Multi Question Post, MPG Readout/Air Intake
Thread Starter
Burning Brakes
Joined: May 2006
Posts: 898
Likes: 0
From: Avatar Nazi Land Orange County, CA
Multi Question Post, MPG Readout/Air Intake
Okie dokie, I was just forced to replace my cats so i put Magnaflow High flows and damn the car has ********* again! It get's up and goes like a *****! I didn't realize just how bad it ran because it was all clogged up, and it sounds a hell of a lot better too. I had put custom exhaust on with turbo mufflers last year but held out on the cats. Well my question is, is there anything better than the stock air box + K&N air filter that I can get for a decent price, or is the stock box fine?
Second question, my MPG readout on my digital dash has worked fine up until this morning where now it just says "0" for the left side where it usually shows an estimate of how many miles remain, and on the right side where it usually displays a number with instant MPG, now it just displays a ".1"... WTF?!?
Any ideas what's up with the readout?
Second question, my MPG readout on my digital dash has worked fine up until this morning where now it just says "0" for the left side where it usually shows an estimate of how many miles remain, and on the right side where it usually displays a number with instant MPG, now it just displays a ".1"... WTF?!?
Any ideas what's up with the readout?
Burning Brakes
Joined: Apr 2004
Posts: 762
Likes: 2
From: Huntington ma
1. The airbox alone really won't do much for you - the whole intake system is cable of about the same flow, ALL of the components need to be changed to see any real gain in capability. Air box, MAF, MAF tube, Throttle body, the whole intake - plenum, runners, base. Then the Heads, and the Cam. There is no one single part that restricts the intake airflow more than the Rest of the components..
2. The ECM needs two inputs for the MPG calculations - fuel flow and MPH. The Fuel flow numbers ( the internal ECM fuel flow rate) aren't going to just Stop working - not if the car is still running.
The Speed number, tho... The speed signal (really a pulsed Ground, but call it an input) to the ECM comes from the digital dash. The dash gets It's input from the speed sensor on the transmission. If the Speedometer is working than the dash is getting It's signal. It may not be providing the pulse to the ECM that it needs, though.
Is the car an automatic? If it is, and the converter lockup is working the same, then the ECM must be getting It's speed signal OK. If a manual transmission I"m not sure that there is as simple and quick a way to tell... a Scan tool would show you (while driving).
Anyhow - assuming that the ECM IS getting it's speed input, and assuming that it's actually Outputting the resulting information to the "operator information center" brain, that brain/display is going to be the problem. I have seen those OIC switches be bad, before...
2. The ECM needs two inputs for the MPG calculations - fuel flow and MPH. The Fuel flow numbers ( the internal ECM fuel flow rate) aren't going to just Stop working - not if the car is still running.
The Speed number, tho... The speed signal (really a pulsed Ground, but call it an input) to the ECM comes from the digital dash. The dash gets It's input from the speed sensor on the transmission. If the Speedometer is working than the dash is getting It's signal. It may not be providing the pulse to the ECM that it needs, though.
Is the car an automatic? If it is, and the converter lockup is working the same, then the ECM must be getting It's speed signal OK. If a manual transmission I"m not sure that there is as simple and quick a way to tell... a Scan tool would show you (while driving).
Anyhow - assuming that the ECM IS getting it's speed input, and assuming that it's actually Outputting the resulting information to the "operator information center" brain, that brain/display is going to be the problem. I have seen those OIC switches be bad, before...
Melting Slicks
Joined: Feb 2008
Posts: 3,286
Likes: 6
From: Palm Beach
How does the ECM determine fuel flow?
1. The airbox alone really won't do much for you - the whole intake system is cable of about the same flow, ALL of the components need to be changed to see any real gain in capability. Air box, MAF, MAF tube, Throttle body, the whole intake - plenum, runners, base. Then the Heads, and the Cam. There is no one single part that restricts the intake airflow more than the Rest of the components..
2. The ECM needs two inputs for the MPG calculations - fuel flow and MPH. The Fuel flow numbers ( the internal ECM fuel flow rate) aren't going to just Stop working - not if the car is still running.
The Speed number, tho... The speed signal (really a pulsed Ground, but call it an input) to the ECM comes from the digital dash. The dash gets It's input from the speed sensor on the transmission. If the Speedometer is working than the dash is getting It's signal. It may not be providing the pulse to the ECM that it needs, though.
Is the car an automatic? If it is, and the converter lockup is working the same, then the ECM must be getting It's speed signal OK. If a manual transmission I"m not sure that there is as simple and quick a way to tell... a Scan tool would show you (while driving).
Anyhow - assuming that the ECM IS getting it's speed input, and assuming that it's actually Outputting the resulting information to the "operator information center" brain, that brain/display is going to be the problem. I have seen those OIC switches be bad, before...
2. The ECM needs two inputs for the MPG calculations - fuel flow and MPH. The Fuel flow numbers ( the internal ECM fuel flow rate) aren't going to just Stop working - not if the car is still running.
The Speed number, tho... The speed signal (really a pulsed Ground, but call it an input) to the ECM comes from the digital dash. The dash gets It's input from the speed sensor on the transmission. If the Speedometer is working than the dash is getting It's signal. It may not be providing the pulse to the ECM that it needs, though.
Is the car an automatic? If it is, and the converter lockup is working the same, then the ECM must be getting It's speed signal OK. If a manual transmission I"m not sure that there is as simple and quick a way to tell... a Scan tool would show you (while driving).
Anyhow - assuming that the ECM IS getting it's speed input, and assuming that it's actually Outputting the resulting information to the "operator information center" brain, that brain/display is going to be the problem. I have seen those OIC switches be bad, before...
