Update#2. Re: Failed Emissions Inspection. AGAIN!!!!!

["therealdmcvegas" <DMCVegas@xxxx>]

After running thru a little "cocktail" comprised of Berryman's Chemtool, and 
Bardhal FI detergent, the engine actually did indeed run cleaner. The HC's 
dropped down to 380ppm at idle. Unfortunetly, that still means that it failed. 
Sooo, I tried adding in some denatured alcohol. Lo and behold, the emissions 
became worse than before!!!!! Dammit! Maybe I did something wrong, but I've 
had it up to here trying the "better living thru chemistry" route of automotive 
repairs. I'm not going to put my motor at any more risk by trying to run 
distillates and detergents thru it.

So it's back to the drawing board, and doing what I refused to admit that I had 
to do before: actual repair work. I'll see about pulling the sparkplugs, and 
inspecting them for not just fouling, but variations between themslelves 
individually, as well as following the procedures for checking the equal output 
of the fuel injectors. I've no test tubes, nor baby food jars lying around, so I'll 
need to wrangle some up. Along with the regular testing for vacuum leaks on 
the rubber hoses.

So far though, here is what I do know:

I have NOT replaced anything on the system at all this year. All of that was 
done last year. The mechanic determined the problem to be caused by faulty 
sparkplug wires, that had bad shielding, and were arcing around a couple of 
plugs. While I didn't care for the plugs wires, and tend to agree they were a 
problem with a test light I used on them myself, I don't believe that this was the 
root cause of the problem. I firmly believe that the repairs made last year didn't 
fix the problem, so much as they simply reset the delay on it again, in order for 
it to remanifest. Since this had occured, all ignition components were 
replaced with BOSCH cap, rotor, spiral wires, and copper plugs.

Now we know what symptoms this repair treated, but what in the hell is the 
cause of it? It's either a weak spark, a fuel system imbalance, or a vacuum 
leak somewere. I do know that I have a bad diaphram in my mode control 
switch that will hiss unless I bump the knob, and then it goes away. I'm unable 
to remove the Cold Start Valve, as the screws stripped themselves as I tried to 
remove them. However, I shoved some q-tips in the tube where the Idle 
Speed Regulator fits. I ran the fuel pump for 30 seconds, and all were dry 
when I pulled them out immediatly. The fuel injection system is 3 years old 
now, and was installed by Garden Grove (the final garage the car went to 
when the previous family decided to finally send the car to a specialist, and 
not just all the various hole-in-the-wall garages where it had been before). So 
if there is a descrepency with the injector output/spray pattern, is it better to 
clean them, or to replace them? John Hervey sells a remaned set for only $80 
which is quite temping.

In addition, I have these questions as well:
1. With the higher output ignition coil, it's was reccomended that I should 
increase the gap of the plugs. This I can handle, but would it be to my 
advantage to use BOSCH +4 plugs? And if so, which ones should I get to 
accomodate the new gap size?

2. How do I go about adjusting the ignition timing if nessisary? Has anyone 
done this without removing the intake manifold? And with the new coil, and 
variance in spark plug gap, is this something else that I should adjust as well?

3. At what point have all options been exhausted, and repairs/replacements 
been made that the mixture screw needs to be adjusted? I'm not trying to 
touch the thing, I just want to make sure that I can stay away from having to 
touch it as possible.

4. For performing the Valve adjustment, and/or if I had to remove the intake 
manifold to repair vacuum leaks, what are the approximate times/procedures 
involved? Since I've only one car, and I'm having to borrow garage space to 
boot, I need to budget time even stricter than my pocketbook.

If anything good came out off all this today, I did end up finally meeting a 
fellow DeLorean owner in the wild as I left the smog check station! If it was 
indeed fate, then it sure had a funny way of manifesting itself!

-Robert
vin 6585 "X"