reading the tutorial on above.

the charcoal canister needs to be disabled only during VE learn?

is this for datalogging with a WB input only or for any VE learn sessions(NB)?

 

CCP disabled only during the VE Learn. Otherwise it will add fuel which will cause the learned in VE tables to be incorrect. This is for both NB & WB O2.

RBob.

 

RBob,

That's new info. I thought this was for WB Learn only. Do I pull the plug on the CC solenoid or block off the purge line to the manifold?

 

Not really all that new. I prefer to plug the vacuum line and port that goes to the TB. If you have a soleniod actived cannister the N2O output can be used to run it. The other method is to do it how the trucks and early cars did it. A simple cannister with the vacuum line on a ported TB port.

RBob.

 

RBob, on a relevant but different note I am using EGR on my 350. Should I do the learn with it disabled or enabled since the ECM is no longer running it. I have been VE learning with it hooked up to the ported vacuum connection and a delay valve in the hose. I still get a light hesitation off-idle with it hooked up. What is your take on this.

If I can't get rid of the hesitation/surging at low engine speeds and loads, I will hook it up to the nitrous control and set the minimum RPM/load for it to operate.

 

RBob,

The 7747 didn't have control of the CCP. So I assumed that the CCP valve was always purging. My CCP line works in series with the PCV on the drivers side valve cover. Guess I could plug the line from the canister and the port on the PCV. What happens to your tune once the CCP is re-connected?

 

I would do the VE Learn with the EGR connected and operational. In this manner it is compensated for.

Using the N2O output is a good idea. Will need to ground the arming input for it to go active. If you are not using the electric fan output, that can be used to ground the N2O arming input. This way it will only be active above a certain temperature (say 120 F), and inactive under WOT mode.

RBob.

 

The '7747 equiped vehicles used a cannister w/o a soleniod. Just a restricted line to a ported vacuum source.

If you have a soleniod it is either always on, or not at all. Depends whether the soleniod is NO or NC. Can use the N2O output by setting the TPS% to around 12%, MPH to 20, then the RPM window from say 1600 to 6375.

Once purge starts taking place the INT & BLM can drop like a rock. How much depends upon how long the car has been sitting and under what temperature conditions. It can help to place a small restriction in the vacuum line to limit the speed of the purge.

Once purged (meaning the cannister is clean) the INT & BLM values return to there normal values. Which is 128 if all else is good.

RBob.

 

RBob,

I have gone back to my Shop Manual. The ECM energizes the solenoid by grounding it and turning the purge off. Also in the manual there's an illustration showing the solenoid as an N.O. type. So that appears to confirm that the purge is always on if the solenoid in not grounded by the ECM. And since mine is not connected to the ECM, I will assume the CCP is always purging. Should be interesting to see what change takes place in the VE table and where with the CCP disabled. Thanks again.

 

Unfortunately this is inverted function. I just ran into the same thing on another vehicle (I'm testing the EBL on a port setup. Runs nice). The N2O output is active low, which is the opposite of what is required with a N.O. soleniod type. It is always in purge mode. Drives the VE table down.

Can invert the output with a resistor and transister or a relay. I can also make a code change to allow the N2O output to be inverted. Originally I didn't want to do that because it is the N2O output.

RBob.

 

Bob,

Would it be possible to use an Option Word in order to assign the N2O output for use with either NOS or CCP? At this point I'll just block off the CC line to the manifold for VE Learn.

 

I am thinking along several lines to be able to have dual functionality. For those not using N2O have the output available for something else. Same with the TCC output, it is only used when one has an Auto with a lockup.

As for a CCP soleniod, the '92 f-body TBI units are N.C. This matches the requirements of the N2O output with no other changes. I'm going to find one at the junkyard this weekend and try it out. From the service manual it looks like a direct replacement.

RBob.

 

wait a minute....to remove the charcoal canister you have to tune it out!?
I pulled mine out for weight savings.what happens if i don't tune it out?

 

If there isn't one then no need to tune it out. The stock ECM will enable it, but without any real purge the ECM will always see it as 'clean.'

In the above posts it is the opposite issue. When the CPP is active it will affect the fueling. This needs to be accounted for while doing VE table tuning. To do so the physical purge capability is disabled. Then once the VE tables are learned in CCP can be re-enabled.

RBob.