S4 TII with S5 TII swapped leaning out and detonationing at 3800rpm only in boost.
10-22-14, 09:58 PM
#1
S4 TII with S5 TII swapped leaning out and detonationing at 3800rpm only in boost.
What I have is an 88' S4T chassis with its ECU and wiring harnesses attached to an S5T JDM engine with the Manifolds and garret turbo (with chopped turbine fins) that came with it. The engine came with all trailing plugs installed and a Exedy flywheel. 2.25 exhaust with just a high flow muffler and a K&N cone intake filter. The air control valve and rats nest has been removed, no egr. The s5 BAC is still installed because I haven't made a block off plate yet but it is not plugged in. I have a innovate LM-2 wideband installed 2.5 feet away from the turbo and an autometer boost gauge. I am premixing 1oz per gallon tc-3w. I had to solder on some plugs to fit the s5 block like the TPS narrow range and the injectors (which are Hi Imp). I have put over 3 thousand miles on it since I finished the swap (and paint) a few months ago. It has good compression, over 100 psi.
Here is my issue. The car runs fantastic under 3800 RPM but after that it hesitates horribly and gets very lean (so I of course back off of it, and shift). I have downshifted to try starting off at 4000+ rpm and it is still super lean when I accelerate. I made it detonate right at 3800 once accidently going past that mark under boost.
While in vacuum and hardly accelerating I can go past 3800 without it being super lean and without the violent bucking/hesitation. The turbo I have installed easily will exceed the factory ecu limit thus initializing fuel cut. I know exactly what that feels like and I keep it below 6lbs. That is one of the reasons I got the aftermarket gauge. I have taken my intake off multiple times trying to fix this. It also gets lean crusing at certain RPM's. Like around 2800 in fifth gear ill get into the 19-20 afr.
Things I have tested and tried are:
I tested the TPS. no dead spots.
I installed a restrictor pellet inline to the boost sensor.
I uninstalled my BoV because it was leaking.
Swapped the airflow meter for my s4 NA one (No change at 3800).
Cleaned my existing grounds (on EM harness to center iron and pwr harness to shock tower) and ran a new one in 8AWG from the battery to the block to the Chassis and added another (8) from the battery directly to the ECU. I also added two 18AWG from the block to the ECU. I have the ones going to the ECU bolted onto one of the m10 ECU mounting bolts. Redoing the grounds did seem to help it a little bit.
Cleaned out my injectors and tested them.
Changed out my new fuel filter for another new one.
Replaced my new stock fuel pump with an FD fuel pump w fc sock.
Tested continuity from the ECU pins to injector plugs to make sure they are in the right spots and to test the wires.
Changed my sparkplugs, I am running leading and trailing now.
My in-dash pressure gauge does not match my aftermarket gauge all the time and sometimes my in dash gauge goes in-op.
The fuel is hitting the pulsation dampener first, FPR last.
My vacuum lines are hooked up following "rotary resurrection"s emissions delete website.
The boost sensor is coming of one of the three nips on the front of the intake.
Water sensor plug has seen better days but seems okay..
In neutral I can rev to redline.
I am truly at a loss and beginning to think that its because of my high flow intake and exhaust. Either that or I have a bad ECU. Maybe the P.O. burned out the secondary injector electronics in the ecu using the wrong impedance?
I am thinking of deleting the Fuel pump resistor that is still installed.
I have not taken a timing light to it yet, but I believe it should be the same from s5 to s4 right?
I know it has to be something with the secondaries coming on and the transition between the primaries being put into a lower cycle at that rpm.
I have searched and searched for 3 months now trying to fix this myself so if you have any suggestions please share them.
Thank you guys!
Reddon
Now in Southern Tennessee!
Here is my issue. The car runs fantastic under 3800 RPM but after that it hesitates horribly and gets very lean (so I of course back off of it, and shift). I have downshifted to try starting off at 4000+ rpm and it is still super lean when I accelerate. I made it detonate right at 3800 once accidently going past that mark under boost.
While in vacuum and hardly accelerating I can go past 3800 without it being super lean and without the violent bucking/hesitation. The turbo I have installed easily will exceed the factory ecu limit thus initializing fuel cut. I know exactly what that feels like and I keep it below 6lbs. That is one of the reasons I got the aftermarket gauge. I have taken my intake off multiple times trying to fix this. It also gets lean crusing at certain RPM's. Like around 2800 in fifth gear ill get into the 19-20 afr.
Things I have tested and tried are:
I tested the TPS. no dead spots.
I installed a restrictor pellet inline to the boost sensor.
I uninstalled my BoV because it was leaking.
Swapped the airflow meter for my s4 NA one (No change at 3800).
Cleaned my existing grounds (on EM harness to center iron and pwr harness to shock tower) and ran a new one in 8AWG from the battery to the block to the Chassis and added another (8) from the battery directly to the ECU. I also added two 18AWG from the block to the ECU. I have the ones going to the ECU bolted onto one of the m10 ECU mounting bolts. Redoing the grounds did seem to help it a little bit.
Cleaned out my injectors and tested them.
Changed out my new fuel filter for another new one.
Replaced my new stock fuel pump with an FD fuel pump w fc sock.
Tested continuity from the ECU pins to injector plugs to make sure they are in the right spots and to test the wires.
Changed my sparkplugs, I am running leading and trailing now.
My in-dash pressure gauge does not match my aftermarket gauge all the time and sometimes my in dash gauge goes in-op.
The fuel is hitting the pulsation dampener first, FPR last.
My vacuum lines are hooked up following "rotary resurrection"s emissions delete website.
The boost sensor is coming of one of the three nips on the front of the intake.
Water sensor plug has seen better days but seems okay..
In neutral I can rev to redline.
I am truly at a loss and beginning to think that its because of my high flow intake and exhaust. Either that or I have a bad ECU. Maybe the P.O. burned out the secondary injector electronics in the ecu using the wrong impedance?
I am thinking of deleting the Fuel pump resistor that is still installed.
I have not taken a timing light to it yet, but I believe it should be the same from s5 to s4 right?
I know it has to be something with the secondaries coming on and the transition between the primaries being put into a lower cycle at that rpm.
I have searched and searched for 3 months now trying to fix this myself so if you have any suggestions please share them.
Thank you guys!
Reddon
Now in Southern Tennessee!
10-23-14, 12:20 AM
#2
Is the ECU a USDM or JDM?
If you pull the plugs to the TPS and boost sensor that will trick the ECU into thinking it's under load, thus when you rev to over 3800 rpm in idle the secondaries should be triggered. This will allow you to check the ECU injector drivers. The wires to the secondary injectors from the ECU should drop to about 6 volts when triggered.
If you pull the plugs to the TPS and boost sensor that will trick the ECU into thinking it's under load, thus when you rev to over 3800 rpm in idle the secondaries should be triggered. This will allow you to check the ECU injector drivers. The wires to the secondary injectors from the ECU should drop to about 6 volts when triggered.
10-23-14, 01:37 AM
#3
And the over the top switch (5th gear) changes the timing a bit which produces a lean affect so the cruising mpg improves a bit.
And how about using the factory vacuum spot for the boost sensor. Using any vacuum port can cause an uneven vacuum level which could cause fuel cut if there are spikes in the vacuum level.
And when free reving the secondaries are not used.
And how about using the factory vacuum spot for the boost sensor. Using any vacuum port can cause an uneven vacuum level which could cause fuel cut if there are spikes in the vacuum level.
And when free reving the secondaries are not used.
10-23-14, 02:18 AM
#4
talking head
sound like lots of new ground loops with all these added earths
on the wiring loom just out from ecu main plug is a brass crimp that bundles all the ecu and instrument and shield earths together
it requires a wire added, resoldered , and that wire earthed to the ecu case
this should be the only earth you need to add in
,, after ensuring the little one to top of block ( under nest ) is still there
on the wiring loom just out from ecu main plug is a brass crimp that bundles all the ecu and instrument and shield earths together
it requires a wire added, resoldered , and that wire earthed to the ecu case
this should be the only earth you need to add in
,, after ensuring the little one to top of block ( under nest ) is still there
10-28-14, 12:46 AM
#5
It is a USDM ECU. I did unplug and test the voltage and it is good! I also swapped the line to the nip right above where the ACV was and that helped a bunch. I did some more searching and found out what the nips do. I did not realize they were as different as they are!
My problem still persisted, although I was not getting lean while cruising anymore and the car ran much better knowing the correct pressure. Thank you Satch!
What did fully fix my problem was unwrapping the wires and finding the two crimps on the grounds that go to different spots on the ecu from the emissions harness. I filled them with solder and now I have only a minor hesitation at 3800! Of course I cannot go WOT yet because of the fuel cut and oversized turbo but it feels great being able to rev it up! No more crazy lean conditions while the secondaries are on. Thank you Bumpstart!
I did not get a chance to add another ground to the factory splice spot yet (because I was soldering in the dark) but I will try that too. I saw on the wiring diagram that they both do tie into each other and of course there is the chassis ground that binds them but should I go ahead and add a jumper on each and bring them to the ECU?
I should probably take off my 9 LBS of ground wire I installed as well I bet.. Thanks a million guys!
My problem still persisted, although I was not getting lean while cruising anymore and the car ran much better knowing the correct pressure. Thank you Satch!
What did fully fix my problem was unwrapping the wires and finding the two crimps on the grounds that go to different spots on the ecu from the emissions harness. I filled them with solder and now I have only a minor hesitation at 3800! Of course I cannot go WOT yet because of the fuel cut and oversized turbo but it feels great being able to rev it up! No more crazy lean conditions while the secondaries are on. Thank you Bumpstart!
I did not get a chance to add another ground to the factory splice spot yet (because I was soldering in the dark) but I will try that too. I saw on the wiring diagram that they both do tie into each other and of course there is the chassis ground that binds them but should I go ahead and add a jumper on each and bring them to the ECU?
I should probably take off my 9 LBS of ground wire I installed as well I bet.. Thanks a million guys!
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