EGR 89GT bypass [tru cold air]

[yellow3800]

I plugged the vacuum line going to my vacuum style EGR valve in attempt to raise combustion temperatures [by cold air intake] for greater efficiency.

MY OXY SENSOR code 13 is cycling on/off while driving at 50mph every ... seems like a fixed time interval... stays on for some seconds [prob not over a min, but could be close to] and stays off for a while... returns... repeats

I'm running NON alcoholic 87 octane [texaco sells this for those of you non turbo high compression people].

my question is, since my o2 sensor is older... [mid life, 8k mi on it] is it going out?
should my ecu need modifying/replacing?
is the o2 signal off the map now due to egr bypass?

I wonder if I can put a bosch sensor in there... but if its off the computer map, then it won't make a difference, which is why I post here...

Where is the info on bypassing this?

Andy <--- surely not the first to do this

[IsaacHayes]

Blocking the EGR shouldn't affect the O2 at all.

Don't get Bosch sensors they aren't good. Go with Denso or AC Delco. www.sparkplugs.com has Denso for cheap, is where I got mine.

Check the wires going to the O2, maybe it's as simple as a broken wire or something.

[Bandit]

I plugged the vacuum line going to my vacuum style EGR valve in attempt to raise combustion temperatures [by cold air intake] for greater efficiency.

MY OXY SENSOR code 13 is cycling on/off while driving at 50mph every ... seems like a fixed time interval... stays on for some seconds [prob not over a min, but could be close to] and stays off for a while... returns... repeats

I'm running NON alcoholic 87 octane [texaco sells this for those of you non turbo high compression people].

my question is, since my o2 sensor is older... [mid life, 8k mi on it] is it going out?
should my ecu need modifying/replacing?
is the o2 signal off the map now due to egr bypass?
I wonder if I can put a bosch sensor in there... but if its off the computer map, then it won't make a difference, which is why I post here...

Where is the info on bypassing this?

Andy <--- surely not the first to do this

The o2 sensor has nothing to do with the MAP sensor. The o2 simply reads the amount of un-burned fuel in the exhaust to adjust A/F ratio accordingly. Now, I could see blocking off the EGR causng a MAP sensor light due to the fact that you don't have exhaust gases traveling into the intake anymore.


SIDE NOTE --- if you are trying to make a "true cold air intake" did you already bypass the coolant lines running into the T/B? Otherwise blocking off the EGR did no real gain if you still have coolant lines hooked up to your T/B.

[IsaacHayes]

I think he means by "off the map" like "off the charts" "way off reading" etc...

And since the older ones were vacuum only I don't think you will even get a check engine light. Now something like a 3100 will know if it's not flowing even due to a blocked passage AFTER the EGR!! It does read the MAP and expect a change when it opens the EGR.

[Bandit]

Yea, now that I read that again I see that. When I read it the first time I thought he meant his MAP sensor. Not "off the map" LOL Oops....

[Money pit Beretta]

Not to be a jerk, but the older cars didn't have coolant lines to the TB.

[Cliff8928]

Yes they do....

[Ninety1BerettaGT]

Yes they do, and simply plugging off the EGR's vacuum will not create a colder intake charge. The exhaust gas still heats up the EGR tube to the exhaust manifold and in turn heats the aluminum EGR valve base, which will still heat the intake manifold.

I'm no tree hugger, but it's put there for a reason, you should be using it.

[Styluss]

Just to clarify, YES, older models have the coolant lines on the throttle body. I removed it on my '89 and have yet to do it on my '90. And as far as I know... removing the EGR will do nothing for performance.

[IsaacHayes]

1994 3100's don't have it though.

[Ninety1BerettaGT]

I'd also like to point out, blocking off the EGR as per the service manual ...

Too little or no EGR flow allows combustion temperatures to get too high. This could cause : Spark knock (detonation). , Engine overheating. , and Emission Test Failure.

Aka blocking it off, does exactly the opposite of what you wanted to achieve.

[Money pit Beretta]

I could swear that my old 90GT didn't have the lines.

[3X00-Modified]

1994 3100's don't have it though.

94-95 lacked them 96 they came back.

[#1 stunna]

Doesn't the EGR only operate until the motor gets warm anyhoo?

[IsaacHayes]

It operates at partial throttle at like cruise mainly highway speeds. And when slowing down to around 40 I think it opens then too.