new greddy type rs and injen intake causing worse gas milage???? Help!!!

[kcwiggs]

Hi everyone, i recently installed a greddy type rs knock off on ebay and an authentic injen intake with no blow off return line on my 1997 eclipse gst automatic. I installed everything with no problems and every hose is tight and clamped up. However since installing these mods i noticed my gas milage decreased terribly to around 18 mpg. Also on the highway when cruising at about 80 mph then putting the pedal to the metal there is a whistling sound as i am accelerating. I was wondering what the problem could be and where to possibly look.

 

[DSMSpyder99]

Hi everyone, i recently installed a greddy type rs knock off on ebay and an authentic injen intake with no blow off return line on my 1997 eclipse gst automatic. I installed everything with no problems and every hose is tight and clamped up. However since installing these mods i noticed my gas milage decreased terribly to around 18 mpg. Also on the highway when cruising at about 80 mph then putting the pedal to the metal there is a whistling sound as i am accelerating. I was wondering what the problem could be and where to possibly look.

That is your problem. DSM MUST RECIRCULATE WITH STOCK MAF! Obviously someone isn't using this website to learn the basics

 

[djjohns55]

That is your problem. DSM MUST RECIRCULATE WITH STOCK MAF! Obviously someone isn't using this website to learn the basics

I agree

Was the whistling sound evident before you put on the aftermarket intake pipe?
The whitstling might be the turbo spooling. The rubber pipe is a sound deadener.

 

[kenamond]

I agree with the other two guys about recirculating. This is a very common mistake. The MAS measures air before the intake pipe. When the BOV is open, it is supposed to recirculate back to the intake pipe. Venting the recirculated air loses air the MAS had measured, so the ECU thinks it has more air than the motor is actually getting. It injects too much fuel as a result, and you run rich. That might be part of your mileage problem.

The other thing you should do is a boost leak test. It's a very similar issue when compressed air (from the turbo) leaks out of the system; the MAS measured it all, but some leaked, and the ECU injects too much fuel.

If your intake pipe doesn't have the BOV recirc pipe, you need to either mod the intake or sell it and get one with the recirc tube.

You also need to do that boost leak test. If you've never done one, you've probably got leaks. When you swapped the BOV, it might be leaking.

Good luck!

 

[50trimmed1g]

I agree with the other two guys about recirculating. This is a very common mistake. The MAS measures air before the intake pipe. When the BOV is open, it is supposed to recirculate back to the intake pipe. Venting the recirculated air loses air the MAS had measured, so the ECU thinks it has more air than the motor is actually getting. It injects too much fuel as a result, and you run rich. That might be part of your mileage problem.

The other thing you should do is a boost leak test. It's a very similar issue when compressed air (from the turbo) leaks out of the system; the MAS measured it all, but some leaked, and the ECU injects too much fuel.

If your intake pipe doesn't have the BOV recirc pipe, you need to either mod the intake or sell it and get one with the recirc tube.

You also need to do that boost leak test. If you've never done one, you've probably got leaks. When you swapped the BOV, it might be leaking.

Good luck!

I'm not arguing here at all and I think venting without proper support is stupid. But I don't think he is getting worse gas mileage because of the running rich after the blow off because that fuel was already going to be injected so that wouldn't cause a change in fuel consumption. He isn't running rich due to an excess in fuel, he is running rich because a loss of metered air. The noise leaking noise is normal when under vacuum because bov's upon due to vacuum. You are only hearing it more because you don't have the return tube muffling the squeaking noise. That, or that knock off is leaking . I may be wrong but this is what my intuition is telling me.

 

[rich3389]

So you bought an injen intake and a ebay BOV, sounds like you should have done it the other way around.

 

[kcwiggs]

thanks all for the replies. If all dsms need the blow off return line why does injen even make intakes without it? Also with having the return line will i still be able to hear the loud blow off from my bov?

 

[knochgoon24]

You can run setups with a GM MAF and a translator. This is usually installed about 8" before the throttle body elbow.

With this setup, you'll only read the air that goes into the throttle body, so you can vent all you want. That's why injen makes intakes without a recirc spot.

 

[Matrixhunter]

But I don't think he is getting worse gas mileage because of the running rich after the blow off because that fuel was already going to be injected so that wouldn't cause a change in fuel consumption.

"He isn't running rich due to an excess in fuel, he is running rich because a loss of metered air. I may be wrong but this is what my intuition is telling me."

1. Fuel is injected based on the amount of air entering the engine "measured at the airflow sensor.

2.A loss of metered air would cause him to run lean!!!!!! not rich

 

[knochgoon24]

1. Fuel is injected based on the amount of air entering the engine "measured at the airflow sensor.

2.A loss of metered air would cause him to run lean!!!!!! not rich

Ummm...nope.

The air comes in the air filter, through the MAS, then into the turbo, through your IC and then either into the engine or out the BOV and back into the intake via the recirc tube AFTER THE MAS. Either way, the car injects enough fuel for the air that has passed the MAS.

If air is lost, via the BOV venting to the atmosphere, that fuel has already been injected, but that air is gone. More fuel with less air makes your run RICH not lean.