90-92 SD IROC & Z28 or any Camaro mod to SD can fall out of P.E. mode with modified engines. Can anyone guess why before I tell you?

 

pulling vacuum at WOT?

 

No! Try again.

 

Having studied the disassembled binary, I know the answer...but I'm not saying.

 

High Knock counts?

 

I'll agree with Kevin C.

Its known on the prom board and even the issue is dissected.

later
JEremy

 

So the answer is.......

 

Well, its not even every 90-92. Only certain bcc are affected as far as I can tell, might be wrong. BUt the two common ones in those years have a lot of little differences, moreso codewise than actual tune.

later
JEremy

 

So which BCC's are affected?

 

aujp positively.

I ran anjf for a long time just for that very reason and some other code issues like 800 rpm in gear max idle and a few other issues that have been well covered there.

I havent traced this particular affliction in the anjf code so it may be there as well, although I cannot confirm 100% either way.

More of a pulsewidth duration issue figured in airflow calcs than anything else though

later
Jeremy

 

Any manual BINs that you know of?

 

Anyone mind actually converting the abbreviations and acronyms to English so I might try to understand - seeing I have a 91 that I may mod at some point beyond the normal bolt-ons.

 

ARFP always did me right, I used that as my bin base for over a year after I did my 6-speed swap.

 

The FAQ and whatnot in the DIY-PROM forum is a great starting place.

 

Can you provide me a link(s) to the problem, solution, and discusion. I posted HERE and never got the definitive solution to my issue. Searching recently I never saw an update or a similar instance discused or solved.


Thanks in advance,
James

 

The answer is the rubber boot that goes from the throttle body to the intake snorkel. When the weather gets hot the rubber softens up and when you are at wide open throttle in a 5 or 6 speed car and shifting on an off the gas, the rubber collapes between shifts cutting off the air to the engine. I saw this when I was reving the engine. Problem solved!

 

How can that keep you from going into PE? The rubber is restricting the intake. I haven't looked at the TPI code but in TBI a restriction will not effect PE. But if the rubber is blocking the intake tract, you are technically pulling a vacuum. That makes the first response right.

 

When it blocks the air the kpa drops in the 70's and shut the fuel off.

 

Yep...here is an example from a link I provided above......

 

Then you are talking about something completely different than all these other guys. They are referring to a problem (or potential problem) with several BCCs. What you are saying would be common to all cars regardless of what BCC they use.

By the way if your rubber boot is collapsing, throw it away and get a factory one. There is no way I can picture a factory boot collapsing. They are pretty thick, and hard to squish by hand.

 

This is no secret, and the ECM is not dropping out of PE mode. Every induction system is subject to this issue. Observe this thread and the date stamp on it:

https://www.thirdgen.org/techbb2/sho...hreadid=202458

RBob.

{edit: fixed link}

 

Hey, Vincent thank you for the information.

 

It is the factory 90-92 IROC Z28 boot

Thread doesn't work.

JamesZ28 had the same problem and could never figure it out. This is something that needs to be check if you have the same problem.

 

link fixed