another 60K. Worse case, a front head with cams. Surgery is scheduled monday. Stay tuned.

 

[projectSHO89]

When you pull that front valve cover, check for:

1) Failed chain tensioner

2) Stretched chain

3) Damaged (or even sheared) camshaft

If the exhaust cam is severely late (rotationally speaking), it can cause the backfiring you are describing.

Steve

 

[ghostrider]

Weirdest thing about this, was everything was smooth as butter. In the afternoon it was running good. That night it was like, I'm gonna run like crap. One of my good buddies was possibly thinking it had something to do with the valves, like them not closing as they should, or a tossed shims. I hope its not the latter. We'll see what it looks like soon. D@mn these cars..... hate it now, but once its running I know I'll love it all over again.

 

[shelby_sho]

Before you go and tear the engine apart looking for the noise, verify that it is not the intake manifold runner control plates (the little throttle plates in each set of runners) by unpluging the electrical connector leading to the vacuum canister on the rear of the intake manifold (between cyl 2 & 3). Unplugging this connecter causes the plates to open and if the ticking noise stops, you are not hearing a valvetrain noise. It is common for the 3.0L engines to make this noise.

 

[ghostrider]

I tried as you said, shelby sho, and the sound is definitely coming from the front head unfortunately. Who knows. I'm just hoping it hasn't thrown a shim, and that shim is thrashing my cams.

 

[shelby_sho]

Hmmm, in that case you better take a look soon! Sounds serious.

 

[Off Road SHO]

Did you check to see if one of the spark plugs loosened up?

Tom

 

[ghostrider]

You know what Tom.... I checked the front plugs, and a buddy checked the back ones. To make sure that theyre in all the way. I also pulled the plug wires, and plugs from the front, since its easy. Well the #3 plug wire couldn't of been seated all the way, which allowed some water to get in there, and probably froze. Which then popped the wire the rest of the way off. Got the intake off and cleaned out the hole. Little bit of oil, and some water in there. That plug was all carboned up, so I replaced it. All others looked great. The heads them selves look fanominal!!! Wish I had a camera. Look like new. Cams the same way. Going to check the valve clearances since its already open, and there was that tapping/ticking coming from #4 or 5 cynlinder. Chains look nice and tight. I would never of guessed this motor had 100K on it. I'm excited that its nothing major. Anyway, been a long night, talk to yall later.

 

[Dr. Tweak]

beer

Good news! Let us know what happened!

 

[ghostrider]

Hidy ** folks, just got home a little bit ago. Checked all the valves on both heads. About the worst gap was a .209 on the intake. And a .312 on one of the exhaust valves. Pretty dead on I think. I did find out that the guy who did the 60K on this, didn't replace the plug well seals, and the valve cover gaskets. The O rings were hard and brittle. The valve cover gaskets weren't to bad. I changed them anyway. Intake manifold was pretty clean. I think the ticking is actually coming from a noisey injector. It has plenty of power. Going to try and do a cylinder balance check. But everything seems fine. The intake went right back on, and fired right up. Don't about that noisey injector, shrug , we'll see.