Injectors going static? A little WOT help please
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From: Mesa, AZ
Car: A Camaro
Engine: Weak
Transmission: Weaker
Injectors going static? A little WOT help please
Hey everyone
Well, I'm fairly sure that my injectors are going static. I started tuning WOT using my wideband about a month or two ago and I never even considered it, but it seemed I kept tinkering with the VE2 tables and nothing seemed to change past 4000 rpms. When I tried to hold a 12.5 AFR at around 4000, the AFR would drop down to 12 by 4200 then start to climb back up and would be at 13 by 4800. No matter what I'd do, it'd do this. So I tried pulling fuel out in a large amount and sure enough the AFR would hold at 13 until around 4300, but then it'd drop down a little and follow the same line back up to 13 at 4800. So I raised my fuel pressure up to 14.5 psi (up from a stock 12 psi) and changed the BPW constant from 134 to 122. Now the whole thing seems to be starting all over again, this time at 4600, peaking low (around 12) at 4700 and then rising at a linear rate again. This leads me to believe my injectors are going static, no? The fuel pressure is pretty much turned all the way up on the factory regulator, I don't think there were any more turns left in the screw. I'm thinking I need a new fuel pump to support some more pressure. I really don't want to buy new injectors because I'm a cheap bastard
. I just put down the dyno numbers in my sig, which work out to ~240 hp at the flywheel. This is on stock injectors (55 pph?), stock throttle body and stock heads. Anyone think it's time for new injectors? New fuel pump so I can raise the fuel pressure more?
Thanks so much
Tony
Well, I'm fairly sure that my injectors are going static. I started tuning WOT using my wideband about a month or two ago and I never even considered it, but it seemed I kept tinkering with the VE2 tables and nothing seemed to change past 4000 rpms. When I tried to hold a 12.5 AFR at around 4000, the AFR would drop down to 12 by 4200 then start to climb back up and would be at 13 by 4800. No matter what I'd do, it'd do this. So I tried pulling fuel out in a large amount and sure enough the AFR would hold at 13 until around 4300, but then it'd drop down a little and follow the same line back up to 13 at 4800. So I raised my fuel pressure up to 14.5 psi (up from a stock 12 psi) and changed the BPW constant from 134 to 122. Now the whole thing seems to be starting all over again, this time at 4600, peaking low (around 12) at 4700 and then rising at a linear rate again. This leads me to believe my injectors are going static, no? The fuel pressure is pretty much turned all the way up on the factory regulator, I don't think there were any more turns left in the screw. I'm thinking I need a new fuel pump to support some more pressure. I really don't want to buy new injectors because I'm a cheap bastard
. I just put down the dyno numbers in my sig, which work out to ~240 hp at the flywheel. This is on stock injectors (55 pph?), stock throttle body and stock heads. Anyone think it's time for new injectors? New fuel pump so I can raise the fuel pressure more? Thanks so much
Tony
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From: Portland, OR www.cascadecrew.org
Car: 1990 Camaro RS
Engine: Juiced 5.0 TBI - 300rwhp
Transmission: T5
Axle/Gears: 3.42 Eaton Posi, 10 Bolt
its very likely. You should spit out your injector PW in the ALDL stream, and find out for sure if you are going static.
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From: Mesa, AZ
Car: A Camaro
Engine: Weak
Transmission: Weaker
Oooh, that sounds like changing code, I'm still a virgin on that. Could you put me in the right direction? Thanks Dewey
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Joined: Mar 2001
Posts: 6,577
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From: Portland, OR www.cascadecrew.org
Car: 1990 Camaro RS
Engine: Juiced 5.0 TBI - 300rwhp
Transmission: T5
Axle/Gears: 3.42 Eaton Posi, 10 Bolt
Of course I can point.
Here is the pertinant text from the original post about this.
Link: https://www.thirdgen.org/techbb2/sho...hreadid=210908
The first quote is info for the 747 ECM, I then asked him what the addresses for the 8746 were, so the second quote is the info you need, but it does refrence the first post, so I quoted both of them.
Hope that helps...
John
Here is the pertinant text from the original post about this.
Link: https://www.thirdgen.org/techbb2/sho...hreadid=210908
The first quote is info for the 747 ECM, I then asked him what the addresses for the 8746 were, so the second quote is the info you need, but it does refrence the first post, so I quoted both of them.
Hope that helps...
John
Then to get the sync PW on the ALDL line make these changes at the addresses shown:
Addr: Value:
$D4E7 $00
$D4E8 $AB
$D4E9 $00
$D4EA $AC
This puts the PW into the PROMID field of the scan tool. Take whatever value is displayed and multiply it by .01526 and add in the injector bias value (from $D2DA) and the end result is the PW in milli-seconds. So if the PROMID is 232 and the injector bias is .397 msec, then 232 * .01526 + 0.397 = 3.94 milli-seconds.
Have fun,
RBob.
Addr: Value:
$D4E7 $00
$D4E8 $AB
$D4E9 $00
$D4EA $AC
This puts the PW into the PROMID field of the scan tool. Take whatever value is displayed and multiply it by .01526 and add in the injector bias value (from $D2DA) and the end result is the PW in milli-seconds. So if the PROMID is 232 and the injector bias is .397 msec, then 232 * .01526 + 0.397 = 3.94 milli-seconds.
Have fun,
RBob.
Addr: Value:
$D414 $00
$D415 $61
$D416 $00
$D417 $62
The math will be the displayed PROMID value * .352 + the initial timing as set in the bin.
So a PROMID of 91 and 6 deg of initial = 91 * .352 + 6 = 38.0 deg SA.
If you want the PW then use $AA and $AB instead of the $61 & $62. The math will be as it is for the '747 above.
RBob.
$D414 $00
$D415 $61
$D416 $00
$D417 $62
The math will be the displayed PROMID value * .352 + the initial timing as set in the bin.
So a PROMID of 91 and 6 deg of initial = 91 * .352 + 6 = 38.0 deg SA.
If you want the PW then use $AA and $AB instead of the $61 & $62. The math will be as it is for the '747 above.
RBob.
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