I gained hp when I disconnected my battery? Please help me find out why?

[Black1987Stang]

k so my car was running OK, didnt surge but didnt like to run great when cold start up came around, even after 20 minutes i would go and start it and it would start and the rpms would drop down to like 600?rpms then catch itself and then go up then down getting better each time like once or twice and stabilize at idle,and would do this once and a while when i pushed in the clutch......I had disconnected the battery for a little bit and HOLY **** It felt like a new car, it ran better than it ever has and had so much more power and bottom end grunt. Also now at Cold start ups, it starts in half the cranks, starts out around 1100 rpm for 10 seconds? like it should then start to come down to a nice idle, and runs soooo smoooth now, no bucks or anything, ran MINT...BUT now I can feel it losing that niceness and going back to its oldself. I didnt change anything or put on anything, just disconnected the battery which reset the computer. My 02 sensors are pretty new, Im yet to pull the codes since I reconnected the battery....Im still confused what it could be ...seems like its something to do with the adaptive learning system of the computer Anyone????

 

[HISSIN50]

Your thoughts parallel mine. Something is up with a sensor, mods or something else and the adaptive strategy is kicking in. I have seen this on cars with FP kicked up via an AFPR. I wonder if your mods are not causing some learned behavior from the computer that causes it to adapt funny.

If you have the ability to datalog or stream data, that could be telling.

Otherwise, knowing you, I can see you installing a toggle switch on the PCM constant (memory) power supply wire, so you can reset the KAM at the flick of a switch.

 

[Roland69]

thats actually a good idea lol.

 

[sgarlic]

ROFL. It's sort of like the doctors office visits where the doctor says, "well, if it hurts to move your left arm, don't move your left arm" type thing.. if it runs better when the KAM is cleared, install a switch. Ehh.. it's late.. free bump for ya.

 

[Black1987Stang]

Your thoughts parallel mine. Something is up with a sensor, mods or something else and the adaptive strategy is kicking in. I have seen this on cars with FP kicked up via an AFPR. I wonder if your mods are not causing some learned behavior from the computer that causes it to adapt funny.

If you have the ability to datalog or stream data, that could be telling.

Otherwise, knowing you, I can see you installing a toggle switch on the PCM constant (memory) power supply wire, so you can reset the KAM at the flick of a switch.

hmmmmm...never thought of that, wheres that wire lol


I wish i had a tweecer or something with datalogging, dont have the money right now

But I think ur on the right track I did recently turn up the fuel pressure since I was running lean (plugs were white), i did notice a better increase of power right after I did it, but had just went down from there. What could this be from?
Right now I do have the stock 19lb injectors because I think my 24lb Pro-M is faulty, but didnt have time to check it out since its my d/d so i just threw on the stock stuff for now. I guess my next step would be to pull the codes and see if theres anything useful? What could cause the adaptive strategy to kick in. Thanks for the quick reply, im off to bed now

 

[90mustangGT]

...But I think ur on the right track I did recently turn up the fuel pressure since I was running lean (plugs were white), i did notice a better increase of power right after I did it, but had just went down from there. What could this be from?
Right now I do have the stock 19lb injectors because I think my 24lb Pro-M

There you go, wrong MAF calibration to the injectors. Adjusting fuel pressure won't do the trick. With a factory EFI car, the plugs will tend to be on the white side because your motor constantly switches from rich to lean, this is for emmisions reasons.

With good O2's, if you were to put a can on a gas anyalizer or A/F gauge you can change the fuel pressure up and down all you want, at first the readings would change, but in a few seconds to a minute, the computer will compensate and the readings will go back where they were before. Unless of course you go so far out of range in either direction that the computer cannot compensate, then of course it will just run like crap.

 

[Michael Yount]

diddle - "....since I was running lean (plugs were white)..."

Almost ANY car with a contemporary efi and electronic ignition keeps the plugs VERY white. That DOES NOT necessarily mean you're running lean. The 65K mile plugs that came out of my wife's newer BMW looked almost identical to the brand new ones in the box -- but for some grime on the threads, I wouldn't have been able to tell them apart.

If you added fuel pressure because your plugs were white -- you made an error. Set your fuel pressure back to stock (38-39 psig measured at warm idle with the vacuum line temporarily off and plugged); disconnect the battery and clear the KAM; and then drive the car to let it adjust to the proper fuel pressure.

If you want to make adjustments -- either data log and get the car on a dyno with a wideband so you'll have actual a/f data. Guessing based on looking at plugs on an efi car isn't gonna get you anywhere but into trouble.

Remember, most of the time the computer will keep the car right around stoichiometric a/f ratio, or slightly RICHER. White or ivory plugs are the result. I doubt very seriously you were running lean to start with. If you were, you'd have been getting CEL's and error codes.

 

[Black1987Stang]

diddle - "....since I was running lean (plugs were white)..."

Almost ANY car with a contemporary efi and electronic ignition keeps the plugs VERY white. That DOES NOT necessarily mean you're running lean. The 65K mile plugs that came out of my wife's newer BMW looked almost identical to the brand new ones in the box -- but for some grime on the threads, I wouldn't have been able to tell them apart.

If you added fuel pressure because your plugs were white -- you made an error. Set your fuel pressure back to stock (38-39 psig measured at warm idle with the vacuum line temporarily off and plugged); disconnect the battery and clear the KAM; and then drive the car to let it adjust to the proper fuel pressure.

If you want to make adjustments -- either data log and get the car on a dyno with a wideband so you'll have actual a/f data. Guessing based on looking at plugs on an efi car isn't gonna get you anywhere but into trouble.

Remember, most of the time the computer will keep the car right around stoichiometric a/f ratio, or slightly RICHER. White or ivory plugs are the result. I doubt very seriously you were running lean to start with. If you were, you'd have been getting CEL's and error codes.

Thanks Mike and everyone else, I knew the computer adjusted it with the pulsewidth but didnt think the plugs should be white (I think I was thinking of carburetor cars), and they actually did look somewhat like new plugs when i had them out except for the grime on the threads etc. like you said. Im going to pull the codes now just to see if theres anything new, drop the fuel pressure back to stock then disconnect the battery then drive her around and pull the codes again, and hopefully she keeps that niceness it had the other day.


BTW i do have the proper maf and injectors, I just meant the Pro-M was faulty and didnt have time to check it out so I put on the stock maf and stock injectors for now. so yes theyre matching

 

[Black1987Stang]

I just pulled the codes and I got...
Active Memory...
21-Engine Coolant Temps sensor...wtf? Its brand new
24-Air Charge Temp Sensor...This is fairly new too
82-Air Diverter solenoid...dont have them anymore,
95-Fuel Pump Secondary circuit Fault...always had it, not sure what it means

Continous Memory codes...
29-Vehicle Speed Sensor...my year doesnt have it and now have maf computer from mass air car.
32-EGR valve not seated...my heads dont even have provisions for the exhaust so not sure if it matters?
95-Fuel Pump Secondary Circuit...again not sure about this one


Ive always had these except for the ECT and the ACT codes, the ECT is few months old and the ACT i swapped in from a spare I had laying around, but ive never ever gotten these codes before even after i put them in until now...
I guess ill lower the fuel pressure, erase the codes and go for a spin and go from there.

 

[HISSIN50]

The VSS code comes up with MAF swaps IIRC. I think you knew that.

Jrichker has posted values for the thermistors (ACT/ECT) so I would do a couple checks on those at a couple temps to check calibration. I would really want to check the wiring values to and from the sensors, since both are popping up.

95 can be from a FP burp of some sort. It is often a ghost code. If you have had issues with the fuel pump cutting out, I would look into it. Otherwise I might not deal with that right now.

Michael's thoughts about reading EFI plugs agree with my thoughts. Someone on here recently disagreed with me, saying that he could do a WOT-shutdown reading, and I still feel that this is not very revealing, and can be a good bit misleading.

Good luck bud.

 

[Black1987Stang]

The VSS code comes up with MAF swaps IIRC. I think you knew that.

Jrichker has posted values for the thermistors (ACT/ECT) so I would do a couple checks on those at a couple temps to check calibration. I would really want to check the wiring values to and from the sensors, since both are popping up.

95 can be from a FP burp of some sort. It is often a ghost code. If you have had issues with the fuel pump cutting out, I would look into it. Otherwise I might not deal with that right now.

Michael's thoughts about reading EFI plugs agree with my thoughts. Someone on here recently disagreed with me, saying that he could do a WOT-shutdown reading, and I still feel that this is not very revealing, and can be a good bit misleading.

Good luck bud.

Ive always had code 95 even with my old stock motor so im not worried about it, and the vss code im aware is from the maf swap
Ill check the values of the two sensors with Jrichkers chart...Seems weird they could both go at the same time (it IS the same sensor internally im pretty sure)When i bought the ECT I checked it with my electric stove and ohmeter and went up and down nicely...Ill check that and the wiring to the computer. and see if their codes pop up again this time. My other thread I have about my friend with codes 41 and 91, he's still saying the plugs should have a tan electrode. not white...

 

[Michael Yount]

I think a w.o.t.-shutdown run can be revealing; but if everything is working correctly, the computer is gonna control things to be a bit enriched (safe) at w.o.t. - so they might show a bit tan. Under normal driving, it's gonna keep it as close to stoich as it can - so they're gonna show pretty white, as they should.

Follow the codes.....

 

[Black1987Stang]

I think a w.o.t.-shutdown run can be revealing; but if everything is working correctly, the computer is gonna control things to be a bit enriched (safe) at w.o.t. - so they might show a bit tan. Under normal driving, it's gonna keep it as close to stoich as it can - so they're gonna show pretty white, as they should.

Follow the codes.....

I gotcha, when my friend is pulling the plugs it is just after normal driving (non-WOT). Just curious what part of the plug should be white? The electrode arm? or also the normally white electrode insulator too? Because he is saying the insulator is whitish but hes saying the electrode arm is tan right now and what should be tan under normal driving? What is everybody else talking about? the arm or insulator?...... Mike I just saw ur answer on the other thread