Bogs for a second and then takes off

[secondchance]

Originally Posted by Johnny5

"It appears that Z owners that is having the problem have in commons are: 1) the secondaries eliminated
2) Haibeck chip

How about the injectors. What injectors do you have currently installed. I have talked to Marc in regards to this concern and he has 2 1990 that are doing the same thing as well. He suspecting injectors. I'm going to data log and check the car out this weekend. Will let you know what I find out. We can make some changes to the fuel trim if need be."

I have a 1991 (27k miles) that is all stock so I did not delete the secondaries or have a chip. (The secondaries won't open up either) it currently has the stock injectors as well and I noticed my car bogs or surges when cold too! I'll see if it does this after changing the injectors. I just ordered the obd2 to obd1 conversion so i can see if I get any codes from my scanner.

Assumption that secondary removal and Heibeck chip causes stumble is not true. I had my secondaries removed and run Heibeck chip. I had stumbling problem but the issue turned out to be O2 sensors. Replacement of O2 sensors fixed the problem. After another couple of months stumbling returned. This time the cause was TPS going bad. MAP sensor going bad will cause the car to stumble also. Bear in mind that our cars are 20 plus years old resulting in some sensors giving up the ghost.

Done correctly, secondary removal and Heibeck chip to run both injectors are worthwhile modification.

In your situation, with OEM injectors, I'll bet your injectors are failing. I've seen enough ZR-1s with OEM injector failures.

[XfireZ51]

Originally Posted by Johnny5

"It appears that Z owners that is having the problem have in commons are: 1) the secondaries eliminated
2) Haibeck chip

How about the injectors. What injectors do you have currently installed. I have talked to Marc in regards to this concern and he has 2 1990 that are doing the same thing as well. He suspecting injectors. I'm going to data log and check the car out this weekend. Will let you know what I find out. We can make some changes to the fuel trim if need be."

I have a 1991 (27k miles) that is all stock so I did not delete the secondaries or have a chip. (The secondaries won't open up either) it currently has the stock injectors as well and I noticed my car bogs or surges when cold too! I'll see if it does this after changing the injectors. I just ordered the obd2 to obd1 conversion so i can see if I get any codes from my scanner.

I have secondaries removed for many years using my own calibration.
I don't have any bog. Just sayin.

[rkreigh]

I have no issues with the secondaries gone other than the simplified maint and increased performance

it's not a good idea for passing emissions but the lt5 don't need no stinkin secondaries IMHO and marcs cal is spot on with this mod

don't expect too much in terms of additional hp unless you really open up the ports in the head to take advantage of the intake porting

even without the additional porting, I like the sharper throttle response, increased mid range torq (about 8 fts on the lt5) and likely about 5 hp up top

the flappers are only a few cfm in restriction but they really are better off gone and passed on to someone who wants to keep the car stock

very happy I did this mod with Marc. get rid of the air pump too and lighten up the car

"parts left out don't break"

it's not a hack, it's a really nice mod

[Hog]

I don't think anyone would see any negatives with a good ECM recalibration, such as a Haibeck chip.

[Johnny5]

I was quoting someone else to say that my secondaries are not deleted and it does bog occasionally

[Paul Workman]

Originally Posted by Johnny5

"It appears that Z owners that is having the problem have in commons are: 1) the secondaries eliminated
2) Haibeck chip

Apples n oranges... At issue is bogging upon acceleration. The occasional stalling on de-cel has a different set of circumstances and characteristics; perhaps coincidental to secondary delete and Marc's calibration. But, it is certainly NOT a new phenomenon, and NOT exclusive to the LT5 at all.

And, with regard to deleting the secondaries, in many cases, it is often in conjunction with some amount of porting; porting which alters the AF requirements a bit which may well "poke the bear" a bit.

So, IMO it would be a mistake at this time to make attempt to codify a connection between the secondary port throttle (SPT) elimination OR Marc' calibrations exclusively (others do both as well). Juuuust sayin.

[Johnny5]

Ok, so i was replying to Bennie C on Page 2 quoting him that all these issues were from deleted sec, and chip. I stated that mine does that and i have neither. So i dont believe that is an issue. My 91 is stock, i believe i have an injector and/or pump issue. Waiting til Spring to do a tuneup.