Good idle, backfire/stumble under load (vid inside)
#1
Good idle, backfire/stumble under load (vid inside)
I don't know what the hell is going on here
Idles fine..blip the gas and it'll usually stall
Put on load on it in neutral, sometimes it'll rev, other times it'll backfire and stumble
Driving it is impossible
When it does stall, its usually hard to restart
New fuel pump, plugs, injectors, PFC is new, pulls 12-13inHg at idle, no emissions and running on a PFC
video:
http://www.youtube.com/watch?v=Li7d7a_MBvs
Idles fine..blip the gas and it'll usually stall
Put on load on it in neutral, sometimes it'll rev, other times it'll backfire and stumble
Driving it is impossible
When it does stall, its usually hard to restart
New fuel pump, plugs, injectors, PFC is new, pulls 12-13inHg at idle, no emissions and running on a PFC
video:
http://www.youtube.com/watch?v=Li7d7a_MBvs
#2
looks like u have 0 oil preassure idk if thats it but. temp is a little high but its a s5 so that could mean nothing. i assume u have an after market boost gauge cause its steady in the middle. u swap out the computer?
#5
filter is fine, no cat
this car is getting parted out soon, I have never been so aggravated in my life...sick of dumping money and time into it just to have the thing **** me over every time I want to drive it...5k on the odometer since 2006, I'm done
this car is getting parted out soon, I have never been so aggravated in my life...sick of dumping money and time into it just to have the thing **** me over every time I want to drive it...5k on the odometer since 2006, I'm done
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#9
Joined: Jan 2008
Posts: 4,834
Likes: 318
From: Indiana
Just because we supplied you with a map does not mean that it is going to fix everything else wrong with your car.
I would say you need to start by checking your TPS voltages on the commander and make sure there are not any issues with the sensor.
#10
hey chris
But if it is what chris is saying, we can only add this: It is a base map. You need to get it well tuned on the dyno.
If i see your vid i would guess it has not been tuned yet.
I also bought a pfc and other stuff at banzai lately, chris also made me a base map for stock and 800cc injectors, but he can't guess how the whole map should be from a distance.
I wonder how mine will run and if i can get it to the uk to get remapped
kevin
But if it is what chris is saying, we can only add this: It is a base map. You need to get it well tuned on the dyno.
If i see your vid i would guess it has not been tuned yet.
I also bought a pfc and other stuff at banzai lately, chris also made me a base map for stock and 800cc injectors, but he can't guess how the whole map should be from a distance.
I wonder how mine will run and if i can get it to the uk to get remapped
kevin
#11
A bad leading coil gave me similar symptoms to what you're having. One night everything was fine. I started the next morning 8 hours later and the car had trouble starting. Idled steady, but vacuum was poor, and was reluctant to rev and sometimes wanted to die out. So... spend another $25 in the for sale section and see if you can get a "new" leading coil to test.
#12
um... you need to have it tuned. he gave you a base map. there is now way he can give you a map, and all of a sudden you have a powerhouse with out actually tuning it.
plus, chris said it was a basemap, so... get it tuned.
plus, chris said it was a basemap, so... get it tuned.
#13
+1 on the tps. What is the PFC showing the voltage is at idle, and at WOT? Have you set it with a multimeter, or using the test light method (I had better luck with this method)? It should be done, then your idle will probably need to be adjusted via the idle stop screw.
Are you sure you don't have a vacuum leak? My car has 18psi of vacuum at idle.
Are you sure you don't have a vacuum leak? My car has 18psi of vacuum at idle.
#14
+1 on the tps. What is the PFC showing the voltage is at idle, and at WOT? Have you set it with a multimeter, or using the test light method (I had better luck with this method)? It should be done, then your idle will probably need to be adjusted via the idle stop screw.
Are you sure you don't have a vacuum leak? My car has 18psi of vacuum at idle.
Are you sure you don't have a vacuum leak? My car has 18psi of vacuum at idle.
18 psi? mine idles with 8 psi.
#16
just to set things straight...
After the PFC was installed 6 months ago, it had a whacked out map in it. The car was at my tuners (DSG in Mass, VERY well known). They called Chris, sent him the map, he said WTF is this, told them he could write me a new one for a few $$ (which I had NO PROBLEM with) but I had to call him. So I did, gave him a few specs on the car, paypal'd a couple bucks, new map was written, installed, and slightly tinkered with at DSG. It did not get tuned that day due to another issue which I straightened out but the car ran 110% for months after the map was loaded. It was running in the high 80's (Celsius), due to the OEM radiator so I bought a Koyo N-Flo, installed it, and have never been able to drive the car since.
I said it was wasted money because I should have left the car alone a long time ago. I knew in the back of my head it was going to be a trouble ridden car but ignored my gut.
TPS ohms out 100% in spec both narrow and wide ranges with a nice steady sweep
Leading coil ohm'd out in spec but I changed it anyway, no difference
Plugs have been changed, no difference
After the PFC was installed 6 months ago, it had a whacked out map in it. The car was at my tuners (DSG in Mass, VERY well known). They called Chris, sent him the map, he said WTF is this, told them he could write me a new one for a few $$ (which I had NO PROBLEM with) but I had to call him. So I did, gave him a few specs on the car, paypal'd a couple bucks, new map was written, installed, and slightly tinkered with at DSG. It did not get tuned that day due to another issue which I straightened out but the car ran 110% for months after the map was loaded. It was running in the high 80's (Celsius), due to the OEM radiator so I bought a Koyo N-Flo, installed it, and have never been able to drive the car since.
I said it was wasted money because I should have left the car alone a long time ago. I knew in the back of my head it was going to be a trouble ridden car but ignored my gut.
TPS ohms out 100% in spec both narrow and wide ranges with a nice steady sweep
Leading coil ohm'd out in spec but I changed it anyway, no difference
Plugs have been changed, no difference
Last edited by hosmer; 11-01-10 at 05:46 AM.
#17
Joined: Jan 2008
Posts: 4,834
Likes: 318
From: Indiana
OK, so then spending money on a map was not wasted. You are saying the car ran perfect with our base map until now.
Once the PFC is installed the TPS is no longer about ohms, it is all voltage. You check the TPS on the sensor screen of the commander. The TPS is VTA1 & VTA2. The same screen will help you to identify what else could be wrong with your car as it contains all the data for all the sensors and solenoids.
Verify that your fuel pump has not develpoed an issue, check your fuel pressure. Do you have the pump wired to 12V constant?
Once the PFC is installed the TPS is no longer about ohms, it is all voltage. You check the TPS on the sensor screen of the commander. The TPS is VTA1 & VTA2. The same screen will help you to identify what else could be wrong with your car as it contains all the data for all the sensors and solenoids.
Verify that your fuel pump has not develpoed an issue, check your fuel pressure. Do you have the pump wired to 12V constant?
#18
Yes, the car ran 100% with the map
I checked fuel pressure and even swapped the pump out for a spare (new) walbro I had...and yes it's rewired for a constant 12v
I'll double check the sensor screen after work, I know the VMOP(?) reads 0.00 but when I looked it up it was for something I no longer have, cant remember off the top of my head and I'm typing this from my phone.
The "FUEL" sensor reads 4.98, I remember this because it's always highlighted (like the VMOP), but I swear it's always read that...maybe I've gone mad with rage but I'm pretty sure that's been the voltage since it's been installed
I checked fuel pressure and even swapped the pump out for a spare (new) walbro I had...and yes it's rewired for a constant 12v
I'll double check the sensor screen after work, I know the VMOP(?) reads 0.00 but when I looked it up it was for something I no longer have, cant remember off the top of my head and I'm typing this from my phone.
The "FUEL" sensor reads 4.98, I remember this because it's always highlighted (like the VMOP), but I swear it's always read that...maybe I've gone mad with rage but I'm pretty sure that's been the voltage since it's been installed
#19
Your blue led digital meter (in the video showing 14.8) is that Battery Voltage or A/F?
What else did you change when you changed radiators? Did you install an electric cooling fan also, were you already using one, or were/are you using the oem fan and shroud?
I'm just thinking that maybe if you installed an electric fan at the same time. Is it possible that where you wired it to the thermosensor (however you're triggering it high speed) it's changed the input to the PFC and in turn is effecting how it's running.
It just seems strange that your problems started after upgrading the radiator. I would question every step that was performed during the mod like they are the prime suspects in the disorder.
What else did you change when you changed radiators? Did you install an electric cooling fan also, were you already using one, or were/are you using the oem fan and shroud?
I'm just thinking that maybe if you installed an electric fan at the same time. Is it possible that where you wired it to the thermosensor (however you're triggering it high speed) it's changed the input to the PFC and in turn is effecting how it's running.
It just seems strange that your problems started after upgrading the radiator. I would question every step that was performed during the mod like they are the prime suspects in the disorder.
#20
Joined: Jan 2008
Posts: 4,834
Likes: 318
From: Indiana
VMOP is the Oil metering pump, if you have it blocked off it will be highlighted, FUEL is the fuel temp sensor, which your car does not have. Neither of these will cause the car to run poorly.
You are premixing 2 cycle in your fuel tank?
You are premixing 2 cycle in your fuel tank?
Last edited by Banzai-Racing; 11-01-10 at 10:32 AM.
#21
I'm running premix (always have a case from Petit in the trunk, never trusted the OMP's)..also, have an s4 block with s5 manifolds/sensors so I can't plug it in anyway
Well I can, but I don't like the idea of it zip-tied to the unibody banging around up there...
It's a wideband gauge, electric fan has been on the car for years
Well I can, but I don't like the idea of it zip-tied to the unibody banging around up there...
It's a wideband gauge, electric fan has been on the car for years
#24
Coolant temp is fine...high 70's on the PFC (Celsius)
TPS 0%
VTA1 - 0.78
VTA2 - 1.00
100%
VTA1 - 3.83
VTA2 - 4.67
The following sensors are highlighted while the car is idling:
NTR
ELD
HWL
FPD
APR
CCN
trying to find out what they all are, but I can't seem to find a "list" so-to-speak
also I noticed my o2 sensor is reading 0.7 at idle which seems high?
TPS 0%
VTA1 - 0.78
VTA2 - 1.00
100%
VTA1 - 3.83
VTA2 - 4.67
The following sensors are highlighted while the car is idling:
NTR
ELD
HWL
FPD
APR
CCN
trying to find out what they all are, but I can't seem to find a "list" so-to-speak
also I noticed my o2 sensor is reading 0.7 at idle which seems high?
Last edited by hosmer; 11-01-10 at 06:03 PM.