View Full Version : Check engine light

10-26-2004, 04:25 PM
I hope someone here can help me out. I recently (5 weeks ago) put a bassani o/r x-pipe and catback on my car. I am using MIL's that the shop includes in their package for o/r pipes. I did have to replace both my cat monitors about 2 weeks after installation due to broken ceramics inside the sensors. At this time I also had steeda underdrive pullies installed. I had no problems until last week. Them my check engine light came on. I took it to Autozone so they could read the codes. And the code that came up was a slow response from bank 2 sensor 1. Well later that day it must have corrected itself because it shut off. But now it has come back on, and it's the same thing. I am assuming that sensor 1 is the one before the cats or cat monitors. My question is if I am using MIL's, is it possible that I have a bad MIL, or cat monitor but with the MIL's the OBDll is saying it's the first sensor? And what should be my first plan of attack on correcting this problem? I just paid $80 for two new cat monitors from the dealer, I would hate to have to pay for 2 or 4 new sensors, even though I get a break in price, because of family.

Thanks in advance,
lost and confused :dunno: :confused:

10-27-2004, 07:17 AM
I've noticed a trend of that bassani X on '01 cobras over the years. I don't know what to tell ya though. I just noticed a lot of people have had problems with bassani x pipes and that check engine light. If you have a predator, or a custom chip, have them shut the rear o2 sensors off. If it was me, I'd put new front o2 sensors in, even though they are pricey.

10-27-2004, 08:05 AM
The front O2 sensors go bad and should be replaced about every 50,000 - 60,000 miles. The rear O2 sensors can go baq as well though they are less critical because they do not affect the performance/gas mileage of your car (the fronts do). Even with MIL's if you have a bad rear O2 sensor you'll get a check engine light. The MIL eliminator modifies the signal so that it is in the required range of operation. If the sensor is bad (not sending a signal or the signal is so far out of range) then the MIL will still alter the bad signal and the computer will see it's not in the correct range and trip the light.

Sensor 1 would be the front O2 sensor. Bank 1 and Bank 2 represent the driver side or passenside while Sensor 1 would be front and Sensor 2 would be rear.

10-27-2004, 11:24 AM
Thanks Tom and Smashedheadcat,

So do you guys think I should just go ahead and replace the front 02 sensor? I don't mind doing this, but I wanted to make sure that the MIL wouldn't have anything to do with it, before I go and spend $$ on the sensor. Also which side is bank 2? I'm guessing it's the passenger side. Even though I'm not modded out I am thinking about having a air/fuel ratio gauge installed. I am going to have a steeda t/a installed next week. The shop owner said he was just going to set it at 14 degrees and not even check it, doesn't sound safe to me to do that. I would think you would want to check for the air/fuel and where the best performance is. What do you guy's think.


10-27-2004, 11:31 AM
Always replace both at the same time (both fronts).

You can't just add an air-fuel ratio gauge, you have to add a Wideband O2 sensor and something that knows how to interpret the signal (our O2 sensors are narrow band). Expect about $400 or so for the Wideband O2 equipment and then another $100 for a good meter for it.

10-27-2004, 02:06 PM
Well I guess I won't be getting a air/fuel ratio gauge. Didn't know all that went into it. I guess I'll wait until I'm running boost. I'm just worried after I get the t/a on that my ratio will be off. And the installer doesn't sound like he wants to mess with checking the ratio and adjusting the timing, to where I get the most power with a safe ratio. I guess I might have to take my business elsewhere. It's just hard to find a good mustang shop here in the northwest without driving hours.

Thanks Tom

10-27-2004, 03:06 PM
The timing adjuster shouldn't be hard to change. Have it installed and then hit the dyno (with wideband A/F metering) to see where you are.

It's a good idea anyway to check your power on the dyno because sometimes more timing does not equal more power. Conservatively, I'd start at 12 degrees...

10-27-2004, 03:37 PM
I asked the shop owner about installing one and getting on the dyno to check for a/f ratio and to check for power increase. He said there really is no need to put it on a dyno. He said I'll be fine ratio wise at 14 degrees BTDC and that I'd gain about 1.5 times the power than what I did with the pullies. But I wanted him to do it anyways to play it safe. It just sounds like he doesn't want to mess with it. I guess I'll have to find another shop with a dyno to do it.


Mr. Ed
10-27-2004, 10:39 PM
Deja Vu! Been there! Done most of that! Ended up "trashing" the Bassani X-Cat. Tom Crews and many others remember the trials and tribulations I had with mine. All had excellent advice to offer, but I quickly became tired of that incessant "Map Light" on my instrument cluster.:eek: If ya wanna know "my fix" for this issue, email me(elbcar@comporium.net) and I'll be glad to pass it along! Since the "fix", my CE light has gone OFF and never came back on!:thumbsup: :bounce: