7dust

iTrader: (14)

I have a half bridgeported FD with the IAC valve removed. EMS is PFC.

I have recently got my AC working in the car now and works great at speed. However if the compressor kicks on with the car at idle, it promptly kills the car.


I have also noticed that just feathering the gas pedal at lights really doesn't work. The bridge really isn't happy idling with the AC on. It sounds labored and it loses its happy brap if I use the toe on the pedal method at stop lights. Plus - it is a pain in the ***.


I think there may be more to just adding air when the AC is on - as if I need to retune some areas of the map to compensate for the load of the compressor. Should I allow the PFC to control timing at idle? I have also noticed that as the car warms up, the car is even more reluctant to idle with the AC on.


Before someone says it - setting the idle a few hundred higher does not work. 2000 rpm isn't enough to compensate for when the compressor kicks on and I don't want my idle higher than that when the compressor is of.


SO, what are my chances of getting the stock IAC to idle up the car when the AC is on? Anyone ever had success on a half bridge? This thing likes a LOT of air and fuel.


Should I give up on the IAC and just install a generic 12V air solenoid with some type of manual bleeder to tune it?

What is the meaning of life?


I'd prefer an answer from one of the bridgeport elite and not someone speculating / guessing / criticizing. Ive done enough of that already.

arghx

iTrader: (3)

Your description of the problem is necessary but not sufficient. Post data logs (.txt file) of the problem and your map (.dat file). Make sure you have an accurate wideband input.

In the monitor window of the FC-Edit software, select "sensors" "Aux" and "Advanced" You do have a Datalogit right?

7dust

iTrader: (14)

Well ****. I have all that but its hard to log when the car kills itself with the AC on. I will be the first to admit I am not very proficient with the datalogit.

I truly thought it had to be a mechanical issue (add air somehow) and not a tuning issue.

rx7rcer09

i would take it to your tuner and have them adjust the idle map for load with the AC on. im taking a guess that you got it turned without AC so the idle was probably adjusted to run no load.

7dust

iTrader: (14)

I guess my next question is CAN a half bridge happily brap along at idle with the AC going?

rx7rcer09

yes it can a half bridge is an aggressive port and putting the AC on is sucking power. what is your idle RPM wit the AC off you can adjust your car to Idle higher until you get another map.

7dust

iTrader: (14)

^^^ The thing is that I can only control fuel and timing. The IAC is removed and I'm not sure if the stock one can compensate for the bridge anyway. Would I be wasting my time reinstalling it?

thewird

iTrader: (8)

More timing. Set your timing map to advance when the RPM drops & load is applied. Make sure extra fuel is being added as well.

thewird

neit_jnf

iTrader: (17)

42

ryan1

iTrader: (5)

Put your iac back in, and fix the issue caused by making a single turbo harness. When you cut stuff out of the harness you killed the 12v feed to the iac. If you run a new 12v feed wire to the iac the pfc will control the iac and make your issue much easier to deal with.

thewird

iTrader: (8)

The ISC won't work as well with a bridgeport due to fixed default idle timing values. It can be made to work but there is no need, you can do your own idle control using the ignition and fuel tables and it will burn cleaner with the higher timing.

thewird

peejay

No, because the load from the A/C compressor should be enough load on the engine to make it run smoothly.

My half bridge N/A stops brapping and runs smoothly just from turning the fans on. I've a video on YouTube of the thing just sitting there idling at 1000rpm like a stocker. (I want to link it instead of embedding it but the forum software won't let me.)

If you can, put your normal idle timing "in a hole", so that when RPM drops and load goes up, like when the A/C engages, timing advance increases so that the engine can make more power instead of stalling. You put the idle in a timing hole so that it's not idling at 2500rpm when the A/C is not engaged. Makes sense?

arghx

iTrader: (3)

After setting up the options in the monitor window ("Advance," "aux," "switches," everything else off), here is your procedure.

1) Key on, engine off. Make sure all accessory loads are switched off
2) Begin logging.
3) Start cold engine and keep vehicle in neutral
4) allow engine to warm up on its own. when operating temperature is reached, save log
5) start logging again. switch on all accessories (headlights, defrost) except A/C. save log
6) turn all other accessories off. start log. switch on A/C. Vehicle should die according to your description, but logging will continue because the key is still in the ON position. Save log

7) turn off all accessories. start logging again. start engine and go drive around... while the vehicle is moving pop in the clutch or come to a stop. save log. you are trying to observe how it normally behaves when the idle is settling down.
8) Get moving again. turn on A/C. Find a safe place where you can pop in the clutch or otherwise come to a stop, and log it while it dies. save file.

8) zip the files and upload them (.txt files and the .dat file)

The whole point of this is to gather data on how the engine behaves when it's stalling and when it's not stalling.

It's possible you have a mechanical issue but you really need data to start diagnosing. Keep in mind that I am basically offering to look at logs in this thread, for free, for the benefit of you and the benefit of anybody reading. You can guess and screw around with it or you can take data in a methodical way and at the very least rule some things out or figure out what direction you want to go.

7dust

iTrader: (14)

Captain Guess and Screw Around checking IN!

I have actually taken this opportunity to work my way around the datalogit software.

Already I have improved my fuel map somewhat just to practice.

I have found that by advancing the (hole) leading timing area where the car wants to idle with AC on has made a difference. Car still dies - but just the tip of my toe on the accelerator will keep car running. Car wants about 42 degrees advance with AC off. Car seems to like 44 degrees advance with AC on. Advancing timing more seems to have no effect.

I am still learning timing settings so I'm not sure what to do with the trailing. However, I think that at this point if I was able to introduce just a tiny it of air via hooking up the ISC or wiring in my own 12V air solenoid activated by AC clutch... the car MIGHT idle.

Anyhoo, I will submit the logs requested above - once I get them.

thewird

iTrader: (8)

43 degrees is too much timing... If its needing that much timing with no load applied, add more idle air and drop the timing to 20 or so with no load.

thewird

7dust

iTrader: (14)

^^^ Its a bridgeport.

Started working on the map with what I believe was a BDC basemap. I have looked a a few examples of bridgeport basemaps and they seem to have about 38 - 40 degrees in the idle area. Mine wants 40-42. I'm not trying to rewrite the book here.

thewird

iTrader: (8)

Yes... bridgeport is in the title of the thread... Just do it and report back results. A base map is just to get the car started, not a proper tune. I idle full bridge and peripheral ports at 20 degrees of timing with no load. You could do it with even less timing to give you more room for A/C timing.

Just think about it, if your running max timing to get the car to idle happy, how are you going to apply more timing when A/C/fans come on??

thewird

milano maroon

iTrader: (1)

Mine does. But I'm running an Idle Speed Control and letting the PFC control the idle.

Post a log. Arghx is very good at troubleshooting them.

7dust

iTrader: (14)

I'm pretty embarassed to post my map or log because I'm still learning. It really sucks and needs some polishing.

I'll get it posted but not until I get tired Guessing and Screwing Around.

I talked with Chuck Westbrook last night and thing I have a good strategy to nail down the idle under load. He proposes that I get the idle under load where I want it by adjusting timing and air. Once I get that working, turning off the load should only raise the RPM by a few hundred and then I can work on the normal idle area. Its kind of a backwards appproach to what I have been trying but it makes sense.

7dust

iTrader: (14)

Success for now until a variable changes.

I like a 1700RPM idle speed but the best I could manage is to split the diffference.

Idle with the AC off is 1800RPM. Idle with the AC on is about 1500RPM. When the car is warmed up it sounds powerful with the AC on and off.

I set my normal timing at 20 degrees at zero split. AC idle area is 39 degrees now and zero split. I had to take a little fuel (5% or so) out of the AC idle area.

I think I can bring the AC area down even more in timing but for now I'm going to try this and wait for more input.

thewird

iTrader: (8)

Try lowering timing even further and cracking in more idle air. You learn by trying different things.

thewird

7dust

iTrader: (14)

Agree. I already feel 1000% better making changes and working through the settings.

I accomplished what I did in about an hour. Best part is that it cost me nothing and added no further compllexity with valves and solenoids.

Thank all for being patient and putting up with guessing and screwing around.

I hope this helps someone else trying to get their bridge more civil (if thats possible) with some AC.

peejay

I idle at 0-10 degrees (no split)... less timing means less vacuum means less exhaust dilution means less fuel needed. Also a lot better drivability.

It also means less brap brap brap, but I don't bridge port for the sound, I do it for the torque.

thewird

iTrader: (8)

Hence what I was getting at "try lowering the timing even further and add more idle air". I've only ever tuned brideports that only see the track excluviely so my only goal there is to give it a strong clean idle with the brap brap hehe.

I figure with more timing and a larger split it will burn the fuel cleaner though. That's my thought about it anyway.

So 7dust, how comes your idle progress?

thewird

arghx

iTrader: (3)

Even though you've got a laptop, it's like adjusting a carb in many ways. You adjust one thing one way, keep it steady, and then adjust another thing. Just try difference combinations.

So you can try a lot of idle air, through the throttle valve opening angle or the air bypass screw, and then retard the timing. Or you can use a lot of timing and less air. Another thing to keep in mind is hot starts. When you hot start, the air temperature sensor reads hotter. This can cause a lean condition, so you have to tweak the air temperature compensation table or possible move around/replace your air temperature sensor.

I'm not sure if you have the idle speeds set in the PFC or if you have manual idle control. If you have manual idle control (all idle speeds set to 0) then you are exclusively going off the main IGL and IGT maps. If you have the idle speeds in the PFC, the PFC will bump up the timing when the load condition changes.

When you are doing your logs, select "sensors" so you can view when A/C and electrical load switches on and off.