tmdz28

iTrader: (2)

Well, right around last month, I did a dyno and my car pulled 306rwhp but the AFR ratio was at 14.1 from 3500 to 5000rpm. Now after the dyno, i changed the plugs and wires, and it turns out my plugs were shot to hell, some of them have a gap at .070 or higher. After the plug were changed, the car runs a lot smoother and idle better. So, right now, I really need to make sure that my afr is good, therefore I think a tune is necessary. Current mods: SLP lid and SLP dual/dual.

I am worried driving the car at 14.1 afr, so i am gonna bite the bullet and get a tune to make sure my engine is healthy. I am not planning to add anymore power mods, just suspension mods in the foreseeable future.

Another question: If i get a tune now, and I add more mods in the future and I go back to my original tuner, do I still have to pay full price, assuming I do not do any internal mods? Generally speaking of course.

What do you guys think?

Bird

iTrader: (25)

If you're still running the stock tune, then I venture to say that the lean condition was caused by the misfiring spark plugs. Chances are you've already remedied the situation with the new plugs / wires, but another quick dyno run would verify that for you. The stock tunes from the factory have a tendency to tun 'over-rich' for safety purposes and even adding the lid / exhaust, you should still be very safe.

A tune right now would add some power, but to maximize your savings, just wait until you get more mods before you worry about getting a tune.

Bird

jimmyblue

iTrader: (11)

Misfires will fake the wideband lean. Overgapping (or
erosion) is one way to get spark blow-out. You would
also like to know that you don't have any kind of fuel
fade or injector imbalance problems, which are also age /
maintenance issues. You should have a clean fuel filter,
air filter, MAF, and maybe even injector service before
you go in for a tune on an older vehicle.

98Z28CobraKiller

iTrader: (17)

Couple of things. IF it was really reading a solid 14.1 from 3500 to 5000, then my guess is that there is something wrong with the wideband. I've never seen a wideband not fluctuate at least a couple of tenths in that large of a spread.

14.1 cruising around part throttle is fine.

tmdz28

iTrader: (2)

That's what I was thinking, the reading looks very odd to me during the dyno.

I already replaced the fuel filter and check my fuel pressure and it shows 60psi throughout all rpm.

The only thing I haven't check, which I will this friday, are the injectors. If that checks out, I will wait for the tune on the 30th and hopefully through it, it can be confirmed that my car is healthy while gaining some power in the process.

Plus, my tuner said that if I do add bolt ons in the future, he will re-tune it for free.

Ryne @ CMS

iTrader: (10)

yes i will!!

tmdz28

iTrader: (2)

ls2formula

iTrader: (7)

If the wideband being used is a sniffer up the tail pipe type, you could have an exhaust leak. In a free flowing exhaust system, a leak can actually draw fresh air in depending on the location.

tmdz28

iTrader: (2)

It is actually a sniffer in the exhaust pipe, and I will post my dyno graph later on today to show that AFR was at 14.1 and does not change at all throughout 3500rpm to about 5200rpm or so.

SweetS10V8

iTrader: (4)

I know that in stock tunes, a lot of the time, there is a setting to where PE mode wont kick in until a certain RPM. I seem to remember it being set to 4000 or 5000 which could be the problem your seeing.

tmdz28

iTrader: (2)

Ok, I checked my injectors and at warm (not hot) the ohm was between 14.5-14.7 for all injectors, I checked a few when cold and it pegged between 12.4 - 12.6 for all injectors. I guess I'll wait until the tune to see if my car still runs lean. I hope not.