The_Punisher454

I have installed some 22lb design III's in a 305 tpi for a friend. They seem to be running richer than the 22lb multec's that were in it before.
To be clear, these are the 0-280-155-700 design III's as found on many fords and a popular swap for GM guys. and yes the multec's were the 22lb versions and not the 19's like a 305 comes with. The TPI is a retrofit to a 1981 305 in a street rod application.
Anyhow, in SAUJP4 there seem to be two tables:
1. Injector PW LOW offset vs Base Pulse Width
2. Injector PW correction vs Battery Voltage

Does anyone have the correct offests for design 3's? I strongly believe they are a lot more responsive than the multec's and it only makes sense to me that this needs to be accounted for.

Thanks
Marvin

edit;
The 0-280-155-700 mentioned above flow 19lbs at 3 bar and 22.4lbs at 4bar, which is what I used here.

shuanm

I'm looking for the same information.

RBob

iTrader: (1)

The type III injectors flow more fuel at small PWs then at larger PWs. Because of this it is best to zero out the low PW offset table. As that table can only add to the injector PW at 3.9 mSec and less.

As for the voltage offset table, what fuel pressure (vac line off) are you using?

RBob.

shuanm

I'm using 44 psi, but I can't speak for punisher. 0s for Low PW offset. Gotcha. Thanks again.

RBob

iTrader: (1)

From what I've found on the 'net the 280-155-700 injector is a 19#/hr. But that is with a substitute liquid (not gasoline).

I'm not sure if I used the correct data sheet. As the 280-155-700 is a Bosch number which Ford doesn't use. I used the Ford 19 #/hr data.

With that here is the data for the injector at 44 psi, values in mSec:

6.4 V: 3.07851247
8.0 V: 1.85340073
9.6 V: 1.30766195
11.2 V: 0.99121428
12.8 V: 0.76537403
14.4 V: 0.60906068
15.0 V: 0.55248610*

Can round as required and extrapolate from the 14.4 V and 15 V for the 16 V entry.

Minimum PW is: 0.853 mSec

RBob.

shuanm

I have the datasheet for the injectors that they sent me, but I don't know how to work the math to get the values in between as they have 6,8,10,11,12,13,14,15 volts. I can't divide the value of 11 by the value of 12 and multiply by value of 11 to get value of 10, The math doesn't work so I can't make a formula for the in betweens. Maybe you have some insite. FIC sent me the tables for M-9593-BB302 which I could already get from Ford, but I can't get the math to work right with percentages so it must not be linear. I'll have to get a mathbook out and relearn nonlinear equations If my brain can still learn that kinda thing. Long time since I had to learn something from a textbook. Minimum PW on my sheet says 0.776. Is a mSec*1000=uSec?

1tpi

Did you just talk about this?

shuanm

I did, but punisher hasn't.

RBob

iTrader: (1)

The M-9593-BB302 calibration sheet matches 30#/hr injectors. Maybe check for a Bosch number on them and run the 'net for it.

Here is the PW offset vs. Bat for the 'BB302 injectors:

@44 psi

6.4 V: 3.01787012 milli-seconds
8.0 V: 2.04425964
9.6 V: 1.52886932
11.2 V: 1.20760185
12.8 V: 0.97447267
14.4 V: 0.77577132
15.0 V: 0.74079391*

RBob.

shuanm

Mine are 30lb custom @43.5. How do you get that math? Is it a secret? I appreciate you making me a table, but I would also like to know where those numbers came from so I don't have to ask again if I change injectors in the future. The Bosch number is 0 280 155 759. I looked it up, and it gave me the same chart that ford gave me. Thanks once again. With your help I'll be running smooth as silk in no time.

The_Punisher454

Thanks for all the info.

To get the values at different voltages I think I'd just graph it out and then interpolate the values.

I looked for those charts before but couldnt find them. I'd love to know the '700 '710 and '811 plus a few other common ones.

BTW;
I have a homemade 4 injector flow bench with 3' tall 410cc graduated cylinders. It is programmable using an AVR microcontroller and LCD display. I've used it to verify equal flow on several sets of injectors I've reconditioned myself using an ultrasonic cleaner. I currently flow test with water and plan to temporarily run E10 gasoline through it sometime soon and work out a conversion factor for water to gasoline.
Anyhow, I suppose I should reprogram it to run a test series to determine voltage vs. low PW flow rates.
The super tall skinny cylinders make it really easy to get nice accurate measurements

I plan to upgrade the flowbench and do quite a bit of testing this summer, I'll be sure to post any significant findings.

I built it last year when I needed to test some vortec injectors for my suburban, I was just trying to whip up something temporary for one project but once I had the injector driver running I decided to go all the way. When I'm done I will share the design here. By using a uC instead of a bunch of timers its a really simple circuit.

RBob

iTrader: (1)

To do the math I use software that fits a curve to the provided data points. Then interpolates on the curve to get the points that match our tables.

For the offset vs battery data first fit a curve to the FNPW_OFFCOMP data. Then get the compensation for the fuel pressure being used from that curve (interpolated look up on the curve).

Using this value compensate the values in the FNPW_OFFSET table (VAL *= comp).

Now fit a curve to the resulting table of data and interpolate for the values that match our offset compensation table axis values (battery voltage).

The key is being able to fit a curve to the data and then interpolating on the curve.

RBob.

The_Punisher454

Sounds like something that could be setup in Excel.

shuanm

I never though of that. I'm not much with excel, but I'm trying to learn a little. I have a program called GraphNow Visual Fitting. Would that work for that task? I'll have to study it as I haven't a clue how it works, but it looks somewhat like excel and supposedly will fit a nonlinear equation and graph it. That's good information to have. I thought maybe RBob kept the numbers in his head since he has the code memorized. I wish I had that much capacity.

kevinc

I just finished dialing in these new red Ford BB302 injectors on my LS1, and they were a pain.

Much higher offset values than the factory LS1/LS6 injectors in the main table, but lower offset values in the low-pulsewidth table.

shuanm

Please share. What were your injectors before? What did you come up with for offsets?

kevinc

Please share how it's useful outside the LS1 PCM...here ya go. X and Y labels can be found on LS1tech, it's voltage across the horizontal axis and manifold pressure across the vertical axis.

28 columns wide, by 17 rows tall.

Factory 28.8# LS1/LS6 injector offset table:
4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10 10.5 11 11.5 12 12.5 13 13.5 14 14.5 15 15.5 16 16.5 17 17.5 18
8.8298 8.8298 8.8298 3.6626 2.9635 2.2492 1.9301 1.5957 1.3982 1.2006 1.0638 0.9271 0.8359 0.7447 0.6687 0.5927 0.5319 0.4711 0.4103 0.3495 0.304 0.2584 0.2128 0.1672 0.1368 0.1064 0.076 0.0456
8.8754 8.8754 8.8754 3.7082 2.9939 2.2796 1.9453 1.6109 1.4134 1.2006 1.079 0.9422 0.8511 0.7599 0.6839 0.5927 0.5471 0.4863 0.4407 0.3799 0.3191 0.2736 0.228 0.1976 0.1672 0.1216 0.0912 0.0608
8.9058 8.9058 8.9058 3.7386 3.0091 2.2948 1.9605 1.6261 1.4134 1.2158 1.079 0.9422 0.8511 0.7751 0.6839 0.6079 0.5471 0.5015 0.4407 0.3799 0.3343 0.2736 0.2432 0.1976 0.1672 0.1368 0.1064 0.0608
8.9514 8.9514 8.9514 3.7842 3.0395 2.31 1.9757 1.6413 1.4286 1.2158 1.079 0.9422 0.8511 0.7751 0.6991 0.6079 0.5623 0.5015 0.4407 0.3951 0.3343 0.2888 0.2432 0.2128 0.1824 0.1368 0.1064 0.076
8.9818 8.9818 8.9818 3.8146 3.0699 2.3252 1.9909 1.6565 1.4438 1.231 1.079 0.9422 0.8511 0.7599 0.6839 0.6079 0.5623 0.5015 0.4559 0.3951 0.3495 0.2888 0.2584 0.228 0.1824 0.152 0.1216 0.0912
9.0426 9.0426 9.0426 3.8754 3.1155 2.3404 2.0061 1.6717 1.459 1.2462 1.0942 0.9574 0.8663 0.7903 0.6991 0.6231 0.5623 0.5167 0.4559 0.3951 0.3495 0.2888 0.2584 0.2128 0.1824 0.152 0.1064 0.076
9.1033 9.1033 9.1033 3.9362 3.1459 2.3708 2.0213 1.6717 1.459 1.2462 1.1094 0.9574 0.8815 0.7903 0.7143 0.6231 0.5775 0.5167 0.4559 0.4103 0.3495 0.2888 0.2584 0.2128 0.1824 0.152 0.1064 0.076
9.1641 9.1641 9.1641 3.997 3.1915 2.386 2.0365 1.6869 1.4742 1.2614 1.1094 0.9726 0.8815 0.8055 0.7143 0.6383 0.5775 0.5167 0.4711 0.4103 0.3495 0.2888 0.2584 0.2128 0.1824 0.1368 0.1064 0.076
9.2249 9.2249 9.2249 4.0578 3.2371 2.4012 2.0517 1.7021 1.4894 1.2766 1.1246 0.9726 0.8663 0.7599 0.6991 0.6383 0.5927 0.5319 0.4711 0.4103 0.3495 0.2888 0.2584 0.2128 0.1824 0.1368 0.1064 0.0608
9.2705 9.2705 9.2705 4.1033 3.2675 2.4164 2.0669 1.7021 1.4894 1.2614 1.1246 0.9726 0.8967 0.8055 0.7295 0.6383 0.5775 0.5167 0.4711 0.4103 0.3495 0.2888 0.2432 0.2128 0.1672 0.1368 0.0912 0.0608
9.3161 9.3161 9.3161 4.1489 3.2979 2.4468 2.0821 1.7173 1.4894 1.2614 1.1246 0.9878 0.8967 0.8055 0.7295 0.6383 0.5775 0.5167 0.4559 0.3951 0.3343 0.2736 0.2432 0.2128 0.1672 0.1368 0.0912 0.0608
9.3617 9.3617 9.3617 4.1945 3.3283 2.462 2.0973 1.7325 1.4894 1.2614 1.1246 0.9878 0.8967 0.8055 0.7295 0.6383 0.5775 0.5167 0.4559 0.3951 0.3343 0.2736 0.2432 0.1976 0.1672 0.1368 0.0912 0.0608
9.4073 9.4073 9.4073 4.2401 3.3587 2.4772 2.1125 1.7325 1.5046 1.2614 1.1246 0.9878 0.8815 0.7751 0.6991 0.6383 0.5775 0.5167 0.4559 0.3951 0.3343 0.2736 0.228 0.1976 0.1672 0.1216 0.0912 0.0608
9.4833 9.4833 9.4833 4.3161 3.4043 2.4924 2.1125 1.7477 1.5046 1.2614 1.1246 0.9878 0.9119 0.8207 0.7295 0.6383 0.5775 0.5167 0.4559 0.3951 0.3343 0.2736 0.228 0.1976 0.1672 0.1216 0.0912 0.0608
9.5441 9.5441 9.5441 4.3769 3.4347 2.4924 2.1277 1.7477 1.5198 1.2766 1.1398 1.003 0.9119 0.8207 0.7295 0.6383 0.5775 0.5167 0.4559 0.3951 0.3343 0.2736 0.228 0.1976 0.1672 0.1216 0.0912 0.0608
9.6201 9.6201 9.6201 4.4529 3.4802 2.5076 2.1277 1.7629 1.5198 1.2766 1.1398 1.003 0.9119 0.8207 0.7295 0.6383 0.5775 0.5167 0.4559 0.3951 0.3343 0.2736 0.228 0.1976 0.1672 0.1216 0.0912 0.0608
9.6809 9.6809 9.6809 4.5137 3.5258 2.5228 2.1429 1.7629 1.535 1.2918 1.1398 1.003 0.8967 0.7903 0.7143 0.6383 0.5775 0.5167 0.4559 0.3951 0.3343 0.2736 0.228 0.1976 0.1672 0.1216 0.0912 0.0608


SVO BB302 offset table:
4.951074962 4.449718946 3.993940749 3.579596934 3.202920739 2.826244544 2.449568348 2.072892153 1.900795011 1.728697868 1.556600726 1.384503584 1.270531967 1.156560349 1.06709263 0.97762491 0.901833785 0.826042659 0.75424054 0.682438421 0.6351402 0.587841979 0.573652512 0.569395672 0.568118621 0.567735505 0.56762057 0.56758609
4.966699962 4.484873946 4.040815749 3.622566934 3.253700739 2.869214544 2.469098348 2.104142153 1.928140011 1.756042868 1.568320726 1.404033584 1.293971967 1.187810349 1.08662263 1.00105991 0.901833785 0.845572659 0.77377054 0.725408421 0.6781052 0.599561979 0.597087512 0.604550672 0.603273621 0.587265505 0.59105557 0.59102109
4.982324962 4.520028946 4.087690749 3.665536934 3.304480739 2.912184544 2.488628348 2.135392153 1.955485011 1.783387868 1.580040726 1.423563584 1.317411967 1.219060349 1.10615263 1.02449491 0.901833785 0.865102659 0.79330054 0.768378421 0.7210702 0.611281979 0.620522512 0.639705672 0.638428621 0.606795505 0.61449057 0.61445609
5.029199962 4.578623946 4.138470749 3.712411934 3.339640739 2.935624544 2.504253348 2.154922153 1.955485011 1.787292868 1.591760726 1.439188584 1.321316967 1.238590349 1.11005763 1.03230991 0.905738785 0.872917659 0.79330054 0.780098421 0.7210702 0.622996979 0.620522512 0.643610672 0.638428621 0.622420505 0.61449057 0.61836109
5.076074962 4.637218946 4.189250749 3.759286934 3.374800739 2.959064544 2.519878348 2.174452153 1.955485011 1.791197868 1.603480726 1.454813584 1.325221967 1.258120349 1.11396263 1.04012491 0.909643785 0.880732659 0.79330054 0.791818421 0.7210702 0.634711979 0.620522512 0.647515672 0.638428621 0.638045505 0.61449057 0.62226609
5.134669962 4.684093946 4.243940749 3.813971934 3.409955739 2.978594544 2.531598348 2.186172153 1.975015011 1.802917868 1.607385726 1.454813584 1.333036967 1.262025349 1.11786763 1.04402991 0.913553785 0.884637659 0.79720554 0.791818421 0.7210702 0.634711979 0.620522512 0.647515672 0.638428621 0.638045505 0.61449057 0.62226609
5.193264962 4.730968946 4.298630749 3.868656934 3.445110739 2.998124544 2.543318348 2.197892153 1.994545011 1.814637868 1.611290726 1.454813584 1.340851967 1.265930349 1.12177263 1.04793491 0.917463785 0.888542659 0.80111054 0.791818421 0.7210702 0.634711979 0.620522512 0.647515672 0.638428621 0.638045505 0.61449057 0.62226609
5.267484962 4.785658946 4.341600749 3.923346934 3.472455739 3.013749544 2.566753348 2.205702153 2.006265011 1.822447868 1.615195726 1.458718584 1.344756967 1.269840349 1.12958763 1.05965491 0.925273785 0.888542659 0.80892554 0.791818421 0.7210702 0.634711979 0.620522512 0.647515672 0.638428621 0.638045505 0.61449057 0.62226609
5.341704962 4.840348946 4.384570749 3.978036934 3.499800739 3.029374544 2.590188348 2.213512153 2.017985011 1.830257868 1.619100726 1.462623584 1.348661967 1.273750349 1.13740263 1.07137491 0.933083785 0.888542659 0.81674054 0.791818421 0.7210702 0.634711979 0.620522512 0.647515672 0.638428621 0.638045505 0.61449057 0.62226609
5.384669962 4.887223946 4.431445749 4.028816934 3.546675739 3.048904544 2.598003348 2.225232153 2.029705011 1.830257868 1.630820726 1.474343584 1.352566967 1.285465349 1.13740263 1.07137491 0.940898785 0.888542659 0.81674054 0.791818421 0.7210702 0.634711979 0.620522512 0.647515672 0.638428621 0.638045505 0.61449057 0.62226609
5.427634962 4.934098946 4.478320749 4.079596934 3.593550739 3.068434544 2.605818348 2.236952153 2.041425011 1.830257868 1.642540726 1.486063584 1.356471967 1.297180349 1.13740263 1.07137491 0.948713785 0.888542659 0.81674054 0.791818421 0.7210702 0.634711979 0.620522512 0.647515672 0.638428621 0.638045505 0.61449057 0.62226609
5.474509962 4.988783946 4.521285749 4.118656934 3.613080739 3.084059544 2.625348348 2.244762153 2.041425011 1.830257868 1.646445726 1.486063584 1.356471967 1.297180349 1.13740263 1.07137491 0.948713785 0.888542659 0.81674054 0.791818421 0.7210702 0.634711979 0.620522512 0.647515672 0.638428621 0.638045505 0.61449057 0.62226609
5.521384962 5.043468946 4.564250749 4.157716934 3.632610739 3.099684544 2.644878348 2.252572153 2.041425011 1.830257868 1.650350726 1.486063584 1.356471967 1.297180349 1.13740263 1.07137491 0.948713785 0.888542659 0.81674054 0.791818421 0.7210702 0.634711979 0.620522512 0.647515672 0.638428621 0.638045505 0.61449057 0.62226609
5.583884962 5.102063946 4.634565749 4.231936934 3.683390739 3.111404544 2.648783348 2.252572153 2.041425011 1.830257868 1.650350726 1.486063584 1.356471967 1.297180349 1.13740263 1.07137491 0.948713785 0.888542659 0.81674054 0.791818421 0.7210702 0.634711979 0.620522512 0.647515672 0.638428621 0.638045505 0.61449057 0.62226609
5.646384962 5.160658946 4.704880749 4.306156934 3.734170739 3.123124544 2.652688348 2.252572153 2.041425011 1.830257868 1.650350726 1.486063584 1.356471967 1.297180349 1.13740263 1.07137491 0.948713785 0.888542659 0.81674054 0.791818421 0.7210702 0.634711979 0.620522512 0.647515672 0.638428621 0.638045505 0.61449057 0.62226609
5.724509962 5.238783946 4.775190749 4.364751934 3.765420739 3.130934544 2.652688348 2.252572153 2.041425011 1.830257868 1.650350726 1.486063584 1.356471967 1.297180349 1.13740263 1.07137491 0.948713785 0.888542659 0.81674054 0.791818421 0.7210702 0.634711979 0.620522512 0.647515672 0.638428621 0.638045505 0.61449057 0.62226609
5.802634962 5.316908946 4.845500749 4.423346934 3.796670739 3.138744544 2.652688348 2.252572153 2.041425011 1.830257868 1.650350726 1.486063584 1.356471967 1.297180349 1.13740263 1.07137491 0.948713785 0.888542659 0.81674054 0.791818421 0.7210702 0.634711979 0.620522512 0.647515672 0.638428621 0.638045505 0.61449057 0.62226609

shuanm

I'm not sure how its useful outside that specific pcm. I was just interested in the differences. I wasn't aware that there were so many variables in the LS pcm for those tables. It's such a small table in the 730. No wonder you had such a time with it. I was looking for how they compare, but they don't in any way. Sorry I asked about that. I didn't mean to cause you a lot of trouble for something that wouldn't translate in anyway. I just learning this stuff and like to see how different pcms go about taking care of things, but obviously I shouldn't take on an LS anytime soon.

The_Punisher454

I thought the newer PCM's had two offset tables. The one above looks like the 3D voltage vs map table and there is also a 2D voltage vs PW offset table that is similar to the one on the OBD1 ecu's.

Here are two images I just found posted on HPtooners forums.

These are from a 6cylinder something or other. One table is for the Bosch III's which come on the 3800SC (white 0280155811). The other of for the stock 22lb that cam on what they were working on. I think they are the skinny Delphi or Seimens type.

It looks to me that any voltage < 6v would have a very steep increase in the PW offset curve. It also seems a bit ridiculous to have data points below 5V or even 6v

kevinc

No sweat, it was just a copy & paste of the tables, I was curious how it would be of any value.

Back when I was running a Stealth Ram and L98, I had tried a set of 28# LS1 injectors and couldn't get the flow rate constant dialed in w/ my 730 ECM. I calculated their flow rate at TPI delivery pressure, but my BLMs were all over the place...>140 at idle, but reasonably close to 128 at higher revs if memory serves. Adjusting the flow rate constant downward brought the idle into controllable BLM range, but then the cruising and higher RPM BLMs showed super rich and ran somewhat poorly.

Ended up selling the LS1 injectors and going with Ford blue-tops instead.

The LS1 PCM is a wonderful thing but has enough tuning parameters to make your head spin.

RBob

iTrader: (1)

Maybe set up for a constant fuel pressure. ALA', a no return system?

RBob.

JekyllandHyde

iTrader: (3)

I was actually able to set up Excel to interpolate the values and am in the process of extrapolating data for the 16V figure as per RBob's method. I wanted to ask though, would it be worth it to extrapolate for the lower voltage values as well? In the AUJP code, the voltage PW offset table has balues for 1.6, 3.2, and 4.8. Would I do better to just zero these out if I'm running Borsch Design IIIs?

shuanm

I couldn't input anything on this, but I would like to see your values. I like the bosch 3 injectors except a little variance in voltage and the blms are skewed. Maybe I should have used another injector.

JekyllandHyde

iTrader: (3)

I plugged in the values I came up with and left the values for 1.6, 3.2 and 4.8 the same as stock and it made a hell of a difference. Where I was getting BLMs of 160 at idle before, I'm now idling at 140-150 BLMs and I cruise slightly rich. The injectors I'm using are Ford SVT "Terminator" injectors that were used on the Cobra and the Lightnings. These injectors are rated at 39lbs/hr at 39psi fuel pressure. Bosch Part number is 280-156-127, Ford part number is M-9593-M39. The datasheet for my injectors are here:

http://www.fordracingparts.com/parts/ics/m-9593-m39.pdf

I'm running the injectors at 50 psi because my SLP T-RAM won't let me go below that psi. The values I got were:

6.4v: 4.228464500
8.0v: 2.440028500
9.6v: 1.826366100
11.2v: 1.394513900
12.8v: 1.128367500
14.4v: 0.922612600
16.0v: 0.836133669

1991CamaroRslow

iTrader: (3)

subbed

profootbrake2

Are these injectors the same one that fuel injector connection sells for the L98

the blur

I too have a TPI LB9 that came with factory 21# injectors. But now my BLM's are way high with new injectors. But the car runs great.

hellz_wings

iTrader: (2)

All LB9's came with 19lbs injectors.

the blur

Then why wouldn't my car run with 19lb accel's. wouldn't idle. wouldn't run above 4000 RPM, it would starve out/

Then I switched to 21lb, and it runs AMAZING. 99% stock.

Dominic Sorresso

Blur,

Are you now running the Accel #21 injector for Fords?

hellz_wings

iTrader: (2)

This has happened before for some other people, it could be that whatever changed in the fueling just happened to make the engine run better, or atleast seem like it ran better. Are you able to datalog and see the BLM's?

the blur

It happened to other people too because the OEM injectors must be 22lb.
The BLM's are 150 +, with the 21lb injectors. LB9

the blur

I'm running Accel 21lb from summit.com

hellz_wings

iTrader: (2)

19lbs is what LB9's came with. All 305 TPI's came with 19lbs injectors.

See here: http://tpiparts.net/305_tpi_to_350_tpi_conversion

350 engines had 22lbs injectors stock. BLM's in the 150+ range suggests that it is lean, but in reality, this is because your PROM is tuned for 19lbs injectors so perhaps there is too much fuel and so the computer sees this via the O2 sensor and leans it out alot to try and correct it, giving you the lean BLM reading that you are getting. 21lbs is good for a 305 but it needs a tune for it to run properly. 150 is not right, it should be around 128.

the blur

Not so. 150 means it's adding fuel. Not subtracting. And if the car came with 19's, it would be pig rich now, but it's not. Open loop proves it more, because it runs perfect in open loop, which is strictly off the tables in the PROM.

and I don't believe everything I read on the internet. Nothing is verified.

TTOP350

iTrader: (8)

All 305 TPIs had 19s stock and 350s had 22s stock.
If you don't believe us or the net, check every GM parts book and the PT#s on your stock injs.
They are so close in ratings they will run with each others chips just fine.

the blur

My car would not run on 19lb injectors. starved for fuel.
and I can't believe the peanut cam and the big 1LE cam used the same injectors.

hellz_wings

iTrader: (2)

I was hypothesizing the reason why it is lean, in any case, I just thought of something, it has something to do with the way the injector fires.. The point is, that without a tune, the injectors spray differently because they will spray a certain amount with 19lbs, but then with 21lbs, if you don't tune for 21lbs injectors, I THINK it will actually spray less fuel so the computer tries to make up for it. So pretty sure it is actually leaner because the computer thinks there's still 19lbs injectors in there, but you have 21lbs injectors in there (Or is it the opposite?? I can't remember exactly).... and in open loop how do you know it runs better?? You cannot see the BLM's in open loop since the O2 sensor is not being used at this time. Another thing is that quite possibly the original injectors were just that crappy (stock injectors were all crap apparently) or were not working properly, and the new injectors seem to run alot better, but at 150BLM that is far from perfect and requires a tune IMO.

the blur

Thank you for your thoughts, but it's opposite. With a 19lb prom, 21lb injectors would be flowing more fuel than the original design; as the time constants are not changing.

As far as open loop. On cold starts, now the car runs normal, where as it was undriveable before. because there wasn't enough fuel.

TTOP350

iTrader: (8)

Thats odd, I have had 19s in my 400 stroker (pushing700hp) and it ran just fine around town and a few quick blasts up to 6k rpm. (yes it has the proper 60s in it now). Not undriveable at all.
I have also used 32lb injs on a stock tune. A lil rich but worked fine.

What year is your car??
Did you purchase this car new and know 100% for sure that it had 22s in it from the factory? Have you checked your chips tune? 350 injs and chip work were popular in the early days.

the blur

1989 Original owner. 305 T5
I know I'm not the only one with this problem.

I'm going to have to start data logging.

TTOP350

iTrader: (8)

Still have the org 22lb injs? Post a pic and the numbers off of them. I may have my org 89 formula 350s INJs someplace.

the blur

My biggest mistake. I sold the 6 good ones to a corvette guy. At this point, I would have had them flowed just to see.

TTOP350

iTrader: (8)

I'm not tryn 2 b that guy, I just like to dig for oddball info and the only way to find out sometimes is to ask direct questions.

hellz_wings

iTrader: (2)

So you are the original owner? That makes it easier.. Was going to suggest maybe it wasn't a 305 for a sec there lol.. So, when did you switch to the 19lbs accel injectors? Were they new or used? Perhaps they were not installed correctly or there was some other issue?.. I mean, you are basing the notion that it didn't have 19's stock on the fact that now it runs better with 21's instead of 19's.. There are other variables to consider I think before coming to that conclusion, plus the fact that all 305 TPI's that i've seen over the years had 19's in them and ran fine, including mine and it makes almost 300HP (not stock at all though). Is your engine otherwise stock? (like cam, heads, etc. stuff that would generally require more fuel). Also what is your fuel pressure at? Do you have an adjustable regulator?

the blur

I factory ordered the car. The accel 19lbs were new. Summit refused to take them back. It's all stock except the cat back, and TB which I just added 2 weeks ago. The fuel pressure regulator is OEM. Never touched. I'm thinking, I have the N10 dual exhaust, the bigger cam. T5. The 3:45 gears. It's the same motor as the 1LE cars. Maybe the N10 cars had bigger injectors. How can GM use the same tables, with single cat and dual cat cars ???

I'm ready to install a holley AFPR, or go up to 22lb injectors. But the car runs too good to mess around. My concern is I am so close to 160 BLM's, I might run lean without realizing it.

TTOP350

iTrader: (8)

My 350 car is built within a month or 2 after the N10 was released.
If GM had upgraded the heads or the intake/ intake system for more air I could see bigger injs.
2 cats just helps reduce a backpressure bottleneck that exsited in the exhaust.
The 1LE 305 and G92(camaro) and R6P(birds) motors are all the same with or with out the N10.
I doubt there is much of anything different in the chips programing with and without N10.

the blur

My car is May, 1989. If your reducing the backpressure, it needs more air and fuel. Then the CAT-back helps even more. And the E10 fuel runs leaner too, which was not available in 89. So maybe it's a combination of things.

TTOP350

iTrader: (8)

If backpressure is reduced, the exhaust just exits more efficiently (inturn making a bit more power). It doesn't "make" more air go thru the motor.
There are many restrictions from the airfilter to the combustion chamber that limit the fuel requirements.

the blur

I disagree. Then there is no reason there is a power increase with a cat back.