Well, just finished replacing my OEM Delco platinum spark plugs with AC Delco Rapidfire #14s. As I suspected, all of the platinum pucks on the originals were missing, and the car only has 39k miles on it. The plugs looked beat down, to say the least. My brother did the driver's side plugs, and I handled the passenger side. He took off the ASR modulde, and AC compressor brackets to give him more hand room, while I was stuck with a space barely big enough to get a couple of fingers in, let alone my whole hand. Stupid AIR tube and diptstick tube. Anyway, I have some Taylor Spiro Pro Wires that we were going to put on, but we kinda ran out of time and decided to save that for next weekend.

Now for the surprise. We took the injector covers off for some reason, I can't remember what, but after we did I noticed an unconnected tube running to the intake manifold. Huh, it was running to a vacuum connection and had a screw plugging the other end. Interesting. Well, that's when I noticed there was nothing connected to the vacuum inlet of my fuel pressure regulator. Hmmmmm. The car had been like this from the day I bought it, two years ago, evidently. No wonder it always felt like it was running rich!

Well, driving the car home tonight there was a noticeable improvement. I still want to take it to the track to see what the real difference is, but the butt dyno says it's significant.

My question is this, though. With the car running that rich for that long, should I have gotten a code??? Is it possible I have a bad O2 sensor???

I'm not looking forward to doing the driver's side wire replacement. Anyone got any pointers? By next weekend, all of the scars should have healed from replacing the plugs :lol:

 

Spark plug wires are just as bad as plugs in my book.You will donate a little blood to the vette .Also you might want to go and get some of the wire holders(looms) from gm dealer this week.I broke 3 of them when i changed my wires.The only hint i have for you is a cold motor and cold beer makes it easier .

 

Yeah, I removed the metal brackets that bolt into the head and hold the wire holders to give me more working room on the passenger's side. I broke two of the plastic holders taking them off, they were so brittle. In fact, I just left off the metal bracket attached directly above plugs #8 and #6, because it looked like it was going to be a pain to put back on, and the wires were in no danger of touching anything hot or sharp.

I think I will look into getting some more holders and looms. I'll try the dealer, and then maybe the local speed shop.

 

I had to lube my wires with dielectric grease to get the drivers side to fit through that small opening behind the PS pump. I also used some long needle nose pliers and removed the inner fender well cover to gain easier access. Cold engine and cold beer do help alot too.

 

I have a feeling there's going to be some disassembly involved; I really don't like cramming my hand into small, sharp spaces unless absolutely necessary (although if I'm pissed enough I sometimes do it anyway.... blood? What blood?).

 

Very good find! I have written some posts in regard to this very thing subject. There are some nice writeups that you should look up under my user name that will explain in detail the problems you were causing yourself, or should I say you inherited from the previous owner. :rolleyes:

Yes you would have been running pig rich at part throttle. However your WOT should stay the same, since your regulator is referencing the same pressure as atmosphere at WOT. Atmosphere is the same as you would have been getting with the vac line disconnected.

What you doing with not having your vac line hooked up is making your ECM do a TON of correcting. This makes for sluggish and terrible part throttle driving.

Glad you found the problem! :cheers:

PS you might want to change out your o2 sensor since its probably been hammered for the past years with an overly rich tune. It might be the icing on the cake for your tuneup! :cheers:

 

That's exactly what I was thinking.

Thanks for the info! :cheers:

 

If you're going to install the 8 mm wires you might think about drilling the stock holes in the looms a tiny bit...they will fit without drilling but I'm not crazy about crimping and squishing them to do so... just a thought....good luck...

Fuzzy

 

Dremel tool! Thanks.

 

When I did my driver side, I removed the tension pulley and another guide pulley. That dropped the belt and gave me enough room to work. Still a biatch! Have fun. I also went to Auto Zone and bought new looms and holders. I got red, the wires are Taylor 8mm. They come with chrome pieces that I bent and shaped instead of the stock pieces that were bolted to the head. Cleaned it up a little and they are made for 7 or 8mm wires. Only gave a small amount of blood, but then again, everytime you work on your car you donate blood....lol

 

Ooh those metal brackets are supposed to have plastic holders on the end. Looks like someone previously broke mine for me. Off to GM I go.
Good luck the back plugs are almost painful to change.

 

Best just to find a nice sharp place and draw blood before you start, that way you will finish much quicker. We all know no job on an auto is every done until blood is drawn.... :smash:

 

What really ticks you off is when you pull the heads and look at the cylinders with the vertical score marks where the pucks got stuck in the rings and did their work.

GM should have fixed every engine for this problem -- the LT5 had the same problem.

Tom Piper

 

:iagree:


Also, when I did my plugs, I went a step further. You guys might think I'm even crazier for this one. I did what's called "indexing" the plugs. You mark the end of the plug so you know where the open side of the spark is. Then you try to get them to face up so the fuel hitting the plug doesn't have anything in the way. So when you screw it in, if you don't see your mark on top you take that plug out and try another one, and so on, and so on. It's said it helps with smoother operation. Iv'e heard that's what they do in race cars. I got 6 out of 8 facing up. Hope it actually works after all that.