well that sounds like an Fcon map or settings issue

The Fcon have various submaps that depend on intake temp or coolant temp, these may be set to add too much fuel when it reaches a certain temperature.

Or it could also be a map issue with the main map having some adjacent cells too far in value from each other and when there is a slight change in the vacumm it starts to stumble.

 

so you don't think it could be a map sensor issue eh? I was going to order one just to try it out.

 

no, if the vacuum is steady or at least close enough without wild swings or reading close to what it should be then it is not a sensor issue, I would lean to a mapping issue in the Fcon whether the fuel map tuning around the idle area or the temperature dependent submaps

 

well i thought the f-con had its own map sensor? If so that wouldn't show the variations on the evc would it?

 

yes you are right, w/o a navigator you can't see the map signal for the Fcon.

the map sensors I have seen go bad usually are bad all the time not the way you describe

 

I would hook up Cipher and datalog the sensors you suspect of causing problems.

If you can't determine the problem by inspection, I don't see any other way to proceed. It appears that you can hear the car start to miss when the problem occurs. Check that time period in your Cipher graphs and see if any sensors change dramatically.

 

ok i bought a navigator today so i can at least get sensor readouts from the f-con so we will see what that shows.


now i am reallllllyyyyy broke lol

 

Hey man... I'll hire you to punch state farm in the face

 

WestPak is VERY knowledgable on the Fcon...he was one of the first people to introduce me to the system...I agree with him 100 percent...this does sound like a sub map issue with temp compensation...as the cars indicated temps change, the Temperature compensation maps will pull/add fuel to allow the car to run smoothly...if these maps are not setup for your specific configuration they can cause the said result. ...on the same note...if the temp sensor's element is failing...it can create an excessive subtraction from the map due to extreme changes in the resistance value....either way...the navigator is a great tool for any Fcon owner....keep us posted with your findings!!

-Jack

 

Thanks for the reply Jack. I agree w/ you that westpack knows his stuff, thats why i pm'd him asking for his input.

I actually went ahead and picked up a navigator on Friday and hooked it up today. I ran the car and it seems that all the sensors are functioning correctly. Only semi strange thing i noticed is that a couple of times it seemed like my battery voltage meter dropped a tad for a split second then surged back up.

The car once again ran for about 15 min and according to the navigator waas running at around 90 degrees celcius at idle. It hovered at this temp for a while so the problem might not be so much heat dependent as it is time dependent. I am freaking lost here

 

ya but wouldnt the tuner know right away if he adjusted those settings? from the thread, it appears nothing special/out of the ordinary was set.

have you made sure that your maf voltage is steady at idle when the car starts to act up? how about swappin in a utec wuth a simple greddy map to see if the problem reproduces itself?

good luck!!

 

Thats the problem w/ this POS FCON, i can't connect to it to see **** and verify w/ JT or someone else the sub map settigns. I liked how smooth the car ran w/ when it was running, but i kind of wish i had gone w/ the haltech instead.

To my knowledge the car is now running on a map sensor and the maf is pretty much eliminated (maf is still hooked up, but the Fcon is controlling everything from the map sensor). I would love to try a utec to see if that eliminates the problem, but the only other person in my area that is boosted also runs the FCON lol (he is using smaller injectors than me)

 

We've got one here with your name on it jk, well, sort of.

Have you been able to reproduce the problem while watching the Navigator? Also how much did battery voltage drop/bounce? Fuel should be corrected according to voltage, so if it was a large change that could be something.

 

Well i am not ready to drop another 2.5k on another ems just yet lol.

I was able to reproduce the problem while in the driveway w/ the navigator in hand. I would say when it started stumbing the votage dropped a couple of volts. It was running a stable 13 volts when the car was running right.

 

A couple volts is significant.... did it stay low or momentary spike?

 

If the voltage changes happen when the idles becomes erratic then that is the cause.

With an issue like this it is tough to find the root cause when looking at a bunch of symptoms.

With the navigator you can look at a lot of things now, I would keep an eye on IAT and Coolant temps and record their readings when the idle becomes erratic.

I am still leaning towards a tunning/setting issue.

There is a submap that is based on Air Temp and also another based on coolant temp, these submaps may not have come into play during the original setup becuase they didn't reach the same temps at that time.

Also the main fuel map could have a cell that is adjacent to the area that got tuned for idle that has a big difference in value and if it comes into play it will start the loopy hunting idle and wont stop. The idle is just a ***** to get perfect, it took me a while to get mine down.

 

it dropped as soon as the car started to stumble i think. It then stayed around 12 after the car killed.

A couple of days ago i checked the fp while the car was acting up and it seemed to stay sufficient (ie voltage to the pump was being killed)

 

IAT and Coolant temps stayed stable during the stumbling. The only erratic readings i got was the voltage and the ign timming was jumping all over, but i think that was from the fluctuations in the rpm bouncing up and down.

 

I wasn't looking for erratic behavior of the IAT or coolant temps, just for you to keep an eye on them as they climb and see if the idle issues start at a specific temp or if the temp is steady and the idle issues start without the temps climbing.

If the temps have been steady and the idle issues start then those submaps are not an issue. Then it is probably the main fuel map.

did you verify the boost/vacuum readings are ok using the navigator?

 

oh ok gotcha. Yea i was looking to see if it was a specific temp that triggered the problem, but it doesn't appear to be. The temps stabilized and held for several mins and there were no fluctuations when the problem occured.

Yes boost and vaccum are fine, but when the car starts dying the vaccum drops due to the rpm dropping.


BTW i am not sure if you have read the whole thread or not, but the issue will also occur WHILE driving. Its like my car is only able to run for about 15 mins. I can't even drive the damn thing from my fiance's house to my house for fear that it will stall out on the way.