95LT1conv

seems one side may be leaner than the other.could very well be a bad wire on that side not firing. pull the plugs from the low o2 side and see what they look like

TA76

After the previous testing session I pulled the plugs and found #7 fouled out covered in very dark soot, #5 clean and pristine as the day it was put in. All the others looked about the same, used but not nasty like #7. These were new plugs put in for and about 30 minutes of runtime. I'll try and take a photo of the plugs this evening.

I'd also thought of the burnt wire because I think the right-side O2 is pretty close to the header BUT that is the opposite side from the bad #7 and weird #5 plug???

Z95m6

Since i have a 95 Z i've never messed with the early opti's but i know its very possible to install them just a few teeth off. This would throw off your timing and could easily cause "popping/backfiring".

TA76

Is there anyway to tell via scan software if the timing is off?

fbodycarl

I had the same problem you are having in November when I rebuilt the LT1 in my 1994 Z28. What happened was, even though I followed the procedure in the haynes manual for adjusting the tightness of the rockers, I guess because of the new cam, they were too tight. I took the valve covers off, backed the nuts off 1/4 to 1/2 turn. After that the car ran perfect! It's worth giving it a try and only takes about 15 minutes to do. I hope it works for you.

TA76

Thanks Carl, I'll give it a try.

Injuneer

No. All a scan will tell you is what value the PCM is picking off the timing tables. There is no way to know from a scan if the Opti is indexed correctly to the cam sprocket.

I'll take a look at your DataMaster file.

TA76

OK, here is a photo of my plugs... not sure how well it will show up but these were brand new when I installed them. #5 is really cleaner than it looks in the photo, #7 is black as night, the rest are fairly uniform. There is about 30 minutes of run time on these.

Sweetred95ta

My plugs looked like that (certain cylinders running richer than others), and it was due to a bad coil. You could try this test:

http://shbox.com/1/coil_testing.jpg

I just swapped coils out (using someone else's) and found the culprit.

TA76

Hey thanks sweetred, I'll give that a shot. That is one of the components I've not tested yet.

sandman2100

Any luck?

Why is it nobody ever comes back to give updates????

TA76

Hey, it was the Opti... short story I ended up having to sell the car and the new owner replace the opti and no more miss.

sandman2100

AHHHHHH

Good to know. I have a new opti, so cant help me

Thanks for the update!

sandman2100

Fixed it.

Previous owner had #6 and #8 crossed
Plugs gapped at .060
and a burnt #5 he tried to cover with tape

Runs like a champ with the exception of the header collector leak causing a pop in the system, going with Longtubes real soon and a better catback....... this one sounds like chit