eksigned

iTrader: (1)

Can someone chime in specifically regarding our cars - do CEL's really throw the car into some what of a given "limp mode" - ie retarding timing, rich afr...? Asking only because I have test pipes, and accordingly...I do get a CEL on here and there. I always thought it was just nothing, but I was told today that it actually puts the car back into a "stock" like mode (but more "safe" in terms of afr values); BAD for me considering all my modifications and given tune. I opened the car up today with the CEL on (idiot!) without thinking much of it (I was told that the CEL was only a light - I just figured with the TPS...it was bound to happen).

I had it reflashed today; turned off the codes.


Thoughts?

Thanks all,
Eric

jamesshifflett

iTrader: (8)

I've been running with my CEL on for about a month now (installed FI hfc's). Nothing noticable but I might be an idiot so I'm curious to hear some feedback.

eksigned

iTrader: (1)

Actually, in all honesty...like I said, I didn't think much of it at all. But my buddy (owns the shop my car was tuned at; also learning to tune at the moment), informed me today.

jamesshifflett

iTrader: (8)

^How much does your buddy charge to tune? I'm looking to getting a tune ASAP.

eksigned

iTrader: (1)

I got a buddy-buddy deal, but even then it was a little pricey. $700 otd. They did a phenomenal job. The main tuner went to Japan to do most of his training. I really appreciate that he tunes based on the CAR and not "off the shelf" numbers. It's a true custom tune. Much better than the other guys in my greater area.

When you get that tune of yours, make sure you do plugs.

By the way, how's that pulley treating you? I WANT! But i hear it throws off some harmonic (not engine harmonic balancer), but something between the clutch/flywheel + pulley?

TomPeters

I've read other places to get new plugs before the tune..... what's the reasoning behind that?

eksigned

iTrader: (1)

^ i seem to be blanking at the moment. lol...i can't seem to remember specifically why! but all in all, new plugs are needed prior to tuning, essentially because your original plugs get warn out/charred from breather modifications. when you modify your car with breather mods that introduce more O2 into your system per every set given amount of intake (your car can only breathe so much), your car basically tries to compensate by adding more fuel. the stock map can only accommodate so much for all that extra air. in doing so, it essentially overly leans the car out - leading to bad plugs. your car won't tune all that well with worn out plugs. does that help tom?

Neal376

iTrader: (1)

no.
especially since the rear o2 sensor just measures catalyst efficiency.

there is a "High detonation" Map that is triggered when there is a ton of engine knock. i.e. if you fill up with 87 grade gas and run it at the redline for 1/2 an hour LOL. its very noticeable when it happens

The cars run very rich from the factory. Some aftermarket intakes, like the stillen, reposition the MAF sensor so its sort of mechanically scaled to run the car lean. at least this is what I have extrapolated from reading dyno sheets off the intex

jran76

iTrader: (2)

Your tuner should be able to disable those faults in the UpRev software (catalyst efficiency codes). There is an option in the tuning software for this specific case. The ECU will basically just ignore a fault from those sensors.

As far as a CEL effecting performance, it depends on the fault. The downstream O2 sensor are only to measure the efficiency of your cats, so it will not impact performance (they are not used for any type of map or tuning).

RISKY GUY

iTrader: (9)

Of you have an uprev tune, they can deactivate the.cel from test pipes.
Was getting cel every 500 to 600 miles.
No light since tune 3 months ago.

Yes you loose major hp when cel is on.

Engine timing is reduced by 5 degrees, when cel is on or when intake temps reach 110+.

And the car runs very rich from factory.

Neal376

iTrader: (1)

5 degrees of timing lost with a PO420? who told you this?

TomPeters

Yes, that makes sense. I was only running my breather mods for ~4k miles pre Uprev tune so who knows if it would have made a difference. Thanks for the clarification

Neal376

iTrader: (1)

they just want your car to be running optimally before you bring it in.
i.e. tuning your car with a bad fuel pump is going to cause a lot of headaches.

most people here dont have to worry about this because everyones cars are fairly new

eksigned

iTrader: (1)

thanks for the information all. actually...i already knew that the uprev software could default some codes thrown to be ignored. i've done so accordingly. p0158/7 have already been turned off. from what i recall, my tuner may have also disabled the lower O2 sensors as well though. AFTER THE FACT, I was still getting codes. hence the question about running the car with a cel, moderately hard (my daily driving habits).

is it true that there're almost ~8 sensors that contribute to the O2 sensor codes? i'm confused...-__-

i'm thinking that i might have him turn back on the rear O2 sensors again. after we turned off p0157...that's when the cel came on, the NEXT day. sorry...thoughts are a little scattered .

Neal376

iTrader: (1)

yea. o2 can report many errors, voltage errors, heater circuit errors etc etc.

obviously bring it back to the tuner. he might have not turned off the correct code or forgot to load the corrected rom. Unless there is a new trick i dont know, its the PO420 you want disabled when you are running test pipes. Your CEL could also be something completely unrelated