a week or so ago,
i was in hot stop-n-go traffic, on a very hot day, and the temp needle was getting near the 200-230 mark.
all the traffic sped off from a stop when the light changed, and to keep up with the flow, i gave it near WOT.
after several seconds,
the Check Engine Light came on and stayed on the rest of the way home. I jumpered the ALDL and got Code 32.
i've since been easier on the car, even keeping the A/C fan on the whole hot commute home, rather than just turning it on when the needle reached the mid-point.
the question i have,
is a result of 2 things: when i got the car emissions-tested, i set the basal timing back to 10degrees btdc.(the car passed squeakyclean!)
and i haven't touched it since. the engine is noticeably less perky than it was when the timing was 11-13degrees.
the other issue, is that i have the Hot Air Intake, and i imagine that when i gunned the engine at the light after sitting for several minutes idling, that the compartment air was probably searing hot.
so,
would the scenario i just described lend itself to setting the code? would the air being so 'lean' lead to a lack of vacuum such that the conditions could have been created under which the EGR solenoid switch would trip?
am i making any sense?
the short version, is: i've since begun reinstalling the OEM intake stuff, and Rodney's True Cold Air kit,
does the engine REALLY need cold outside air in order to not set codes when stressed on a very hot day? was it starved for air?
is manifold vacuum and timing related in any way?

i want the car to be its perky self again, despite the heat. should i put the timing back to its slight advacement over factory spec,
in addition to giving it a decent intake setup?
the car hasn't tripped any codes in 4 years now, since i begun working on it, so is this just a fluke?
sorry if the post is a bit incoherent; engines aren't my forte'.
thanks!

Yes advance can effect vacuum. moreso at idle tho. I think you might just have an egr solenoid getting flakey, I would check the vacuum lines to the egr and attached to the solenoid (above the waterpump).
You will be MUCH better off with the cold air intake system, you will see a bit of gain there over the engine compartment hot air.
the oldschool rule of thumb was 1 hp per 10 degree's cooler, for an 8 cylinder.
as for the timing, I run mint at 12, and it flew thru emissions at levels that meet new car levels.

ps, in stop 'n 'go driving, the egr rarely activates, the wot and rpm factor is what caused that to activate.

[This message has been edited by tjm4fun (edited 06-27-2007).]

quote Originally posted by tjm4fun: ... in stop 'n 'go driving, the egr rarely activates ...

I have to disagree. The EGR is normally most active at low to moderate throttle and moderate RPM, and is turned off at full throttle and/or high RPM. You don't have to take my word for it ... connect a scan tool and watch it for yourself.


And to answer the original question ... yes, spark advance can affect manifold vacuum somewhat.

[This message has been edited by Marvin McInnis (edited 06-27-2007).]

thanks a lot, guys, that help confirm what i've thought.
i'll tweak the timing, and get my cold air set put in, and see what i see. it's not even July yet! : (
the EGR solenoid, the EGR Valve, and the EGR tube are all new, and i hope the 'new' solenoid isn't going bad already. 2 years is not long enough, when they cost a hundred bux, y'know?
i'll report back the difference in a week. : )

quote Originally posted by Marvin McInnis: I have to disagree. The EGR is normally most active at low to moderate throttle and moderate RPM, and is turned off at full throttle and/or high RPM.

i agree but not below about 35 MPH. i've done a lot of testing with a 6' hose and a vacuum gauge running in to my car about code 32 until you're at 35 in 3rd gear or 40-ish in 4th gear with mild foot feed there is no vacuum at the EGR valve.
**note, i have not tested to see if the solenoid it being energized, i only know there is no vacuum at the valve itself.

quote Originally posted by Marvin McInnis: You don't have to take my word for it ... connect a scan tool and watch it for yourself.

one of these days i'll have to hook up my winaldl AND the vacuum gauge at the same time and see what happens

quote Originally posted by Marvin McInnis: And to answer the original question ... yes, spark advance can affect manifold vacuum somewhat.

agreed

[This message has been edited by buddycraigg (edited 06-27-2007).]

quote Originally posted by Marvin McInnis: I have to disagree. The EGR is normally most active at low to moderate throttle and moderate RPM, and is turned off at full throttle and/or high RPM. You don't have to take my word for it ... connect a scan tool and watch it for yourself.

I was pretty sure that it only activates over 2000 rpm. (roughly)
from the FSM for 32:
Code 32 means that the egr diagnostic switch was not detected closed under the following conditions:

Coolant temperature greater than 80C (176F)
EGR duty cycle commanded by the ECM is greater than 50%
Manifold pressure less than 25 kPa (7" vacuum)

All conditions above must be met for 8 seconds.

notice the last part, and the manifold pressure, stop n go driving only will minimally activate the egr, and certainly not for 8 seconds. and manifold pressure is usually 7" above 2000 rpm, normally cruising speed state. As I said the egr was not designed for stop n go driving, it was deisigned for hiway cruising. it will activate briefly at times in town driving, but is not being checked, so they really don;t care if it is working

quote Originally posted by tjm4fun: I was pretty sure that it only activates over 2000 rpm. (roughly)

I agree with you on that part. For the rest, connect a scan tool and check for yourself. Once the engine is up to temperature, the ECM will almost always be commanding some EGR when cruising down city streets at a steady 35 to 45 mph. It's quite common to see commanded EGR duty cycles of less than 50% under those conditions.

quote Originally posted by buddycraigg: i've done a lot of testing with a 6' hose and a vacuum gauge running in to my car about code 32 until you're at 35 in 3rd gear or 40-ish in 4th gear with mild foot feed there is no vacuum at the EGR valve. **note, i have not tested to see if the solenoid it being energized, i only know there is no vacuum at the valve itself.

Interesting observation. Cruising at a steady 35 to 45 mph, it's not unusual for a scan tool to show an EGR duty cycle of 10 to 20%. Maybe that's sometimes not enough to produce significant vacuum at the EGR valve itself.

[This message has been edited by Marvin McInnis (edited 06-28-2007).]

the egr itself is run from ported vacuum, and they infer in the 32 chart of the manual that it needs 7" of ported vacuum to start to activate the valve itself. that whole design is flakey enough that all our observations are likely true for each specific car. I never logged a stop n go session to see what the egr command is doing. considering mine is even still hooked up is a minor miracle in itself, so I leave well enough alone til it breaks . (if it ain;t broke don;t fix it)

quote Originally posted by tjm4fun: that whole design is flakey enough

HA, the best way i knew how to explain it in my code 32 thread is that "it's kinda a controlled vacuum leak"