Ok sooo a problem that i thought was my starter seems it may not actually be the starter after all. Sometimes the car will just sit there and crank and crank and may or may not turn on. If it doesnt turn on the first time, the second time ill usually tap the gas and maybe after 6 cranks it may turn on.

Today i noticed my AFR's will jump randomly from 13-16 even to 17 sometimes, at idle, cruising at same throttle position and when i advance the throttle it will shoot lean.

Seems to be fueling? Plugs? Fuel pump maybe? what do you guys think?

 

Sounds like its your tune to me. MAP Volatge or just simple fuel tuning. When's the last time you changed your plugs though?

 

Vacuum leak, possibly.

 

how can my tune just randomly change? tune was on point.

But i havent changed my plugs in a while. Going to go grab some today.

 

Have you unplugged the negative terminal of your battery lately? Reset the ECU at all? And it's probably the plugs.. they can go bad pretty quick if you're running too lean or too rich.

 

Ill reset the ecu and see if that helps.

 

No no. Don't do that. I was saying if you DID that, it'll change how your FIC is running your car. It might make things worse. If it DID fix anything (if it was tune related), it would only be temporary, as the ECU will re-learn it's parameters. I think your best bet would be your plugs... then if you wanted, you can reset your ECU. But I know for a fact, I tuned my car a few times within a month, until I got it perfect, as the ECU was learning how I drove. If I reset my ECU now (which I have before), my car runs like ____ until it learns how I drive again.

 

I can re-upload the map? Ill change plugs and re-upload the original map?
would it be possible that the SAME map wouldnt run as smoothly for some odd reason?
my car was sitting for about 2 months with a bad master cyl, and i ran into these problems after i put a new one in.

(i have taken out the battery during the install to get it charged)

 

You have an FIC, correct? AEM? Not a standalone, right?

 

Yes. AEM FIC. also just had to swap the MAP sensor out on it.

 

Swear im about to just go grab an ultimate. this fic has annoyed me for over a year.

 

Okay, well, this is MY understanding of an FIC. The FIC INTERCEPTS your ECU's numbers and changes them to alter the amount of fuel and rate of injection. PLEASE keep in mind, it's not just fuel and injection... MAP voltages play a part too.

The ECU, over time, will adjust to your driving habits. Based upon how you have driven before you got your tune, the ECU adjusted for the change in the amounts of air (to an extent) by adding more fuel. Lets say the ECU said 1.00 (just to better understand) was the right amount of fuel to add when you were 1/2 throttle in boost. Now, obviously, you're running 11.5 PSI, more than double what the ECU could handle itself. So, YOU need 2.00... so in your FIC, you say you want it to add 1.00 to the original 1.00. Now you have your car "tuned" and running how you want it.

If you reset this ECU, that has over time learned that 1.00 was needed, it believes that you are driving with a normally aspirated engine... so now you only need .35... which causes you to be .65 short under 1/2 throttle until it learns again that it needs to apply 1.00 instead of .35 --

Now, your ECU controls everything. When you reset it, it reverts it back to stock parameters, and naturally aspirated. This changed everything. Maybe your tuner had to add a little extra fuel with the FIC and a little less timing to allow it to cold start properly? That's all gone now because the ECU is no longer compensating for the forced induction aspect of it.

I'm sorry - I'm probably all over the place... lol

 

I have an AEM FIC, and I love it. It works 100% of the time, perfectly. 14.7 idling, 14.5 - 14.9 cruising, and perfect numbers under boost. Took me a long time to get it tuned correctly, but I believe it's because the ECU is no longer changing it's parameters.

 

SO long story short i need a retune?

 

Partially, in my opinion. But it would be pointless, because he would be tuning an ECU that hasn't compensated itself for the change in induction. You need to get other people's opinions on this. I don't want to be giving you advice that has you spend money. Try spark plugs first... but I for some reason believe that it's in your tune. I think your FIC is pulling timing for cold starting and pulling fuel, which your tuner tuned for because the ECU was accustomed to this cold start. Now it's not. So you're lacking timing and proper fuel (which, if you tap the pedal, and constantly crank, it'll eventually start).

 

Thing is lets say like... 3 days ago the car was running solid after i swapped the MAP sensor out. seemed like my tune was on point. Then the car wasnt cranking at all, yesterday, tapped the starter, and it started. installed a new oil psi and boost gauge same night. then i started driving, and all this lean-age started taking place and random AFR jumping.


I currently have to keep unplugging the FIC until i install the auto ecu relay to stop from the throttle body from keep getting power. every time i turn car off.

 

Well, the gauges will have nothing to do with it. So we can throw that out. And you said you figured out it wasn't the starter? So it can't be that. MAP sensor? That is the only thing that could be causing your problems from what you just said.

 

I just replaced it though lol...

 

Honestly.. I would give your tuner a call and say you have a problem cold starting. Are you in S. Florida? I can recommend somebody... I PMed you my number.

 

My tuner is Mike in orlando.... wont really go anywhere else.