Chevy Impala SS Forum banner

1 - 20 of 20 Posts

·
Registered
Joined
·
295 Posts
Discussion Starter #1
I know this topic has been beaten to death, but the answer seems to be constantly changing with new manufacturing techniques and product development.
I believe my vented Optispark II is causing a misfire in my #1 and #2 cylinders and with 133,000 miles on it I’m suspecting it’s in need of replacement.
What is the most highly recommended current solution to Optispark issues as of late.
Like I said, things change with regards to the latest general consensus on what is the best solution.
Thank you for any advice you have to offer.
 

·
Registered
Joined
·
8,455 Posts
If you have a AC Delco Opti with 133k mi it is time (100k) to change the cap & rotor

This may be all that is wrong with your opt now. You would better know once you remove the old one and see evidence of wear & cross arc, especially for cyl 1&2

Your plug and or Wires could also be suspect if they have that kind of mileage on them

If just a cap & rotor, MSD makes a good kit

If Opti, get a reman AC Delco if you can find one. Everything else is a crap shoot.

Delphi are very good but they seem to be extinct now
 

·
Premium Member
Joined
·
20,281 Posts

·
Registered
Joined
·
295 Posts
Discussion Starter #4
Yes, I replaced the rotor, distributor cap, plug wires, and spark plugs about 20,000 miles ago and car was running great. I had an EGR valve problem with CEL just prior to the miss developing, I put in what was supposed to be the 214-2270 Professional EGR valve which initially turned the CEL off but within 2 weeks the CEL light started to come on and off again intermittently (I think it was a knock off fake reproduction) which led to me putting a new ACDelco 214-5084 EGR valve in purchased from the dealership, however I did not replace the vacuum control solenoid. Perhaps I should but the codes being thrown are cylinders missing, not EGR emission codes.
 

·
Registered
Joined
·
295 Posts
Discussion Starter #5
Thank you BALLSS and Baraka for your quick and helpful replies...
So is a miss between two cylinders that are consecutive in the firing order (#1 - #2) a symptom of an Optispark problem ?
I would expect misfires being random across many of the cylinders from a bad Optispark, not just two specific cylinders.
Clogged injectors perhaps ?
 

·
Registered
Joined
·
6,739 Posts
Maybe carbon tracking inside cap.Opti failures are not this subtle as a rule.
 

·
Registered
Joined
·
8,455 Posts
OP

what was the brand of the distributor cap you replaced 20k mi ago??

If you have tracking inside the cap between 2 cyl...you should be able to see once you pull the cap
 

·
Banned
Joined
·
3,437 Posts
you replaced the rotor cap and plug wires sounds good @100K .. did you remove opti and replace seals ? check for rotor wobble ? use a good amount of silicone dielectric grease in the plug wire boots all ? then what cap used ?

What was the opti condition internally ?
 

·
Registered
Joined
·
295 Posts
Discussion Starter #9
I can’t temember the brand of cap and rotor I used but I think it was a respected brand name high performance set. I always try to replace parts with the best quality I can find.
Inside Optispark looked good, no corrosion or carbon tracking. No signs of scraping or wiggle in the rotor. Ran great for 18,000 miles. I didn’t do the install so I can’t comment on sealing the unit.
 

·
Registered
Joined
·
295 Posts
Discussion Starter #10
Yes. I put on a new water pump and replaced all the seals at that time.
 

·
Registered
Joined
·
295 Posts
Discussion Starter #11
Replaced seal in back of Optispark and on back of water pump
 

·
Registered
Joined
·
295 Posts
Discussion Starter #13
My mechanic is tracing the wires to the vacuum solenoid, he says it’s getting intermittent drops in the signal to the solenoid.
Finger crossed...
Thank you all for your help and input. Please keep offering suggestions and help. I need it !
 

·
Registered
Joined
·
295 Posts
Discussion Starter #14
When we did the cap and rotor (and water pump) we did all the shafts and seals associated with the replacements. Used top quality seals and he assured me he used Loctite on the rotor screws, he’s very detail oriented.
I’m the kind of guy who puts new stuff in and around whatever I’m doing whenever I’m into different areas of the engine.
 

·
Registered
Joined
·
295 Posts
Discussion Starter #15
On another forum they mentioned the ECT on the water pump causing misfires. It’s a two wire temperature sensing unit that communicates with the PCM monitoring temp and affecting the timing.
Any thoughts on this idea ?
 

·
Banned
Joined
·
3,437 Posts
On another forum they mentioned the ECT on the water pump causing misfires. It’s a two wire temperature sensing unit that communicates with the PCM monitoring temp and affecting the timing.
Any thoughts on this idea ?
possible the ECT, like if he dropped it . or damaged the connector. but you say miss fires so I would be looking at a seal gone bad ,loose rotor ,if OEM original coil / ICM replace those as they are too old . the we get into the Opti venting harness .. did he test that ? I do this test every year as it does reveal opti cap leaks/venting harness issues .
the aftermarket caps get distorted in the hot temps ... then leaks ..

vacuum solenoid what is that ? I doubt miss fires but if a vacuum leak high idle also fuel trims off..
 

·
Registered
Joined
·
295 Posts
Discussion Starter #18
OP

what was the brand of the distributor cap you replaced 20k mi ago??

If you have tracking inside the cap between 2 cyl...you should be able to see once you pull the cap
What does “tracking” look like inside the distributor cap ? I’m not familiar with the term or condition.
 

·
Banned
Joined
·
3,437 Posts
What does “tracking” look like inside the distributor cap ? I’m not familiar with the term or condition.
carbon tracking is when arcing is jumping around inside the cap. so if you see a dull discoloration that could be a carbon track which causes the high voltage to jump around ..

the way to test this properly is to use a special testing device . the tool creates high voltage and then indicates if the terminals have a conductive path between them..

I have a tool like this ,, it has a hand crank that outputs 5KV .. then if there is a carbon track/leakage the device will indicate the ohms .. if no tracking then ohms will be infinity no conduction ..
 

·
Registered
Joined
·
8,455 Posts
looks like a electrical short circuit

IDK what brand of Opti you had put in...anything other than a AC Delco cap (with exception to the MSD cap) has been known to be junk and the electrical passages inside the cap that go to each terminal can "arc" together...aka "tracking"

if you were doing this work yourself..or whoever is doing it, took pictures of the inside of the cap we could see if there appears to bethis problem. It may not...just you mention 1&2 misfire..this could be the cause..or plug wires could be arcing against something

a spray bottle misting water on plug wires at night will reveal these kind of arc
 
1 - 20 of 20 Posts
Top