i am doing a secondary delete tomarrow for....

[GOLDCYLON]

Originally Posted by VetteMed

First time around I had some lean codes, even with the Haibeck chip. However, those disappeared after new FIC injectors and new fuel pumps were installed. Not a peep out of the ECM since then

Andrew

Cool. Lean codes? Now thats a Hoot. Would not be codes I would expect

[VetteMed]

Originally Posted by GOLDCYLON

Cool. Lean codes? Now thats a Hoot. Would not be codes I would expect

Well, think about it - you're doubling the airflow to each cylinder - if fuel delivery is not up to par, due to a clogged injector, low fuel pressure, etc, then the mixture will be lean. The Haibeck chip changes the injector programming so that both injectors fire any time the throttle is off idle, but obviously that's only as good as the quality of the injector performance, and fuel delivery to the injectors!

[A26B]

"Doubling the air flow" is not exactly accurate. Without the secondary throttle system operating, "impeding" or "restricting" is more accurate. An engine is essentially a positive displacement air pump. It's only going to take in so much air, directly proportional to the displacement. In operation, the secondary throttle system is like a supermax port job.

[VetteMed]

Originally Posted by A26B

"Doubling the air flow" is not exactly accurate. Without the secondary throttle system operating, "impeding" or "restricting" is more accurate. An engine is essentially a positive displacement air pump. It's only going to take in so much air, directly proportional to the displacement. In operation, the secondary throttle system is like a supermax port job.

Jerry, perhaps in the interest of brevity I over-simplified. When the secondary system is either removed, or latched open, it's allowing all 16 intake runners to feed air to the cylinders. This is double the air compared to what is delivered when the secondary throttle plates are closed. If the secondary fuel injectors are not delivering fuel (due to faulty injectors, poor fuel pressure, or an ECM command to not fire), but the secondary throttle plates are open, there's bound to be a lean mixture.

In my situation, the immediate lean mixture led to a code being set, which then caused the ECM to completely disable the secondary injectors, while the throttle plates were still open (nonexistent).

I am not under any false illusion that simply removing the secondary system doubles the potential airflow through the secondary intake ports.

Hope this clarifies what I was getting at.

[PhillipsLT5]

No secondaries here! Love it!
Ditto

[Kevin]

i really need to drive a no secondary car, and I don't mean romp on it type of drive, but just a cruise around town to see how it deals with every day driveablity

[PhillipsLT5]

Hard to tell the difference with or without them except more power now and less junk in the way

[XfireZ51]

Gentlemen,

The motor is going to use X amount of air and fuel at a given throttle opening. Simply activating the secondaries doesn't "make" the motor use more air/fuel. At part throttle cruise, the amount of air/fuel charge is going to be delivered either by one port and one injector OR split between two runners and two injectors. The fuel tables in the cal only deal with total VE at a given MAP, fuel delivered either by one or two injectors. Wth proper tuning, the difference in single or double runner cruising should be not very discernible especially if mods are done to move more air through the system(i.e. headers, freer exhaust)

[VetteMed]

Originally Posted by XfireZ51

Gentlemen,

The motor is going to use X amount of air and fuel at a given throttle opening. Simply activating the secondaries doesn't "make" the motor use more air/fuel. At part throttle cruise, the amount of air/fuel charge is going to be delivered either by one port and one injector OR split between two runners and two injectors. The fuel tables in the cal only deal with total VE at a given MAP, fuel delivered either by one or two injectors. Wth proper tuning, the difference in single or double runner cruising should be not very discernible especially if mods are done to move more air through the system(i.e. headers, freer exhaust)

Agreed 100%, makes perfect sense.

[sammy]

guys first off thanx for all the responses/help. . this really was an easy job to do .we used aircraft wire to wire the secondaries open. we pulled all the vacum tubing and pieces . i also had to replace the starter motor as the dealership that he bought the steamed cleaned the motor before he too k delivery . it sure is one nice 90 the metalic rad paint with manual air and polished stk 90 wheels . the grin on his face was worth the 230 mile trip one way to help him . he was so frustrated he wanted to sell the car .but i told him our cars make us earn the right to own them and this was just a test.lol also told him his new mistress liked it rough, that the more you beat on her the happier she is . the look on his face was priceless