Critter

94 lt1 a4 with mods in sig.
nkg plugs t55 i believe gapped at 43, new msd 8.5 wires, new coil wire, new opti.

Its been fouling out plugs since the heads cam install, but i'm not going to pass blame on the tune just yet. i have seen a few things that i think may have caused this.

• My Pcm was not grounded, i fixed this after it fouled out the plugs the first time.
  
  Car ran and slowly got worse until today it would not start, checked the plugs and fouled.
  
• the water temperature sensor (gauge not pcm) on the driver side head was not working, i just now fixed this today
• there was a small vacume leak on the back of the intake manifold, i just fixed this today also

MAIN QUESTION!: could these things have cause the plugs to foul out?
If it still happens after this where should i look?

sbca96

What coil are you running? Possibly a bad coil. I had an unfortunate run with
an Accel coil. It went bad within a week, after reading all the hype about the
opti, I spent over 600 bucks at the dealer for one (didnt know about Dal). It
was a big waste of money since it wasnt the problem. I also changed a host
of other parts, then it was finally found by the dealer that the NEW coil was
bad. I bought a standard replacement Wells coil from Autozone and that was
almost 100k ago. Car currently has 233,000 miles on it.

Tom

Guest47904

If you are sure you don't have any dead cylinders.See what the O2's are showing and the fuel trims with a scanner. Snap the throttle and see what the MAF reads. See if by disconnecting one of the O2s, forcing it to stay in open loop, it runs better.

If the right O2 signal looks funny, look at the harness snap tied to the inner fender that goes down past the headers. It's the small foil wrapped one. See how close it is to the headers. Mine was good for about a year and half until it just cooked the O2 leads inside and the insulation just got brittle and fell off the wires even though the foil looked untouched on the outside.

Critter

msd blaster coil spaced away from the block with washers to keep it cooler. its putting out good spark as far as i know.

Critter

i know that the harness is out of the way i made sure it was as far from the headers as possible.

I have a laptop, would it be best for me to download some type of program to record whats going on with my car and post it? if so what would i need?

1. laptop
2. program (which one?)
3. data cable?

Injuneer

You have several choices for scan software.....

TTS DataMaster (free for 20 uses)
http://www.ttspowersystems.com/

FreeScan (free)
http://www.andywhittaker.com/Home/tabid/36/Default.aspx

EFILive V4
http://www.efilive.com/default.aspx

pcmcomm (bundled with LT1_Edit)
http://carputing.com

Cable:
http://www.akmcables.com/

Critter

thanks man.

i'm new to it,, is there one you would recommend?

reamo04

j/w...but would it being gapped at 43 have any effect on it? I know mine are gapped at 50

Critter

stock is 50, with my car having more compression because of the milled heads i closed it some, not sure if i needed to but seemed like i should so it wouldn't blow out the spark. i could be wrong tho.

also the more gap you have i've read that its harder on the opti?

reamo04

id say the 2nd part is true about more gap = harder on opti because it has to work harder to make it jump the gap....

Injuneer

Plugs foul for two reasons..... 1) they are too cold a heat range (not in your case, since you have the stock heat range); 2) running excessively rich. Its not because of the gap.

There are several ways the PCM can cause the engine to run excessively rich:
-faulty O2 sensors
-faulty O2 sensor wiring
-high voltage wires running in parallel with O2 sensor wiring
-exhaust leaks before the O2 sensors
-misfires
-incorrect coolant temp sensor info (the one in the water pump. The one in the head did not cause your problem)
-Excessively high MAP readings

Critter

aight thanks man