Just when I think everything is finally sorted, on my '96 that I put back on the road a year or so ago after it spent 4-5 years in my parents' garage, I seem to have an intermittent ignition problem. It happened a couple of weeks ago -- just for a short time, the engine started missing, almost stalled at a stop, missed a few times for a minute or two... and then went back to running normally.  No problems for the past 2 weeks.

Today, it did it again -- the engine stalled as I was decelerating to turn onto an on-ramp.  After I started up again, it continued to miss for a few miles -- but, naturally, seemed fine when I got home.

So I'm thinking maybe I should look through the service paperwork and see if the spark plug wires have been changed, as part of any of the things I had done.  Apparently not.

So I look at the manual, then go on-line for more detail -- and run across a really detailed explanation-with-pictures (on another forum) about how tricky it is to replace the wires -- they have to be routed juuuuust right, there are some very tight spots they have to get through, and all in all, it is nothing like doing the same procedure on the only other Chevy V-8 I've had, that being a '74 C-20 pickup, on which the operation would take about 10 minutes with no difficulty at all.

Is this really as hard as it sounds?  Or, what else would seem to be a likely candidate to cause the very-occasional problem I've described?

Urb


|UPDATED|9/3/2012 3:19:13 PM (AZT)|/UPDATED|


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on my 90 they are not really that hard to change. the only two wires that have to be routed a certain way are the #2 and #3 wire. the only other wires would be the #5 and #7 should not overlap.

did you check for any codes? check to make sure all the wires are tight on the plugs and cap. check the condition of wires. one may have a crack in it and only certain conditions will  it show. if they were never changed it may be a good idea to change them.


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the dynamic duo

c3vr life member #97

I'm a n00b, not an old salt like you "eddie", but even I know there's a difference between a 90 and a 96 ignition system. A 90 has a distributor in the rear; yes the wires are not hard to change.  The OP has a 96 with optispark.  Good luck. You can hardly see the wires, much less route them and get them in the clips. You can't see a thing down there.

A 96 is OBD II. Misfires caused by ignition wires should set P0300 for multiple misfires, or P0301-P0308 for a specific cylinder. I'm always amused when 96 owners don't take advantage of the OBD II capabilities built into their cars. I wish my 85 had the OBD II capability.

My guess is how old is the fuel pump? How long since the last fuel filter change? Plug wires usually are bad or not, the problem doesn't come and go.


|UPDATED|9/3/2012 7:35:19 PM (AZT)|/UPDATED|

Hmmmm.  It's showing a P0100 "MAF or VAF A Circuit Malfunction," not a misfire message (which I was getting for a long time, and which a couple of mechanics had failed to find the cause of, until I finally took it to the guy my Dad used to use... that would be Gunther Baburins of Clay Nissan, for those in the Boston area -- Gunther found that it had a broken exhaust valve spring -- I'm surprised it didn't burn up the valve).

What would the P0100 suggest?  The fuel filter was changed recently -- when I first put it on the road last year, I took it to a dealer and had them do a 30,000-mile service (and a bunch of other things, which cost me a bundle).

When I had the first hiccup a couple of weeks ago, the idea did occur that it could be a fuel problem -- back in the day, you'd say "bad gas" and not worry about it unless it happened again, so that's pretty much what I did. Something like a cracked wire would probably be a continuous problem, ya.  I'm starting to miss my Dad, who was 10x the diagnostician I'll ever be.  In any case, I'll have a look at the wires, but I will NOT try to change them myself.

Thanks,

Urb

PS -- I "Just F890ing Googled It" and found that the message means the Mass Air Flow sensor or circuit may be acting up.  Will follow up.


|UPDATED|9/4/2012 4:03:50 AM (AZT)|/UPDATED|


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new or old dave it doesnt matter. i know that the systems were changed but never really studied the new style as i dont have it. saw newer vettes with hood open and most had covers over it to have that "clean" look. guess what i was trying to say is that is that maybe it looks and sounds harder than what it is.

on my 90 it takes about 20 minutes to change the spark plugs on the drivers side. the passenger side looks as easy but it takes twice as long. guess i shouldn't have answered when i didn't know.

agree with plug wires being bad or not but not the second part of statement. one of my wires got a slit in it that you could not see as it was small. wouldnt get the miss all the time. i had all the wires off and when i was checking each one found a little slit in the one.

as a backyard mechanic, i like to think i do pretty good. i am not a trained mechanic but tinker with a lot of things. my 90 was the first computer car that i started to mess with the computer settings. as i am like a lot of other members on here that like to try to fix their own stuff. i have a 2003 escalade with obdII and yes i wish i knew how to use all the capablities of it.

the way i look at it is i like to make people happy and i appreciate any help i can get with the things i dont know.



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the dynamic duo

c3vr life member #97

BTW, I plead guilty to being (a) not much of a mechanic, and (b) a total neophyte when it comes to the diagnostic chip.  We have actually had an OBDII car for 12 years (2000 Cherokee), yet I never had a scanner until recently, probably because the Cherokee has been pretty reliable, and whenever anything has gone wrong, it's always been something obvious (like the clutch going to the floor, or a drunk driver T-boning us, etc.).  It was only when I inherited this problematic Vette -- with the Service light that kept coming on, blinking, going off of its own accord, etc. -- that I smartened up a little and decided, hey, maybe I should get a scanner, so I'll have some idea what's going on!"  Light dawns on Marblehead, you might say. 

The "not much of a mechanic" part is that I was my Dad's garage assistant growing up -- it started when I was maybe 6-7 years old; he'd put a wrench on a bolt, tell me to hold onto it, then go under the car and loosen the nut on the other side, etc.  As I grew up, I was able to do more and more of the wrench-turning, until I eventually did a lot of the stuff with just my Dad telling me what to do.  (For his day job, he was a brilliant scientist at MIT, and I can't tell you how many times he figured out a way to do something that the shop manual, and other mechanics who worked on cars for a living, said was impossible!).

I held the trouble light while he worked on everything from a Jag E-Type (the oil filler cap in my profile pic is the only remaining part from that car -- which I'd have to say is the only car I like better than the Vette), a couple of Triumph TR7s, various American and Japanese workaday uninteresting cars, a VW or two, an old Mercedes sedan, and so on.  My Dad wasn't really an "enthusiast" per se -- he liked sports cars (I was almost born in a '53 Ferrari 212 Inter), but most of it was just that he was a cheapskate; why buy a new car, when you can buy an old one and keep it running?  We worked on cars on weekends because he and/or my Mom needed to get to work on Monday morning!

But I never assimilated his diagnostic acumen.  I can diagnose simple stuff and do easy repairs that just involve replacing something that's obviously broken (e.g., an alternator, a muffler, a starter, a radiator, hoses and belts, brake shoes/pads), but any complicated repair, I generally hand off to someone who knows what he's doing.  I can see that this is going to be so with the Vette, the vast majority of the time.  If I'd known how much trouble it was going to be, I'd have insisted my Dad keep it on the road after my Mom died in 2008, and taken it for a spin every so often, to get the moving parts moving.  Letting it sit in the garage for so long was not good!

But in any case, it's great to be able to post dumb questions here and get smart answers.  Thanks for y'all's help!

Urb


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Replacing plug wires on a LTX engine  is pretty time consuming and a PIA as compared to other SBCs IMO.....because of the distributor location as someone else said. I replaced mine (and the spark plugs) when I replaced the opti distributor and the water pump was removed....even at that it still took some time.