Did anyone here have those codes for a heavily modded NA Revup motor that isn't tuned for the mods? I think I finally reached the limit of the ECU compensating fuel for the mods without tuning to add more fuel so it's throwing the codes. The car is running very lean as the sensors are white in color.

 

is your motor built?
cuz mine is and i wasnt lean before i got it tuned

 

It's stock with a lot of boltons.

 

What is the heavily modded part of a bolt on motor?

 

^This

 

ROFL @ heavily modded. The codes could be anything, leaking intake gasket, torn silicone hose behind the maf, vaccuum hose fell off. LMAO again tho.

 

Obliviously I wouldn't be asking the question if I didn't check for an obvious vacuum leak first and preventing vacuum leaks is the reason the motor has aluminum valve covers. The mod list is in the garage.

and the amount of mods in not important since one mod can make all the difference.

I only need to know if there is a limit is on how many mods an NA motor can have before it runs lean and the ECU stops compensating fuel throwing those codes without a tune to add more.


Thanks for being unhelpful.

 

Buy or borrow a Cipher cable and log your fuel trims. If you see them max out (iirc it is something like plus or minus 25%) and you are positive it is not a fuel pressure problem or a vacuum leak, then I would say yes you have reached the limit. Also it would be best to have a wideband O2 sensor so you can monitor the A/F and make sure it really is "lean" - I wouldn't really trust the factory O2 sensors.

 

The stock sensors are wideband sensors. I know for a fact it's lean because the sensors are white in color and not because of a head gasket problem getting the sensors contaminated in coolant. I also swapped sensors with new ones. Stock ones worked fine and passed testing.

I have to get the tuner version of Osiris sooner or later, I was hoping I could drag it out longer without tuning.

 

True the sensors are wideband and yes you'll need a tune. Mine threw a couple of codes when I did the intakes. not the codes you had, but I had two codes intermittent and alternating when reset. The car felt like it was running just fine. Vacuums, votages, sensors themselves, etc all check out. The car is running lean so I'm going for another tune.

 

I wouldn't assume that it is lean just because the sensor tips are white. How did you perform this analysis? Drive it at WOT and then turn the key off right before you hit redline then pull over and take out the sensor to look at it?

Do you have Cipher? What are you reading for A/F at WOT? What are your fuel trims?

 

Ya that's exactly what I did

 

Pretty sure everything bolts on to a motor. I haven't seen anyone welding in pistons.

 

There are 8 different possible codes or so for each of the those sensors. Out of the 8 or so possible codes, the one the ECU is throwing is for a lean condition. Coupled with the fact the sensors are as white in color as plain white paper, it's undoubtedly very lean.

I also just checked for exhaust leaks just now and I am also preventing the gas tank from venting gas vapors to possibly increase fuel pressure. I also went and got a half a gallon of E85 to 6 gallons of 93 octane to clear dirty injectors if they are dirty.


Problem is the ECU is retarding timing, A LOT whenever it's throwing those codes and it's like running a 4 cylinder motor in a car that weighs nearly 3500lbs and it's very annoying.

 

Who told you that white O2 sensors mean you are running lean? White sensor is usually silicone contamination either from RTV gasket maker or coolant.

Oh and by the way, stoichimetric for E85 is 9.8:1 so by adding half a gallon of it to your tank you are only helping the engine run leaner . If you have 6 gallons of regular gas in your tank and a half gallon on E85, stoich will be roughly 13.3:1. So if your fuel trims weren't maxed out before, they probably are now!

"E85 requires the use of 40 to 50 percent larger fuel injectors, to compensate for its 40-45 percent increase in fuel demand. The change in stoichiometric AFR from 14.7:1 with gasoline to 9.76:1 with E85 is 66 percent, but the resulting flow needed is only 40 percent greater, due to E85's higher density than gasoline; your vehicle's check engine light (CEL) may flash a "lean condition" code, resultant of this."

 

Again, do you have Cipher? Have you logged this? If not, how do you know?

 

 

Obviously you do not know or realize that when the gas tank is constantly venting with the EVAP system removed, the motor turns over additional times before it starts because there is no pressure in the fuel line.


I see starting this thread was pointless since I know more than the people I'm addressing the question to.
Have you ever seen a dyno run of a wideband VQ without the codes and one with the codes? Power is A LOT lower and power falls off a cliff above 5k RPMs.

Obviously I'm running a mixture to possibly clean the injectors (which is gone now anyway) and obviously it's not something that I'm doing permanently. and if you read the above post I already looked at an obvious and possible head gasket problem. I do not have air bubbles in the radiator neck when the car is running and it's not losing any coolant. I am also not seeing any sign of oil contamination in the coolant. And it's not overheating no matter how hard I run it. I also have the Tstat removed which would make a head gasket problem a lot more apparent.

 

It's a blown head gasket. It failed the combustion gas test. Time to swap it for another motor. Cant rebuild it. I don't have the cash.

 

how in the world did you blow a HG? musta been seriously modd'ed

also, just because your blew your HG does not in any way mean you need a new motor. take it to a shop that knows what they are talking about