s4 t2 bogs at 3700 rpm help!!
02-21-15, 12:07 PM
#29
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Start with that big black power wire..
Check voltage at the ign switch against battery voltage.. they should be within 0.2v. Make sure you turn loads on when you do, like lights, heater etc.
Check voltage at the ign switch against battery voltage.. they should be within 0.2v. Make sure you turn loads on when you do, like lights, heater etc.
02-25-15, 02:27 PM
#30
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OK so finally got around to messing with the car I noticed that the main ecu harness ground had a tear in it so I re did the wire and added an extra one going from where it bolts to the rotor housing to the ground on the battery still the same results also checked voltage while the car is running at all the fuses inside and had close to 14v on all of them still have the same hesitation/brick wall at 3500+ rpm when over a 1/4 throttle last thing to check would be the injectors I guess as I doubt its still a grounding issue.... Also could one of the coil packs cause this they fire fine at idle?
02-25-15, 07:16 PM
#32
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I re did the torn wire by soldering it I tried the tps in plugged haven't tried to in plug the vacume line to boost sensor yet and I didn't run the extra ground direct to the battery I ran it to the bolt that's holding the battery ground on the strut tower
02-26-15, 01:29 AM
#34
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Are you talking about not making the wire hot enough to make a good solder connection or the pens that they have that heat up fast to solder with less heat soak to the wire
02-26-15, 09:53 AM
#36
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I've done plenty of soldering and have gotten pretty good at it throughout all the cars I've owned so no I don't think I cold soldered a joint
02-26-15, 02:44 PM
#37
Just to clarify, can you free rev just fine? Have you tested the boost sensor. W/key to on the Brown/Rd wire should read between 2.3 to 2.7 volts. And does the vacuum hose run to the stock vacuum position? And have you dealt w/the FCD to see if it was causing your issue?
Last edited by satch; 02-26-15 at 02:48 PM.
02-26-15, 04:37 PM
#38
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I tried it without the fcd same story almost seemed to sputter worse boost sensor is showing 5v at the brown and white wire and 2.3 at the brown and red I know in a previous thread I had like 2.0v but now have 2.3 since I replaced the old battery with a new one boost sensor is on the same vaccum port its always been on I pulled the block off plate off and looked like it may have been leaking a little so I added high temp rtv and waiting for it to dry now crossing my fingers hope that's it and no it does not free rev just fine it does the exact same thing as if I were driving under load
02-26-15, 07:47 PM
#41
Was there anything done to the car such that it was not performing as it should be afterwards? Were the injectors changed and the problem occurred, and what are the size of the injectors?
And do the Light Green injector wires read 12 volts at the ECU w/key to on?
And do the Light Green injector wires read 12 volts at the ECU w/key to on?
Last edited by satch; 02-26-15 at 07:50 PM.
02-26-15, 10:22 PM
#42
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Nothing was changed just started all of a sudden the injectors are the stock 550cc haven't checked the green wires yet I will tomorrow morning that's the last check on my list also haven't driven it since resealing the acv block off plate so crossing my fingers on that will update tomorrow
02-27-15, 08:04 PM
#43
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Finally checked the green wires on the ecu had 12v with the key on with other lead to ground and simulated a load on car by unplugging tps and boost sensor hose and capping it reved it past 4000 and volt meter stayed at 0-2v the whole time back probed at the plug and plugged into the ecu and the other lead to a + source so I opened the ecu and found this
Don't know what it does but its defenantly burnt so will be looking for another ecu
Don't know what it does but its defenantly burnt so will be looking for another ecu
03-02-15, 02:06 AM
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The D1415 is a transistor, they're typically used to drive solenoids/relays. I haven't spent much time mapping out the analog board on the S4 ECU -- but I'd assume that is likely an injector driver. If nothing else looks toasted and there's no other issues with traces, you could possibly just replace the transistor.
Think it's rated at 100V, 7A
Think it's rated at 100V, 7A
03-04-15, 10:03 PM
#46
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So put In the new ecu today and had the same problem still :/ it seems to free rev a little better and if you slowly rev it past the 3500 mark free reving it seems to rev fine after that if you floor it this really has me stumped don't know what else it could be
