: After WOT engine started missing.



infin1ty
04-26-04, 11:17 PM
After recently performing a 2nd gear WOT maneuver :) my engine, which had been running perfectly, has developed an intermittent miss which hasn't yet set the check engine light. I had replaced the plugs 5k miles ago at the 100k recommended interval. The old ones had dark brown fuzzy deposits (carbon?) on them. The spark plug cables are origional. I purchased a new DELCO set today but have yet to install them. My questions are: Could carbon, dislodged during WOT, foul a plug? Or, being that it is intermittent, is another part of the ignition system to blame? Finally, is there a cable routing diagram on the internet? None was included with the new set.

Thanks for all of your expertise.

kevinK
04-27-04, 09:53 AM
I bet you it is the wire set.

Alldatadiy.com has the front wire, but not the rear wire diagram. The service manual has good diagram for both. The rear wires need to be routed carefully according to the diagram to prevent misfire.

BeelzeBob
04-27-04, 03:54 PM
Check the plug boot to the spark plug terminal connection. Sometimes the small "umbrella" on the large plug boot that seals to the cam cover surface will exert enough force to pull the boot upward off the plug and cause the terminal to disconnect. If the miss persists, check the plug wire crimped on terminals to make sure they are there, crimped securely and that the core of the spark plug cable is exposed and visible and under the crimp. Sometimes, if the crimp is bad or the terminal is loose, the core can arc and burn back into the core of the wire causing a disconnect or gap in the connection.... You can check from one crimped terminal to the other end with a VOM for resistence to see if the cable has continuity. Good thing to check on the old cables coming off to see if there is an open cable that could have caused the problem.....

infin1ty
04-30-04, 10:23 PM
While replacing the wires, I removed the plugs for inspection. Several had brown deposits on them. They were Champion double platinums (the auto parts store didn't have Delcos at the time). Cleaned the plug seat areas in the bore with a damp paper towel attached to a part retriever. Replaced with new Delco plugs gapped at .050"(the underhood emissions tag called for .060" but the Delco phone rep said .050" was correct). Installed the new wires. It now runs very smooooth.

I didn't get a chance to continuity test the old wires before they were gone. One problem I did experience was that one of the coil pack's high voltage connectors had much corrosion (rust) on it. I sanded it clean and gave it a light coating of grease.

This forum and GM are great!

Jack Ammann
05-02-04, 11:55 PM
After recently performing a 2nd gear WOT maneuver :) my engine, which had been running perfectly, has developed an intermittent miss which hasn't yet set the check engine light. I had replaced the plugs 5k miles ago at the 100k recommended interval. The old ones had dark brown fuzzy deposits (carbon?) on them. The spark plug cables are origional. I purchased a new DELCO set today but have yet to install them. My questions are: Could carbon, dislodged during WOT, foul a plug? Or, being that it is intermittent, is another part of the ignition system to blame? Finally, is there a cable routing diagram on the internet? None was included with the new set.

Thanks for all of your expertise.

Infinity: The exact same thing happened to me. The first thing I did was to start pulling wires outta the coil packs to see which "hole" was dead. Well "lo & behold", an entire coil pack (two cylinders) was dead and I really had two dead holes instead of just one. I replaced the coil pack (one coil) and presto, I was back in business. And by the way, a V8 Jeep Grand Cherokee wanted a little piece of my '94 ETC out of a stop light and I smoked him on 6 cylinders...LOL...wasn't by a whole lot, but never the less...

Lawrence
05-03-04, 11:56 AM
And by the way, a V8 Jeep Grand Cherokee wanted a little piece of my '94 ETC out of a stop light and I smoked him on 6 cylinders...LOL...wasn't by a whole lot, but never the less...

71 years old and still draggin', gotta love it!

Jack Ammann
05-03-04, 12:15 PM
71 years old and still draggin', gotta love it!

Yep...and I think I have just the vehicle to do it with...LOL. And I'm thinkin' about gettin' a CTS-V...hehehe...so I can whip-up on the remaining 1% of the cars I can't beat. But the old ETC just don't get beat too often. I've done alot of neat easy stuff to the car. One thing that works really well was the Goodyear Eagle F1's in 225x50x16 on the stock wheels and they are 2" shorter in diameter than the OEM tires and have an AA traction rating....can you say that I effectively went from a 3.71 differential to about a 4.11?...LOL

Lawrence
05-03-04, 12:41 PM
:) :) :)