Injector PW

[Turbo Talon DL]

If somebody were to log 19.7 ms for injector pulsewidth and 90% IDC on stock fuel what would you think of this? I run 13psi on EVO III, cams, stock fuel, 9:1 compression. My O2s are always in the mid .80-.85 volts and maybe 1-3 counts of knock under WOT. The ECU runs in batch fire when under WOT but sequential otherwise? I know I need larger fuel injectors and pump with the performance I run. Thats an issue to be addre$$ed at another time.

 

[DJ23GSX]

If somebody were to log 19.7 ms for injector pulsewidth and 90% IDC on stock fuel what would you think of this? I run 13psi on EVO III, cams, stock fuel, 9:1 compression. My O2s are always in the mid .80-.85 volts and maybe 1-3 counts of knock under WOT. The ECU runs in batch fire when under WOT but sequential otherwise? I know I need larger fuel injectors and pump with the performance I run. Thats an issue to be addre$$ed at another time.

I've been through numerous threads on idc's lately and i've seen mixed emotions on idc's over 85% Some swear by being under that as a good margin of safety and some say they've been running close to 100% idc's for years with no troubles. It all depends where your confortable zone is. Its obvious you'll need bigger injectors when you decide to up the boost but i personally wouldn't run for the hills at 90% idc's but on the other had i wouldn't raise the boost either.

 

[Turbo Talon DL]

I've been through numerous threads on idc's lately and i've seen mixed emotions on idc's over 85% Some swear by being under that as a good margin of safety and some say they've been running close to 100% idc's for years with no troubles. It all depends where your confortable zone is. Its obvious you'll need bigger injectors when you decide to up the boost but i personally wouldn't run for the hills at 90% idc's but on the other had i wouldn't raise the boost either.

I understand the thing about IDCs and the recommended range being 80% and below. I dont plan on upping the boost any further for a while. The car actually beats out some of the older V-8 Mustangs already (not a fair comparison but still...). I was more worried about the injector PW being 19.7 max at 13psi and 6900 ish RPMs. My IDCs are anywhere from high 70%s to lower-mid 90%s at WOT depending if I shift at 5000rpm or redline. Air temp also effects this value too.

 

[DJ23GSX]

I was more worried about the injector PW being 19.7 max at 13psi and 6900 ish RPMs. My IDCs are anywhere from high 70%s to lower-mid 90%s at WOT depending if I shift at 5000rpm or redline. Air temp also effects this value too.

If your pw is 19.7 at 6900rpm then your idc's are over 100% according to this chart Duty Cycle vs Pulse Width

 

[Turbo Talon DL]

Im not sure what it really means anymore... All I know is that the last time I dusted off an older V-8 Stang (not really fair for him I know) my PW was 19.7 and my IDCs peaked at 90 something %. I could have bad injectors or a bad injector drive circuit but it hasnt acted up in such a long time and no DTCs. Im gonna get some old EVO III 510 cc injectors and use a hacked airflow sensor. Is that PW vs RPM chart generic or DSM specefic? My airflow is pegged at 1599 Hz if that helps. The stock boost gauge follows my autometer pretty closely at WOT.

 

[DJ23GSX]

Im not sure what it really means anymore... All I know is that the last time I dusted off an older V-8 Stang (not really fair for him I know) my PW was 19.7 and my IDCs peaked at 90 something %. I could have bad injectors or a bad injector drive circuit but it hasnt acted up in such a long time and no DTCs. Im gonna get some old EVO III 510 cc injectors and use a hacked airflow sensor. Is that PW vs RPM chart generic or DSM specefic? My airflow is pegged at 1599 Hz if that helps. The stock boost gauge follows my autometer pretty closely at WOT.

The only way your idc's would be affected by a bad injector is if you are using some sort of piggyback tuning device (safc) to richen up to compensate for a bad injector. Idc's are calculated by the amout of air the ecu reads at the maf not by actual fuel your flowing. You'll need bigger injectors and a way to control them to run more boost. A hacked maf isn't the best way to run bigger injectors.

 

[timloomis]

The datalogger can only read up to 1599 hz in stock form. But it just sounds like you need bigger injectors/pump is all. The stock system maxes out at ~16psi with the 14b, so i'd say the evo3 at 13psi is pushing a little more cfm than the 14b is at 16.

 

[Turbo Talon DL]

The datalogger can only read up to 1599 hz in stock form. But it just sounds like you need bigger injectors/pump is all. The stock system maxes out at ~16psi with the 14b, so i'd say the evo3 at 13psi is pushing a little more cfm than the 14b is at 16.

I am using an old style AFC set at 10%+ from 800-4000 rpm just to bring my fuel trims closer to 100%. I understand my stock setup is maxed and have never hit fuel cut because I never set boost past 13 psi. The hacked MAF i ran before required me to set the AFC about 20% or more to get the air fuel ratio to cycle back and forth. Im not too worried about WOT because I dont get any knock and my O2s are mid .8s in warmer weather and low .9s in the winter. Thanks for the input though.

 

[Maglin]

Injector PW/RPM is a set thing. It has to do with crank speed and the amount of time available for the injector to actually injector fuel into the cylinder. That grap will work for any 4 stroke piston engine. When it comes to rotory's that grap isn't even close as their is far less time to injector fuel. IDC% is just using math and taking PW/RPM into account but it's not always correct on the logger. You can pretty much guarantee that anything over 18ms is hitting close to full open.

 

[Turbo Talon DL]

Injector PW/RPM is a set thing. It has to do with crank speed and the amount of time available for the injector to actually injector fuel into the cylinder. That grap will work for any 4 stroke piston engine. When it comes to rotory's that grap isn't even close as their is far less time to injector fuel. IDC% is just using math and taking PW/RPM into account but it's not always correct on the logger. You can pretty much guarantee that anything over 18ms is hitting close to full open.

Ok thanks for telling me that I am killing my fuel system now! I have a pump and injectors but no cash for a good FPR yet. Even at 9psi on this turbo my PW is about 15-16ms.

 

[Maglin]

Your profile doesn't show what injectors you are running, but I did see a Keydriver EEPROM. You might want to talk to jeff about getting your chip reburned with 2x MAF readings. It helps a lot when you start seeing MAF overrun. In your post you said stock fuel. I take it you are still on the NT injectors? If so did you put a turbo ECU in the car along with the injector resistor pack? If you put a Turbo ECU in along with the resitor pack and using the NT injectors that is the majority of your issues. Turbo injectors are low impediance injectors and the NT uses high impediance injectors. Put some stock 450's in from a turbo car. They are cheap. You can still use the NT FPR and have your global injector size set to 500ish. That should be close to what they would be like in flow with the NT FPR. Then zero out the AFC. If Jeff still does a fairly tuned fuel table you shouldn't really ahve to mess with the AFC. Just leave it at Zero and see how it runs.

 

[Turbo Talon DL]

Your profile doesn't show what injectors you are running, but I did see a Keydriver EEPROM. You might want to talk to jeff about getting your chip reburned with 2x MAF readings. It helps a lot when you start seeing MAF overrun. In your post you said stock fuel. I take it you are still on the NT injectors? If so did you put a turbo ECU in the car along with the injector resistor pack? If you put a Turbo ECU in along with the resitor pack and using the NT injectors that is the majority of your issues. Turbo injectors are low impediance injectors and the NT uses high impediance injectors. Put some stock 450's in from a turbo car. They are cheap. You can still use the NT FPR and have your global injector size set to 500ish. That should be close to what they would be like in flow with the NT FPR. Then zero out the AFC. If Jeff still does a fairly tuned fuel table you shouldn't really ahve to mess with the AFC. Just leave it at Zero and see how it runs.

My car has stock 450 cc injectors and the 1g fuel press reg. I have a stock 1g ECU that runs 40* of timing advance at part-throttle. I just looked at the logs again and miss-read them from what I previously talked about. The PW was 19.4 at around 5000. Above that they began to drop down to 17-16 close to 6500. IDCs are still at 90% when its cold in the morning.

 

[DJ23GSX]

You get no knock so try leaning out the afc till you see a few counts. That will bring your idc's down.

 

[Turbo Talon DL]

I only get knock counts under part throttle because of the engine timimg probably. I get knock when the water temp is above 195* at 70mph or 3000 rpm. Anywhere below that speed the knock goes away. If I run lower coolant temps (say around 180-190) then the knock will go away then too. I dont run the EGR and my compression is 9:1. I understand the IDCs and PW vs RPM now. Only an ECU rechip and larger injectors will fix these problems. I cant lean anything out with my AFC. Its the old style and only effects part throttle fuel trims under low, medium, and high loads. It has 5 knobs for different rpm ranges. I can run it max lean and it will still be rich under boost.

 

[timloomis]

You shouldn't get any part throttle knock. How old is the sensor? But like you said, 40* of timing isnt good on a turbo car. You should look into getting a turbo ecu if you dont run one already asap.

 

[Turbo Talon DL]

It has a turbo ECU. It runs (up to) 40* of timing advance just during part throttle driving. It backs down to around 18* under WOT and continues to advance it until it sees 2 counts of knock. Thats all I get when I boost 14psi is 2 counts of knock. I put in a can of B-12 Chemtool and it quenched most of the knock so far. Sensor age is unknown. It came on the engine when I swapped it into the car. It could probably stand a replacement now...

 

[timloomis]

2 counts of knock is nothing. I'm getting 18* of timing with my evo3 16g at 20 psi with pte 680 injectors. Sounds like your sensor is going. Just look for the black goo coming out of the back of it.