suspected timing issue

[jreis91]

Hi all,

first post on this forum, have some questions for the educated ls motor gurus so figured i would come here.

Info of the motor from previous owner:

2002 LS1 with approximately 85K miles
All seals and gaskets were replaced 25K ago
LS6 intake manifold
K&N air filter
Jantzer ported TB
Cartek custom grind cam 230/234 598/603 113 lsa
Stock 241 heads
Patriot gold dual valve springs
Titanium retainers and locks
Thunder Racing hardened pushrods
LS2 timing chain
SLP 25% underdrive crank pulley
PCM tuned by NickD in Mesa, AZ
405rwhp/362rwtq


I have put about 10,000km on the setup (myself onto of whatever the PO claimed) and have to say it runs great. This summer I decided to do some maintenance and change the fuel filter because by the end of last season the car felt sluggish (or i was getting bored of the power).

As I was inspecting the plugs, I noticed that the whole "Ground Electrode" was greyish. The research I did led me to believe the timing is off on the car, possibly too advanced? I have done some tuning and research myself, but am still learning.

I have not changed the plugs yet. My tuner is going to have a look and let me know what he thinks. any help on here would be great, thanks!

[SMWS6TA]

fuel trim tables could be off a bit.


Are you able to hook up a wide band and see what the F/A ratio is? That would help tune it more precise.


Also on the injectors, how much load are they under? Meaning are they able to handle the new cam?

[pajeff02]

Gray is what you want to see: How to Read Used Plugs: DENSO Iridium

Black is rich, white is too hot (or lean), speckles are bad, physical damage is bad, and oily or wet is bad. You need to clean the MAF if you run an oiled cotton gauze air filter like a K&N. If the timing is running too advanced, you would either have detonation or the knock sensors pulling timing (which would affect power). Curious as to what you find...

[pajeff02]

BTW - welcome to the site!

[jreis91]

Thanks for the welcome!!

I am still running stock injectors, walbro 255 and Aeromotive A1000 FPR. I was under the impression at my power levels the stock injectors are pushing it, but have been done many times.

No wideband as of now, it is going to be ordered soon. I am hoping it is just a tuning issue (ignition timing too advanced), the car does seem to have less power then when I first seated driving it.

Funny you mention the maf, I went to clean it the other day and it was spotless!! The grills have been removed form the PO which I wasn't too happy about, but the engine overall is very clean.

I am hoping to head over to my tuner during work tomorrow, I will post any updates, along with dyne vids when it does get tuned. Any other information would be greatly appreciated.

[pajeff02]

Here's a good site with a formula for calculating fuel injector size: RC Fuel Injection

[jreis91]

I calculated my setup and looks like the stock injectors are at about 85-90%. Up the injector size and tune, or just keep running it how its been running?

I was able to stop by my tuners shop today and he had a look at the plugs. He thinks they look fine, and think the little residue on them could be from the 94 fuel.

I still suspect something is wrong because to me the car does not feel as fast as 400whp in a 2400lb car should. I am going to post a picture of the plug. The issue was not the grey colour, but more that the WHOLE ground electrode was grey.

Apparently online I read (I will try and find the source) that the transition from the colour on the ground electrode should be somewhere around the 90deg bend. If the whole ground electrode is grey, it could be a sign of advanced timing. Again this is just something I read, and am coming here for more information on it.

I am planning to run the car on the circuit so I really want to make sure I don't have any issues.

Thanks again for the help.

[pajeff02]

What be the "2,400 pound car" -- certainly not a Camaro or Trans Am?

[35th-ANV-SS]

Probably a type-o and means 3,400 lbs

[jreis91]

no type-o, car is a gutted Mazda rx-7 with a cage.

Anyone have any more info on the plugs/timing? maybe I am overthinking it.

[35th-ANV-SS]

Bet that car scoots pretty good then.

[jreis91]

Update.

Changed the fuel filter today and it really opened the car up. The old filter I wasn't even able to see through to the other side, where the new one I was clearly able to see the mesh filter inside and light coming through.

Fresh gas is going in tomorrow (car has been sitting since last summer). Im debating weather I should change the plugs and tune or just drive the car. any input helps.

[Firebirdjones]

Unless you are running leaded fuel (only in racing fuels down here), it's difficult at best to read the plugs. Unleaded fuel doesn't leave much color behind like the leaded fuels used to do. At best while running unleaded you can look at the plugs and judge whether it's really lean (white) or really fat (black) Anything in between is almost impossible. It's till good to look at the plugs for signs of detonation (black specs on porcelin) and to see if the AFR is way off, but no real good way to nail down the AFR reading the plugs anymore with unleaded fuels. You really just need to hone that in with a wideband. Since you have a light greyish color, it sounds fine to me. Not too fat and not too lean, I'd probably leave it alone until you get a wideband on it. Keep in mind if you are running 10% ethanol blend fuels up there that increases the stoich AFR to 14:1 (not your normal 14.7:1)

I can say with 99% certainty that if Nic D tuned the car down in Phoenix, you can bet the AFR is spot on as well as the rest of the tune. He's regarded as one of the best in the valley down here.

You guys still have leaded fuel up in the great white north?

[pajeff02]

Not a drop of leaded anywhere around our area that I am aware of.

[jreis91]

I can say with 99% certainty that if Nic D tuned the car down in Phoenix, you can bet the AFR is spot on as well as the rest of the tune. He's regarded as one of the best in the valley down here.

You guys still have leaded fuel up in the great white north?

Thanks for the help, that makes me feel better about the tune. I will leave the plugs in the car for this summer and just drive the damn thing.

No all fuel up in the north is unleaded. I run petro canada's 94 octane in the car.

[0rion]

just from reading through this it doesn't really sound to me like you have a problem. Probably just getting used to the power. The track will really tell you what you have. Get out there and make some passes. I would probably look at an injector swap at some point. You're right on the ragged edge of what those injectors can do.