Fault codes after injector swap and car wont run.

[A4 TSCHUSS]

I decided to put in my 750cc injectors to see if the car would run good with them or not. I tried to start the car and it would start for a split second and then die. Did this many times. I ran Vag Com and it had a code for each injector saying:

Cyl 1 Fuel Inj. Circ. Short to B+

And the same for 2, 3 and 4 with the code for that cylinder. Any idea what is going on. All I did was unplug the cam position sensor and then unbolt fuel rail then put in the new injectors, turn key a few times to prime the fuel rail then try to start car and had the above issues.

[AudiA4_20T]

your ECU is telling those injectors to pulse the same amount as the 550ccs which obviously each pulse is a SHITLOAD more fuel... your probably so damn rich that your just washing shit out

also, are the 750cc high impedance injectors? if your switching from high to low the ECU isnt going to know wtf is going on unless you have a resistor box

[Das General]

don't injectors have to be scaled properly, which is independent of your tune.

[AudiA4_20T]

don't injectors have to be scaled properly, which is independent of your tune.

which is why I love the idea of tuning my own car...

and Derek, why your buddy Marc can't tune anything with any other injector (because he doesn't know how) lol

[Das General]

which is why I love the idea of tuning my own car...

and Derek, why your buddy Marc can't tune anything with any other injector (because he doesn't know how) lol

My buddy? Negative Commander.

[A4 TSCHUSS]

First off I have a 440cc file not 550 and I was running 630cc injectors perfectly so by your theory the 440 file would be telling the 630s to spray the same and would be spraying way to much which clearly wasnt the case since the car ran perfect. I am just limited to 100% duty cycle of the injector at 24psi therefore needing a bigger injector. Also the computer had zero correction while running the 630 in block 032 of vag com.

[AudiA4_20T]

First off I have a 440cc file not 550 and I was running 630cc injectors perfectly so by your theory the 440 file would be telling the 630s to spray the same and would be spraying way to much which clearly wasnt the case since the car ran perfect. I am just limited to 100% duty cycle of the injector at 24psi therefore needing a bigger injector. Also the computer had zero correction while running the 630 in block 032 of vag com.

you were running 630cc injectors on the 440cc file with the same maf? The ME7 can actually adapt up to 25% or so I hear, and the wideband makes it easier for tuners to lay back on, but your running such a different sized injector now it seems like it can't compensate

Can you confirm that the 750cc are high impedance? Im assuming they are but I'd imagine running low impedance injectors without the resistor box would give you some kind of code like your getting

[A4 TSCHUSS]

you were running 630cc injectors on the 440cc file with the same maf? The ME7 can actually adapt up to 25% or so I hear, and the wideband makes it easier for tuners to lay back on, but your running such a different sized injector now it seems like it can't compensate

Can you confirm that the 750cc are high impedance? Im assuming they are but I'd imagine running low impedance injectors without the resistor box would give you some kind of code like your getting

I didnt think about the 750s being low impedance which they are and the 630s are high impedance.

And yes I am running 630s on the 440 file with the same maf sensor but I put it in a 3" housing.

[AudiA4_20T]

I didnt think about the 750s being low impedance which they are and the 630s are high impedance.

And yes I am running 630s on the 440 file with the same maf sensor but I put it in a 3" housing.

right, but the housing scales the airflow. So the car is seeing less air and requesting less fuel, but still shooting for the target AFR and that allows it to be within the 25% range...

Anyway, yea man, you need a resistor box... Shit is annoying isn't it? Theres so many dumb things I never imagined Id have to get

[brewmastr]

ohm the injectors with a multimeter, if you went from a saturated type injector then to a peak and hold type injector the ecu is going to have problems, a saturated injector is going to have higher resistance around 10-14ohms, a peak and hold will be lower around 1-4 ohms, i think our ecu's are setup to use saturated injectors and thats why you need an resistor box to use peak and hold, the computer will draw too much amperage trying to operate the injectors and recognize it as short to positive and effectively shut down that driver in the ecm.

[A4 TSCHUSS]

Yes, I didnt pay attention when I bought them if they were high or low impedance, I just got what the tuner told me to get since he said the 630s I had would be maxed out easily which go figure they are at 24psi.

The 630s are high impedance and the 750s are low impedance so that is my problem, no need to do any ohm testing.

[k0mpresd]

you will fry the injector drivers in the ecu if you keep trying to run the car. you either need high impedence injectors or resistors.

[AudiA4_20T]

expect to pay like $50 for a resistor box, or try to find a junkyard.... they come off of hondas, at least the ones that TAPP uses

[k0mpresd]

expect to pay like $50 for a resistor box, or try to find a junkyard.... they come off of hondas, at least the ones that TAPP uses

or these little guys. :)

[AudiA4_20T]

how much were those Ian?

[B6Lovin]

^i was already looking for the thread where those first came up and then i scrolled down to post and saw you beat me to it lol.

david, i still don't understand why your car is maxed on 630's when they can supposedly support a much higher amount of power than anyone here should be making. even on a cammed 2L with a 3076 that seems a bit far fetched. and i'm not doubting that they're running at 100% duty - but we never eliminated all the other reasons for WHY. it could be that the car is trying to make up for fuel that the pump or filter won't supply/let through by opening the injectors up.

i think that it'd be worth your time to go ahead and throw that pump in before you start throwing around money on resistors, boxes, or getting it re-tuned right away on the new injectors - especially since you'll be putting that thing in eventually anyways. it really cleaned up my A/F's and i want to see if it will atleast help your problem some.

[AudiA4_20T]

^i was already looking for the thread where those first came up and then i scrolled down to post and saw you beat me to it lol.

david, i still don't understand why your car is maxed on 630's when they can supposedly support a much higher amount of power than anyone here should be making. even on a cammed 2L with a 3076 that seems a bit far fetched. and i'm not doubting that they're running at 100% duty - but we never eliminated all the other reasons for WHY. it could be that the car is trying to make up for fuel that the pump or filter won't supply/let through by opening the injectors up.

i think that it'd be worth your time to go ahead and throw that pump in before you start throwing around money on resistors, boxes, or getting it re-tuned right away on the new injectors - especially since you'll be putting that thing in eventually anyways. it really cleaned up my A/F's and i want to see if it will atleast help your problem some.

I agree with you but Sean (Don Supreme) is close to maxing out his 630cc injectors with essentially the same engine setup but a 35R over the 30R... I'd say with David's meth and the fact that he is running more boost... he could be close too

Don't get me wrong, I would try the pump and other things first, but I wouldnt rule out that the 630ccs can flow enough with high boost + meth

[k0mpresd]

how much were those Ian?

i forget to be honest. it was <$20 though.

[AudiA4_20T]

True, Ian I left you my #, hit me up tomorrow man

[k0mpresd]

i got it. i was busy playing gears of war 2 tonight. :p and some other random things i had going on.

[B6Lovin]

I agree with you but Sean (Don Supreme) is close to maxing out his 630cc injectors with essentially the same engine setup but a 35R over the 30R... I'd say with David's meth and the fact that he is running more boost... he could be close too

Don't get me wrong, I would try the pump and other things first, but I wouldnt rule out that the 630ccs can flow enough with high boost + meth

right.... but that's a 35R.. idk if you've held a 35R next to a 3076, but it's not exactly what i'd call "close". and that's another thing, sean is CLOSE to maxing his out - and is flowing more air.. so there's no feasible way that david is completely maxing his out on the amount of air he's pushing through his motor.

even if he's close, we know that he's not as close as others, and from what we've seen in his logs that means that there must be another problem.

not trying to be overly nit-picky... i just wish he'd get that damn pump in already so that we can get another solid bit of info about our fuel systems. I know that my A/F's have improved dramatically since putting in my 040, and i'm hoping to see that trend continue so that we can be a little more precise when helping out other people in the future who want to follow in our footsteps.

[dougyfresh]

^i was already looking for the thread where those first came up and then i scrolled down to post and saw you beat me to it lol.

david, i still don't understand why your car is maxed on 630's when they can supposedly support a much higher amount of power than anyone here should be making. even on a cammed 2L with a 3076 that seems a bit far fetched. and i'm not doubting that they're running at 100% duty - but we never eliminated all the other reasons for WHY. it could be that the car is trying to make up for fuel that the pump or filter won't supply/let through by opening the injectors up.

i think that it'd be worth your time to go ahead and throw that pump in before you start throwing around money on resistors, boxes, or getting it re-tuned right away on the new injectors - especially since you'll be putting that thing in eventually anyways. it really cleaned up my A/F's and i want to see if it will atleast help your problem some.

Bingo..! Come on. Put that damn fuel pump in and it will help a lot of your problems. It is meant to be used in your gas tank. Not sitting on your rear seat looking pretty. You already spent that money. Might as well use it before spending more money.

[Don Supreme]

I can't believe you bought low impedance injectors.......................... You should have purchased even larger injectors if you are going that route..

I also recommend that you change your fuel pump first.

----For those use my setup as an example, you are leaving out and important detail.

I am only running 17-17.5 psi right now and only revving to 7200 which has me close to 85% duty cycle on my ~70 lbs setup (044 pump + 4 bar FPR). I would like to believe that A4Tschuss' setup is blowing as much if not more air @ 24 psi!

[Don Supreme]

right.... but that's a 35R.. idk if you've held a 35R next to a 3076, but it's not exactly what i'd call "close".

... They are actually the same physical size -----------

(The wheels are different)

[B6Lovin]

yeah - and it's an obvious physical difference. We held my turbo next to a 35r beforenit went in and it just made me cry a little bit inside

Kind of like a 3076 next to a 3071 - but even bigger difference

[A4 TSCHUSS]

630s back in and purring like a kitten. 3/4 tank of fuel, gonna go drive around and maybe put the pump in later.

[CO AVANT]

right.... but that's a 35R.. idk if you've held a 35R next to a 3076, but it's not exactly what i'd call "close". and that's another thing, sean is CLOSE to maxing his out - and is flowing more air.. so there's no feasible way that david is completely maxing his out on the amount of air he's pushing through his motor.

That's why I'm wondering why his mass air flow readings (g/s) are lower than mine while using the same MAF setup. Map changes between the 440 and 550 file?

[A4 TSCHUSS]

My car is special. It doesnt run without the MAF, it shows nothing but 0 in block 032 (no correction). And I have always been able to run more timing than Shawn while also having a smaller intercooler.


O yeah and it is in an elite club where few have seen 12s

[Don Supreme]

yeah - and it's an obvious physical difference. We held my turbo next to a 35r beforenit went in and it just made me cry a little bit inside

Kind of like a 3076 next to a 3071 - but even bigger difference

I was referring to a 3076 and 35r - same size. (Assuming t04s cover)

[CO AVANT]

My car is special. It doesnt run without the MAF, it shows nothing but 0 in block 032 (no correction). And I have always been able to run more timing than Shawn while also having a smaller intercooler.

I have been logging 032 for the last 50 miles and have yet to pull anything but 0's... (without clearing my fault codes)

[dirtybrd]

I doubt you maxed 630s.

[A4 TSCHUSS]

I doubt you maxed 630s.

I dont know if they are or not, I am just going by what Sean (Don Supreme) said after me posting a log of a block of Injector on time which I have no clue how to read.

What can I log for someone to see what they are doing? I dont know how to do/read logs about injector duty cycle to see what they are running at.

All I do know is I have the car at 23psi and 12-15 degrees of timing (probably gonna add .75 more with lemmi) and im going out to spank some ass tonight at a car meet.

Here is a log I just did

[dirtybrd]

Nice log, but I'm sure you've heard that before...Keys Boy.

[A4 TSCHUSS]

If you mean from the girlies, yes

[dirtybrd]

Noooooooope

[AudiA4_20T]

LOL, perfect...

anyway, 15 degrees up top, decent timing for revo

[A4 TSCHUSS]

Here is a log I did of a friends Tapp Tuned B5 A4 with GT3071r

The log isnt as good as mine as far as rpm range through gears since the sample rate sucked skipping alot of areas of rpms but you can get an idea

23psi, 93 octane and meth injection, same as me.

[dirtybrd]

That kinda sucks, he wasn;t 100% WOT and it goes from 7k back down to 5k and back up. It looks as if his TB only opens 86.8% he needs to check his throttle cable. And his MAF reads really low.

[A4 TSCHUSS]

4" maf

[dirtybrd]

Oh.