Tune up LS1

[Chate]

I think one of my plugs is bad, i'm nearing the 100k mark so its about time...anyway is changing plugs and wires in the vette pretty standard? Anything special i should be aware/afraid of or can i just buy the parts and do this in an hour at the apartment?

[Vettezuki]

I think one of my plugs is bad, i'm nearing the 100k mark so its about time...anyway is changing plugs and wires in the vette pretty standard? Anything special i should be aware/afraid of or can i just buy the parts and do this in an hour at the apartment?

The two things that are particularly important are making sure the gap is to spec (you'll need a feeler gauge), and torquing them down to spec. I think a lot of people have a tendency to over torque spark plugs, which can create nightmare scenarios during the next change.

Make sure you get LS motor specific plug wires WITH heath shields, or take the heat shields off your plug wires and put them on the new wires. The stock plug wires are just fine. You can pic these up on LS1Tech real cheap sometimes, or Ebay motors etc.

In addition to Plugs and Wires, you'll need:
- Spark Plug Socket
- Extension (8" or more)
- Torque Wrench
- Feeler gauge

You can probably buy everything you need, get the specs and borrow the tools from AutoZone.

I don't clearly remember what it's like in the C5 Engine Compartment. (The F-Body is a fu*king nightmare.)

First time on your own, take your time: 1 - 2 hours total. :huh:

[enkeivette]

Why do you think that one went bad? Unless your LS1 is supercharged and you cracked a plug, they normally don't go bad. They'll foul over time, slowly, and for the most part evenly.

If you feel a miss or something like that it could be a wire, melted or loose contact. But it could be something else also, any trouble codes?

I've had good luck with Autolite plugs, they're normally always to spec. And stay away from the fancy platinum plugs. Copper is a better conductor, and they're cheaper.

[ls1z28]

I think one of my plugs is bad, i'm nearing the 100k mark so its about time...anyway is changing plugs and wires in the vette pretty standard? Anything special i should be aware/afraid of or can i just buy the parts and do this in an hour at the apartment?


If you are nearing the 100k mark Coil replacment is recommended. So add another $400.00 To $600.00 for new coils. I would also recommend you go with Delco Iridium spark plugs. You can buy GM performance parts plug wires for less than half the stock ones will cost.

[Chate]

I noticed a rough idle once last week but now its gone, i dunno i thought maybe its a plug but the problem is intermittent...i dunno

service manual says just plugs and wires at 100K...coil REPLACEMENT?? I think i'll just let it die...my wallet cant take it any more haha

[Vettezuki]

I noticed a rough idle once last week but now its gone, i dunno i thought maybe its a plug but the problem is intermittent...i dunno

service manual says just plugs and wires at 100K...coil REPLACEMENT?? I think i'll just let it die...my wallet cant take it any more haha

You might wanna make a trip to ls1z28's house so he can thoroughly interrogate your computer and poke around. You'll have a much better picture of what's going on and can decide from there what you should do.

[Chate]

so
This problem happened months ago, went away, came back, went away and i finally changed the plugs, had the codes looked at, full on diagnostic shit checking fuel air ratios and all this crazy crap that my science brain didnt fully comprehend (he spent like 2 hrs on it hooked up to a scan tool, stopped, moving, revving, iono) anyways, it looked like my plug changing didnt do shit and the rough idle seems to occur only when its not near a mechanic and not hooked up to any scanners...
and when it does happen, i smell fuel, let it run, rev it, and then it works fine...so heck i have no idea wtf is going on and i'm just gonna leave it till it becomes a real and consistant problem...till then screw it i hate paying money for diagnostics haha

[Vettezuki]

so
This problem happened months ago, went away, came back, went away and i finally changed the plugs, had the codes looked at, full on diagnostic shit checking fuel air ratios and all this crazy crap that my science brain didnt fully comprehend (he spent like 2 hrs on it hooked up to a scan tool, stopped, moving, revving, iono) anyways, it looked like my plug changing didnt do shit and the rough idle seems to occur only when its not near a mechanic and not hooked up to any scanners...
and when it does happen, i smell fuel, let it run, rev it, and then it works fine...so heck i have no idea wtf is going on and i'm just gonna leave it till it becomes a real and consistant problem...till then screw it i hate paying money for diagnostics haha

Have the O2 sensors been changed ever? Did this Vette ever do dyno pulls while being tuned? O2 sensors on these motors are pretty important to feed the computer data and adjust the A/F accordingly. If they are old (more than 100k) or if ever the car did a hard pull on the dyno while being tuned and there was a backfire or really lean condition, they can be severly damaged Another possibility, though pretty unlikely unless someone tinkered with it, is a damaged MAF. :huh:. It isn't running an aftermarket MAF is it?

[Chate]

The MAF is stock AFAIK, the mechanic said the o2 sensors seemed ok based on the scantool thing, but he said that the reading isn't standardized to a new o2 sensor, but rather what it tells him is that both o2 sensors are working at the same level...he did notice that at low RPM it runs rich though...damn i wish i knew more about this stuff, i'm tempted to take mechanic school after pharm school just for peace of mind haha but let me describe what it was then you might be able to deduce its real meaning:

So while hooked up to this scanning thing, he went into a menu that resulted in two realtime output graphs that checked the voltage output of the sensors, he said that though this wont tell you if they're good or not, they'll tell you if one is bad vs. the other one (something about the spectrum at which the sensors read is narrow so once levels are beyond a certain limit it'll just saturate the sensor and it'll read max or something) anyway, so with this thing hooked up, he revd the engine hard and quickly released and said that the peaks output by both sensors seem to be equal, indicating that they are functioning properly in relation to each other

It made sense to me at the time, i dunno why i was just smiling and nodding. My dad does all his work stuff thru this guy and he's regarded as trustworthy, he spent a lot of time trying to figure it out but basically just said, the damn thing looks fine just runs rich for some reason under 1k, once it gets going its fine (the scanner thing had another option where it tests bank 1 vs bank 2 and outputs a % which tells you something about fuel air ratio? he said its typically supposed to be +/- 5% and on bank 1 the vette was at 9% when idling, and normalized during acceleration/motion)

Damn thing has 0 codes, history, current, nothing. No misfire readings in realtime or history, but he also said that misfire detection was still new (started in like 1996 or something and my car is a 1998 so it was put together in 1997 or so i'm guessing?)

I dunno, all I've learned is I need to buy some wood and 4 jack stands because these damn cars aren't as scary as the vette shops make them out to be...if you can take it apart, it likely can be put together again, just will take time. I think I've been shy of doing bolt ons this long because i didnt want to pay those absurd labor costs (90/hr- 120/hr depending on the shop wtf is that) so maybe this summer i'll start tinkering with it myself haha

Happy new year everyone!

[Chate]

Actually, Ben, is there any book out there besides the dealer service manual for the 1997-2001 vette? For the accord i used to have this 'haynes manual' and that thing basically let me take apart everything and put it together again (as much as i needed to anyway). I know theres alot of DIYs and writeups on corvetteforum and stuff, but just as an added reference. I am eventually going to tear out the interior and dynamat it at some point (if/when i do the speakers) so some kinda guide would help!

[Vettezuki]

The MAF is stock AFAIK, the mechanic said the o2 sensors seemed ok based on the scantool thing, but he said that the reading isn't standardized to a new o2 sensor, but rather what it tells him is that both o2 sensors are working at the same level...he did notice that at low RPM it runs rich though...damn i wish i knew more about this stuff, i'm tempted to take mechanic school after pharm school just for peace of mind haha but let me describe what it was then you might be able to deduce its real meaning:

So while hooked up to this scanning thing, he went into a menu that resulted in two realtime output graphs that checked the voltage output of the sensors, he said that though this wont tell you if they're good or not, they'll tell you if one is bad vs. the other one (something about the spectrum at which the sensors read is narrow so once levels are beyond a certain limit it'll just saturate the sensor and it'll read max or something) anyway, so with this thing hooked up, he revd the engine hard and quickly released and said that the peaks output by both sensors seem to be equal, indicating that they are functioning properly in relation to each other

It made sense to me at the time, i dunno why i was just smiling and nodding. My dad does all his work stuff thru this guy and he's regarded as trustworthy, he spent a lot of time trying to figure it out but basically just said, the damn thing looks fine just runs rich for some reason under 1k, once it gets going its fine (the scanner thing had another option where it tests bank 1 vs bank 2 and outputs a % which tells you something about fuel air ratio? he said its typically supposed to be +/- 5% and on bank 1 the vette was at 9% when idling, and normalized during acceleration/motion)

Damn thing has 0 codes, history, current, nothing. No misfire readings in realtime or history, but he also said that misfire detection was still new (started in like 1996 or something and my car is a 2000 so it was put together in 1999 or so i'm guessing?)

I dunno, all I've learned is I need to buy some wood and 4 jack stands because these damn cars aren't as scary as the vette shops make them out to be...if you can take it apart, it likely can be put together again, just will take time. I think I've been shy of doing bolt ons this long because i didnt want to pay those absurd labor costs (90/hr- 120/hr depending on the shop wtf is that) so maybe this summer i'll start tinkering with it myself haha

Happy new year everyone!


The C5s were somewhat notorious for being tuned on the rich side, but it sounds like you're having another issue.

You can of course do a lot of your own work, but there are quirks and gotchas. One the pops into my head is that you have to be careful abot where and how you jack up a C5 or something breaks pretty easy. I've never worked on a C5 so I can't remember what it is, just that if carelessly put the jack where it seems like a good idea and jack away, you may have undesirable results. :barf:

I'll PM ls1z28 with this thread and see what he has to say.

[Vettezuki]

Actually, Ben, is there any book out there besides the dealer service manual for the 1997-2001 vette? For the accord i used to have this 'haynes manual' and that thing basically let me take apart everything and put it together again (as much as i needed to anyway). I know theres alot of DIYs and writeups on corvetteforum and stuff, but just as an added reference. I am eventually going to tear out the interior and dynamat it at some point (if/when i do the speakers) so some kinda guide would help!


That's an interesting question. I don't know. Haynes may ave assumed that C5 owners would never wrench on their Vettes themselves or the number would be too small to warrant publishing a guide. But I don't know. Anyway, while they're expensive, I'm a fan of the original GM Factory Service manuals. The tend to come with more "tips" and procedures that aren't covered in haynes manuals.

[big2bird]

If this is a 2000 vette, you need to learn how to pull up and read all the codes. These things throw codes up if your wiper washer fluid is low. :sm_laughing:

[mybad79]

This little tool that you can buy for around $10 on Ebay makes the job so much easier - it was a nightmare when I tried to change the plugs on my LS1 Fbody without it.

http://www.vettemod.com/forum/imagehosting/2148661f1d3ddba.jpg

http://www.vettemod.com/forum/imagehosting/2148661f1e98354.jpg

wires: my stock wires measured 300 Ohms, the MSD wires only 28 Ohms.... huge difference but absolutely not noticeable when driving... engine ran fie before and after, the new wired looked nicer (red)...that's about it...