After a year & a half, I've finally got the problems with my car completely sorted out....finally I can move on with the rest of my restoration! But a couple questions maybe you can help me understand better.
Here's what's been done to my car to clear all codes:

• Wiring going to various sensors & circuits were replaced with new
• New reman. Bosch® MAF
• New relays (MAF, MAF burn-off)
• Throttle blade angle recalibrated
• TPS sensor recalibrated to .545v @ idle
• New fuel pump

>>>>Now, my symptoms<<<<

As you can imagine, my car runs much much better now....but not quite perfect. I don't think I'm asking too much really, and here's why it's not perfect:

• The idle is around 700 RPMs in Park (valve cover has a pronounced leak). 600 RPMs in drive.
• The idle is smooth...but a quiet slight, slight miss can be heard every 3 seconds from the exhaust.
• The car has a slight stumble when throttle is stabbed from idle, during both open and closed loop...
• Exhaust smell has a slight hint of richness..the exhaust out of the tail pipe is visible @ times (but I have a drilled out CAT).
• With stock chip part-throttle & WOT acceleration are fine..seems to be burning smoothly, but slightly rich.
• If I take out the stock chip & put in the Hypertech- during part-throttle acceleration (not WOT) the exhaust sounds like it's drowning with gas (rapid "chug-chug-chug" sound). Part-throttle acceleration is also slower than with stock chip.

>>>>Now, my questions<<<<

The plugs & O2 sensor may be fouled, since the car ran rich for months before I had everything fixed.

If I replaced the plugs and O2 sensor, would that cure the above problems? Do bad plugs generally relate to these kind of symptoms?

If the plugs are fouled and not completely combusting the mixture, does that make the ECM reduce the pulse-width according to the O2 sensor? Or will the car run slightly rich with bad plugs?

I like more technical feedback, as to what is happening internally in the engine with bad plugs and O2 sensor.

I appreciate the help,

Corey

 

your talkin like 30 bucks in parts. And yes those are good symptoms of a rich running engine and that could be due to a bad o2 sensor, but I am guessing that you have headers but maybe not. I think you should check for exhaust leaks where the headers meet the block. doesnt sound like a fouled plug though cause you would feel that at all rpms if it is poor idle quality I would look for a vacuum or exaust leak.

 

Like the other guy said, plugs and a new O2 sensor are so cheap, that if you suspect them at all, go ahead and change them.

Other than that, doesn't sound like you have any real problems.

600rpm (+100 for PN adder) is completely normal for an LB9. And besides, the factory tach isn't that accurate anyway really.

The slight stumble in the idle, and coming off idle also don't sound like big deals to me. Not sure how bad yours is, but mine has those 'symptoms' too. Anyhow, i just passed emmisions with flying colors, so i am sure that slight roll in the idle is nothing. If it was a miss, my e-check would have showed it. The stumble off idle doens't concern me because it doesn't actually effect my acceleration, i only notice it if i rev i and listen for the very slight dead spot.

As for the rich smelling exhaust, completely normal when you don't have cats.

The hypertech chip probably runs like crap because it is total junk. The jet / hypertech / PR chips all have timing added in stupid places. It probably slows down from extreme knock retard.

As for you thinking it is rich at WOT, sounds like you're just guessing. Rich / lean isn't something you form a theory about, it's something you test with trial and error at a track or dyno. You're only rich if you go faster from leaning it out.

 

Mr. Maher & Eric,

Thanks for your responses and help. I don't have a lot of hands-on experiance with engines...spent most of my time reading manuals, magazines, and well...these forums.
I realize the Hypertech chip is junk. I bought it before the 'DIY PROM' board was even added here...so I had no guidance in that respect
I'd like to learn more of the fundamentals of engine managment though, to start programming my own PROMs...Grumpy lives a couple minutes from me (if I only I could get him to let me hang around him!)
But, anyhow would this Hypertech chip be useful for when I start burning my own proms in the coming months? It appears the Hypertech ePROM is the same byte size as the stock, plus it's easily removable. Someone tell me I didn't completely waste my money.
The reason I will be needing a custom PROM, is because I'm going with L31 heads, undecieded cam, and SDPC intake manifold. I feel that L31 heads are the best bang for the buck, providing I can find a good used set to be machined. I'm definitely purchasing this combo this spring, unless I can be shown a better combo for the same amount of money. I've also got a few questions about this combo though too...but I'll do a search, and make a new thread later with anything I couldn't find or need elaborated on.

Thanks again guys...it's people like you, who make this board what it is.

Corey